PR c/77531 - __attribute__((alloc_size(1,2))) could also warn on multiplication overflow

PR c/77531 - __attribute__((alloc_size(1,2))) could also warn on multiplication overflow
PR c/78284 - warn on malloc with very large arguments

gcc/c-family/ChangeLog:

	PR c/78284
	* c.opt (-Walloc-zero, -Walloc-size-larger-than): New options.

gcc/ChangeLog:

	PR c/78284
	* builtin-attrs.def (ATTR_ALLOC_SIZE, ATTR_RETURNS_NONNULL): New
	identifier tree nodes.
	(ATTR_ALLOCA_SIZE_1_NOTHROW_LEAF_LIST): New attribute list.
	(ATTR_MALLOC_SIZE_1_NOTHROW_LIST): Same.
	(ATTR_MALLOC_SIZE_1_NOTHROW_LEAF_LIST): Same.
	(ATTR_MALLOC_SIZE_1_2_NOTHROW_LEAF_LIST): Same.
	(ATTR_ALLOC_SIZE_2_NOTHROW_LEAF_LIST): Same.
	* builtins.c (expand_builtin_alloca): Call
	maybe_warn_alloc_args_overflow.
	* builtins.def (aligned_alloc, calloc, malloc, realloc):
	Add attribute alloc_size.
	(alloca): Add attribute alloc_size and returns_nonnull.
	* calls.h (maybe_warn_alloc_args_overflow): Declare.
	* calls.c (alloc_max_size, operand_signed_p): New functions.
	(maybe_warn_alloc_args_overflow): Define.
	(initialize_argument_information): Diagnose overflow in functions
	declared with attaribute alloc_size.
	* doc/invoke.texi (Warning Options): Document -Walloc-zero and
	-Walloc-size-larger-than.

gcc/testsuite/ChangeLog:

	PR c/78284
	* gcc.dg/attr-alloc_size-3.c: New test.
	* gcc.dg/attr-alloc_size-4.c: New test.
	* gcc.dg/attr-alloc_size-5.c: New test.
	* gcc.dg/attr-alloc_size-6.c: New test.
	* gcc.dg/attr-alloc_size-7.c: New test.
	* gcc.dg/attr-alloc_size-8.c: New test.
	* gcc.dg/attr-alloc_size-9.c: New test.
	* gcc/testsuite/gcc.dg/errno-1.c: Adjust.

From-SVN: r243470

1 files changed, 22 insertions, 0 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 02a34fb..0c61232 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -257,6 +257,7 @@ Objective-C and Objective-C++ Dialects}.
 @gccoptlist{-fsyntax-only  -fmax-errors=@var{n}  -Wpedantic @gol
 -pedantic-errors @gol
 -w  -Wextra  -Wall  -Waddress  -Waggregate-return  @gol
+-Walloc-zero -Walloc-size-larger-than=@var{n}
 -Walloca -Walloca-larger-than=@var{n} @gol
 -Wno-aggressive-loop-optimizations -Warray-bounds -Warray-bounds=@var{n} @gol
 -Wno-attributes -Wbool-compare -Wbool-operation @gol
@@ -5099,6 +5100,27 @@ annotations.
 Warn about overriding virtual functions that are not marked with the override
 keyword.
 
+@item -Walloc-zero
+@opindex Wno-alloc-zero
+@opindex Walloc-zero
+Warn about calls to allocation functions decorated with attribute
+@code{alloc_size} that specify zero bytes, including those to the built-in
+forms of the functions @code{aligned_alloc}, @code{alloca}, @code{calloc},
+@code{malloc}, and @code{realloc}.  Because the behavior of these functions
+when called with a zero size differs among implementations (and in the case
+of @code{realloc} has been deprecated) relying on it may result in subtle
+portability bugs and should be avoided.
+
+@item -Walloc-size-larger-than=@var{n}
+Warn about calls to functions decorated with attribute @code{alloc_size}
+that attempt to allocate objects larger than the specified number of bytes,
+or where the result of the size computation in an integer type with infinite
+precision would exceed @code{SIZE_MAX / 2}.  The option argument @var{n}
+may end in one of the standard suffixes designating a multiple of bytes
+such as @code{kB} and @code{KiB} for kilobyte and kibibyte, respectively,
+@code{MB} and @code{MiB} for magabyte and mebibyte, and so on.
+@xref{Function Attributes}.
+
 @item -Walloca
 @opindex Wno-alloca
 @opindex Walloca