[PATCH v4 10/11] compile: compile printf: gdbserver support

[Jan Kratochvil <jan.kratochvil@redhat.com>]

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.
---
 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 684d328..14805bc 100644
--- a/gdb/compile/compile-c-support.c
+++ b/gdb/compile/compile-c-support.c
@@ -209,13 +209,21 @@ 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:
@@ -234,10 +242,15 @@ 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:
@@ -433,7 +446,7 @@ 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 852f875..0be47ca 100644
--- a/gdb/compile/compile-object-load.c
+++ b/gdb/compile/compile-object-load.c
@@ -652,7 +652,8 @@ 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 87145db..067f549 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.  */
 
@@ -101,6 +102,20 @@ 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.
@@ -119,6 +134,7 @@ 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;
@@ -138,7 +154,7 @@ 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);
@@ -165,8 +181,42 @@ 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 8277fb5..ba819a4 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -17243,7 +17243,9 @@ Compile and execute @code{printf} function call with the compiler
 language found as the current language in @value{GDBN}
 (@pxref{Languages}).  This command is not asynchronous signal safe for
 the inferior, calling it in an inappropriate moment may crash the
-inferior or cause other undefined inferior behavior.
+inferior or cause other undefined inferior behavior.  The value is
+printed by @value{GDBN} and not the inferior, inferior does not execute
+specifically the function @code{printf}.
 
 @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\\."