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[PATCH] Remove NOTHROW from {,v}{,f}{print,scan}f, {,f}printf_unlocked and __{,v}{,f}printf_chk builtins

From: Jakub Jelinek <jakub at redhat dot com>
To: gcc-patches at gcc dot gnu dot org
Date: Mon, 3 Sep 2007 05:47:44 -0400
Subject: [PATCH] Remove NOTHROW from {,v}{,f}{print,scan}f, {,f}printf_unlocked and __{,v}{,f}printf_chk builtins
Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!

In glibc the following functions aren't throw(), because they are
possible cancellation points (when a thread doing say a write within
fprintf is cancelled, we need forced unwinding to work).

DEF_LIB_BUILTIN        (BUILT_IN_FPRINTF, "fprintf", BT_FN_INT_FILEPTR_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_2_3)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_FPRINTF_UNLOCKED, "fprintf_unlocked", BT_FN_INT_FILEPTR_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_2_3)
DEF_LIB_BUILTIN        (BUILT_IN_FSCANF, "fscanf", BT_FN_INT_FILEPTR_CONST_STRING_VAR, ATTR_FORMAT_SCANF_2_3)
DEF_LIB_BUILTIN        (BUILT_IN_PRINTF, "printf", BT_FN_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_1_2)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_PRINTF_UNLOCKED, "printf_unlocked", BT_FN_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_1_2)
DEF_LIB_BUILTIN        (BUILT_IN_SCANF, "scanf", BT_FN_INT_CONST_STRING_VAR, ATTR_FORMAT_SCANF_1_2)
DEF_LIB_BUILTIN        (BUILT_IN_VFPRINTF, "vfprintf", BT_FN_INT_FILEPTR_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_2_0)
DEF_C99_BUILTIN        (BUILT_IN_VFSCANF, "vfscanf", BT_FN_INT_FILEPTR_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_2_0)
DEF_LIB_BUILTIN        (BUILT_IN_VPRINTF, "vprintf", BT_FN_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_1_0)
DEF_C99_BUILTIN        (BUILT_IN_VSCANF, "vscanf", BT_FN_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_1_0)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_FPRINTF_CHK, "__fprintf_chk", BT_FN_INT_FILEPTR_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_3_4)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_PRINTF_CHK, "__printf_chk", BT_FN_INT_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_2_3)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_VFPRINTF_CHK, "__vfprintf_chk", BT_FN_INT_FILEPTR_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_3_0)
DEF_EXT_LIB_BUILTIN    (BUILT_IN_VPRINTF_CHK, "__vprintf_chk", BT_FN_INT_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_2_0)

Without this patch, all functions using ATTR_FORMAT_* are automatically
nothrow.  While the non-__ builtins are DECL_ANTICIPATED in C++ and thus
the builtin's TREE_NOTHROW is ignored, for __builtin_* variants that
doesn't happen and the __[^b]*_chk builtins aren't even marked
DECL_ANTICIPATED, even when they should (see PR33289).
Without the patch we have unwind pad in bar, but not in foo.

struct A { A(); ~A(); };
extern "C" int printf (const char *);
int foo ()
{
  A a;
  return __builtin_printf ("abcde");
}
int bar ()
{
  A a;
  return printf ("abcde");
}

Ok for trunk?

2007-09-03  Jakub Jelinek  <jakub@redhat.com>

	* builtin-attrs.def (ATTR_NONNULL_3): New.
	(DEF_FORMAT_ATTRIBUTE): Use just ATTR_NONNULL_##FA instead of
	ATTR_NOTHROW_NONNULL_##FA.
	(DEF_FORMAT_ATTRIBUTE_NOTHROW, DEF_FORMAT_ATTRIBUTE_BOTH): New macros.
	(ATTR_FORMAT_PRINTF_NOTHROW_2_0, ATTR_PRINTF_NOTHROW_2_3,
	ATTR_FORMAT_PRINTF_NOTHROW_3_0, ATTR_FORMAT_PRINTF_NOTHROW_3_4,
	ATTR_FORMAT_PRINTF_NOTHROW_4_0, ATTR_PRINTF_NOTHROW_4_5,
	ATTR_FORMAT_PRINTF_NOTHROW_5_0, ATTR_FORMAT_PRINTF_NOTHROW_5_6,
	ATTR_FORMAT_SCANF_NOTHROW_2_0, ATTR_FORMAT_SCANF_NOTHROW_2_3,
	ATTR_FORMAT_STRFTIME_NOTHROW_3_0, ATTR_FORMAT_STRFMON_NOTHROW_3_4):
	New.
	(ATTR_FORMAT_PRINTF_4_0, ATTR_PRINTF_4_5, ATTR_FORMAT_PRINTF_5_0,
	ATTR_FORMAT_PRINTF_5_6, ATTR_FORMAT_STRFTIME_3_0,
	ATTR_FORMAT_NOTHROW_3_4): Remove.
	* builtins.def (snprintf, sprintf, sscanf, vsnprintf, vsprintf,
	vsscanf, strfmon, strftime, __snprintf_chk, __sprintf_chk,
	__vsnprintf_chk, __vsprintf_chk): Use ATTR_FORMAT_*_NOTHROW_*
	instead of ATTR_FORMAT_*_*.

--- gcc/builtin-attrs.def.jj	2007-08-13 15:11:18.000000000 +0200
+++ gcc/builtin-attrs.def	2007-09-03 11:26:13.000000000 +0200
@@ -118,6 +118,8 @@ DEF_ATTR_TREE_LIST (ATTR_NONNULL_LIST, A
 DEF_ATTR_TREE_LIST (ATTR_NONNULL_1, ATTR_NONNULL, ATTR_LIST_1, ATTR_NULL)
 /* Functions whose second parameter is a nonnull pointer.  */
 DEF_ATTR_TREE_LIST (ATTR_NONNULL_2, ATTR_NONNULL, ATTR_LIST_2, ATTR_NULL)
+/* Functions whose third parameter is a nonnull pointer.  */
+DEF_ATTR_TREE_LIST (ATTR_NONNULL_3, ATTR_NONNULL, ATTR_LIST_3, ATTR_NULL)
 /* Nothrow functions with the sentinel(1) attribute. */
 DEF_ATTR_TREE_LIST (ATTR_NOTHROW_SENTINEL_1, ATTR_SENTINEL, ATTR_LIST_1, \
 			ATTR_NOTHROW_LIST)
@@ -157,24 +159,38 @@ DEF_ATTR_TREE_LIST (ATTR_MALLOC_NOTHROW_
   DEF_ATTR_TREE_LIST (ATTR_##TYPE##_##VALUES, ATTR_NULL,		 \
 		      ATTR_##TYPE, ATTR_LIST_##VALUES)			 \
   DEF_ATTR_TREE_LIST (ATTR_FORMAT_##TYPE##_##VALUES, ATTR_FORMAT,	 \
+		      ATTR_##TYPE##_##VALUES, ATTR_NONNULL_##FA)
+#define DEF_FORMAT_ATTRIBUTE_NOTHROW(TYPE, FA, VALUES)			 \
+  DEF_ATTR_TREE_LIST (ATTR_##TYPE##_##VALUES, ATTR_NULL,		 \
+		      ATTR_##TYPE, ATTR_LIST_##VALUES)			 \
+  DEF_ATTR_TREE_LIST (ATTR_FORMAT_##TYPE##_NOTHROW_##VALUES, ATTR_FORMAT,\
+		      ATTR_##TYPE##_##VALUES, ATTR_NOTHROW_NONNULL_##FA)
+#define DEF_FORMAT_ATTRIBUTE_BOTH(TYPE, FA, VALUES)			 \
+  DEF_ATTR_TREE_LIST (ATTR_##TYPE##_##VALUES, ATTR_NULL,		 \
+		      ATTR_##TYPE, ATTR_LIST_##VALUES)			 \
+  DEF_ATTR_TREE_LIST (ATTR_FORMAT_##TYPE##_##VALUES, ATTR_FORMAT,	 \
+		      ATTR_##TYPE##_##VALUES, ATTR_NONNULL_##FA)	 \
+  DEF_ATTR_TREE_LIST (ATTR_FORMAT_##TYPE##_NOTHROW_##VALUES, ATTR_FORMAT,\
 		      ATTR_##TYPE##_##VALUES, ATTR_NOTHROW_NONNULL_##FA)
 DEF_FORMAT_ATTRIBUTE(PRINTF,1,1_0)
 DEF_FORMAT_ATTRIBUTE(PRINTF,1,1_2)
-DEF_FORMAT_ATTRIBUTE(PRINTF,2,2_0)
-DEF_FORMAT_ATTRIBUTE(PRINTF,2,2_3)
-DEF_FORMAT_ATTRIBUTE(PRINTF,3,3_0)
-DEF_FORMAT_ATTRIBUTE(PRINTF,3,3_4)
-DEF_FORMAT_ATTRIBUTE(PRINTF,4,4_0)
-DEF_FORMAT_ATTRIBUTE(PRINTF,4,4_5)
-DEF_FORMAT_ATTRIBUTE(PRINTF,5,5_0)
-DEF_FORMAT_ATTRIBUTE(PRINTF,5,5_6)
+DEF_FORMAT_ATTRIBUTE_BOTH(PRINTF,2,2_0)
+DEF_FORMAT_ATTRIBUTE_BOTH(PRINTF,2,2_3)
+DEF_FORMAT_ATTRIBUTE_BOTH(PRINTF,3,3_0)
+DEF_FORMAT_ATTRIBUTE_BOTH(PRINTF,3,3_4)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(PRINTF,4,4_0)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(PRINTF,4,4_5)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(PRINTF,5,5_0)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(PRINTF,5,5_6)
 DEF_FORMAT_ATTRIBUTE(SCANF,1,1_0)
 DEF_FORMAT_ATTRIBUTE(SCANF,1,1_2)
-DEF_FORMAT_ATTRIBUTE(SCANF,2,2_0)
-DEF_FORMAT_ATTRIBUTE(SCANF,2,2_3)
-DEF_FORMAT_ATTRIBUTE(STRFTIME,3,3_0)
-DEF_FORMAT_ATTRIBUTE(STRFMON,3,3_4)
+DEF_FORMAT_ATTRIBUTE_BOTH(SCANF,2,2_0)
+DEF_FORMAT_ATTRIBUTE_BOTH(SCANF,2,2_3)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(STRFTIME,3,3_0)
+DEF_FORMAT_ATTRIBUTE_NOTHROW(STRFMON,3,3_4)
 #undef DEF_FORMAT_ATTRIBUTE
+#undef DEF_FORMAT_ATTRIBUTE_NOTHROW
+#undef DEF_FORMAT_ATTRIBUTE_BOTH
 
 /* Construct a tree for a format_arg attribute.  */
 #define DEF_FORMAT_ARG_ATTRIBUTE(FA)					\
--- gcc/builtins.def.jj	2007-08-30 18:46:59.000000000 +0200
+++ gcc/builtins.def	2007-09-03 10:52:18.000000000 +0200
@@ -553,16 +553,16 @@ DEF_EXT_LIB_BUILTIN    (BUILT_IN_PUTCHAR
 DEF_LIB_BUILTIN        (BUILT_IN_PUTS, "puts", BT_FN_INT_CONST_STRING, ATTR_NONNULL_LIST)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_PUTS_UNLOCKED, "puts_unlocked", BT_FN_INT_CONST_STRING, ATTR_NONNULL_LIST)
 DEF_LIB_BUILTIN        (BUILT_IN_SCANF, "scanf", BT_FN_INT_CONST_STRING_VAR, ATTR_FORMAT_SCANF_1_2)
-DEF_C99_BUILTIN        (BUILT_IN_SNPRINTF, "snprintf", BT_FN_INT_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_3_4)
-DEF_LIB_BUILTIN        (BUILT_IN_SPRINTF, "sprintf", BT_FN_INT_STRING_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_2_3)
-DEF_LIB_BUILTIN        (BUILT_IN_SSCANF, "sscanf", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_FORMAT_SCANF_2_3)
+DEF_C99_BUILTIN        (BUILT_IN_SNPRINTF, "snprintf", BT_FN_INT_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_NOTHROW_3_4)
+DEF_LIB_BUILTIN        (BUILT_IN_SPRINTF, "sprintf", BT_FN_INT_STRING_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_NOTHROW_2_3)
+DEF_LIB_BUILTIN        (BUILT_IN_SSCANF, "sscanf", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_FORMAT_SCANF_NOTHROW_2_3)
 DEF_LIB_BUILTIN        (BUILT_IN_VFPRINTF, "vfprintf", BT_FN_INT_FILEPTR_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_2_0)
 DEF_C99_BUILTIN        (BUILT_IN_VFSCANF, "vfscanf", BT_FN_INT_FILEPTR_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_2_0)
 DEF_LIB_BUILTIN        (BUILT_IN_VPRINTF, "vprintf", BT_FN_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_1_0)
 DEF_C99_BUILTIN        (BUILT_IN_VSCANF, "vscanf", BT_FN_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_1_0)
-DEF_C99_BUILTIN        (BUILT_IN_VSNPRINTF, "vsnprintf", BT_FN_INT_STRING_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_3_0)
-DEF_LIB_BUILTIN        (BUILT_IN_VSPRINTF, "vsprintf", BT_FN_INT_STRING_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_2_0)
-DEF_C99_BUILTIN        (BUILT_IN_VSSCANF, "vsscanf", BT_FN_INT_CONST_STRING_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_2_0)
+DEF_C99_BUILTIN        (BUILT_IN_VSNPRINTF, "vsnprintf", BT_FN_INT_STRING_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_NOTHROW_3_0)
+DEF_LIB_BUILTIN        (BUILT_IN_VSPRINTF, "vsprintf", BT_FN_INT_STRING_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_NOTHROW_2_0)
+DEF_C99_BUILTIN        (BUILT_IN_VSSCANF, "vsscanf", BT_FN_INT_CONST_STRING_CONST_STRING_VALIST_ARG, ATTR_FORMAT_SCANF_NOTHROW_2_0)
 
 /* Category: ctype builtins.  */
 DEF_LIB_BUILTIN        (BUILT_IN_ISALNUM, "isalnum", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
@@ -693,8 +693,8 @@ DEF_GCC_BUILTIN        (BUILT_IN_RETURN_
 DEF_GCC_BUILTIN        (BUILT_IN_SAVEREGS, "saveregs", BT_FN_PTR_VAR, ATTR_NULL)
 DEF_GCC_BUILTIN        (BUILT_IN_SETJMP, "setjmp", BT_FN_INT_PTR, ATTR_NULL)
 DEF_GCC_BUILTIN        (BUILT_IN_STDARG_START, "stdarg_start", BT_FN_VOID_VALIST_REF_VAR, ATTR_NULL)
-DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRFMON, "strfmon", BT_FN_SSIZE_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_STRFMON_3_4)
-DEF_LIB_BUILTIN        (BUILT_IN_STRFTIME, "strftime", BT_FN_SIZE_STRING_SIZE_CONST_STRING_CONST_PTR, ATTR_FORMAT_STRFTIME_3_0)
+DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRFMON, "strfmon", BT_FN_SSIZE_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_STRFMON_NOTHROW_3_4)
+DEF_LIB_BUILTIN        (BUILT_IN_STRFTIME, "strftime", BT_FN_SIZE_STRING_SIZE_CONST_STRING_CONST_PTR, ATTR_FORMAT_STRFTIME_NOTHROW_3_0)
 DEF_GCC_BUILTIN        (BUILT_IN_TRAP, "trap", BT_FN_VOID, ATTR_NORETURN_NOTHROW_LIST)
 DEF_GCC_BUILTIN        (BUILT_IN_UNWIND_INIT, "unwind_init", BT_FN_VOID, ATTR_NULL)
 DEF_GCC_BUILTIN        (BUILT_IN_UPDATE_SETJMP_BUF, "update_setjmp_buf", BT_FN_VOID_PTR_INT, ATTR_NULL)
@@ -730,10 +730,10 @@ DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRCAT_
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRCPY_CHK, "__strcpy_chk", BT_FN_STRING_STRING_CONST_STRING_SIZE, ATTR_NOTHROW_NONNULL)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRNCAT_CHK, "__strncat_chk", BT_FN_STRING_STRING_CONST_STRING_SIZE_SIZE, ATTR_NOTHROW_NONNULL)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_STRNCPY_CHK, "__strncpy_chk", BT_FN_STRING_STRING_CONST_STRING_SIZE_SIZE, ATTR_NOTHROW_NONNULL)
-DEF_EXT_LIB_BUILTIN    (BUILT_IN_SNPRINTF_CHK, "__snprintf_chk", BT_FN_INT_STRING_SIZE_INT_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_5_6)
-DEF_EXT_LIB_BUILTIN    (BUILT_IN_SPRINTF_CHK, "__sprintf_chk", BT_FN_INT_STRING_INT_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_4_5)
-DEF_EXT_LIB_BUILTIN    (BUILT_IN_VSNPRINTF_CHK, "__vsnprintf_chk", BT_FN_INT_STRING_SIZE_INT_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_5_0)
-DEF_EXT_LIB_BUILTIN    (BUILT_IN_VSPRINTF_CHK, "__vsprintf_chk", BT_FN_INT_STRING_INT_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_4_0)
+DEF_EXT_LIB_BUILTIN    (BUILT_IN_SNPRINTF_CHK, "__snprintf_chk", BT_FN_INT_STRING_SIZE_INT_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_NOTHROW_5_6)
+DEF_EXT_LIB_BUILTIN    (BUILT_IN_SPRINTF_CHK, "__sprintf_chk", BT_FN_INT_STRING_INT_SIZE_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_NOTHROW_4_5)
+DEF_EXT_LIB_BUILTIN    (BUILT_IN_VSNPRINTF_CHK, "__vsnprintf_chk", BT_FN_INT_STRING_SIZE_INT_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_NOTHROW_5_0)
+DEF_EXT_LIB_BUILTIN    (BUILT_IN_VSPRINTF_CHK, "__vsprintf_chk", BT_FN_INT_STRING_INT_SIZE_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_NOTHROW_4_0)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_FPRINTF_CHK, "__fprintf_chk", BT_FN_INT_FILEPTR_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_3_4)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_PRINTF_CHK, "__printf_chk", BT_FN_INT_INT_CONST_STRING_VAR, ATTR_FORMAT_PRINTF_2_3)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN_VFPRINTF_CHK, "__vfprintf_chk", BT_FN_INT_FILEPTR_INT_CONST_STRING_VALIST_ARG, ATTR_FORMAT_PRINTF_3_0)

	Jakub
Follow-Ups:
- Re: [PATCH] Remove NOTHROW from {,v}{,f}{print,scan}f, {,f}printf_unlocked and __{,v}{,f}printf_chk builtins
  - From: Mark Mitchell
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