diff mbox

Canonicalize conversion operators

Message ID 1508278336-8655-1-git-send-email-keiths@redhat.com
State New
Headers show

Commit Message

Keith Seitz Oct. 17, 2017, 10:12 p.m. UTC
Consider a conversion operator such as:

operator foo const* const* ();

There are two small parser problems, highlighted by this test:

(gdb) p operator foo const* const*
There is no field named operatorfoo const* const *

GDB is looking up the symbol "operatorfoo const* const*" -- it is missing a
space between the keyword "operator" and the type name "foo const* const*".
Pedro also discovered this problem and has a patch for it pending on his
cxx-breakpoint-improvements branch.

However, something not address by Pedro's patch is that this input of the
user-defined type needs to be canonicalized so that different "spellings" of
the type are recognized:

(gdb) p operator const foo* const *
There is no field named operator const foo* const *

gdb/ChangeLog:

	* c-exp.y (oper): Canonicalize conversion operators of user-defined
	types.
	Add whitespace to front of type name.

gdb/testsuite/ChangeLog:

	* gdb.cp/cpexprs.cc (base) <operator fluff const* const*>: New
	method.
	(main): Call it.
	* gdb.cp/cpexprs.exp: Add new conversion operator to test matrix.
	Add additional user-defined conversion operator tests.
---
 gdb/c-exp.y                      | 10 ++++++++--
 gdb/testsuite/gdb.cp/cpexprs.cc  |  2 ++
 gdb/testsuite/gdb.cp/cpexprs.exp | 16 ++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

Comments

Pedro Alves Oct. 18, 2017, 11:19 a.m. UTC | #1
On 10/17/2017 11:12 PM, Keith Seitz wrote:
> Consider a conversion operator such as:
> 
> operator foo const* const* ();
> 
> There are two small parser problems, highlighted by this test:
> 
> (gdb) p operator foo const* const*
> There is no field named operatorfoo const* const *
> 
> GDB is looking up the symbol "operatorfoo const* const*" -- it is missing a
> space between the keyword "operator" and the type name "foo const* const*".
> Pedro also discovered this problem and has a patch for it pending on his
> cxx-breakpoint-improvements branch.
> 
> However, something not address by Pedro's patch is that this input of the
> user-defined type needs to be canonicalized so that different "spellings" of
> the type are recognized:
> 
> (gdb) p operator const foo* const *
> There is no field named operator const foo* const *
> 

Indeed.


> @@ -1630,7 +1630,13 @@ oper:	OPERATOR NEW
>  
>  			  c_print_type ($2, NULL, &buf, -1, 0,
>  					&type_print_raw_options);
> -			  $$ = operator_stoken (buf.c_str ());
> +
> +			  /* This also needs canonicalization.  */
> +			  std::string canon
> +			    = " " + cp_canonicalize_string (buf.c_str ());
> +			  if (canon.length () == 1)
> +			    canon = " " + buf.string ();
> +			  $$ = operator_stoken (canon.c_str ());

The length() == 1 check gave me pause.  It's checking that
cp_canonicalize_string returned empty of course, but it
wasn't super clear on a quick skim.

I think you could write it like this, making that part clearer,
and also saving a few string dups and copies:

			  /* This also needs canonicalization.  */
			  std::string canon
			    = cp_canonicalize_string (buf.c_str ());
			  if (canon.empty ())
			    canon = std::move (buf.string ());
			  $$ = operator_stoken ((" " + canon).c_str ());


>  
> +# Make sure conversion operator names are canonicalized and properly
> +# "spelled."

Period should outside the quote, I think.

Otherwise OK.

Thanks,
Pedro Alves
Keith Seitz Oct. 18, 2017, 6:28 p.m. UTC | #2
On 10/18/2017 04:19 AM, Pedro Alves wrote:
>> @@ -1630,7 +1630,13 @@ oper:	OPERATOR NEW
>>  
>>  			  c_print_type ($2, NULL, &buf, -1, 0,
>>  					&type_print_raw_options);
>> -			  $$ = operator_stoken (buf.c_str ());
>> +
>> +			  /* This also needs canonicalization.  */
>> +			  std::string canon
>> +			    = " " + cp_canonicalize_string (buf.c_str ());
>> +			  if (canon.length () == 1)
>> +			    canon = " " + buf.string ();
>> +			  $$ = operator_stoken (canon.c_str ());
> 
> The length() == 1 check gave me pause.  It's checking that
> cp_canonicalize_string returned empty of course, but it
> wasn't super clear on a quick skim.
> 
> I think you could write it like this, making that part clearer,
> and also saving a few string dups and copies:
> 
> 			  /* This also needs canonicalization.  */
> 			  std::string canon
> 			    = cp_canonicalize_string (buf.c_str ());
> 			  if (canon.empty ())
> 			    canon = std::move (buf.string ());
> 			  $$ = operator_stoken ((" " + canon).c_str ());
> 
> 

Yes, indeed. ISTR having something similar to that at one point, but I don't know why I changed it. [Maybe that was during the C++03/C++11 shake out?]

In any case, committed with that change.

Thank you for the review.

Keith
diff mbox

Patch

diff --git a/gdb/c-exp.y b/gdb/c-exp.y
index 7c050b4..dbb88fb 100644
--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -1554,7 +1554,7 @@  oper:	OPERATOR NEW
 	|	OPERATOR '>'
 			{ $$ = operator_stoken (">"); }
 	|	OPERATOR ASSIGN_MODIFY
-			{ const char *op = "unknown";
+			{ const char *op = " unknown";
 			  switch ($2)
 			    {
 			    case BINOP_RSH:
@@ -1630,7 +1630,13 @@  oper:	OPERATOR NEW
 
 			  c_print_type ($2, NULL, &buf, -1, 0,
 					&type_print_raw_options);
-			  $$ = operator_stoken (buf.c_str ());
+
+			  /* This also needs canonicalization.  */
+			  std::string canon
+			    = " " + cp_canonicalize_string (buf.c_str ());
+			  if (canon.length () == 1)
+			    canon = " " + buf.string ();
+			  $$ = operator_stoken (canon.c_str ());
 			}
 	;
 
diff --git a/gdb/testsuite/gdb.cp/cpexprs.cc b/gdb/testsuite/gdb.cp/cpexprs.cc
index f70fd51..a2364eb 100644
--- a/gdb/testsuite/gdb.cp/cpexprs.cc
+++ b/gdb/testsuite/gdb.cp/cpexprs.cc
@@ -270,6 +270,7 @@  public:
   operator int () const { return 21; } // base::operator int
   operator fluff* () const { return new fluff (); } // base::operator fluff*
   operator fluff** () const { return &g_fluff; } // base::operator fluff**
+  operator fluff const* const* () const { return &g_fluff; } // base::operator fluff const* const*
 };
 
 class base1 : public virtual base
@@ -448,6 +449,7 @@  test_function (int argc, char* argv[]) // test_function
   char* str = a;
   fluff* flp = a;
   fluff** flpp = a;
+  fluff const* const* flcpcp = a;
 
   CV_f(CV::i);
 
diff --git a/gdb/testsuite/gdb.cp/cpexprs.exp b/gdb/testsuite/gdb.cp/cpexprs.exp
index d0f41b2..463e89c 100644
--- a/gdb/testsuite/gdb.cp/cpexprs.exp
+++ b/gdb/testsuite/gdb.cp/cpexprs.exp
@@ -407,6 +407,10 @@  add {base::operator int} \
     {int (const base * const)} \
     - \
     -
+add {base::operator fluff const* const*} \
+    {const fluff * const *(const base * const)} \
+    - \
+    -
 
 # Templates
 add {tclass<char>::do_something} \
@@ -746,5 +750,17 @@  gdb_test "p CV_f(CV::i)" " = 43"
 gdb_test "p CV_f('cpexprs.cc'::CV::t)" \
     { = {int \(int\)} 0x[0-9a-f]+ <CV_f\(int\)>}
 
+# Make sure conversion operator names are canonicalized and properly
+# "spelled."
+gdb_test "p base::operator const fluff * const *" \
+    [get "base::operator fluff const* const*" print] \
+    "canonicalized conversion operator name 1"
+gdb_test "p base::operator const fluff* const*" \
+    [get "base::operator fluff const* const*" print] \
+    "canonicalized conversion operator name 2"
+gdb_test "p base::operator derived*" \
+    "There is no field named operator derived\\*" \
+    "undefined conversion operator"
+
 gdb_exit
 return 0