[deliverable/binutils-gdb.git] / gdb / compile / compile-c-support.c

/* C language support for compilation.

   Copyright (C) 2014-2018 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "compile-internal.h"
#include "compile.h"
#include "gdb-dlfcn.h"
#include "c-lang.h"
#include "macrotab.h"
#include "macroscope.h"
#include "regcache.h"
#include "common/function-view.h"
#include "common/preprocessor.h"

/* See compile-internal.h.  */

const char *
c_get_mode_for_size (int size)
{
  const char *mode = NULL;

  switch (size)
    {
    case 1:
      mode = "QI";
      break;
    case 2:
      mode = "HI";
      break;
    case 4:
      mode = "SI";
      break;
    case 8:
      mode = "DI";
      break;
    default:
      internal_error (__FILE__, __LINE__, _("Invalid GCC mode size %d."), size);
    }

  return mode;
}

/* See compile-internal.h.  */

std::string
c_get_range_decl_name (const struct dynamic_prop *prop)
{
  return string_printf ("__gdb_prop_%s", host_address_to_string (prop));
}

\f

/* Helper function for c_get_compile_context.  Open the GCC front-end
   shared library and return the symbol specified by the current
   GCC_C_FE_CONTEXT.  */

static gcc_c_fe_context_function *
load_libcc (void)
{
  gcc_c_fe_context_function *func;

   /* gdb_dlopen will call error () on an error, so no need to check
      value.  */
  gdb_dlhandle_up handle = gdb_dlopen (STRINGIFY (GCC_C_FE_LIBCC));
  func = (gcc_c_fe_context_function *) gdb_dlsym (handle,
						  STRINGIFY (GCC_C_FE_CONTEXT));

  if (func == NULL)
    error (_("could not find symbol %s in library %s"),
	   STRINGIFY (GCC_C_FE_CONTEXT),
	   STRINGIFY (GCC_C_FE_LIBCC));

  /* Leave the library open.  */
  handle.release ();
  return func;
}

/* Return the compile instance associated with the current context.
   This function calls the symbol returned from the load_libcc
   function.  This will provide the gcc_c_context.  */

struct compile_instance *
c_get_compile_context (void)
{
  static gcc_c_fe_context_function *func;

  struct gcc_c_context *context;

  if (func == NULL)
    {
      func = load_libcc ();
      gdb_assert (func != NULL);
    }

  context = (*func) (GCC_FE_VERSION_0, GCC_C_FE_VERSION_0);
  if (context == NULL)
    error (_("The loaded version of GCC does not support the required version "
	     "of the API."));

  return new_compile_instance (context);
}

\f

/* Write one macro definition.  */

static void
print_one_macro (const char *name, const struct macro_definition *macro,
		 struct macro_source_file *source, int line,
		 ui_file *file)
{
  /* Don't print command-line defines.  They will be supplied another
     way.  */
  if (line == 0)
    return;

  /* None of -Wno-builtin-macro-redefined, #undef first
     or plain #define of the same value would avoid a warning.  */
  fprintf_filtered (file, "#ifndef %s\n# define %s", name, name);

  if (macro->kind == macro_function_like)
    {
      int i;

      fputs_filtered ("(", file);
      for (i = 0; i < macro->argc; i++)
	{
	  fputs_filtered (macro->argv[i], file);
	  if (i + 1 < macro->argc)
	    fputs_filtered (", ", file);
	}
      fputs_filtered (")", file);
    }

  fprintf_filtered (file, " %s\n#endif\n", macro->replacement);
}

/* Write macro definitions at PC to FILE.  */

static void
write_macro_definitions (const struct block *block, CORE_ADDR pc,
			 struct ui_file *file)
{
  gdb::unique_xmalloc_ptr<struct macro_scope> scope;

  if (block != NULL)
    scope = sal_macro_scope (find_pc_line (pc, 0));
  else
    scope = default_macro_scope ();
  if (scope == NULL)
    scope = user_macro_scope ();

  if (scope != NULL && scope->file != NULL && scope->file->table != NULL)
    {
      macro_for_each_in_scope (scope->file, scope->line,
			       [&] (const char *name,
				    const macro_definition *macro,
				    macro_source_file *source,
				    int line)
	{
	  print_one_macro (name, macro, source, line, file);
	});
    }
}

/* Helper function to construct a header scope for a block of code.
   Takes a scope argument which selects the correct header to
   insert into BUF.  */

static void
add_code_header (enum compile_i_scope_types type, struct ui_file *buf)
{
  switch (type)
    {
    case COMPILE_I_SIMPLE_SCOPE:
      fputs_unfiltered ("void "
			GCC_FE_WRAPPER_FUNCTION
			" (struct "
			COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
			" *"
			COMPILE_I_SIMPLE_REGISTER_ARG_NAME
			") {\n",
			buf);
      break;
    case COMPILE_I_PRINT_ADDRESS_SCOPE:
    case COMPILE_I_PRINT_VALUE_SCOPE:
      /* <string.h> is needed for a memcpy call below.  */
      fputs_unfiltered ("#include <string.h>\n"
			"void "
			GCC_FE_WRAPPER_FUNCTION
			" (struct "
			COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
			" *"
			COMPILE_I_SIMPLE_REGISTER_ARG_NAME
			", "
			COMPILE_I_PRINT_OUT_ARG_TYPE
			" "
			COMPILE_I_PRINT_OUT_ARG
			") {\n",
			buf);
      break;

    case COMPILE_I_RAW_SCOPE:
      break;
    default:
      gdb_assert_not_reached (_("Unknown compiler scope reached."));
    }
}

/* Helper function to construct a footer scope for a block of code.
   Takes a scope argument which selects the correct footer to
   insert into BUF.  */

static void
add_code_footer (enum compile_i_scope_types type, struct ui_file *buf)
{
  switch (type)
    {
    case COMPILE_I_SIMPLE_SCOPE:
    case COMPILE_I_PRINT_ADDRESS_SCOPE:
    case COMPILE_I_PRINT_VALUE_SCOPE:
      fputs_unfiltered ("}\n", buf);
      break;
    case COMPILE_I_RAW_SCOPE:
      break;
    default:
      gdb_assert_not_reached (_("Unknown compiler scope reached."));
    }
}

/* Generate a structure holding all the registers used by the function
   we're generating.  */

static void
generate_register_struct (struct ui_file *stream, struct gdbarch *gdbarch,
			  const unsigned char *registers_used)
{
  int i;
  int seen = 0;

  fputs_unfiltered ("struct " COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG " {\n",
		    stream);

  if (registers_used != NULL)
    for (i = 0; i < gdbarch_num_regs (gdbarch); ++i)
      {
	if (registers_used[i])
	  {
	    struct type *regtype = check_typedef (register_type (gdbarch, i));
	    std::string regname = compile_register_name_mangled (gdbarch, i);

	    seen = 1;

	    /* You might think we could use type_print here.  However,
	       target descriptions often use types with names like
	       "int64_t", which may not be defined in the inferior
	       (and in any case would not be looked up due to the
	       #pragma business).  So, we take a much simpler
	       approach: for pointer- or integer-typed registers, emit
	       the field in the most direct way; and for other
	       register types (typically flags or vectors), emit a
	       maximally-aligned array of the correct size.  */

	    fputs_unfiltered ("  ", stream);
	    switch (TYPE_CODE (regtype))
	      {
	      case TYPE_CODE_PTR:
		fprintf_filtered (stream, "__gdb_uintptr %s",
				  regname.c_str ());
		break;

	      case TYPE_CODE_INT:
		{
		  const char *mode
		    = c_get_mode_for_size (TYPE_LENGTH (regtype));

		  if (mode != NULL)
		    {
		      if (TYPE_UNSIGNED (regtype))
			fputs_unfiltered ("unsigned ", stream);
		      fprintf_unfiltered (stream,
					  "int %s"
					  " __attribute__ ((__mode__(__%s__)))",
					  regname.c_str (),
					  mode);
		      break;
		    }
		}

		/* Fall through.  */

	      default:
		fprintf_unfiltered (stream,
				    "  unsigned char %s[%d]"
				    " __attribute__((__aligned__("
				    "__BIGGEST_ALIGNMENT__)))",
				    regname.c_str (),
				    TYPE_LENGTH (regtype));
	      }
	    fputs_unfiltered (";\n", stream);
	  }
      }

  if (!seen)
    fputs_unfiltered ("  char " COMPILE_I_SIMPLE_REGISTER_DUMMY ";\n",
		      stream);

  fputs_unfiltered ("};\n\n", stream);
}

/* Take the source code provided by the user with the 'compile'
   command, and compute the additional wrapping, macro, variable and
   register operations needed.  INPUT is the source code derived from
   the 'compile' command, GDBARCH is the architecture to use when
   computing above, EXPR_BLOCK denotes the block relevant contextually
   to the inferior when the expression was created, and EXPR_PC
   indicates the value of $PC.  */

std::string
c_compute_program (struct compile_instance *inst,
		   const char *input,
		   struct gdbarch *gdbarch,
		   const struct block *expr_block,
		   CORE_ADDR expr_pc)
{
  struct compile_c_instance *context = (struct compile_c_instance *) inst;

  string_file buf;
  string_file var_stream;

  write_macro_definitions (expr_block, expr_pc, &buf);

  /* Do not generate local variable information for "raw"
     compilations.  In this case we aren't emitting our own function
     and the user's code may only refer to globals.  */
  if (inst->scope != COMPILE_I_RAW_SCOPE)
    {
      int i;

      /* Generate the code to compute variable locations, but do it
	 before generating the function header, so we can define the
	 register struct before the function body.  This requires a
	 temporary stream.  */
      gdb::unique_xmalloc_ptr<unsigned char> registers_used
	= generate_c_for_variable_locations (context, var_stream, gdbarch,
					     expr_block, expr_pc);

      buf.puts ("typedef unsigned int"
		" __attribute__ ((__mode__(__pointer__)))"
		" __gdb_uintptr;\n");
      buf.puts ("typedef int"
		" __attribute__ ((__mode__(__pointer__)))"
		" __gdb_intptr;\n");

      /* Iterate all log2 sizes in bytes supported by c_get_mode_for_size.  */
      for (i = 0; i < 4; ++i)
	{
	  const char *mode = c_get_mode_for_size (1 << i);

	  gdb_assert (mode != NULL);
	  buf.printf ("typedef int"
		      " __attribute__ ((__mode__(__%s__)))"
		      " __gdb_int_%s;\n",
		      mode, mode);
	}

      generate_register_struct (&buf, gdbarch, registers_used.get ());
    }

  add_code_header (inst->scope, &buf);

  if (inst->scope == COMPILE_I_SIMPLE_SCOPE
      || inst->scope == COMPILE_I_PRINT_ADDRESS_SCOPE
      || inst->scope == COMPILE_I_PRINT_VALUE_SCOPE)
    {
      buf.write (var_stream.c_str (), var_stream.size ());
      buf.puts ("#pragma GCC user_expression\n");
    }

  /* The user expression has to be in its own scope, so that "extern"
     works properly.  Otherwise gcc thinks that the "extern"
     declaration is in the same scope as the declaration provided by
     gdb.  */
  if (inst->scope != COMPILE_I_RAW_SCOPE)
    buf.puts ("{\n");

  buf.puts ("#line 1 \"gdb command line\"\n");

  switch (inst->scope)
    {
    case COMPILE_I_PRINT_ADDRESS_SCOPE:
    case COMPILE_I_PRINT_VALUE_SCOPE:
      buf.printf (
"__auto_type " COMPILE_I_EXPR_VAL " = %s;\n"
"typeof (%s) *" COMPILE_I_EXPR_PTR_TYPE ";\n"
"memcpy (" COMPILE_I_PRINT_OUT_ARG ", %s" COMPILE_I_EXPR_VAL ",\n"
	 "sizeof (*" COMPILE_I_EXPR_PTR_TYPE "));\n"
			  , input, input,
			  (inst->scope == COMPILE_I_PRINT_ADDRESS_SCOPE
			   ? "&" : ""));
      break;
    default:
      buf.puts (input);
      break;
    }

  buf.puts ("\n");

  /* For larger user expressions the automatic semicolons may be
     confusing.  */
  if (strchr (input, '\n') == NULL)
    buf.puts (";\n");

  if (inst->scope != COMPILE_I_RAW_SCOPE)
    buf.puts ("}\n");

  add_code_footer (inst->scope, &buf);
  return std::move (buf.string ());
}
Commit	Line	Data
	1	/* C language support for compilation.
	2
	3	Copyright (C) 2014-2018 Free Software Foundation, Inc.
	4
	5	This file is part of GDB.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 3 of the License, or
	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	19
	20	#include "defs.h"
	21	#include "compile-internal.h"
	22	#include "compile.h"
	23	#include "gdb-dlfcn.h"
	24	#include "c-lang.h"
	25	#include "macrotab.h"
	26	#include "macroscope.h"
	27	#include "regcache.h"
	28	#include "common/function-view.h"
	29	#include "common/preprocessor.h"
	30
	31	/* See compile-internal.h. */
	32
	33	const char *
	34	c_get_mode_for_size (int size)
	35	{
	36	const char *mode = NULL;
	37
	38	switch (size)
	39	{
	40	case 1:
	41	mode = "QI";
	42	break;
	43	case 2:
	44	mode = "HI";
	45	break;
	46	case 4:
	47	mode = "SI";
	48	break;
	49	case 8:
	50	mode = "DI";
	51	break;
	52	default:
	53	internal_error (__FILE__, __LINE__, _("Invalid GCC mode size %d."), size);
	54	}
	55
	56	return mode;
	57	}
	58
	59	/* See compile-internal.h. */
	60
	61	std::string
	62	c_get_range_decl_name (const struct dynamic_prop *prop)
	63	{
	64	return string_printf ("__gdb_prop_%s", host_address_to_string (prop));
	65	}
	66
	67	\f
	68
	69	/* Helper function for c_get_compile_context. Open the GCC front-end
	70	shared library and return the symbol specified by the current
	71	GCC_C_FE_CONTEXT. */
	72
	73	static gcc_c_fe_context_function *
	74	load_libcc (void)
	75	{
	76	gcc_c_fe_context_function *func;
	77
	78	/* gdb_dlopen will call error () on an error, so no need to check
	79	value. */
	80	gdb_dlhandle_up handle = gdb_dlopen (STRINGIFY (GCC_C_FE_LIBCC));
	81	func = (gcc_c_fe_context_function *) gdb_dlsym (handle,
	82	STRINGIFY (GCC_C_FE_CONTEXT));
	83
	84	if (func == NULL)
	85	error (_("could not find symbol %s in library %s"),
	86	STRINGIFY (GCC_C_FE_CONTEXT),
	87	STRINGIFY (GCC_C_FE_LIBCC));
	88
	89	/* Leave the library open. */
	90	handle.release ();
	91	return func;
	92	}
	93
	94	/* Return the compile instance associated with the current context.
	95	This function calls the symbol returned from the load_libcc
	96	function. This will provide the gcc_c_context. */
	97
	98	struct compile_instance *
	99	c_get_compile_context (void)
	100	{
	101	static gcc_c_fe_context_function *func;
	102
	103	struct gcc_c_context *context;
	104
	105	if (func == NULL)
	106	{
	107	func = load_libcc ();
	108	gdb_assert (func != NULL);
	109	}
	110
	111	context = (*func) (GCC_FE_VERSION_0, GCC_C_FE_VERSION_0);
	112	if (context == NULL)
	113	error (_("The loaded version of GCC does not support the required version "
	114	"of the API."));
	115
	116	return new_compile_instance (context);
	117	}
	118
	119	\f
	120
	121	/* Write one macro definition. */
	122
	123	static void
	124	print_one_macro (const char name, const struct macro_definition macro,
	125	struct macro_source_file *source, int line,
	126	ui_file *file)
	127	{
	128	/* Don't print command-line defines. They will be supplied another
	129	way. */
	130	if (line == 0)
	131	return;
	132
	133	/* None of -Wno-builtin-macro-redefined, #undef first
	134	or plain #define of the same value would avoid a warning. */
	135	fprintf_filtered (file, "#ifndef %s\n# define %s", name, name);
	136
	137	if (macro->kind == macro_function_like)
	138	{
	139	int i;
	140
	141	fputs_filtered ("(", file);
	142	for (i = 0; i < macro->argc; i++)
	143	{
	144	fputs_filtered (macro->argv[i], file);
	145	if (i + 1 < macro->argc)
	146	fputs_filtered (", ", file);
	147	}
	148	fputs_filtered (")", file);
	149	}
	150
	151	fprintf_filtered (file, " %s\n#endif\n", macro->replacement);
	152	}
	153
	154	/* Write macro definitions at PC to FILE. */
	155
	156	static void
	157	write_macro_definitions (const struct block *block, CORE_ADDR pc,
	158	struct ui_file *file)
	159	{
	160	gdb::unique_xmalloc_ptr<struct macro_scope> scope;
	161
	162	if (block != NULL)
	163	scope = sal_macro_scope (find_pc_line (pc, 0));
	164	else
	165	scope = default_macro_scope ();
	166	if (scope == NULL)
	167	scope = user_macro_scope ();
	168
	169	if (scope != NULL && scope->file != NULL && scope->file->table != NULL)
	170	{
	171	macro_for_each_in_scope (scope->file, scope->line,
	172	[&] (const char *name,
	173	const macro_definition *macro,
	174	macro_source_file *source,
	175	int line)
	176	{
	177	print_one_macro (name, macro, source, line, file);
	178	});
	179	}
	180	}
	181
	182	/* Helper function to construct a header scope for a block of code.
	183	Takes a scope argument which selects the correct header to
	184	insert into BUF. */
	185
	186	static void
	187	add_code_header (enum compile_i_scope_types type, struct ui_file *buf)
	188	{
	189	switch (type)
	190	{
	191	case COMPILE_I_SIMPLE_SCOPE:
	192	fputs_unfiltered ("void "
	193	GCC_FE_WRAPPER_FUNCTION
	194	" (struct "
	195	COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
	196	" *"
	197	COMPILE_I_SIMPLE_REGISTER_ARG_NAME
	198	") {\n",
	199	buf);
	200	break;
	201	case COMPILE_I_PRINT_ADDRESS_SCOPE:
	202	case COMPILE_I_PRINT_VALUE_SCOPE:
	203	/* <string.h> is needed for a memcpy call below. */
	204	fputs_unfiltered ("#include <string.h>\n"
	205	"void "
	206	GCC_FE_WRAPPER_FUNCTION
	207	" (struct "
	208	COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG
	209	" *"
	210	COMPILE_I_SIMPLE_REGISTER_ARG_NAME
	211	", "
	212	COMPILE_I_PRINT_OUT_ARG_TYPE
	213	" "
	214	COMPILE_I_PRINT_OUT_ARG
	215	") {\n",
	216	buf);
	217	break;
	218
	219	case COMPILE_I_RAW_SCOPE:
	220	break;
	221	default:
	222	gdb_assert_not_reached (_("Unknown compiler scope reached."));
	223	}
	224	}
	225
	226	/* Helper function to construct a footer scope for a block of code.
	227	Takes a scope argument which selects the correct footer to
	228	insert into BUF. */
	229
	230	static void
	231	add_code_footer (enum compile_i_scope_types type, struct ui_file *buf)
	232	{
	233	switch (type)
	234	{
	235	case COMPILE_I_SIMPLE_SCOPE:
	236	case COMPILE_I_PRINT_ADDRESS_SCOPE:
	237	case COMPILE_I_PRINT_VALUE_SCOPE:
	238	fputs_unfiltered ("}\n", buf);
	239	break;
	240	case COMPILE_I_RAW_SCOPE:
	241	break;
	242	default:
	243	gdb_assert_not_reached (_("Unknown compiler scope reached."));
	244	}
	245	}
	246
	247	/* Generate a structure holding all the registers used by the function
	248	we're generating. */
	249
	250	static void
	251	generate_register_struct (struct ui_file stream, struct gdbarch gdbarch,
	252	const unsigned char *registers_used)
	253	{
	254	int i;
	255	int seen = 0;
	256
	257	fputs_unfiltered ("struct " COMPILE_I_SIMPLE_REGISTER_STRUCT_TAG " {\n",
	258	stream);
	259
	260	if (registers_used != NULL)
	261	for (i = 0; i < gdbarch_num_regs (gdbarch); ++i)
	262	{
	263	if (registers_used[i])
	264	{
	265	struct type *regtype = check_typedef (register_type (gdbarch, i));
	266	std::string regname = compile_register_name_mangled (gdbarch, i);
	267
	268	seen = 1;
	269
	270	/* You might think we could use type_print here. However,
	271	target descriptions often use types with names like
	272	"int64_t", which may not be defined in the inferior
	273	(and in any case would not be looked up due to the
	274	#pragma business). So, we take a much simpler
	275	approach: for pointer- or integer-typed registers, emit
	276	the field in the most direct way; and for other
	277	register types (typically flags or vectors), emit a
	278	maximally-aligned array of the correct size. */
	279
	280	fputs_unfiltered (" ", stream);
	281	switch (TYPE_CODE (regtype))
	282	{
	283	case TYPE_CODE_PTR:
	284	fprintf_filtered (stream, "__gdb_uintptr %s",
	285	regname.c_str ());
	286	break;
	287
	288	case TYPE_CODE_INT:
	289	{
	290	const char *mode
	291	= c_get_mode_for_size (TYPE_LENGTH (regtype));
	292
	293	if (mode != NULL)
	294	{
	295	if (TYPE_UNSIGNED (regtype))
	296	fputs_unfiltered ("unsigned ", stream);
	297	fprintf_unfiltered (stream,
	298	"int %s"
	299	" __attribute__ ((__mode__(__%s__)))",
	300	regname.c_str (),
	301	mode);
	302	break;
	303	}
	304	}
	305
	306	/* Fall through. */
	307
	308	default:
	309	fprintf_unfiltered (stream,
	310	" unsigned char %s[%d]"
	311	" __attribute__((__aligned__("
	312	"__BIGGEST_ALIGNMENT__)))",
	313	regname.c_str (),
	314	TYPE_LENGTH (regtype));
	315	}
	316	fputs_unfiltered (";\n", stream);
	317	}
	318	}
	319
	320	if (!seen)
	321	fputs_unfiltered (" char " COMPILE_I_SIMPLE_REGISTER_DUMMY ";\n",
	322	stream);
	323
	324	fputs_unfiltered ("};\n\n", stream);
	325	}
	326
	327	/* Take the source code provided by the user with the 'compile'
	328	command, and compute the additional wrapping, macro, variable and
	329	register operations needed. INPUT is the source code derived from
	330	the 'compile' command, GDBARCH is the architecture to use when
	331	computing above, EXPR_BLOCK denotes the block relevant contextually
	332	to the inferior when the expression was created, and EXPR_PC
	333	indicates the value of $PC. */
	334
	335	std::string
	336	c_compute_program (struct compile_instance *inst,
	337	const char *input,
	338	struct gdbarch *gdbarch,
	339	const struct block *expr_block,
	340	CORE_ADDR expr_pc)
	341	{
	342	struct compile_c_instance context = (struct compile_c_instance ) inst;
	343
	344	string_file buf;
	345	string_file var_stream;
	346
	347	write_macro_definitions (expr_block, expr_pc, &buf);
	348
	349	/* Do not generate local variable information for "raw"
	350	compilations. In this case we aren't emitting our own function
	351	and the user's code may only refer to globals. */
	352	if (inst->scope != COMPILE_I_RAW_SCOPE)
	353	{
	354	int i;
	355
	356	/* Generate the code to compute variable locations, but do it
	357	before generating the function header, so we can define the
	358	register struct before the function body. This requires a
	359	temporary stream. */
	360	gdb::unique_xmalloc_ptr<unsigned char> registers_used
	361	= generate_c_for_variable_locations (context, var_stream, gdbarch,
	362	expr_block, expr_pc);
	363
	364	buf.puts ("typedef unsigned int"
	365	" __attribute__ ((__mode__(__pointer__)))"
	366	" __gdb_uintptr;\n");
	367	buf.puts ("typedef int"
	368	" __attribute__ ((__mode__(__pointer__)))"
	369	" __gdb_intptr;\n");
	370
	371	/* Iterate all log2 sizes in bytes supported by c_get_mode_for_size. */
	372	for (i = 0; i < 4; ++i)
	373	{
	374	const char *mode = c_get_mode_for_size (1 << i);
	375
	376	gdb_assert (mode != NULL);
	377	buf.printf ("typedef int"
	378	" __attribute__ ((__mode__(__%s__)))"
	379	" __gdb_int_%s;\n",
	380	mode, mode);
	381	}
	382
	383	generate_register_struct (&buf, gdbarch, registers_used.get ());
	384	}
	385
	386	add_code_header (inst->scope, &buf);
	387
	388	if (inst->scope == COMPILE_I_SIMPLE_SCOPE
	389	\|\| inst->scope == COMPILE_I_PRINT_ADDRESS_SCOPE
	390	\|\| inst->scope == COMPILE_I_PRINT_VALUE_SCOPE)
	391	{
	392	buf.write (var_stream.c_str (), var_stream.size ());
	393	buf.puts ("#pragma GCC user_expression\n");
	394	}
	395
	396	/* The user expression has to be in its own scope, so that "extern"
	397	works properly. Otherwise gcc thinks that the "extern"
	398	declaration is in the same scope as the declaration provided by
	399	gdb. */
	400	if (inst->scope != COMPILE_I_RAW_SCOPE)
	401	buf.puts ("{\n");
	402
	403	buf.puts ("#line 1 \"gdb command line\"\n");
	404
	405	switch (inst->scope)
	406	{
	407	case COMPILE_I_PRINT_ADDRESS_SCOPE:
	408	case COMPILE_I_PRINT_VALUE_SCOPE:
	409	buf.printf (
	410	"__auto_type " COMPILE_I_EXPR_VAL " = %s;\n"
	411	"typeof (%s) *" COMPILE_I_EXPR_PTR_TYPE ";\n"
	412	"memcpy (" COMPILE_I_PRINT_OUT_ARG ", %s" COMPILE_I_EXPR_VAL ",\n"
	413	"sizeof (*" COMPILE_I_EXPR_PTR_TYPE "));\n"
	414	, input, input,
	415	(inst->scope == COMPILE_I_PRINT_ADDRESS_SCOPE
	416	? "&" : ""));
	417	break;
	418	default:
	419	buf.puts (input);
	420	break;
	421	}
	422
	423	buf.puts ("\n");
	424
	425	/* For larger user expressions the automatic semicolons may be
	426	confusing. */
	427	if (strchr (input, '\n') == NULL)
	428	buf.puts (";\n");
	429
	430	if (inst->scope != COMPILE_I_RAW_SCOPE)
	431	buf.puts ("}\n");
	432
	433	add_code_footer (inst->scope, &buf);
	434	return std::move (buf.string ());
	435	}