diff mbox series

[v2] abg-ir.cc: Improve types_have_similar_structure.

Message ID 20200325141859.93896-1-gprocida@google.com
State Committed
Headers show
Series [v2] abg-ir.cc: Improve types_have_similar_structure. | expand

Commit Message

Giuliano Procida March 25, 2020, 2:18 p.m. UTC
This function is used to determine whether or not type differences are
"local" and is primarily used in --leaf-changes-only mode. The logic
has some issues which are addressed by this patch:

    - Any number of points-to (*) and refers-to (& and &&) components
      are peeled off the types being compared, rather than checking
      these match in number and kind.
    - This peeling is done with peel_typedef_pointer_or_reference_type
      which also peels any number of CV qualifiers (OK) and
      array-of ([N]) type components (not OK).
    - The function sets a state variable (was_indirect_type) to modify
      the behaviour of downstream comparisons, but this cannot be
      passed through recursive calls.

The effect of the indirect_type flag is to switch to comparisons by
name: identically named structs don't get introspected. Arguably, a
more useful behaviour for --leaf-changes-only mode would be to treat
any change to a named type as non-local, except in the context of the
definition of that type itself. This would be a more significant
change in behaviour.

	* include/abg-fwd.h (types_have_similar_structure): In both
	overloads, add an indirect_type argument, defaulting to
	false.
	* src/abg-ir.cc (reference_type_def constructor): Tabify.
	(types_have_similar_structure): In both overloads, add an
	indirect_type argument and update documentation text. In the
	type_base_sptr overload, pass indirect_type in the tail
	call. In the type_base* overload, replace was_indirect_type
	with indirect_type; peel CV qualifiers and typedefs without
	testing as the peel function does this; replace the
	indiscriminate peeling of qualifier/pointer/reference/array
	type components with code that checks the same
	pointer/reference/array type component is used on each side
	and makes recursive calls with indirect_type set to true; pass
	the indirect_type argument recursively when comparing other
	subtypes; move the typeid check earlier, document its purpose
	and remove unneccessary checks after later dynamic casts;
	remove an always-true conditional; add a TODO for comparing
	array types more accurately.
	* tests/data/Makefile.am: Add new test case files.
	* tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc: New
	test case.
	* tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc: Ditto.
	* tests/data/test-abidiff-exit/test-leaf-peeling-report.txt:
	Ditto.
	* tests/test-abidiff-exit.cc: Run new test case.

Signed-off-by: Giuliano Procida <gprocida@google.com>
---
 include/abg-fwd.h                             |   6 +-
 src/abg-ir.cc                                 | 147 ++++++++++--------
 tests/data/Makefile.am                        |   5 +
 .../test-leaf-peeling-report.txt              |  38 +++++
 .../test-abidiff-exit/test-leaf-peeling-v0.cc |  24 +++
 .../test-abidiff-exit/test-leaf-peeling-v0.o  | Bin 0 -> 3704 bytes
 .../test-abidiff-exit/test-leaf-peeling-v1.cc |  24 +++
 .../test-abidiff-exit/test-leaf-peeling-v1.o  | Bin 0 -> 3752 bytes
 tests/test-abidiff-exit.cc                    |   9 ++
 9 files changed, 182 insertions(+), 71 deletions(-)
 create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
 create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
 create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
 create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
 create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.o

Comments

Matthias Maennich March 26, 2020, 11:38 a.m. UTC | #1
Hi!

On Wed, Mar 25, 2020 at 02:18:59PM +0000, Android Kernel Team wrote:
>This function is used to determine whether or not type differences are
>"local" and is primarily used in --leaf-changes-only mode. The logic
>has some issues which are addressed by this patch:
>
>    - Any number of points-to (*) and refers-to (& and &&) components
>      are peeled off the types being compared, rather than checking
>      these match in number and kind.
>    - This peeling is done with peel_typedef_pointer_or_reference_type
>      which also peels any number of CV qualifiers (OK) and
>      array-of ([N]) type components (not OK).
>    - The function sets a state variable (was_indirect_type) to modify
>      the behaviour of downstream comparisons, but this cannot be
>      passed through recursive calls.
>
>The effect of the indirect_type flag is to switch to comparisons by
>name: identically named structs don't get introspected. Arguably, a
>more useful behaviour for --leaf-changes-only mode would be to treat
>any change to a named type as non-local, except in the context of the
>definition of that type itself. This would be a more significant
>change in behaviour.
>
>	* include/abg-fwd.h (types_have_similar_structure): In both
>	overloads, add an indirect_type argument, defaulting to
>	false.
>	* src/abg-ir.cc (reference_type_def constructor): Tabify.
>	(types_have_similar_structure): In both overloads, add an
>	indirect_type argument and update documentation text. In the
>	type_base_sptr overload, pass indirect_type in the tail
>	call. In the type_base* overload, replace was_indirect_type
>	with indirect_type; peel CV qualifiers and typedefs without
>	testing as the peel function does this; replace the
>	indiscriminate peeling of qualifier/pointer/reference/array
>	type components with code that checks the same
>	pointer/reference/array type component is used on each side
>	and makes recursive calls with indirect_type set to true; pass
>	the indirect_type argument recursively when comparing other
>	subtypes; move the typeid check earlier, document its purpose
>	and remove unneccessary checks after later dynamic casts;
>	remove an always-true conditional; add a TODO for comparing
>	array types more accurately.
>	* tests/data/Makefile.am: Add new test case files.
>	* tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc: New
>	test case.
>	* tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc: Ditto.
>	* tests/data/test-abidiff-exit/test-leaf-peeling-report.txt:
>	Ditto.
>	* tests/test-abidiff-exit.cc: Run new test case.
>
>Signed-off-by: Giuliano Procida <gprocida@google.com>
>---
> include/abg-fwd.h                             |   6 +-
> src/abg-ir.cc                                 | 147 ++++++++++--------
> tests/data/Makefile.am                        |   5 +
> .../test-leaf-peeling-report.txt              |  38 +++++
> .../test-abidiff-exit/test-leaf-peeling-v0.cc |  24 +++
> .../test-abidiff-exit/test-leaf-peeling-v0.o  | Bin 0 -> 3704 bytes
> .../test-abidiff-exit/test-leaf-peeling-v1.cc |  24 +++
> .../test-abidiff-exit/test-leaf-peeling-v1.o  | Bin 0 -> 3752 bytes
> tests/test-abidiff-exit.cc                    |   9 ++
> 9 files changed, 182 insertions(+), 71 deletions(-)
> create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
> create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
> create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
> create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
> create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
>
>diff --git a/include/abg-fwd.h b/include/abg-fwd.h
>index 6f2a862c..1aab70a6 100644
>--- a/include/abg-fwd.h
>+++ b/include/abg-fwd.h
>@@ -1293,11 +1293,13 @@ function_decl_is_less_than(const function_decl&f, const function_decl &s);
>
> bool
> types_have_similar_structure(const type_base_sptr& first,
>-			     const type_base_sptr& second);
>+			     const type_base_sptr& second,
>+			     bool indirect_type = false);
>
> bool
> types_have_similar_structure(const type_base* first,
>-			     const type_base* second);
>+			     const type_base* second,
>+			     bool indirect_type = false);
>
> } // end namespace ir
>
>diff --git a/src/abg-ir.cc b/src/abg-ir.cc
>index 2853fe6c..a10b0bb7 100644
>--- a/src/abg-ir.cc
>+++ b/src/abg-ir.cc
>@@ -13573,10 +13573,10 @@ reference_type_def::reference_type_def(const type_base_sptr	pointed_to,
>       decl_base_sptr pto = dynamic_pointer_cast<decl_base>(pointed_to);
>       string name;
>       if (pto)
>-        {
>-          set_visibility(pto->get_visibility());
>-          name = string(pto->get_name()) + "&";
>-        }
>+	{
>+	  set_visibility(pto->get_visibility());
>+	  name = string(pto->get_name()) + "&";
>+	}

Correct, but unrelated. No complaints. :-)

>       else
> 	name = string(get_type_name(is_function_type(pointed_to),
> 				    /*qualified_name=*/true)) + "&";
>@@ -22563,33 +22563,44 @@ function_decl_is_less_than(const function_decl &f, const function_decl &s)
> /// Test if two types have similar structures, even though they are
> /// (or can be) different.
> ///
>-/// Two indirect types (pointers, references, qualified, typedefs)
>-/// have similar structure if their underlying types are of the same
>-/// kind and have the same name.  In this indirect types case, the
>-/// size of the underlying type does not matter.
>+/// const and volatile qualifiers are completely ignored.
>+///
>+/// typedef are resolved to their definitions; their names are ignored.
>+///
>+/// Two indirect types (pointers or references) have similar structure
>+/// if their underlying types are of the same kind and have the same
>+/// name.  In the indirect types case, the size of the underlying type
>+/// does not matter.
> ///
> /// Two direct types (i.e, non indirect) have a similar structure if
> /// they have the same kind, name and size.  Two class types have
>-/// similar structure if they have the same name, size, and if their
>-/// data members have similar types.
>+/// similar structure if they have the same name, size, and if the
>+/// types of their data members have similar types.
> ///
> /// @param first the first type to consider.
> ///
> /// @param second the second type to consider.
> ///
>+/// @param indirect_type whether to do an indirect comparison
>+///
> /// @return true iff @p first and @p second have similar structures.
> bool
> types_have_similar_structure(const type_base_sptr& first,
>-			     const type_base_sptr& second)
>-{return types_have_similar_structure(first.get(), second.get());}
>+			     const type_base_sptr& second,
>+			     bool indirect_type)
>+{return types_have_similar_structure(first.get(), second.get(), indirect_type);}
>
> /// Test if two types have similar structures, even though they are
> /// (or can be) different.
> ///
>-/// Two indirect types (pointers, references, qualified, typedefs)
>-/// have similar structure if their underlying types are of the same
>-/// kind and have the same name.  In this indirect types case, the
>-/// size of the underlying type does not matter.
>+/// const and volatile qualifiers are completely ignored.
>+///
>+/// typedef are resolved to their definitions; their names are ignored.
>+///
>+/// Two indirect types (pointers or references) have similar structure
>+/// if their underlying types are of the same kind and have the same
>+/// name.  In the indirect types case, the size of the underlying type
>+/// does not matter.
> ///
> /// Two direct types (i.e, non indirect) have a similar structure if
> /// they have the same kind, name and size.  Two class types have
>@@ -22600,9 +22611,13 @@ types_have_similar_structure(const type_base_sptr& first,
> ///
> /// @param second the second type to consider.
> ///
>+/// @param indirect_type whether to do an indirect comparison
>+///
> /// @return true iff @p first and @p second have similar structures.
> bool
>-types_have_similar_structure(const type_base* first, const type_base* second)
>+types_have_similar_structure(const type_base* first,
>+			     const type_base* second,
>+			     bool indirect_type)
> {
>   if (!!first != !!second)
>     return false;
>@@ -22610,33 +22625,39 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (!first)
>     return false;
>
>-  if (is_typedef(first) || is_qualified_type(first))
>-    first = peel_qualified_or_typedef_type(first);
>-
>-  if (is_typedef(second) || is_qualified_type(second))
>-    second = peel_qualified_or_typedef_type(second);
>+  // Treat typedefs purely as type aliases and ignore CV-qualifiers.
>+  first = peel_qualified_or_typedef_type(first);
>+  second = peel_qualified_or_typedef_type(second);
>
>-  bool was_indirect_type = (is_pointer_type(first)
>-			    || is_pointer_type(second)
>-			    || is_reference_type(first)
>-			    || is_reference_type(second));
>+  // Eliminate all but N of the N^2 comparison cases. This also guarantees the
>+  // various ty2 below cannot be null.
>+  if (typeid(*first) != typeid(*second))
>+    return false;

Just curious (because I think it is correct): Does it make a measurable
difference?

>
>-  if (was_indirect_type)
>+  // Peel off matching pointers.
>+  if (const pointer_type_def* ty1 = is_pointer_type(first))

A picky compiler might ask you to add some parentheses here.  [-Wparentheses]

>     {
>-      first = peel_typedef_pointer_or_reference_type(first);
>-      second = peel_typedef_pointer_or_reference_type(second);
>+      const pointer_type_def* ty2 = is_pointer_type(second);
>+      return types_have_similar_structure(ty1->get_pointed_to_type(),
>+					  ty2->get_pointed_to_type(),
>+					  true);
>     }
>
>-  if (typeid(*first) != typeid(*second))
>-    return false;
>+  // Peel off matching references.
>+  if (const reference_type_def* ty1 = is_reference_type(first))

As above.

>+    {
>+      const reference_type_def* ty2 = is_reference_type(second);
>+      if (ty1->is_lvalue() != ty2->is_lvalue())
>+	return false;
>+      return types_have_similar_structure(ty1->get_pointed_to_type(),
>+					  ty2->get_pointed_to_type(),
>+					  true);
>+    }
>
>   if (const type_decl* ty1 = is_type_decl(first))
>     {
>       const type_decl* ty2 = is_type_decl(second);
>-      if (ty2 == 0)
>-	return false;
>-
>-      if (!was_indirect_type)
>+      if (!indirect_type)
> 	if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
> 	  return false;
>
>@@ -22646,10 +22667,7 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const enum_type_decl* ty1 = is_enum_type(first))
>     {
>       const enum_type_decl* ty2 = is_enum_type(second);
>-      if (ty2 == 0)
>-	return false;
>-
>-      if (!was_indirect_type)
>+      if (!indirect_type)
> 	if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
> 	  return false;
>
>@@ -22660,20 +22678,16 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const class_decl* ty1 = is_class_type(first))
>     {
>       const class_decl* ty2 = is_class_type(second);
>-      if (ty2 == 0)
>-	return false;
>-
>       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
> 	  && ty1->get_name() != ty2->get_name())
> 	return false;
>
>-      if (!was_indirect_type)
>+      if (!indirect_type)
> 	{
>-	  if (!was_indirect_type)
>-	    if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
>-		|| (ty1->get_non_static_data_members().size()
>-		    != ty2->get_non_static_data_members().size()))
>-	      return false;
>+	  if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
>+	      || (ty1->get_non_static_data_members().size()
>+		  != ty2->get_non_static_data_members().size()))
>+	    return false;
>
> 	  for (class_or_union::data_members::const_iterator
> 		 i = ty1->get_non_static_data_members().begin(),
>@@ -22685,7 +22699,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> 	      var_decl_sptr dm1 = *i;
> 	      var_decl_sptr dm2 = *j;
> 	      if (!types_have_similar_structure(dm1->get_type().get(),
>-						dm2->get_type().get()))
>+						dm2->get_type().get(),
>+						indirect_type))
> 		return false;
> 	    }
> 	}
>@@ -22696,14 +22711,11 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const union_decl* ty1 = is_union_type(first))
>     {
>       const union_decl* ty2 = is_union_type(second);
>-      if (ty2 == 0)
>-	return false;
>-
>       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
> 	  && ty1->get_name() != ty2->get_name())
> 	return false;
>
>-      if (!was_indirect_type)
>+      if (!indirect_type)
> 	return ty1->get_size_in_bits() == ty2->get_size_in_bits();
>
>       return true;
>@@ -22712,13 +22724,13 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const array_type_def* ty1 = is_array_type(first))
>     {
>       const array_type_def* ty2 = is_array_type(second);
>-
>-      if (!was_indirect_type)
>-	if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
>-	    || ty1->get_dimension_count() != ty2->get_dimension_count()
>-	    || !types_have_similar_structure(ty1->get_element_type(),
>-					     ty2->get_element_type()))
>-	  return false;
>+      // TODO: Handle uint32_t[10] vs uint64_t[5] better.
>+      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
>+	  || ty1->get_dimension_count() != ty2->get_dimension_count()
>+	  || !types_have_similar_structure(ty1->get_element_type(),
>+					   ty2->get_element_type(),
>+					   indirect_type))
>+	return false;
>
>       return true;
>     }
>@@ -22726,14 +22738,12 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const array_type_def::subrange_type *ty1 = is_subrange_type(first))
>     {
>       const array_type_def::subrange_type *ty2 = is_subrange_type(second);
>-      if (!ty2)
>-	return false;
>-
>       if (ty1->get_upper_bound() != ty2->get_upper_bound()
> 	  || ty1->get_lower_bound() != ty2->get_lower_bound()
> 	  || ty1->get_language() != ty2->get_language()
> 	  || !types_have_similar_structure(ty1->get_underlying_type(),
>-					  ty2->get_underlying_type()))
>+					   ty2->get_underlying_type(),
>+					   indirect_type))
> 	return false;
>
>       return true;
>@@ -22742,11 +22752,9 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>   if (const function_type* ty1 = is_function_type(first))
>     {
>       const function_type* ty2 = is_function_type(second);
>-      if (!ty2)
>-	return false;
>-
>       if (!types_have_similar_structure(ty1->get_return_type(),
>-					ty2->get_return_type()))
>+					ty2->get_return_type(),
>+					indirect_type))
> 	return false;
>
>       if (ty1->get_parameters().size() != ty2->get_parameters().size())
>@@ -22759,7 +22767,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> 	    && j != ty2->get_parameters().end());
> 	   ++i, ++j)
> 	if (!types_have_similar_structure((*i)->get_type(),
>-					  (*j)->get_type()))
>+					  (*j)->get_type(),
>+					  indirect_type))
> 	  return false;
>
>       return true;
>diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
>index cf7792f1..6d4e2faa 100644
>--- a/tests/data/Makefile.am
>+++ b/tests/data/Makefile.am
>@@ -130,6 +130,11 @@ test-abidiff-exit/test-leaf3-v0.o \
> test-abidiff-exit/test-leaf3-v1.c \
> test-abidiff-exit/test-leaf3-v1.o \
> test-abidiff-exit/test-leaf3-report.txt \
>+test-abidiff-exit/test-leaf-peeling-v0.cc \
>+test-abidiff-exit/test-leaf-peeling-v0.o \
>+test-abidiff-exit/test-leaf-peeling-v1.cc \
>+test-abidiff-exit/test-leaf-peeling-v1.o \
>+test-abidiff-exit/test-leaf-peeling-report.txt \
> \
> test-diff-dwarf/test0-v0.cc		\
> test-diff-dwarf/test0-v0.o			\
>diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
>new file mode 100644
>index 00000000..54a26869
>--- /dev/null
>+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
>@@ -0,0 +1,38 @@
>+Leaf changes summary: 4 artifacts changed
>+Changed leaf types summary: 4 leaf types changed
>+Removed/Changed/Added functions summary: 0 Removed, 0 Changed, 0 Added function
>+Removed/Changed/Added variables summary: 0 Removed, 0 Changed, 0 Added variable
>+
>+'struct foo at test-leaf-peeling.0.cc:1:1' changed:
>+  type size changed from 32 to 64 (in bits)
>+  there are data member changes:
>+    type 'int' of 'foo::z' changed:
>+      type name changed from 'int' to 'long int'
>+      type size changed from 32 to 64 (in bits)
>+    and size changed from 32 to 64 (in bits) (by +32 bits)
>+
>+
>+
>+'struct ops1 at test-leaf-peeling.0.cc:5:1' changed:
>+  type size hasn't changed
>+  there are data member changes:
>+    type 'int*' of 'ops1::x' changed:
>+      pointer type changed from: 'int*' to: 'int**'
>+
>+
>+
>+
>+'struct ops2 at test-leaf-peeling.0.cc:9:1' changed:
>+  type size changed from 320 to 640 (in bits)
>+  there are data member changes:
>+    'foo ops2::y[10]' size changed from 320 to 640 (in bits) (by +320 bits)
>+
>+
>+
>+'struct ops3 at test-leaf-peeling.0.cc:13:1' changed:
>+  type size hasn't changed
>+  there are data member changes:
>+    type 'void (int&)*' of 'ops3::spong' changed:
>+      pointer type changed from: 'void (int&)*' to: 'void (int&&)*'
>+
>+
>diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
>new file mode 100644
>index 00000000..b927d15e
>--- /dev/null
>+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
>@@ -0,0 +1,24 @@
>+struct foo {
>+  int z;
>+};
>+
>+struct ops1 {
>+  int * x;
>+};
>+
>+struct ops2 {
>+  foo y[10];
>+};
>+
>+struct ops3 {
>+  void (*spong)(int & wibble);
>+};
>+
>+void register_ops1(ops1*) {
>+}
>+
>+void register_ops2(ops2*) {
>+}
>+
>+void register_ops3(ops3*) {
>+}
>diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
>new file mode 100644
>index 0000000000000000000000000000000000000000..a556a63560122a5e926ab708bb13f0fd40714638
>GIT binary patch
>literal 3704
>zcmbtXO>7%g5T56a?R7SGoVcZpf{-JD=nuP%ov0+G4TjJ(5v8h-Dx?-j*Us9pu-B1y
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>V3hDc&yu;%2lo;vjnDs_I{$J;aGn)Va
>
>literal 0
>HcmV?d00001
>
>diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
>new file mode 100644
>index 00000000..7c88df9f
>--- /dev/null
>+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
>@@ -0,0 +1,24 @@
>+struct foo {
>+  long z;
>+};
>+
>+struct ops1 {
>+  int ** x;
>+};
>+
>+struct ops2 {
>+  foo y[10];
>+};

There is no apparent difference in ops2 between the test files. What are
we testing?

>+
>+struct ops3 {
>+  void (*spong)(int && wibble);
>+};
>+
>+void register_ops1(ops1*) {
>+}
>+
>+void register_ops2(ops2*) {
>+}
>+
>+void register_ops3(ops3*) {
>+}

Maybe we can add some more test cases:

 - compare reference types and pointer types
 - compare int*** and int* (two levels of peeling)
 - compare uint32_t[10] and uint64_t[5] (with the same TODO as in the code)
 - nested types, e.g. struct ops1_v0* vs. struct ops1_v1*

Nice work. I like it!

Cheers,
Matthias
>diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
>new file mode 100644
>index 0000000000000000000000000000000000000000..e71ade4431f80a78ee73292d60808a2ee5404640
>GIT binary patch
>literal 3752
>zcmbtXO=x3P6h1evNnV>K{Yl4Zsf!f+8^*k8(lRq0ZH=wdX;6nE6lF$fU(%N}O!89l
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>zzl#{<RP#hpQjQOVdXE&Y>MQ;-8v4c0)1;8-eCed(6n_JaO4j{ua=ea_Z2G>>7`LnI
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>e-9reT<MY2oibm%8DQ~~{5+z3ZC}Q2wjQ<DlLOH<z
>
>literal 0
>HcmV?d00001
>
>diff --git a/tests/test-abidiff-exit.cc b/tests/test-abidiff-exit.cc
>index 6ecbfd24..ebac7a00 100644
>--- a/tests/test-abidiff-exit.cc
>+++ b/tests/test-abidiff-exit.cc
>@@ -158,6 +158,15 @@ InOutSpec in_out_specs[] =
>     "data/test-abidiff-exit/test-leaf3-report.txt",
>     "output/test-abidiff-exit/test-leaf3-report.txt"
>   },
>+  {
>+    "data/test-abidiff-exit/test-leaf-peeling-v0.o",
>+    "data/test-abidiff-exit/test-leaf-peeling-v1.o",
>+    "",
>+    "--leaf-changes-only",
>+    abigail::tools_utils::ABIDIFF_ABI_CHANGE,
>+    "data/test-abidiff-exit/test-leaf-peeling-report.txt",
>+    "output/test-abidiff-exit/test-leaf-peeling-report.txt"
>+  },
>   {0, 0, 0 ,0,  abigail::tools_utils::ABIDIFF_OK, 0, 0}
> };
>
>-- 
>2.25.1.696.g5e7596f4ac-goog
>
>
Giuliano Procida March 26, 2020, 12:14 p.m. UTC | #2
Hi.

On Thu, 26 Mar 2020 at 11:38, Matthias Maennich <maennich@google.com> wrote:
>
> Hi!
>
> On Wed, Mar 25, 2020 at 02:18:59PM +0000, Android Kernel Team wrote:
> >This function is used to determine whether or not type differences are
> >"local" and is primarily used in --leaf-changes-only mode. The logic
> >has some issues which are addressed by this patch:
> >
> >    - Any number of points-to (*) and refers-to (& and &&) components
> >      are peeled off the types being compared, rather than checking
> >      these match in number and kind.
> >    - This peeling is done with peel_typedef_pointer_or_reference_type
> >      which also peels any number of CV qualifiers (OK) and
> >      array-of ([N]) type components (not OK).
> >    - The function sets a state variable (was_indirect_type) to modify
> >      the behaviour of downstream comparisons, but this cannot be
> >      passed through recursive calls.
> >
> >The effect of the indirect_type flag is to switch to comparisons by
> >name: identically named structs don't get introspected. Arguably, a
> >more useful behaviour for --leaf-changes-only mode would be to treat
> >any change to a named type as non-local, except in the context of the
> >definition of that type itself. This would be a more significant
> >change in behaviour.
> >
> >       * include/abg-fwd.h (types_have_similar_structure): In both
> >       overloads, add an indirect_type argument, defaulting to
> >       false.
> >       * src/abg-ir.cc (reference_type_def constructor): Tabify.
> >       (types_have_similar_structure): In both overloads, add an
> >       indirect_type argument and update documentation text. In the
> >       type_base_sptr overload, pass indirect_type in the tail
> >       call. In the type_base* overload, replace was_indirect_type
> >       with indirect_type; peel CV qualifiers and typedefs without
> >       testing as the peel function does this; replace the
> >       indiscriminate peeling of qualifier/pointer/reference/array
> >       type components with code that checks the same
> >       pointer/reference/array type component is used on each side
> >       and makes recursive calls with indirect_type set to true; pass
> >       the indirect_type argument recursively when comparing other
> >       subtypes; move the typeid check earlier, document its purpose
> >       and remove unneccessary checks after later dynamic casts;
> >       remove an always-true conditional; add a TODO for comparing
> >       array types more accurately.
> >       * tests/data/Makefile.am: Add new test case files.
> >       * tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc: New
> >       test case.
> >       * tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc: Ditto.
> >       * tests/data/test-abidiff-exit/test-leaf-peeling-report.txt:
> >       Ditto.
> >       * tests/test-abidiff-exit.cc: Run new test case.
> >
> >Signed-off-by: Giuliano Procida <gprocida@google.com>
> >---
> > include/abg-fwd.h                             |   6 +-
> > src/abg-ir.cc                                 | 147 ++++++++++--------
> > tests/data/Makefile.am                        |   5 +
> > .../test-leaf-peeling-report.txt              |  38 +++++
> > .../test-abidiff-exit/test-leaf-peeling-v0.cc |  24 +++
> > .../test-abidiff-exit/test-leaf-peeling-v0.o  | Bin 0 -> 3704 bytes
> > .../test-abidiff-exit/test-leaf-peeling-v1.cc |  24 +++
> > .../test-abidiff-exit/test-leaf-peeling-v1.o  | Bin 0 -> 3752 bytes
> > tests/test-abidiff-exit.cc                    |   9 ++
> > 9 files changed, 182 insertions(+), 71 deletions(-)
> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
> >
> >diff --git a/include/abg-fwd.h b/include/abg-fwd.h
> >index 6f2a862c..1aab70a6 100644
> >--- a/include/abg-fwd.h
> >+++ b/include/abg-fwd.h
> >@@ -1293,11 +1293,13 @@ function_decl_is_less_than(const function_decl&f, const function_decl &s);
> >
> > bool
> > types_have_similar_structure(const type_base_sptr& first,
> >-                           const type_base_sptr& second);
> >+                           const type_base_sptr& second,
> >+                           bool indirect_type = false);
> >
> > bool
> > types_have_similar_structure(const type_base* first,
> >-                           const type_base* second);
> >+                           const type_base* second,
> >+                           bool indirect_type = false);
> >
> > } // end namespace ir
> >
> >diff --git a/src/abg-ir.cc b/src/abg-ir.cc
> >index 2853fe6c..a10b0bb7 100644
> >--- a/src/abg-ir.cc
> >+++ b/src/abg-ir.cc
> >@@ -13573,10 +13573,10 @@ reference_type_def::reference_type_def(const type_base_sptr  pointed_to,
> >       decl_base_sptr pto = dynamic_pointer_cast<decl_base>(pointed_to);
> >       string name;
> >       if (pto)
> >-        {
> >-          set_visibility(pto->get_visibility());
> >-          name = string(pto->get_name()) + "&";
> >-        }
> >+      {
> >+        set_visibility(pto->get_visibility());
> >+        name = string(pto->get_name()) + "&";
> >+      }
>
> Correct, but unrelated. No complaints. :-)
>
> >       else
> >       name = string(get_type_name(is_function_type(pointed_to),
> >                                   /*qualified_name=*/true)) + "&";
> >@@ -22563,33 +22563,44 @@ function_decl_is_less_than(const function_decl &f, const function_decl &s)
> > /// Test if two types have similar structures, even though they are
> > /// (or can be) different.
> > ///
> >-/// Two indirect types (pointers, references, qualified, typedefs)
> >-/// have similar structure if their underlying types are of the same
> >-/// kind and have the same name.  In this indirect types case, the
> >-/// size of the underlying type does not matter.
> >+/// const and volatile qualifiers are completely ignored.
> >+///
> >+/// typedef are resolved to their definitions; their names are ignored.
> >+///
> >+/// Two indirect types (pointers or references) have similar structure
> >+/// if their underlying types are of the same kind and have the same
> >+/// name.  In the indirect types case, the size of the underlying type
> >+/// does not matter.
> > ///
> > /// Two direct types (i.e, non indirect) have a similar structure if
> > /// they have the same kind, name and size.  Two class types have
> >-/// similar structure if they have the same name, size, and if their
> >-/// data members have similar types.
> >+/// similar structure if they have the same name, size, and if the
> >+/// types of their data members have similar types.
> > ///
> > /// @param first the first type to consider.
> > ///
> > /// @param second the second type to consider.
> > ///
> >+/// @param indirect_type whether to do an indirect comparison
> >+///
> > /// @return true iff @p first and @p second have similar structures.
> > bool
> > types_have_similar_structure(const type_base_sptr& first,
> >-                           const type_base_sptr& second)
> >-{return types_have_similar_structure(first.get(), second.get());}
> >+                           const type_base_sptr& second,
> >+                           bool indirect_type)
> >+{return types_have_similar_structure(first.get(), second.get(), indirect_type);}
> >
> > /// Test if two types have similar structures, even though they are
> > /// (or can be) different.
> > ///
> >-/// Two indirect types (pointers, references, qualified, typedefs)
> >-/// have similar structure if their underlying types are of the same
> >-/// kind and have the same name.  In this indirect types case, the
> >-/// size of the underlying type does not matter.
> >+/// const and volatile qualifiers are completely ignored.
> >+///
> >+/// typedef are resolved to their definitions; their names are ignored.
> >+///
> >+/// Two indirect types (pointers or references) have similar structure
> >+/// if their underlying types are of the same kind and have the same
> >+/// name.  In the indirect types case, the size of the underlying type
> >+/// does not matter.
> > ///
> > /// Two direct types (i.e, non indirect) have a similar structure if
> > /// they have the same kind, name and size.  Two class types have
> >@@ -22600,9 +22611,13 @@ types_have_similar_structure(const type_base_sptr& first,
> > ///
> > /// @param second the second type to consider.
> > ///
> >+/// @param indirect_type whether to do an indirect comparison
> >+///
> > /// @return true iff @p first and @p second have similar structures.
> > bool
> >-types_have_similar_structure(const type_base* first, const type_base* second)
> >+types_have_similar_structure(const type_base* first,
> >+                           const type_base* second,
> >+                           bool indirect_type)
> > {
> >   if (!!first != !!second)
> >     return false;
> >@@ -22610,33 +22625,39 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (!first)
> >     return false;
> >
> >-  if (is_typedef(first) || is_qualified_type(first))
> >-    first = peel_qualified_or_typedef_type(first);
> >-
> >-  if (is_typedef(second) || is_qualified_type(second))
> >-    second = peel_qualified_or_typedef_type(second);
> >+  // Treat typedefs purely as type aliases and ignore CV-qualifiers.
> >+  first = peel_qualified_or_typedef_type(first);
> >+  second = peel_qualified_or_typedef_type(second);
> >
> >-  bool was_indirect_type = (is_pointer_type(first)
> >-                          || is_pointer_type(second)
> >-                          || is_reference_type(first)
> >-                          || is_reference_type(second));
> >+  // Eliminate all but N of the N^2 comparison cases. This also guarantees the
> >+  // various ty2 below cannot be null.
> >+  if (typeid(*first) != typeid(*second))
> >+    return false;
>
> Just curious (because I think it is correct): Does it make a measurable
> difference?

The code was there before, after the peeling. However, various ty2
checks were still there, including ones I'd added. Once I went and
reminded myself what typeid meant, the linear code made a lot more
sense.

> >
> >-  if (was_indirect_type)
> >+  // Peel off matching pointers.
> >+  if (const pointer_type_def* ty1 = is_pointer_type(first))
>
> A picky compiler might ask you to add some parentheses here.  [-Wparentheses]

-Wparentheses is already enabled by -Wall which is enabled by ABIGAIL_DEVEL=1.

In any case, there is no ambiguity here.

> >     {
> >-      first = peel_typedef_pointer_or_reference_type(first);
> >-      second = peel_typedef_pointer_or_reference_type(second);
> >+      const pointer_type_def* ty2 = is_pointer_type(second);
> >+      return types_have_similar_structure(ty1->get_pointed_to_type(),
> >+                                        ty2->get_pointed_to_type(),
> >+                                        true);
> >     }
> >
> >-  if (typeid(*first) != typeid(*second))
> >-    return false;
> >+  // Peel off matching references.
> >+  if (const reference_type_def* ty1 = is_reference_type(first))
>
> As above.
>
> >+    {
> >+      const reference_type_def* ty2 = is_reference_type(second);
> >+      if (ty1->is_lvalue() != ty2->is_lvalue())
> >+      return false;
> >+      return types_have_similar_structure(ty1->get_pointed_to_type(),
> >+                                        ty2->get_pointed_to_type(),
> >+                                        true);
> >+    }
> >
> >   if (const type_decl* ty1 = is_type_decl(first))
> >     {
> >       const type_decl* ty2 = is_type_decl(second);
> >-      if (ty2 == 0)
> >-      return false;
> >-
> >-      if (!was_indirect_type)
> >+      if (!indirect_type)
> >       if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
> >         return false;
> >
> >@@ -22646,10 +22667,7 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const enum_type_decl* ty1 = is_enum_type(first))
> >     {
> >       const enum_type_decl* ty2 = is_enum_type(second);
> >-      if (ty2 == 0)
> >-      return false;
> >-
> >-      if (!was_indirect_type)
> >+      if (!indirect_type)
> >       if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
> >         return false;
> >
> >@@ -22660,20 +22678,16 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const class_decl* ty1 = is_class_type(first))
> >     {
> >       const class_decl* ty2 = is_class_type(second);
> >-      if (ty2 == 0)
> >-      return false;
> >-
> >       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
> >         && ty1->get_name() != ty2->get_name())
> >       return false;
> >
> >-      if (!was_indirect_type)
> >+      if (!indirect_type)
> >       {
> >-        if (!was_indirect_type)
> >-          if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
> >-              || (ty1->get_non_static_data_members().size()
> >-                  != ty2->get_non_static_data_members().size()))
> >-            return false;
> >+        if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
> >+            || (ty1->get_non_static_data_members().size()
> >+                != ty2->get_non_static_data_members().size()))
> >+          return false;
> >
> >         for (class_or_union::data_members::const_iterator
> >                i = ty1->get_non_static_data_members().begin(),
> >@@ -22685,7 +22699,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >             var_decl_sptr dm1 = *i;
> >             var_decl_sptr dm2 = *j;
> >             if (!types_have_similar_structure(dm1->get_type().get(),
> >-                                              dm2->get_type().get()))
> >+                                              dm2->get_type().get(),
> >+                                              indirect_type))
> >               return false;
> >           }
> >       }
> >@@ -22696,14 +22711,11 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const union_decl* ty1 = is_union_type(first))
> >     {
> >       const union_decl* ty2 = is_union_type(second);
> >-      if (ty2 == 0)
> >-      return false;
> >-
> >       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
> >         && ty1->get_name() != ty2->get_name())
> >       return false;
> >
> >-      if (!was_indirect_type)
> >+      if (!indirect_type)
> >       return ty1->get_size_in_bits() == ty2->get_size_in_bits();
> >
> >       return true;
> >@@ -22712,13 +22724,13 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const array_type_def* ty1 = is_array_type(first))
> >     {
> >       const array_type_def* ty2 = is_array_type(second);
> >-
> >-      if (!was_indirect_type)
> >-      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
> >-          || ty1->get_dimension_count() != ty2->get_dimension_count()
> >-          || !types_have_similar_structure(ty1->get_element_type(),
> >-                                           ty2->get_element_type()))
> >-        return false;
> >+      // TODO: Handle uint32_t[10] vs uint64_t[5] better.
> >+      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
> >+        || ty1->get_dimension_count() != ty2->get_dimension_count()
> >+        || !types_have_similar_structure(ty1->get_element_type(),
> >+                                         ty2->get_element_type(),
> >+                                         indirect_type))
> >+      return false;
> >
> >       return true;
> >     }
> >@@ -22726,14 +22738,12 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const array_type_def::subrange_type *ty1 = is_subrange_type(first))
> >     {
> >       const array_type_def::subrange_type *ty2 = is_subrange_type(second);
> >-      if (!ty2)
> >-      return false;
> >-
> >       if (ty1->get_upper_bound() != ty2->get_upper_bound()
> >         || ty1->get_lower_bound() != ty2->get_lower_bound()
> >         || ty1->get_language() != ty2->get_language()
> >         || !types_have_similar_structure(ty1->get_underlying_type(),
> >-                                        ty2->get_underlying_type()))
> >+                                         ty2->get_underlying_type(),
> >+                                         indirect_type))
> >       return false;
> >
> >       return true;
> >@@ -22742,11 +22752,9 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >   if (const function_type* ty1 = is_function_type(first))
> >     {
> >       const function_type* ty2 = is_function_type(second);
> >-      if (!ty2)
> >-      return false;
> >-
> >       if (!types_have_similar_structure(ty1->get_return_type(),
> >-                                      ty2->get_return_type()))
> >+                                      ty2->get_return_type(),
> >+                                      indirect_type))
> >       return false;
> >
> >       if (ty1->get_parameters().size() != ty2->get_parameters().size())
> >@@ -22759,7 +22767,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
> >           && j != ty2->get_parameters().end());
> >          ++i, ++j)
> >       if (!types_have_similar_structure((*i)->get_type(),
> >-                                        (*j)->get_type()))
> >+                                        (*j)->get_type(),
> >+                                        indirect_type))
> >         return false;
> >
> >       return true;
> >diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
> >index cf7792f1..6d4e2faa 100644
> >--- a/tests/data/Makefile.am
> >+++ b/tests/data/Makefile.am
> >@@ -130,6 +130,11 @@ test-abidiff-exit/test-leaf3-v0.o \
> > test-abidiff-exit/test-leaf3-v1.c \
> > test-abidiff-exit/test-leaf3-v1.o \
> > test-abidiff-exit/test-leaf3-report.txt \
> >+test-abidiff-exit/test-leaf-peeling-v0.cc \
> >+test-abidiff-exit/test-leaf-peeling-v0.o \
> >+test-abidiff-exit/test-leaf-peeling-v1.cc \
> >+test-abidiff-exit/test-leaf-peeling-v1.o \
> >+test-abidiff-exit/test-leaf-peeling-report.txt \
> > \
> > test-diff-dwarf/test0-v0.cc           \
> > test-diff-dwarf/test0-v0.o                    \
> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
> >new file mode 100644
> >index 00000000..54a26869
> >--- /dev/null
> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
> >@@ -0,0 +1,38 @@
> >+Leaf changes summary: 4 artifacts changed
> >+Changed leaf types summary: 4 leaf types changed
> >+Removed/Changed/Added functions summary: 0 Removed, 0 Changed, 0 Added function
> >+Removed/Changed/Added variables summary: 0 Removed, 0 Changed, 0 Added variable
> >+
> >+'struct foo at test-leaf-peeling.0.cc:1:1' changed:
> >+  type size changed from 32 to 64 (in bits)
> >+  there are data member changes:
> >+    type 'int' of 'foo::z' changed:
> >+      type name changed from 'int' to 'long int'
> >+      type size changed from 32 to 64 (in bits)
> >+    and size changed from 32 to 64 (in bits) (by +32 bits)
> >+
> >+
> >+
> >+'struct ops1 at test-leaf-peeling.0.cc:5:1' changed:
> >+  type size hasn't changed
> >+  there are data member changes:
> >+    type 'int*' of 'ops1::x' changed:
> >+      pointer type changed from: 'int*' to: 'int**'
> >+
> >+
> >+
> >+
> >+'struct ops2 at test-leaf-peeling.0.cc:9:1' changed:
> >+  type size changed from 320 to 640 (in bits)
> >+  there are data member changes:
> >+    'foo ops2::y[10]' size changed from 320 to 640 (in bits) (by +320 bits)
> >+
> >+
> >+
> >+'struct ops3 at test-leaf-peeling.0.cc:13:1' changed:
> >+  type size hasn't changed
> >+  there are data member changes:
> >+    type 'void (int&)*' of 'ops3::spong' changed:
> >+      pointer type changed from: 'void (int&)*' to: 'void (int&&)*'
> >+
> >+
> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
> >new file mode 100644
> >index 00000000..b927d15e
> >--- /dev/null
> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
> >@@ -0,0 +1,24 @@
> >+struct foo {
> >+  int z;
> >+};
> >+
> >+struct ops1 {
> >+  int * x;
> >+};
> >+
> >+struct ops2 {
> >+  foo y[10];
> >+};
> >+
> >+struct ops3 {
> >+  void (*spong)(int & wibble);
> >+};
> >+
> >+void register_ops1(ops1*) {
> >+}
> >+
> >+void register_ops2(ops2*) {
> >+}
> >+
> >+void register_ops3(ops3*) {
> >+}
> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
> >new file mode 100644
> >index 0000000000000000000000000000000000000000..a556a63560122a5e926ab708bb13f0fd40714638
> >GIT binary patch
> >literal 3704
> >zcmbtXO>7%g5T56a?R7SGoVcZpf{-JD=nuP%ov0+G4TjJ(5v8h-Dx?-j*Us9pu-B1y
> >z14$7g5<jB1B7p#@NJ!jz;zo~%3aK}495`{|iiEg;IKa&A8|V4izQ9QPX6Bop_ujm>
> >zv-Z0eFRvwp044z|aHuf~a6fY>S0b?j1(=3w>$iVhzx~dicV2riTznm~jYR=wlsA?S
> >zlfj%KC+eLJj0s_`A!ytJkw}w-8OD-LKZGR7rbwD~<i;L|RE8vgR1^`JPl$~90h#wf
> >zjHgKgNZUAkijPS{1~O(EIj75--=Z>3h{%mUBo5a1I84w0*(i4^a>@}Pj-`k(SyB*p
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> >z`D17;2*b3jbJjD~vLy;wj4T*ttZo#RaK&SfgJrE)hKW@`=bY-Cnnc?MMx}+=C{VaL
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> >z#pgv*yqBC^>5T~k6SX>iqqyq_&4%x773tb-UN0?ly+$(#z3ygbCn#NAq!EH0bcH@k
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> >zTid>{w{+G%yI8avMZ4|>`+jY^+wnWQfxYX$)%3UQ(5<$-U|<jBXb)vL6Sj8-j0=%*
> >z0pQZ=>bc^H7rbiI_2cE(rKeA73!};&iOP%Bzx6VRy}X#6NSk-?G#*8q9-`<)c`ld#
> >zFtM6Vt)T;AWIInrq*3-)WAjkEGz~DE8r#nA{|p!qz(XDeBi_3jeRcya!^n`0O}81)
> >z_xAS821H$_r?X&SM;b;(yyF3r0oehJ03+@;12zLD1~7W(rj<HGwMT4T;;b`Ym-r*d
> >zi5MSsiATLMI?mTn$N2_wC8;~JO!M=O2&d{D;6pSOv#6UB-jw=L4gXE*Gm_JdP*4A)
> >z;;(k3D+*5euS>nH;hR$bT*IXbUuyW4)bDBdDXIUc;g_ZUlZO8x^`9l@eet>Rk#pTv
> >zq+eRT5{z?ROX8e|&%LDi)4d^D((vgRhVxn;3HQ#F=8Znz(vX*&=VgEH6*^v&4s?d<
> >zIaV~B*MC#Pd-ZXG{Wi8taDuQK^KF(wZ!ZLA%MD#{szCrw*K4`XmRH?vY&QLR2W^q;
> >zR;yj_%|5f+b^Qi*VKoH5Odf~e6yVf4?Y4)X8^`a2o`atOI|$v{8#2h--mG`swkH?<
> >zKiMqCQw`O3ic(f+K$?qLZzNxp$WEBv8C}&$k@ff|(MIppe~m9;te%sm<N2$aQB$Me
> >z8}w7OLO}|BB@6P444`{Re%u47ZxUU=N6$(40}1{>ibA^YRkZ0Cxql=tFTYQmLic?U
> >z4a3%dAQ#H<w0`>P=<BC`qvu2j?#uaakfM<8OZ{!w{NKolxK1=b^+|pH9mFUnuM@?H
> >z3i3j5-(j5RXZ|)ChQ&Wdi$bFNr4q+6e;<u3t9}<{yo!;m`+gxYS+1V@x{TlJA+f;w
> >zXZRBo$hE?N<PW9ey40zD^dExbxvsPxeQpZ*PR@TI7fjzn`n90P)0yb+9zsx&_x~m-
> >V3hDc&yu;%2lo;vjnDs_I{$J;aGn)Va
> >
> >literal 0
> >HcmV?d00001
> >
> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
> >new file mode 100644
> >index 00000000..7c88df9f
> >--- /dev/null
> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
> >@@ -0,0 +1,24 @@
> >+struct foo {
> >+  long z;
> >+};
> >+
> >+struct ops1 {
> >+  int ** x;
> >+};
> >+
> >+struct ops2 {
> >+  foo y[10];
> >+};
>
> There is no apparent difference in ops2 between the test files. What are
> we testing?

We are testing the reporting of an indirect change via its dependency
on struct foo (which is reported already).

We could (and I would) argue that the change to ops2 is not local and
people doing kernel ABI diffs might agree as well. However, at the
moment, size changes are considered as local. If y had been a pointer
something something foo, the size would not have changed and this
would not have been reported. I'll add a comment to the test code.

> >+
> >+struct ops3 {
> >+  void (*spong)(int && wibble);
> >+};
> >+
> >+void register_ops1(ops1*) {
> >+}
> >+
> >+void register_ops2(ops2*) {
> >+}
> >+
> >+void register_ops3(ops3*) {
> >+}
>
> Maybe we can add some more test cases:
>
>  - compare reference types and pointer types
>  - compare int*** and int* (two levels of peeling)
>  - compare uint32_t[10] and uint64_t[5] (with the same TODO as in the code)
>  - nested types, e.g. struct ops1_v0* vs. struct ops1_v1*

Agreed. Will do.

> Nice work. I like it!
>
> Cheers,
> Matthias

Thank you,
Giuliano.

> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
> >new file mode 100644
> >index 0000000000000000000000000000000000000000..e71ade4431f80a78ee73292d60808a2ee5404640
> >GIT binary patch
> >literal 3752
> >zcmbtXO=x3P6h1evNnV>K{Yl4Zsf!f+8^*k8(lRq0ZH=wdX;6nE6lF$fU(%N}O!89l
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> >z4)S(3YaO@c@x=cpqkBO;)bARlEYW~86S3|{zB-YeF!RN9btg?W;~zvD-M9Z5U%*&1
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> >z`S8wau_T(lPa@WD{-5zgRXoj~zDDN!xBKKo2<~$Io1|!D)~9#4U;UrBkm?iFr}xvW
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> >zzQytTT_h6J`W5^R3glW+0P`buTw|U3NB?H1c-2>$k6D{Se&G7A@r3C+Nq<F{@w6xA
> >e-9reT<MY2oibm%8DQ~~{5+z3ZC}Q2wjQ<DlLOH<z
> >
> >literal 0
> >HcmV?d00001
> >
> >diff --git a/tests/test-abidiff-exit.cc b/tests/test-abidiff-exit.cc
> >index 6ecbfd24..ebac7a00 100644
> >--- a/tests/test-abidiff-exit.cc
> >+++ b/tests/test-abidiff-exit.cc
> >@@ -158,6 +158,15 @@ InOutSpec in_out_specs[] =
> >     "data/test-abidiff-exit/test-leaf3-report.txt",
> >     "output/test-abidiff-exit/test-leaf3-report.txt"
> >   },
> >+  {
> >+    "data/test-abidiff-exit/test-leaf-peeling-v0.o",
> >+    "data/test-abidiff-exit/test-leaf-peeling-v1.o",
> >+    "",
> >+    "--leaf-changes-only",
> >+    abigail::tools_utils::ABIDIFF_ABI_CHANGE,
> >+    "data/test-abidiff-exit/test-leaf-peeling-report.txt",
> >+    "output/test-abidiff-exit/test-leaf-peeling-report.txt"
> >+  },
> >   {0, 0, 0 ,0,  abigail::tools_utils::ABIDIFF_OK, 0, 0}
> > };
> >
> >--
> >2.25.1.696.g5e7596f4ac-goog
> >
> >
Matthias Maennich March 26, 2020, 12:46 p.m. UTC | #3
On Thu, Mar 26, 2020 at 12:14:20PM +0000, Giuliano Procida wrote:
>Hi.
>
>On Thu, 26 Mar 2020 at 11:38, Matthias Maennich <maennich@google.com> wrote:
>>
>> Hi!
>>
>> On Wed, Mar 25, 2020 at 02:18:59PM +0000, Android Kernel Team wrote:
>> >This function is used to determine whether or not type differences are
>> >"local" and is primarily used in --leaf-changes-only mode. The logic
>> >has some issues which are addressed by this patch:
>> >
>> >    - Any number of points-to (*) and refers-to (& and &&) components
>> >      are peeled off the types being compared, rather than checking
>> >      these match in number and kind.
>> >    - This peeling is done with peel_typedef_pointer_or_reference_type
>> >      which also peels any number of CV qualifiers (OK) and
>> >      array-of ([N]) type components (not OK).
>> >    - The function sets a state variable (was_indirect_type) to modify
>> >      the behaviour of downstream comparisons, but this cannot be
>> >      passed through recursive calls.
>> >
>> >The effect of the indirect_type flag is to switch to comparisons by
>> >name: identically named structs don't get introspected. Arguably, a
>> >more useful behaviour for --leaf-changes-only mode would be to treat
>> >any change to a named type as non-local, except in the context of the
>> >definition of that type itself. This would be a more significant
>> >change in behaviour.
>> >
>> >       * include/abg-fwd.h (types_have_similar_structure): In both
>> >       overloads, add an indirect_type argument, defaulting to
>> >       false.
>> >       * src/abg-ir.cc (reference_type_def constructor): Tabify.
>> >       (types_have_similar_structure): In both overloads, add an
>> >       indirect_type argument and update documentation text. In the
>> >       type_base_sptr overload, pass indirect_type in the tail
>> >       call. In the type_base* overload, replace was_indirect_type
>> >       with indirect_type; peel CV qualifiers and typedefs without
>> >       testing as the peel function does this; replace the
>> >       indiscriminate peeling of qualifier/pointer/reference/array
>> >       type components with code that checks the same
>> >       pointer/reference/array type component is used on each side
>> >       and makes recursive calls with indirect_type set to true; pass
>> >       the indirect_type argument recursively when comparing other
>> >       subtypes; move the typeid check earlier, document its purpose
>> >       and remove unneccessary checks after later dynamic casts;
>> >       remove an always-true conditional; add a TODO for comparing
>> >       array types more accurately.
>> >       * tests/data/Makefile.am: Add new test case files.
>> >       * tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc: New
>> >       test case.
>> >       * tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc: Ditto.
>> >       * tests/data/test-abidiff-exit/test-leaf-peeling-report.txt:
>> >       Ditto.
>> >       * tests/test-abidiff-exit.cc: Run new test case.
>> >
>> >Signed-off-by: Giuliano Procida <gprocida@google.com>
>> >---
>> > include/abg-fwd.h                             |   6 +-
>> > src/abg-ir.cc                                 | 147 ++++++++++--------
>> > tests/data/Makefile.am                        |   5 +
>> > .../test-leaf-peeling-report.txt              |  38 +++++
>> > .../test-abidiff-exit/test-leaf-peeling-v0.cc |  24 +++
>> > .../test-abidiff-exit/test-leaf-peeling-v0.o  | Bin 0 -> 3704 bytes
>> > .../test-abidiff-exit/test-leaf-peeling-v1.cc |  24 +++
>> > .../test-abidiff-exit/test-leaf-peeling-v1.o  | Bin 0 -> 3752 bytes
>> > tests/test-abidiff-exit.cc                    |   9 ++
>> > 9 files changed, 182 insertions(+), 71 deletions(-)
>> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
>> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
>> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
>> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
>> > create mode 100644 tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
>> >
>> >diff --git a/include/abg-fwd.h b/include/abg-fwd.h
>> >index 6f2a862c..1aab70a6 100644
>> >--- a/include/abg-fwd.h
>> >+++ b/include/abg-fwd.h
>> >@@ -1293,11 +1293,13 @@ function_decl_is_less_than(const function_decl&f, const function_decl &s);
>> >
>> > bool
>> > types_have_similar_structure(const type_base_sptr& first,
>> >-                           const type_base_sptr& second);
>> >+                           const type_base_sptr& second,
>> >+                           bool indirect_type = false);
>> >
>> > bool
>> > types_have_similar_structure(const type_base* first,
>> >-                           const type_base* second);
>> >+                           const type_base* second,
>> >+                           bool indirect_type = false);
>> >
>> > } // end namespace ir
>> >
>> >diff --git a/src/abg-ir.cc b/src/abg-ir.cc
>> >index 2853fe6c..a10b0bb7 100644
>> >--- a/src/abg-ir.cc
>> >+++ b/src/abg-ir.cc
>> >@@ -13573,10 +13573,10 @@ reference_type_def::reference_type_def(const type_base_sptr  pointed_to,
>> >       decl_base_sptr pto = dynamic_pointer_cast<decl_base>(pointed_to);
>> >       string name;
>> >       if (pto)
>> >-        {
>> >-          set_visibility(pto->get_visibility());
>> >-          name = string(pto->get_name()) + "&";
>> >-        }
>> >+      {
>> >+        set_visibility(pto->get_visibility());
>> >+        name = string(pto->get_name()) + "&";
>> >+      }
>>
>> Correct, but unrelated. No complaints. :-)
>>
>> >       else
>> >       name = string(get_type_name(is_function_type(pointed_to),
>> >                                   /*qualified_name=*/true)) + "&";
>> >@@ -22563,33 +22563,44 @@ function_decl_is_less_than(const function_decl &f, const function_decl &s)
>> > /// Test if two types have similar structures, even though they are
>> > /// (or can be) different.
>> > ///
>> >-/// Two indirect types (pointers, references, qualified, typedefs)
>> >-/// have similar structure if their underlying types are of the same
>> >-/// kind and have the same name.  In this indirect types case, the
>> >-/// size of the underlying type does not matter.
>> >+/// const and volatile qualifiers are completely ignored.
>> >+///
>> >+/// typedef are resolved to their definitions; their names are ignored.
>> >+///
>> >+/// Two indirect types (pointers or references) have similar structure
>> >+/// if their underlying types are of the same kind and have the same
>> >+/// name.  In the indirect types case, the size of the underlying type
>> >+/// does not matter.
>> > ///
>> > /// Two direct types (i.e, non indirect) have a similar structure if
>> > /// they have the same kind, name and size.  Two class types have
>> >-/// similar structure if they have the same name, size, and if their
>> >-/// data members have similar types.
>> >+/// similar structure if they have the same name, size, and if the
>> >+/// types of their data members have similar types.
>> > ///
>> > /// @param first the first type to consider.
>> > ///
>> > /// @param second the second type to consider.
>> > ///
>> >+/// @param indirect_type whether to do an indirect comparison
>> >+///
>> > /// @return true iff @p first and @p second have similar structures.
>> > bool
>> > types_have_similar_structure(const type_base_sptr& first,
>> >-                           const type_base_sptr& second)
>> >-{return types_have_similar_structure(first.get(), second.get());}
>> >+                           const type_base_sptr& second,
>> >+                           bool indirect_type)
>> >+{return types_have_similar_structure(first.get(), second.get(), indirect_type);}
>> >
>> > /// Test if two types have similar structures, even though they are
>> > /// (or can be) different.
>> > ///
>> >-/// Two indirect types (pointers, references, qualified, typedefs)
>> >-/// have similar structure if their underlying types are of the same
>> >-/// kind and have the same name.  In this indirect types case, the
>> >-/// size of the underlying type does not matter.
>> >+/// const and volatile qualifiers are completely ignored.
>> >+///
>> >+/// typedef are resolved to their definitions; their names are ignored.
>> >+///
>> >+/// Two indirect types (pointers or references) have similar structure
>> >+/// if their underlying types are of the same kind and have the same
>> >+/// name.  In the indirect types case, the size of the underlying type
>> >+/// does not matter.
>> > ///
>> > /// Two direct types (i.e, non indirect) have a similar structure if
>> > /// they have the same kind, name and size.  Two class types have
>> >@@ -22600,9 +22611,13 @@ types_have_similar_structure(const type_base_sptr& first,
>> > ///
>> > /// @param second the second type to consider.
>> > ///
>> >+/// @param indirect_type whether to do an indirect comparison
>> >+///
>> > /// @return true iff @p first and @p second have similar structures.
>> > bool
>> >-types_have_similar_structure(const type_base* first, const type_base* second)
>> >+types_have_similar_structure(const type_base* first,
>> >+                           const type_base* second,
>> >+                           bool indirect_type)
>> > {
>> >   if (!!first != !!second)
>> >     return false;
>> >@@ -22610,33 +22625,39 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (!first)
>> >     return false;
>> >
>> >-  if (is_typedef(first) || is_qualified_type(first))
>> >-    first = peel_qualified_or_typedef_type(first);
>> >-
>> >-  if (is_typedef(second) || is_qualified_type(second))
>> >-    second = peel_qualified_or_typedef_type(second);
>> >+  // Treat typedefs purely as type aliases and ignore CV-qualifiers.
>> >+  first = peel_qualified_or_typedef_type(first);
>> >+  second = peel_qualified_or_typedef_type(second);
>> >
>> >-  bool was_indirect_type = (is_pointer_type(first)
>> >-                          || is_pointer_type(second)
>> >-                          || is_reference_type(first)
>> >-                          || is_reference_type(second));
>> >+  // Eliminate all but N of the N^2 comparison cases. This also guarantees the
>> >+  // various ty2 below cannot be null.
>> >+  if (typeid(*first) != typeid(*second))
>> >+    return false;
>>
>> Just curious (because I think it is correct): Does it make a measurable
>> difference?
>
>The code was there before, after the peeling. However, various ty2
>checks were still there, including ones I'd added. Once I went and
>reminded myself what typeid meant, the linear code made a lot more
>sense.
>
>> >
>> >-  if (was_indirect_type)
>> >+  // Peel off matching pointers.
>> >+  if (const pointer_type_def* ty1 = is_pointer_type(first))
>>
>> A picky compiler might ask you to add some parentheses here.  [-Wparentheses]
>
>-Wparentheses is already enabled by -Wall which is enabled by ABIGAIL_DEVEL=1.
>
>In any case, there is no ambiguity here.
>
>> >     {
>> >-      first = peel_typedef_pointer_or_reference_type(first);
>> >-      second = peel_typedef_pointer_or_reference_type(second);
>> >+      const pointer_type_def* ty2 = is_pointer_type(second);
>> >+      return types_have_similar_structure(ty1->get_pointed_to_type(),
>> >+                                        ty2->get_pointed_to_type(),
>> >+                                        true);
>> >     }
>> >
>> >-  if (typeid(*first) != typeid(*second))
>> >-    return false;
>> >+  // Peel off matching references.
>> >+  if (const reference_type_def* ty1 = is_reference_type(first))
>>
>> As above.
>>
>> >+    {
>> >+      const reference_type_def* ty2 = is_reference_type(second);
>> >+      if (ty1->is_lvalue() != ty2->is_lvalue())
>> >+      return false;
>> >+      return types_have_similar_structure(ty1->get_pointed_to_type(),
>> >+                                        ty2->get_pointed_to_type(),
>> >+                                        true);
>> >+    }
>> >
>> >   if (const type_decl* ty1 = is_type_decl(first))
>> >     {
>> >       const type_decl* ty2 = is_type_decl(second);
>> >-      if (ty2 == 0)
>> >-      return false;
>> >-
>> >-      if (!was_indirect_type)
>> >+      if (!indirect_type)
>> >       if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
>> >         return false;
>> >
>> >@@ -22646,10 +22667,7 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const enum_type_decl* ty1 = is_enum_type(first))
>> >     {
>> >       const enum_type_decl* ty2 = is_enum_type(second);
>> >-      if (ty2 == 0)
>> >-      return false;
>> >-
>> >-      if (!was_indirect_type)
>> >+      if (!indirect_type)
>> >       if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
>> >         return false;
>> >
>> >@@ -22660,20 +22678,16 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const class_decl* ty1 = is_class_type(first))
>> >     {
>> >       const class_decl* ty2 = is_class_type(second);
>> >-      if (ty2 == 0)
>> >-      return false;
>> >-
>> >       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
>> >         && ty1->get_name() != ty2->get_name())
>> >       return false;
>> >
>> >-      if (!was_indirect_type)
>> >+      if (!indirect_type)
>> >       {
>> >-        if (!was_indirect_type)
>> >-          if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
>> >-              || (ty1->get_non_static_data_members().size()
>> >-                  != ty2->get_non_static_data_members().size()))
>> >-            return false;
>> >+        if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
>> >+            || (ty1->get_non_static_data_members().size()
>> >+                != ty2->get_non_static_data_members().size()))
>> >+          return false;
>> >
>> >         for (class_or_union::data_members::const_iterator
>> >                i = ty1->get_non_static_data_members().begin(),
>> >@@ -22685,7 +22699,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >             var_decl_sptr dm1 = *i;
>> >             var_decl_sptr dm2 = *j;
>> >             if (!types_have_similar_structure(dm1->get_type().get(),
>> >-                                              dm2->get_type().get()))
>> >+                                              dm2->get_type().get(),
>> >+                                              indirect_type))
>> >               return false;
>> >           }
>> >       }
>> >@@ -22696,14 +22711,11 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const union_decl* ty1 = is_union_type(first))
>> >     {
>> >       const union_decl* ty2 = is_union_type(second);
>> >-      if (ty2 == 0)
>> >-      return false;
>> >-
>> >       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
>> >         && ty1->get_name() != ty2->get_name())
>> >       return false;
>> >
>> >-      if (!was_indirect_type)
>> >+      if (!indirect_type)
>> >       return ty1->get_size_in_bits() == ty2->get_size_in_bits();
>> >
>> >       return true;
>> >@@ -22712,13 +22724,13 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const array_type_def* ty1 = is_array_type(first))
>> >     {
>> >       const array_type_def* ty2 = is_array_type(second);
>> >-
>> >-      if (!was_indirect_type)
>> >-      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
>> >-          || ty1->get_dimension_count() != ty2->get_dimension_count()
>> >-          || !types_have_similar_structure(ty1->get_element_type(),
>> >-                                           ty2->get_element_type()))
>> >-        return false;
>> >+      // TODO: Handle uint32_t[10] vs uint64_t[5] better.
>> >+      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
>> >+        || ty1->get_dimension_count() != ty2->get_dimension_count()
>> >+        || !types_have_similar_structure(ty1->get_element_type(),
>> >+                                         ty2->get_element_type(),
>> >+                                         indirect_type))
>> >+      return false;
>> >
>> >       return true;
>> >     }
>> >@@ -22726,14 +22738,12 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const array_type_def::subrange_type *ty1 = is_subrange_type(first))
>> >     {
>> >       const array_type_def::subrange_type *ty2 = is_subrange_type(second);
>> >-      if (!ty2)
>> >-      return false;
>> >-
>> >       if (ty1->get_upper_bound() != ty2->get_upper_bound()
>> >         || ty1->get_lower_bound() != ty2->get_lower_bound()
>> >         || ty1->get_language() != ty2->get_language()
>> >         || !types_have_similar_structure(ty1->get_underlying_type(),
>> >-                                        ty2->get_underlying_type()))
>> >+                                         ty2->get_underlying_type(),
>> >+                                         indirect_type))
>> >       return false;
>> >
>> >       return true;
>> >@@ -22742,11 +22752,9 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >   if (const function_type* ty1 = is_function_type(first))
>> >     {
>> >       const function_type* ty2 = is_function_type(second);
>> >-      if (!ty2)
>> >-      return false;
>> >-
>> >       if (!types_have_similar_structure(ty1->get_return_type(),
>> >-                                      ty2->get_return_type()))
>> >+                                      ty2->get_return_type(),
>> >+                                      indirect_type))
>> >       return false;
>> >
>> >       if (ty1->get_parameters().size() != ty2->get_parameters().size())
>> >@@ -22759,7 +22767,8 @@ types_have_similar_structure(const type_base* first, const type_base* second)
>> >           && j != ty2->get_parameters().end());
>> >          ++i, ++j)
>> >       if (!types_have_similar_structure((*i)->get_type(),
>> >-                                        (*j)->get_type()))
>> >+                                        (*j)->get_type(),
>> >+                                        indirect_type))
>> >         return false;
>> >
>> >       return true;
>> >diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
>> >index cf7792f1..6d4e2faa 100644
>> >--- a/tests/data/Makefile.am
>> >+++ b/tests/data/Makefile.am
>> >@@ -130,6 +130,11 @@ test-abidiff-exit/test-leaf3-v0.o \
>> > test-abidiff-exit/test-leaf3-v1.c \
>> > test-abidiff-exit/test-leaf3-v1.o \
>> > test-abidiff-exit/test-leaf3-report.txt \
>> >+test-abidiff-exit/test-leaf-peeling-v0.cc \
>> >+test-abidiff-exit/test-leaf-peeling-v0.o \
>> >+test-abidiff-exit/test-leaf-peeling-v1.cc \
>> >+test-abidiff-exit/test-leaf-peeling-v1.o \
>> >+test-abidiff-exit/test-leaf-peeling-report.txt \
>> > \
>> > test-diff-dwarf/test0-v0.cc           \
>> > test-diff-dwarf/test0-v0.o                    \
>> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
>> >new file mode 100644
>> >index 00000000..54a26869
>> >--- /dev/null
>> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
>> >@@ -0,0 +1,38 @@
>> >+Leaf changes summary: 4 artifacts changed
>> >+Changed leaf types summary: 4 leaf types changed
>> >+Removed/Changed/Added functions summary: 0 Removed, 0 Changed, 0 Added function
>> >+Removed/Changed/Added variables summary: 0 Removed, 0 Changed, 0 Added variable
>> >+
>> >+'struct foo at test-leaf-peeling.0.cc:1:1' changed:
>> >+  type size changed from 32 to 64 (in bits)
>> >+  there are data member changes:
>> >+    type 'int' of 'foo::z' changed:
>> >+      type name changed from 'int' to 'long int'
>> >+      type size changed from 32 to 64 (in bits)
>> >+    and size changed from 32 to 64 (in bits) (by +32 bits)
>> >+
>> >+
>> >+
>> >+'struct ops1 at test-leaf-peeling.0.cc:5:1' changed:
>> >+  type size hasn't changed
>> >+  there are data member changes:
>> >+    type 'int*' of 'ops1::x' changed:
>> >+      pointer type changed from: 'int*' to: 'int**'
>> >+
>> >+
>> >+
>> >+
>> >+'struct ops2 at test-leaf-peeling.0.cc:9:1' changed:
>> >+  type size changed from 320 to 640 (in bits)
>> >+  there are data member changes:
>> >+    'foo ops2::y[10]' size changed from 320 to 640 (in bits) (by +320 bits)
>> >+
>> >+
>> >+
>> >+'struct ops3 at test-leaf-peeling.0.cc:13:1' changed:
>> >+  type size hasn't changed
>> >+  there are data member changes:
>> >+    type 'void (int&)*' of 'ops3::spong' changed:
>> >+      pointer type changed from: 'void (int&)*' to: 'void (int&&)*'
>> >+
>> >+
>> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
>> >new file mode 100644
>> >index 00000000..b927d15e
>> >--- /dev/null
>> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
>> >@@ -0,0 +1,24 @@
>> >+struct foo {
>> >+  int z;
>> >+};
>> >+
>> >+struct ops1 {
>> >+  int * x;
>> >+};
>> >+
>> >+struct ops2 {
>> >+  foo y[10];
>> >+};
>> >+
>> >+struct ops3 {
>> >+  void (*spong)(int & wibble);
>> >+};
>> >+
>> >+void register_ops1(ops1*) {
>> >+}
>> >+
>> >+void register_ops2(ops2*) {
>> >+}
>> >+
>> >+void register_ops3(ops3*) {
>> >+}
>> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
>> >new file mode 100644
>> >index 0000000000000000000000000000000000000000..a556a63560122a5e926ab708bb13f0fd40714638
>> >GIT binary patch
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>> >zi5MSsiATLMI?mTn$N2_wC8;~JO!M=O2&d{D;6pSOv#6UB-jw=L4gXE*Gm_JdP*4A)
>> >z;;(k3D+*5euS>nH;hR$bT*IXbUuyW4)bDBdDXIUc;g_ZUlZO8x^`9l@eet>Rk#pTv
>> >zq+eRT5{z?ROX8e|&%LDi)4d^D((vgRhVxn;3HQ#F=8Znz(vX*&=VgEH6*^v&4s?d<
>> >zIaV~B*MC#Pd-ZXG{Wi8taDuQK^KF(wZ!ZLA%MD#{szCrw*K4`XmRH?vY&QLR2W^q;
>> >zR;yj_%|5f+b^Qi*VKoH5Odf~e6yVf4?Y4)X8^`a2o`atOI|$v{8#2h--mG`swkH?<
>> >zKiMqCQw`O3ic(f+K$?qLZzNxp$WEBv8C}&$k@ff|(MIppe~m9;te%sm<N2$aQB$Me
>> >z8}w7OLO}|BB@6P444`{Re%u47ZxUU=N6$(40}1{>ibA^YRkZ0Cxql=tFTYQmLic?U
>> >z4a3%dAQ#H<w0`>P=<BC`qvu2j?#uaakfM<8OZ{!w{NKolxK1=b^+|pH9mFUnuM@?H
>> >z3i3j5-(j5RXZ|)ChQ&Wdi$bFNr4q+6e;<u3t9}<{yo!;m`+gxYS+1V@x{TlJA+f;w
>> >zXZRBo$hE?N<PW9ey40zD^dExbxvsPxeQpZ*PR@TI7fjzn`n90P)0yb+9zsx&_x~m-
>> >V3hDc&yu;%2lo;vjnDs_I{$J;aGn)Va
>> >
>> >literal 0
>> >HcmV?d00001
>> >
>> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
>> >new file mode 100644
>> >index 00000000..7c88df9f
>> >--- /dev/null
>> >+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
>> >@@ -0,0 +1,24 @@
>> >+struct foo {
>> >+  long z;
>> >+};
>> >+
>> >+struct ops1 {
>> >+  int ** x;
>> >+};
>> >+
>> >+struct ops2 {
>> >+  foo y[10];
>> >+};
>>
>> There is no apparent difference in ops2 between the test files. What are
>> we testing?
>
>We are testing the reporting of an indirect change via its dependency
>on struct foo (which is reported already).
>
>We could (and I would) argue that the change to ops2 is not local and
>people doing kernel ABI diffs might agree as well. However, at the
>moment, size changes are considered as local. If y had been a pointer
>something something foo, the size would not have changed and this
>would not have been reported. I'll add a comment to the test code.

I agree that this should not be considered local then. Dodji, what do
you think?

Cheers,
Matthias

>
>> >+
>> >+struct ops3 {
>> >+  void (*spong)(int && wibble);
>> >+};
>> >+
>> >+void register_ops1(ops1*) {
>> >+}
>> >+
>> >+void register_ops2(ops2*) {
>> >+}
>> >+
>> >+void register_ops3(ops3*) {
>> >+}
>>
>> Maybe we can add some more test cases:
>>
>>  - compare reference types and pointer types
>>  - compare int*** and int* (two levels of peeling)
>>  - compare uint32_t[10] and uint64_t[5] (with the same TODO as in the code)
>>  - nested types, e.g. struct ops1_v0* vs. struct ops1_v1*
>
>Agreed. Will do.
>
>> Nice work. I like it!
>>
>> Cheers,
>> Matthias
>
>Thank you,
>Giuliano.
>
>> >diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
>> >new file mode 100644
>> >index 0000000000000000000000000000000000000000..e71ade4431f80a78ee73292d60808a2ee5404640
>> >GIT binary patch
>> >literal 3752
>> >zcmbtXO=x3P6h1evNnV>K{Yl4Zsf!f+8^*k8(lRq0ZH=wdX;6nE6lF$fU(%N}O!89l
>> >zUbU@=f+Ear6h#DAiVI!25#8%7MK^*A7lMjz-4zt{ocqpAZ*Ni%J&=3O`Oe?H=l;C*
>> >z)vHgf#)JSx0+!%dQz*digU517iY3UxIBcxl{&ns4D@S);_^Q8n3$qQ#09)pb<l|&8
>> >zqsg&ayA8Gw_9}wbA&8iiFoPW@H#yiMZr8}Z4<a!{5<tRk%CUoEav<LD!^n4C4BBra
>> >zW*vYSN|FR%=W+NDe}i(s+)08tciR3Ml_5ezX6Sq3kop#fVHzN9Q;CFh$`ByVCWt9Y
>> >zu^>K3;BrT3h`qIg0iU2D3Ya)0;1UJU5Ct4`1IA7X*r5O#qJXEVv=|fjXR;|PGo2X|
>> >z<H^ypXw3@CPNlA-9!V{vL>8No2Fs4ra`rOLc;G%rrIs)VyMWFa-8nIWwlYQ~*~!KZ
>> >z3Q^8drokB~XD?ueAxxRkQ>M-cau|-I19okhlVlw6*p%}0<rGVk?=4S}?+E$ECUFrD
>> >z<1a?50W7A`j3(>iv#3}=+bYDLnKX{_L}O<JgkBKlo1R<C?|NRd;n$slQ?1JA_%sYg
>> >zWhj1B#Kr6J>80)%voKM!?bmaAe$c4<-gb`8l|)Fm5Vm$9*hL5Ec=bjQdY#SoZcsR(
>> >z6;Eh$ARTZhk~9a`u5aX4&Yv&L=N6ozQ^*x(3k!w9Y%!N_g?qlYSoeId)2O2AcB(sz
>> >z`<E}~FV5%k^<2K@1_yq1r_=V^dqIBBf2rYb=R>#B^a9wtQJB-GR9v5zB~R&v>0XfT
>> >zg`PBX5}yOOwz6_1_s|nwrQ!O~#Pfwq=Zq!D7Q;luKpZ{;Vt-Uj4=3$AxH0!4PCp`f
>> >zXCBXtz8PCdCsxq`F|s{MMx@j1&qwCIb~g1eERE06AAk245WxNJ2P57+B`53_TKbX2
>> >z51whW;KW7lnk|qIP*+!i1=^#lK;%}mVhxEz3(`Fp0ao<z^w=yI?!oB#jca|7y+>@8
>> >zaiuH1#`rzRi4=a?z5BOkO&wX&U!6hKNqVT2O!d`@2&e9C5{NVwG5N3){tfGA41AjP
>> >zDduz{^xZ$F`Rk8US;Hy+IP2F9e4X_}1K(i%V*_UuJ~i+gtbbwPIo5wP@MYG2Ht@e#
>> >z|Bbm?uiDQvUkTOEdG?zy@Xr~aWL)J@=V8h4e}Mh38u%}amyJ9OclVm+Bfr>e7-g>N
>> >zDu4Bcn0SsIXm9oXEg86)|CWKP{(uu4wD8$Q9(E$WqomN=55d`XLl>M%5P;M1ny$0$
>> >zRrcze4Zqe#o0Q#3rQ^ML!t8cjzm6}t9)ce)PlaF!aH{QA%fk<m<F`Z4!B0s(2;J%}
>> >z4)S(3YaO@c@x=cpqkBO;)bARlEYW~86S3|{zB-YeF!RN9btg?W;~zvD-M9Z5U%*&1
>> >zCzVt6+lJ9l<)0+<r)!CVH2RVoa>N024#`iw4fLK8E#lA2N%(gR-X%pN)0f^26C?L`
>> >z`S8wau_T(lPa@WD{-5zgRXoj~zDDN!xBKKo2<~$Io1|!D)~9#4U;UrBkm?iFr}xvW
>> >zzl#{<RP#hpQjQOVdXE&Y>MQ;-8v4c0)1;8-eCed(6n_JaO4j{ua=ea_Z2G>>7`LnI
>> >zzQytTT_h6J`W5^R3glW+0P`buTw|U3NB?H1c-2>$k6D{Se&G7A@r3C+Nq<F{@w6xA
>> >e-9reT<MY2oibm%8DQ~~{5+z3ZC}Q2wjQ<DlLOH<z
>> >
>> >literal 0
>> >HcmV?d00001
>> >
>> >diff --git a/tests/test-abidiff-exit.cc b/tests/test-abidiff-exit.cc
>> >index 6ecbfd24..ebac7a00 100644
>> >--- a/tests/test-abidiff-exit.cc
>> >+++ b/tests/test-abidiff-exit.cc
>> >@@ -158,6 +158,15 @@ InOutSpec in_out_specs[] =
>> >     "data/test-abidiff-exit/test-leaf3-report.txt",
>> >     "output/test-abidiff-exit/test-leaf3-report.txt"
>> >   },
>> >+  {
>> >+    "data/test-abidiff-exit/test-leaf-peeling-v0.o",
>> >+    "data/test-abidiff-exit/test-leaf-peeling-v1.o",
>> >+    "",
>> >+    "--leaf-changes-only",
>> >+    abigail::tools_utils::ABIDIFF_ABI_CHANGE,
>> >+    "data/test-abidiff-exit/test-leaf-peeling-report.txt",
>> >+    "output/test-abidiff-exit/test-leaf-peeling-report.txt"
>> >+  },
>> >   {0, 0, 0 ,0,  abigail::tools_utils::ABIDIFF_OK, 0, 0}
>> > };
>> >
>> >--
>> >2.25.1.696.g5e7596f4ac-goog
>> >
>> >
Dodji Seketeli March 26, 2020, 1:36 p.m. UTC | #4
Hello Giuliano,

Giuliano Procida <gprocida@google.com> a ?crit:

> This function is used to determine whether or not type differences are
> "local" and is primarily used in --leaf-changes-only mode. The logic
> has some issues which are addressed by this patch:
>
>     - Any number of points-to (*) and refers-to (& and &&) components
>       are peeled off the types being compared, rather than checking
>       these match in number and kind.
>     - This peeling is done with peel_typedef_pointer_or_reference_type
>       which also peels any number of CV qualifiers (OK) and
>       array-of ([N]) type components (not OK).
>     - The function sets a state variable (was_indirect_type) to modify
>       the behaviour of downstream comparisons, but this cannot be
>       passed through recursive calls.
>
> The effect of the indirect_type flag is to switch to comparisons by
> name: identically named structs don't get introspected. Arguably, a
> more useful behaviour for --leaf-changes-only mode would be to treat
> any change to a named type as non-local, except in the context of the
> definition of that type itself. This would be a more significant
> change in behaviour.
>
> 	* include/abg-fwd.h (types_have_similar_structure): In both
> 	overloads, add an indirect_type argument, defaulting to
> 	false.
> 	* src/abg-ir.cc (reference_type_def constructor): Tabify.
> 	(types_have_similar_structure): In both overloads, add an
> 	indirect_type argument and update documentation text. In the
> 	type_base_sptr overload, pass indirect_type in the tail
> 	call. In the type_base* overload, replace was_indirect_type
> 	with indirect_type; peel CV qualifiers and typedefs without
> 	testing as the peel function does this; replace the
> 	indiscriminate peeling of qualifier/pointer/reference/array
> 	type components with code that checks the same
> 	pointer/reference/array type component is used on each side
> 	and makes recursive calls with indirect_type set to true; pass
> 	the indirect_type argument recursively when comparing other
> 	subtypes; move the typeid check earlier, document its purpose
> 	and remove unneccessary checks after later dynamic casts;
> 	remove an always-true conditional; add a TODO for comparing
> 	array types more accurately.
> 	* tests/data/Makefile.am: Add new test case files.
> 	* tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc: New
> 	test case.
> 	* tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc: Ditto.
> 	* tests/data/test-abidiff-exit/test-leaf-peeling-report.txt:
> 	Ditto.
> 	* tests/test-abidiff-exit.cc: Run new test case.

Applied to master.

Thanks!
diff mbox series

Patch

diff --git a/include/abg-fwd.h b/include/abg-fwd.h
index 6f2a862c..1aab70a6 100644
--- a/include/abg-fwd.h
+++ b/include/abg-fwd.h
@@ -1293,11 +1293,13 @@  function_decl_is_less_than(const function_decl&f, const function_decl &s);
 
 bool
 types_have_similar_structure(const type_base_sptr& first,
-			     const type_base_sptr& second);
+			     const type_base_sptr& second,
+			     bool indirect_type = false);
 
 bool
 types_have_similar_structure(const type_base* first,
-			     const type_base* second);
+			     const type_base* second,
+			     bool indirect_type = false);
 
 } // end namespace ir
 
diff --git a/src/abg-ir.cc b/src/abg-ir.cc
index 2853fe6c..a10b0bb7 100644
--- a/src/abg-ir.cc
+++ b/src/abg-ir.cc
@@ -13573,10 +13573,10 @@  reference_type_def::reference_type_def(const type_base_sptr	pointed_to,
       decl_base_sptr pto = dynamic_pointer_cast<decl_base>(pointed_to);
       string name;
       if (pto)
-        {
-          set_visibility(pto->get_visibility());
-          name = string(pto->get_name()) + "&";
-        }
+	{
+	  set_visibility(pto->get_visibility());
+	  name = string(pto->get_name()) + "&";
+	}
       else
 	name = string(get_type_name(is_function_type(pointed_to),
 				    /*qualified_name=*/true)) + "&";
@@ -22563,33 +22563,44 @@  function_decl_is_less_than(const function_decl &f, const function_decl &s)
 /// Test if two types have similar structures, even though they are
 /// (or can be) different.
 ///
-/// Two indirect types (pointers, references, qualified, typedefs)
-/// have similar structure if their underlying types are of the same
-/// kind and have the same name.  In this indirect types case, the
-/// size of the underlying type does not matter.
+/// const and volatile qualifiers are completely ignored.
+///
+/// typedef are resolved to their definitions; their names are ignored.
+///
+/// Two indirect types (pointers or references) have similar structure
+/// if their underlying types are of the same kind and have the same
+/// name.  In the indirect types case, the size of the underlying type
+/// does not matter.
 ///
 /// Two direct types (i.e, non indirect) have a similar structure if
 /// they have the same kind, name and size.  Two class types have
-/// similar structure if they have the same name, size, and if their
-/// data members have similar types.
+/// similar structure if they have the same name, size, and if the
+/// types of their data members have similar types.
 ///
 /// @param first the first type to consider.
 ///
 /// @param second the second type to consider.
 ///
+/// @param indirect_type whether to do an indirect comparison
+///
 /// @return true iff @p first and @p second have similar structures.
 bool
 types_have_similar_structure(const type_base_sptr& first,
-			     const type_base_sptr& second)
-{return types_have_similar_structure(first.get(), second.get());}
+			     const type_base_sptr& second,
+			     bool indirect_type)
+{return types_have_similar_structure(first.get(), second.get(), indirect_type);}
 
 /// Test if two types have similar structures, even though they are
 /// (or can be) different.
 ///
-/// Two indirect types (pointers, references, qualified, typedefs)
-/// have similar structure if their underlying types are of the same
-/// kind and have the same name.  In this indirect types case, the
-/// size of the underlying type does not matter.
+/// const and volatile qualifiers are completely ignored.
+///
+/// typedef are resolved to their definitions; their names are ignored.
+///
+/// Two indirect types (pointers or references) have similar structure
+/// if their underlying types are of the same kind and have the same
+/// name.  In the indirect types case, the size of the underlying type
+/// does not matter.
 ///
 /// Two direct types (i.e, non indirect) have a similar structure if
 /// they have the same kind, name and size.  Two class types have
@@ -22600,9 +22611,13 @@  types_have_similar_structure(const type_base_sptr& first,
 ///
 /// @param second the second type to consider.
 ///
+/// @param indirect_type whether to do an indirect comparison
+///
 /// @return true iff @p first and @p second have similar structures.
 bool
-types_have_similar_structure(const type_base* first, const type_base* second)
+types_have_similar_structure(const type_base* first,
+			     const type_base* second,
+			     bool indirect_type)
 {
   if (!!first != !!second)
     return false;
@@ -22610,33 +22625,39 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (!first)
     return false;
 
-  if (is_typedef(first) || is_qualified_type(first))
-    first = peel_qualified_or_typedef_type(first);
-
-  if (is_typedef(second) || is_qualified_type(second))
-    second = peel_qualified_or_typedef_type(second);
+  // Treat typedefs purely as type aliases and ignore CV-qualifiers.
+  first = peel_qualified_or_typedef_type(first);
+  second = peel_qualified_or_typedef_type(second);
 
-  bool was_indirect_type = (is_pointer_type(first)
-			    || is_pointer_type(second)
-			    || is_reference_type(first)
-			    || is_reference_type(second));
+  // Eliminate all but N of the N^2 comparison cases. This also guarantees the
+  // various ty2 below cannot be null.
+  if (typeid(*first) != typeid(*second))
+    return false;
 
-  if (was_indirect_type)
+  // Peel off matching pointers.
+  if (const pointer_type_def* ty1 = is_pointer_type(first))
     {
-      first = peel_typedef_pointer_or_reference_type(first);
-      second = peel_typedef_pointer_or_reference_type(second);
+      const pointer_type_def* ty2 = is_pointer_type(second);
+      return types_have_similar_structure(ty1->get_pointed_to_type(),
+					  ty2->get_pointed_to_type(),
+					  true);
     }
 
-  if (typeid(*first) != typeid(*second))
-    return false;
+  // Peel off matching references.
+  if (const reference_type_def* ty1 = is_reference_type(first))
+    {
+      const reference_type_def* ty2 = is_reference_type(second);
+      if (ty1->is_lvalue() != ty2->is_lvalue())
+	return false;
+      return types_have_similar_structure(ty1->get_pointed_to_type(),
+					  ty2->get_pointed_to_type(),
+					  true);
+    }
 
   if (const type_decl* ty1 = is_type_decl(first))
     {
       const type_decl* ty2 = is_type_decl(second);
-      if (ty2 == 0)
-	return false;
-
-      if (!was_indirect_type)
+      if (!indirect_type)
 	if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
 	  return false;
 
@@ -22646,10 +22667,7 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const enum_type_decl* ty1 = is_enum_type(first))
     {
       const enum_type_decl* ty2 = is_enum_type(second);
-      if (ty2 == 0)
-	return false;
-
-      if (!was_indirect_type)
+      if (!indirect_type)
 	if (ty1->get_size_in_bits() != ty2->get_size_in_bits())
 	  return false;
 
@@ -22660,20 +22678,16 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const class_decl* ty1 = is_class_type(first))
     {
       const class_decl* ty2 = is_class_type(second);
-      if (ty2 == 0)
-	return false;
-
       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
 	  && ty1->get_name() != ty2->get_name())
 	return false;
 
-      if (!was_indirect_type)
+      if (!indirect_type)
 	{
-	  if (!was_indirect_type)
-	    if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
-		|| (ty1->get_non_static_data_members().size()
-		    != ty2->get_non_static_data_members().size()))
-	      return false;
+	  if ((ty1->get_size_in_bits() != ty2->get_size_in_bits())
+	      || (ty1->get_non_static_data_members().size()
+		  != ty2->get_non_static_data_members().size()))
+	    return false;
 
 	  for (class_or_union::data_members::const_iterator
 		 i = ty1->get_non_static_data_members().begin(),
@@ -22685,7 +22699,8 @@  types_have_similar_structure(const type_base* first, const type_base* second)
 	      var_decl_sptr dm1 = *i;
 	      var_decl_sptr dm2 = *j;
 	      if (!types_have_similar_structure(dm1->get_type().get(),
-						dm2->get_type().get()))
+						dm2->get_type().get(),
+						indirect_type))
 		return false;
 	    }
 	}
@@ -22696,14 +22711,11 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const union_decl* ty1 = is_union_type(first))
     {
       const union_decl* ty2 = is_union_type(second);
-      if (ty2 == 0)
-	return false;
-
       if (!ty1->get_is_anonymous() && !ty2->get_is_anonymous()
 	  && ty1->get_name() != ty2->get_name())
 	return false;
 
-      if (!was_indirect_type)
+      if (!indirect_type)
 	return ty1->get_size_in_bits() == ty2->get_size_in_bits();
 
       return true;
@@ -22712,13 +22724,13 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const array_type_def* ty1 = is_array_type(first))
     {
       const array_type_def* ty2 = is_array_type(second);
-
-      if (!was_indirect_type)
-	if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
-	    || ty1->get_dimension_count() != ty2->get_dimension_count()
-	    || !types_have_similar_structure(ty1->get_element_type(),
-					     ty2->get_element_type()))
-	  return false;
+      // TODO: Handle uint32_t[10] vs uint64_t[5] better.
+      if (ty1->get_size_in_bits() != ty2->get_size_in_bits()
+	  || ty1->get_dimension_count() != ty2->get_dimension_count()
+	  || !types_have_similar_structure(ty1->get_element_type(),
+					   ty2->get_element_type(),
+					   indirect_type))
+	return false;
 
       return true;
     }
@@ -22726,14 +22738,12 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const array_type_def::subrange_type *ty1 = is_subrange_type(first))
     {
       const array_type_def::subrange_type *ty2 = is_subrange_type(second);
-      if (!ty2)
-	return false;
-
       if (ty1->get_upper_bound() != ty2->get_upper_bound()
 	  || ty1->get_lower_bound() != ty2->get_lower_bound()
 	  || ty1->get_language() != ty2->get_language()
 	  || !types_have_similar_structure(ty1->get_underlying_type(),
-					  ty2->get_underlying_type()))
+					   ty2->get_underlying_type(),
+					   indirect_type))
 	return false;
 
       return true;
@@ -22742,11 +22752,9 @@  types_have_similar_structure(const type_base* first, const type_base* second)
   if (const function_type* ty1 = is_function_type(first))
     {
       const function_type* ty2 = is_function_type(second);
-      if (!ty2)
-	return false;
-
       if (!types_have_similar_structure(ty1->get_return_type(),
-					ty2->get_return_type()))
+					ty2->get_return_type(),
+					indirect_type))
 	return false;
 
       if (ty1->get_parameters().size() != ty2->get_parameters().size())
@@ -22759,7 +22767,8 @@  types_have_similar_structure(const type_base* first, const type_base* second)
 	    && j != ty2->get_parameters().end());
 	   ++i, ++j)
 	if (!types_have_similar_structure((*i)->get_type(),
-					  (*j)->get_type()))
+					  (*j)->get_type(),
+					  indirect_type))
 	  return false;
 
       return true;
diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
index cf7792f1..6d4e2faa 100644
--- a/tests/data/Makefile.am
+++ b/tests/data/Makefile.am
@@ -130,6 +130,11 @@  test-abidiff-exit/test-leaf3-v0.o \
 test-abidiff-exit/test-leaf3-v1.c \
 test-abidiff-exit/test-leaf3-v1.o \
 test-abidiff-exit/test-leaf3-report.txt \
+test-abidiff-exit/test-leaf-peeling-v0.cc \
+test-abidiff-exit/test-leaf-peeling-v0.o \
+test-abidiff-exit/test-leaf-peeling-v1.cc \
+test-abidiff-exit/test-leaf-peeling-v1.o \
+test-abidiff-exit/test-leaf-peeling-report.txt \
 \
 test-diff-dwarf/test0-v0.cc		\
 test-diff-dwarf/test0-v0.o			\
diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
new file mode 100644
index 00000000..54a26869
--- /dev/null
+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-report.txt
@@ -0,0 +1,38 @@ 
+Leaf changes summary: 4 artifacts changed
+Changed leaf types summary: 4 leaf types changed
+Removed/Changed/Added functions summary: 0 Removed, 0 Changed, 0 Added function
+Removed/Changed/Added variables summary: 0 Removed, 0 Changed, 0 Added variable
+
+'struct foo at test-leaf-peeling.0.cc:1:1' changed:
+  type size changed from 32 to 64 (in bits)
+  there are data member changes:
+    type 'int' of 'foo::z' changed:
+      type name changed from 'int' to 'long int'
+      type size changed from 32 to 64 (in bits)
+    and size changed from 32 to 64 (in bits) (by +32 bits)
+
+
+
+'struct ops1 at test-leaf-peeling.0.cc:5:1' changed:
+  type size hasn't changed
+  there are data member changes:
+    type 'int*' of 'ops1::x' changed:
+      pointer type changed from: 'int*' to: 'int**'
+
+
+
+
+'struct ops2 at test-leaf-peeling.0.cc:9:1' changed:
+  type size changed from 320 to 640 (in bits)
+  there are data member changes:
+    'foo ops2::y[10]' size changed from 320 to 640 (in bits) (by +320 bits)
+
+
+
+'struct ops3 at test-leaf-peeling.0.cc:13:1' changed:
+  type size hasn't changed
+  there are data member changes:
+    type 'void (int&)*' of 'ops3::spong' changed:
+      pointer type changed from: 'void (int&)*' to: 'void (int&&)*'
+
+
diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
new file mode 100644
index 00000000..b927d15e
--- /dev/null
+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.cc
@@ -0,0 +1,24 @@ 
+struct foo {
+  int z;
+};
+
+struct ops1 {
+  int * x;
+};
+
+struct ops2 {
+  foo y[10];
+};
+
+struct ops3 {
+  void (*spong)(int & wibble);
+};
+
+void register_ops1(ops1*) {
+}
+
+void register_ops2(ops2*) {
+}
+
+void register_ops3(ops3*) {
+}
diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v0.o
new file mode 100644
index 0000000000000000000000000000000000000000..a556a63560122a5e926ab708bb13f0fd40714638
GIT binary patch
literal 3704
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literal 0
HcmV?d00001

diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
new file mode 100644
index 00000000..7c88df9f
--- /dev/null
+++ b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.cc
@@ -0,0 +1,24 @@ 
+struct foo {
+  long z;
+};
+
+struct ops1 {
+  int ** x;
+};
+
+struct ops2 {
+  foo y[10];
+};
+
+struct ops3 {
+  void (*spong)(int && wibble);
+};
+
+void register_ops1(ops1*) {
+}
+
+void register_ops2(ops2*) {
+}
+
+void register_ops3(ops3*) {
+}
diff --git a/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o b/tests/data/test-abidiff-exit/test-leaf-peeling-v1.o
new file mode 100644
index 0000000000000000000000000000000000000000..e71ade4431f80a78ee73292d60808a2ee5404640
GIT binary patch
literal 3752
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literal 0
HcmV?d00001

diff --git a/tests/test-abidiff-exit.cc b/tests/test-abidiff-exit.cc
index 6ecbfd24..ebac7a00 100644
--- a/tests/test-abidiff-exit.cc
+++ b/tests/test-abidiff-exit.cc
@@ -158,6 +158,15 @@  InOutSpec in_out_specs[] =
     "data/test-abidiff-exit/test-leaf3-report.txt",
     "output/test-abidiff-exit/test-leaf3-report.txt"
   },
+  {
+    "data/test-abidiff-exit/test-leaf-peeling-v0.o",
+    "data/test-abidiff-exit/test-leaf-peeling-v1.o",
+    "",
+    "--leaf-changes-only",
+    abigail::tools_utils::ABIDIFF_ABI_CHANGE,
+    "data/test-abidiff-exit/test-leaf-peeling-report.txt",
+    "output/test-abidiff-exit/test-leaf-peeling-report.txt"
+  },
   {0, 0, 0 ,0,  abigail::tools_utils::ABIDIFF_OK, 0, 0}
 };