Patchwork [v2,9/9] compile: compile printf: gdbserver support

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Submitter Jan Kratochvil
Date April 6, 2015, 5:27 p.m.
Message ID <20150406172735.31404.5975.stgit@host1.jankratochvil.net>
Download mbox | patch
Permalink /patch/6025/
State New
Headers show

Comments

Jan Kratochvil - April 6, 2015, 5:27 p.m.
Hi,

former patch injects plain:
	printf (...);
This patch injects gdbserver-compatible:
	f = open_memstream (&s, ...);
	fprintf (f, ...);
	fclose (f);
	return s;

Jan


gdb/
2015-04-06  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* compile/compile-c-support.c (add_code_header, add_code_footer)
	(c_compute_program): Use open_memstream, fprintf and fclose.
	* compile/compile-object-load.c (compile_object_load): Set expected
	char * for COMPILE_I_PRINTF_SCOPE.
	* compile/compile-object-run.c: Include gdbcore.h.
	(free_inferior_memory): New function.
	(compile_object_run): Support COMPILE_I_PRINTF_SCOPE's return value.

gdb/doc/ChangeLog
2015-04-06  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.texinfo (Compiling and Injecting Code): Mention for compile
	printf open_memstream and fprintf.

gdb/testsuite/ChangeLog
2015-04-06  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.compile/compile-print.exp (compile printf "0x%x\n", varint)
	(compile printf "0x%x\n"): Remove !is_remote conditional.
Eli Zaretskii - April 6, 2015, 5:43 p.m.
> From: Jan Kratochvil <jan.kratochvil@redhat.com>
> Cc: Phil Muldoon <pmuldoon@redhat.com>
> Date: Mon, 06 Apr 2015 19:27:35 +0200
> 
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -17246,7 +17246,9 @@ multiple-line editor.
>  @item compile printf @var{template}, @var{expressions}@dots{}
>  Compile and execute @code{printf} function call with the compiler
>  language found as the current language in @value{GDBN}
> -(@pxref{Languages}).
> +(@pxref{Languages}).  Inferior executes @code{open_memstream} and
> +@code{fprintf} instead so that the produced string is printed by
> +@value{GDBN} and not the inferior.

Is this really important to say in the manual?

And if it is, why not simply say that the value is printed by GDB
itself, not by calling functions in the inferior?
Jan Kratochvil - April 11, 2015, 7:23 p.m.
On Mon, 06 Apr 2015 19:43:22 +0200, Eli Zaretskii wrote:
> > --- a/gdb/doc/gdb.texinfo
> > +++ b/gdb/doc/gdb.texinfo
> > @@ -17246,7 +17246,9 @@ multiple-line editor.
> >  @item compile printf @var{template}, @var{expressions}@dots{}
> >  Compile and execute @code{printf} function call with the compiler
> >  language found as the current language in @value{GDBN}
> > -(@pxref{Languages}).
> > +(@pxref{Languages}).  Inferior executes @code{open_memstream} and
> > +@code{fprintf} instead so that the produced string is printed by
> > +@value{GDBN} and not the inferior.
> 
> Is this really important to say in the manual?
> 
> And if it is, why not simply say that the value is printed by GDB
> itself, not by calling functions in the inferior?

Used:
	The value is printed by @value{GDBN} and not the inferior, inferior
	does not execute specifically the function @code{printf}.


Jan
Eli Zaretskii - April 11, 2015, 7:31 p.m.
> Date: Sat, 11 Apr 2015 21:23:24 +0200
> From: Jan Kratochvil <jan.kratochvil@redhat.com>
> Cc: gdb-patches@sourceware.org, pmuldoon@redhat.com
> 
> On Mon, 06 Apr 2015 19:43:22 +0200, Eli Zaretskii wrote:
> > > --- a/gdb/doc/gdb.texinfo
> > > +++ b/gdb/doc/gdb.texinfo
> > > @@ -17246,7 +17246,9 @@ multiple-line editor.
> > >  @item compile printf @var{template}, @var{expressions}@dots{}
> > >  Compile and execute @code{printf} function call with the compiler
> > >  language found as the current language in @value{GDBN}
> > > -(@pxref{Languages}).
> > > +(@pxref{Languages}).  Inferior executes @code{open_memstream} and
> > > +@code{fprintf} instead so that the produced string is printed by
> > > +@value{GDBN} and not the inferior.
> > 
> > Is this really important to say in the manual?
> > 
> > And if it is, why not simply say that the value is printed by GDB
> > itself, not by calling functions in the inferior?
> 
> Used:
> 	The value is printed by @value{GDBN} and not the inferior, inferior
> 	does not execute specifically the function @code{printf}.

Fine with me, thanks.

Patch

diff --git a/gdb/compile/compile-c-support.c b/gdb/compile/compile-c-support.c
index 92c41b6..3b9bb52 100644
--- a/gdb/compile/compile-c-support.c
+++ b/gdb/compile/compile-c-support.c
@@ -208,13 +208,21 @@  add_code_header (enum compile_i_scope_types type, struct ui_file *buf)
       break;
     case COMPILE_I_PRINTF_SCOPE:
       fputs_unfiltered ("#include <stdio.h>\n"
-			"void "
+			"char *"
 			GCC_FE_WRAPPER_FUNCTION
 			" (struct "
 			COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
 			" *"
 			COMPILE_I_SIMPLE_REGISTER_ARG_NAME
-			") {\n",
+			") {\n"
+			"\tchar *__gdb_retval;\n"
+			"\tsize_t __gdb_retval_size;\n"
+			"\tFILE *__gdb_outf;\n"
+			"\n"
+			"\t__gdb_outf = open_memstream (&__gdb_retval, "
+						       "&__gdb_retval_size);\n"
+			"\tif (__gdb_outf == NULL)\n"
+			"\t\treturn NULL;\n",
 			buf);
       break;
     case COMPILE_I_RAW_SCOPE:
@@ -233,10 +241,15 @@  add_code_footer (enum compile_i_scope_types type, struct ui_file *buf)
 {
   switch (type)
     {
+    case COMPILE_I_PRINTF_SCOPE:
+      fputs_unfiltered ("\tif (fclose (__gdb_outf) != 0)\n"
+			"\t\treturn NULL;\n"
+			"\treturn __gdb_retval;\n",
+			buf);
+      // FALLTHRU
     case COMPILE_I_SIMPLE_SCOPE:
     case COMPILE_I_PRINT_ADDRESS_SCOPE:
     case COMPILE_I_PRINT_VALUE_SCOPE:
-    case COMPILE_I_PRINTF_SCOPE:
       fputs_unfiltered ("}\n", buf);
       break;
     case COMPILE_I_RAW_SCOPE:
@@ -432,7 +445,7 @@  c_compute_program (struct compile_instance *inst,
       break;
     case COMPILE_I_PRINTF_SCOPE:
       fprintf_unfiltered (buf,
-"printf (%s);\n"
+"fprintf (__gdb_outf, %s);\n"
 			  , input);
       break;
     default:
diff --git a/gdb/compile/compile-object-load.c b/gdb/compile/compile-object-load.c
index bc74590..d7c13c9 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -651,7 +651,8 @@  compile_object_load (const char *object_file, const char *source_file,
       break;
     case COMPILE_I_PRINTF_SCOPE:
       expect_parameters = 1;
-      expect_return_type = builtin_type (target_gdbarch ())->builtin_void;
+      expect_return_type = lookup_pointer_type
+			       (builtin_type (target_gdbarch ())->builtin_char);
       break;
     default:
       internal_error (__FILE__, __LINE__, _("invalid scope %d"), scope);
diff --git a/gdb/compile/compile-object-run.c b/gdb/compile/compile-object-run.c
index 216cbf9..ed56410 100644
--- a/gdb/compile/compile-object-run.c
+++ b/gdb/compile/compile-object-run.c
@@ -27,6 +27,7 @@ 
 #include "block.h"
 #include "valprint.h"
 #include "compile.h"
+#include "gdbcore.h"

 /* Helper for do_module_cleanup.  */

@@ -99,6 +100,18 @@  do_module_cleanup (void *arg)
   xfree (data);
 }

+static void
+free_inferior_memory (CORE_ADDR addr)
+{
+  struct objfile *objf;
+  struct value *func_val = find_function_in_inferior ("free", &objf);
+  struct gdbarch *gdbarch = get_objfile_arch (objf);
+  struct type *addr_type = builtin_type (gdbarch)->builtin_data_ptr;
+  struct value *addr_val = value_from_pointer (addr_type, addr);
+
+  call_function_by_hand (func_val, 1, &addr_val);
+}
+
 /* Perform inferior call of MODULE.  This function may throw an error.
    This function may leave files referenced by MODULE on disk until
    the inferior call dummy frame is discarded.  This function may throw errors.
@@ -117,6 +130,7 @@  compile_object_run (struct compile_module *module)
   struct symbol *func_sym = module->func_sym;
   CORE_ADDR regs_addr = module->regs_addr;
   struct objfile *objfile = module->objfile;
+  enum compile_i_scope_types scope = module->scope;

   data = xmalloc (sizeof (*data) + strlen (objfile_name_s));
   data->executedp = &executed;
@@ -136,7 +150,7 @@  compile_object_run (struct compile_module *module)
       struct type *func_type = SYMBOL_TYPE (func_sym);
       htab_t copied_types;
       int current_arg = 0;
-      struct value **vargs;
+      struct value **vargs, *func_return_value;

       /* OBJFILE may disappear while FUNC_TYPE still will be in use.  */
       copied_types = create_copied_types_hash (objfile);
@@ -163,8 +177,42 @@  compile_object_run (struct compile_module *module)
 	  ++current_arg;
 	}
       gdb_assert (current_arg == TYPE_NFIELDS (func_type));
-      call_function_by_hand_dummy (func_val, TYPE_NFIELDS (func_type), vargs,
-				   do_module_cleanup, data);
+      func_return_value = call_function_by_hand_dummy (func_val,
+						       TYPE_NFIELDS (func_type),
+						       vargs,
+						       do_module_cleanup, data);
+
+      // DATA can be already freed now.
+      data = NULL;
+
+      if (scope == COMPILE_I_PRINTF_SCOPE)
+	{
+	  struct value_print_options opts;
+	  gdb_byte *buffer = NULL;
+	  struct cleanup *old_chain;
+	  int errcode, bytes_read;
+	  struct type *retval_type = value_type (func_return_value);
+	  struct type *char_type;
+
+	  gdb_assert (TYPE_CODE (retval_type) == TYPE_CODE_PTR);
+	  char_type = TYPE_TARGET_TYPE (retval_type);
+	  gdb_assert (TYPE_CODE (char_type) == TYPE_CODE_INT);
+
+	  get_user_print_options (&opts);
+	  errcode = read_string (value_as_address (func_return_value), -1,
+				 TYPE_LENGTH (char_type), opts.print_max,
+				 gdbarch_byte_order (target_gdbarch ()),
+				 &buffer, &bytes_read);
+	  old_chain = make_cleanup (xfree, buffer);
+	  if (errcode != 0)
+	    memory_error (errcode, value_as_address (func_return_value));
+
+	  while (bytes_read-- > 0)
+	    putchar_filtered (*buffer++);
+	  do_cleanups (old_chain);
+
+	  free_inferior_memory (value_as_address (func_return_value));
+	}
     }
   CATCH (ex, RETURN_MASK_ERROR)
     {
diff --git a/gdb/testsuite/gdb.compile/compile-print.exp b/gdb/testsuite/gdb.compile/compile-print.exp
index 14fd489..43b9f24 100644
--- a/gdb/testsuite/gdb.compile/compile-print.exp
+++ b/gdb/testsuite/gdb.compile/compile-print.exp
@@ -57,7 +57,5 @@  gdb_test {print $} " = 256"

 gdb_test "compile print varobject" { = {field = 1}}

-if ![is_remote target] {
-    gdb_test {compile printf "0x%x\n", varint} "\r\n0xa"
-    gdb_test {compile printf "0x%x\n"} "\r\nCompilation failed\\."
-}
+gdb_test {compile printf "0x%x\n", varint} "\r\n0xa"
+gdb_test {compile printf "0x%x\n"} "\r\nCompilation failed\\."
---
 gdb/compile/compile-c-support.c             |   21 ++++++++--
 gdb/compile/compile-object-load.c           |    3 +
 gdb/compile/compile-object-run.c            |   56 ++++++++++++++++++++++++++-
 gdb/doc/gdb.texinfo                         |    4 +-
 gdb/testsuite/gdb.compile/compile-print.exp |    6 +--
 5 files changed, 77 insertions(+), 13 deletions(-)

diff --git a/gdb/compile/compile-c-support.c b/gdb/compile/compile-c-support.c
index 92c41b6..3b9bb52 100644
--- a/gdb/compile/compile-c-support.c
+++ b/gdb/compile/compile-c-support.c
@@ -208,13 +208,21 @@  add_code_header (enum compile_i_scope_types type, struct ui_file *buf)
       break;
     case COMPILE_I_PRINTF_SCOPE:
       fputs_unfiltered ("#include <stdio.h>\n"
-			"void "
+			"char *"
 			GCC_FE_WRAPPER_FUNCTION
 			" (struct "
 			COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
 			" *"
 			COMPILE_I_SIMPLE_REGISTER_ARG_NAME
-			") {\n",
+			") {\n"
+			"\tchar *__gdb_retval;\n"
+			"\tsize_t __gdb_retval_size;\n"
+			"\tFILE *__gdb_outf;\n"
+			"\n"
+			"\t__gdb_outf = open_memstream (&__gdb_retval, "
+						       "&__gdb_retval_size);\n"
+			"\tif (__gdb_outf == NULL)\n"
+			"\t\treturn NULL;\n",
 			buf);
       break;
     case COMPILE_I_RAW_SCOPE:
@@ -233,10 +241,15 @@  add_code_footer (enum compile_i_scope_types type, struct ui_file *buf)
 {
   switch (type)
     {
+    case COMPILE_I_PRINTF_SCOPE:
+      fputs_unfiltered ("\tif (fclose (__gdb_outf) != 0)\n"
+			"\t\treturn NULL;\n"
+			"\treturn __gdb_retval;\n",
+			buf);
+      // FALLTHRU
     case COMPILE_I_SIMPLE_SCOPE:
     case COMPILE_I_PRINT_ADDRESS_SCOPE:
     case COMPILE_I_PRINT_VALUE_SCOPE:
-    case COMPILE_I_PRINTF_SCOPE:
       fputs_unfiltered ("}\n", buf);
       break;
     case COMPILE_I_RAW_SCOPE:
@@ -432,7 +445,7 @@  c_compute_program (struct compile_instance *inst,
       break;
     case COMPILE_I_PRINTF_SCOPE:
       fprintf_unfiltered (buf,
-"printf (%s);\n"
+"fprintf (__gdb_outf, %s);\n"
 			  , input);
       break;
     default:
diff --git a/gdb/compile/compile-object-load.c b/gdb/compile/compile-object-load.c
index bc74590..d7c13c9 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -651,7 +651,8 @@  compile_object_load (const char *object_file, const char *source_file,
       break;
     case COMPILE_I_PRINTF_SCOPE:
       expect_parameters = 1;
-      expect_return_type = builtin_type (target_gdbarch ())->builtin_void;
+      expect_return_type = lookup_pointer_type
+			       (builtin_type (target_gdbarch ())->builtin_char);
       break;
     default:
       internal_error (__FILE__, __LINE__, _("invalid scope %d"), scope);
diff --git a/gdb/compile/compile-object-run.c b/gdb/compile/compile-object-run.c
index 216cbf9..3606d42 100644
--- a/gdb/compile/compile-object-run.c
+++ b/gdb/compile/compile-object-run.c
@@ -27,6 +27,7 @@ 
 #include "block.h"
 #include "valprint.h"
 #include "compile.h"
+#include "gdbcore.h"
 
 /* Helper for do_module_cleanup.  */
 
@@ -99,6 +100,20 @@  do_module_cleanup (void *arg)
   xfree (data);
 }
 
+/* Call inferior function "free" for ADDR.  */
+
+static void
+free_inferior_memory (CORE_ADDR addr)
+{
+  struct objfile *objf;
+  struct value *func_val = find_function_in_inferior ("free", &objf);
+  struct gdbarch *gdbarch = get_objfile_arch (objf);
+  struct type *addr_type = builtin_type (gdbarch)->builtin_data_ptr;
+  struct value *addr_val = value_from_pointer (addr_type, addr);
+
+  call_function_by_hand (func_val, 1, &addr_val);
+}
+
 /* Perform inferior call of MODULE.  This function may throw an error.
    This function may leave files referenced by MODULE on disk until
    the inferior call dummy frame is discarded.  This function may throw errors.
@@ -117,6 +132,7 @@  compile_object_run (struct compile_module *module)
   struct symbol *func_sym = module->func_sym;
   CORE_ADDR regs_addr = module->regs_addr;
   struct objfile *objfile = module->objfile;
+  enum compile_i_scope_types scope = module->scope;
 
   data = xmalloc (sizeof (*data) + strlen (objfile_name_s));
   data->executedp = &executed;
@@ -136,7 +152,7 @@  compile_object_run (struct compile_module *module)
       struct type *func_type = SYMBOL_TYPE (func_sym);
       htab_t copied_types;
       int current_arg = 0;
-      struct value **vargs;
+      struct value **vargs, *func_return_value;
 
       /* OBJFILE may disappear while FUNC_TYPE still will be in use.  */
       copied_types = create_copied_types_hash (objfile);
@@ -163,8 +179,42 @@  compile_object_run (struct compile_module *module)
 	  ++current_arg;
 	}
       gdb_assert (current_arg == TYPE_NFIELDS (func_type));
-      call_function_by_hand_dummy (func_val, TYPE_NFIELDS (func_type), vargs,
-				   do_module_cleanup, data);
+      func_return_value = call_function_by_hand_dummy (func_val,
+						       TYPE_NFIELDS (func_type),
+						       vargs,
+						       do_module_cleanup, data);
+
+      // DATA can be already freed now.
+      data = NULL;
+
+      if (scope == COMPILE_I_PRINTF_SCOPE)
+	{
+	  struct value_print_options opts;
+	  gdb_byte *buffer = NULL;
+	  struct cleanup *old_chain;
+	  int errcode, bytes_read;
+	  struct type *retval_type = value_type (func_return_value);
+	  struct type *char_type;
+
+	  gdb_assert (TYPE_CODE (retval_type) == TYPE_CODE_PTR);
+	  char_type = TYPE_TARGET_TYPE (retval_type);
+	  gdb_assert (TYPE_CODE (char_type) == TYPE_CODE_INT);
+
+	  get_user_print_options (&opts);
+	  errcode = read_string (value_as_address (func_return_value), -1,
+				 TYPE_LENGTH (char_type), opts.print_max,
+				 gdbarch_byte_order (target_gdbarch ()),
+				 &buffer, &bytes_read);
+	  old_chain = make_cleanup (xfree, buffer);
+	  if (errcode != 0)
+	    memory_error (errcode, value_as_address (func_return_value));
+
+	  while (bytes_read-- > 0)
+	    putchar_filtered (*buffer++);
+	  do_cleanups (old_chain);
+
+	  free_inferior_memory (value_as_address (func_return_value));
+	}
     }
   CATCH (ex, RETURN_MASK_ERROR)
     {
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 46a7bf4..4e5ea51 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -17246,7 +17246,9 @@  multiple-line editor.
 @item compile printf @var{template}, @var{expressions}@dots{}
 Compile and execute @code{printf} function call with the compiler
 language found as the current language in @value{GDBN}
-(@pxref{Languages}).
+(@pxref{Languages}).  Inferior executes @code{open_memstream} and
+@code{fprintf} instead so that the produced string is printed by
+@value{GDBN} and not the inferior.
 
 @item compile printf
 @cindex reprint the last value
diff --git a/gdb/testsuite/gdb.compile/compile-print.exp b/gdb/testsuite/gdb.compile/compile-print.exp
index 14fd489..43b9f24 100644
--- a/gdb/testsuite/gdb.compile/compile-print.exp
+++ b/gdb/testsuite/gdb.compile/compile-print.exp
@@ -57,7 +57,5 @@  gdb_test {print $} " = 256"
 
 gdb_test "compile print varobject" { = {field = 1}}
 
-if ![is_remote target] {
-    gdb_test {compile printf "0x%x\n", varint} "\r\n0xa"
-    gdb_test {compile printf "0x%x\n"} "\r\nCompilation failed\\."
-}
+gdb_test {compile printf "0x%x\n", varint} "\r\n0xa"
+gdb_test {compile printf "0x%x\n"} "\r\nCompilation failed\\."