The following is a revamped patch for -Wsizeof-array-argument. Almost two
months back there was an initial attempt by Prathamesh:
<https://gcc.gnu.org/ml/gcc-patches/2014-05/msg00142.html>, but that patch
never made it in. This version implements the warning for both C and C++
FEs, adds more testing, enables the warning by default (I can move it to
-Wall, of course), makes the warning work properly even for multidimensional
arrays, etc.
Its purpose is to detect suspicious usage of the sizeof operator on an array
function parameter. A few years back I fixed exactly this kind of bug in
elfutils - so -Wsizeof-array-argument might be indeed useful. (The warning
didn't
trigger during GCC bootstrap though.)
Jason/Joseph, could you please look at the C++, resp. C FE parts?
Tested x86_64-unknown-linux-gnu, ok for trunk?
2014-06-26 Marek Polacek <pola...@redhat.com>
PR c/6940
* doc/invoke.texi: Document -Wsizeof-array-argument.
c-family/
* c.opt (Wsizeof-array-argument): New option.
c/
* c-decl.c (grokdeclarator): Set C_ARRAY_PARAMETER.
* c-tree.h (C_ARRAY_PARAMETER): Define.
* c-typeck.c (c_expr_sizeof_expr): Warn when using sizeof on an array
function parameter.
cp/
* cp-tree.h (DECL_ARRAY_PARAMETER_P): Define.
* decl.c (grokdeclarator): Set DECL_ARRAY_PARAMETER_P.
* typeck.c (cxx_sizeof_expr): Warn when using sizeof on an array
function parameter.
testsuite/
* c-c++-common/Wsizeof-pointer-memaccess1.c: Use
-Wno-sizeof-array-argument.
* c-c++-common/Wsizeof-pointer-memaccess2.c: Likewise.
* g++.dg/warn/Wsizeof-pointer-memaccess-1.C: Likewise.
* gcc.dg/Wsizeof-pointer-memaccess1.c: Likewise.
* g++.dg/torture/Wsizeof-pointer-memaccess1.C: Likewise.
* g++.dg/torture/Wsizeof-pointer-memaccess2.C: Likewise.
* gcc.dg/torture/Wsizeof-pointer-memaccess1.c: Likewise.
* c-c++-common/sizeof-array-argument.c: New test.
* gcc.dg/vla-5.c: Add dg-warnings.
../libgomp/
* testsuite/libgomp.c/appendix-a/a.29.1.c (f): Add dg-warnings.
diff --git gcc/gcc/c-family/c.opt gcc/gcc/c-family/c.opt
index 1d02bae..3d3cf14 100644
--- gcc/gcc/c-family/c.opt
+++ gcc/gcc/c-family/c.opt
@@ -526,6 +526,10 @@ Wsizeof-pointer-memaccess
C ObjC C++ ObjC++ Var(warn_sizeof_pointer_memaccess) Warning LangEnabledBy(C
ObjC C++ ObjC++,Wall)
Warn about suspicious length parameters to certain string functions if the
argument uses sizeof
+Wsizeof-array-argument
+C ObjC C++ ObjC++ Var(warn_sizeof_array_argument) Warning Init(1)
+Warn when sizeof is applied on a parameter declared as an array
+
Wsuggest-attribute=format
C ObjC C++ ObjC++ Var(warn_suggest_attribute_format) Warning
Warn about functions which might be candidates for format attributes
diff --git gcc/gcc/c/c-decl.c gcc/gcc/c/c-decl.c
index def10a2..a1bc114 100644
--- gcc/gcc/c/c-decl.c
+++ gcc/gcc/c/c-decl.c
@@ -6092,6 +6092,7 @@ grokdeclarator (const struct c_declarator *declarator,
if (decl_context == PARM)
{
tree promoted_type;
+ bool array_parameter_p = false;
/* A parameter declared as an array of T is really a pointer to T.
One declared as a function is really a pointer to a function. */
@@ -6113,6 +6114,7 @@ grokdeclarator (const struct c_declarator *declarator,
"attributes in parameter array declarator ignored");
size_varies = false;
+ array_parameter_p = true;
}
else if (TREE_CODE (type) == FUNCTION_TYPE)
{
@@ -6137,6 +6139,7 @@ grokdeclarator (const struct c_declarator *declarator,
PARM_DECL, declarator->u.id, type);
if (size_varies)
C_DECL_VARIABLE_SIZE (decl) = 1;
+ C_ARRAY_PARAMETER (decl) = array_parameter_p;
/* Compute the type actually passed in the parmlist,
for the case where there is no prototype.
diff --git gcc/gcc/c/c-tree.h gcc/gcc/c/c-tree.h
index 133930f..f97d0d5 100644
--- gcc/gcc/c/c-tree.h
+++ gcc/gcc/c/c-tree.h
@@ -66,6 +66,9 @@ along with GCC; see the file COPYING3. If not see
/* For a FUNCTION_DECL, nonzero if it was an implicit declaration. */
#define C_DECL_IMPLICIT(EXP) DECL_LANG_FLAG_2 (EXP)
+/* For a PARM_DECL, nonzero if it was declared as an array. */
+#define C_ARRAY_PARAMETER(NODE) DECL_LANG_FLAG_0 (NODE)
+
/* For FUNCTION_DECLs, evaluates true if the decl is built-in but has
been declared. */
#define C_DECL_DECLARED_BUILTIN(EXP) \
diff --git gcc/gcc/c/c-typeck.c gcc/gcc/c/c-typeck.c
index b62e830..0b63e98 100644
--- gcc/gcc/c/c-typeck.c
+++ gcc/gcc/c/c-typeck.c
@@ -2731,6 +2731,16 @@ c_expr_sizeof_expr (location_t loc, struct c_expr expr)
else
{
bool expr_const_operands = true;
+
+ if (TREE_CODE (expr.value) == PARM_DECL
+ && C_ARRAY_PARAMETER (expr.value))
+ {
+ if (warning_at (loc, OPT_Wsizeof_array_argument,
+ "%<sizeof%> on array function parameter %qE will "
+ "return size of %qT", expr.value,
+ expr.original_type))
+ inform (DECL_SOURCE_LOCATION (expr.value), "declared here");
+ }
tree folded_expr = c_fully_fold (expr.value, require_constant_value,
&expr_const_operands);
ret.value = c_sizeof (loc, TREE_TYPE (folded_expr));
diff --git gcc/gcc/cp/cp-tree.h gcc/gcc/cp/cp-tree.h
index c1bd7cf..3aac677 100644
--- gcc/gcc/cp/cp-tree.h
+++ gcc/gcc/cp/cp-tree.h
@@ -145,6 +145,7 @@ c-common.h, not after.
DECL_MEMBER_TEMPLATE_P (in TEMPLATE_DECL)
USING_DECL_TYPENAME_P (in USING_DECL)
DECL_VLA_CAPTURE_P (in FIELD_DECL)
+ DECL_ARRAY_PARAMETER_P (in PARM_DECL)
2: DECL_THIS_EXTERN (in VAR_DECL or FUNCTION_DECL).
DECL_IMPLICIT_TYPEDEF_P (in a TYPE_DECL)
3: DECL_IN_AGGR_P.
@@ -3681,6 +3682,11 @@ more_aggr_init_expr_args_p (const
aggr_init_expr_arg_iterator *iter)
#define DECL_VLA_CAPTURE_P(NODE) \
DECL_LANG_FLAG_1 (FIELD_DECL_CHECK (NODE))
+/* Nonzero for PARM_DECL node means that this is an array function
+ parameter, i.e, a[] rather than *a. */
+#define DECL_ARRAY_PARAMETER_P(NODE) \
+ DECL_LANG_FLAG_1 (PARM_DECL_CHECK (NODE))
+
/* Nonzero for FIELD_DECL node means that this field is a base class
of the parent object, as opposed to a member field. */
#define DECL_FIELD_IS_BASE(NODE) \
diff --git gcc/gcc/cp/decl.c gcc/gcc/cp/decl.c
index d548f61..0c2187e 100644
--- gcc/gcc/cp/decl.c
+++ gcc/gcc/cp/decl.c
@@ -8816,6 +8816,7 @@ grokdeclarator (const cp_declarator *declarator,
bool typedef_p = decl_spec_seq_has_spec_p (declspecs, ds_typedef);
bool constexpr_p = decl_spec_seq_has_spec_p (declspecs, ds_constexpr);
bool late_return_type_p = false;
+ bool array_parameter_p = false;
source_location saved_loc = input_location;
const char *errmsg;
@@ -9550,6 +9551,8 @@ grokdeclarator (const cp_declarator *declarator,
array. */
returned_attrs = chainon (returned_attrs,
declarator->std_attributes);
+ if (decl_context == PARM)
+ array_parameter_p = true;
break;
case cdk_function:
@@ -10474,6 +10477,7 @@ grokdeclarator (const cp_declarator *declarator,
if (decl_context == PARM)
{
decl = cp_build_parm_decl (unqualified_id, type);
+ DECL_ARRAY_PARAMETER_P (decl) = array_parameter_p;
bad_specifiers (decl, BSP_PARM, virtualp,
memfn_quals != TYPE_UNQUALIFIED,
diff --git gcc/gcc/cp/typeck.c gcc/gcc/cp/typeck.c
index 65dccf7..ed6a59b 100644
--- gcc/gcc/cp/typeck.c
+++ gcc/gcc/cp/typeck.c
@@ -1614,6 +1614,15 @@ cxx_sizeof_expr (tree e, tsubst_flags_t complain)
&& DECL_TEMPLATE_INSTANTIATION (e))
instantiate_decl (e, /*defer_ok*/true, /*expl_inst_mem*/false);
+ if (TREE_CODE (e) == PARM_DECL
+ && DECL_ARRAY_PARAMETER_P (e)
+ && (complain & tf_warning))
+ {
+ if (warning (OPT_Wsizeof_array_argument, "%<sizeof%> on array function "
+ "parameter %qE will return size of %qT", e, TREE_TYPE (e)))
+ inform (DECL_SOURCE_LOCATION (e), "declared here");
+ }
+
e = mark_type_use (e);
if (TREE_CODE (e) == COMPONENT_REF
diff --git gcc/gcc/doc/invoke.texi gcc/gcc/doc/invoke.texi
index 4df5f81..c8685d9 100644
--- gcc/gcc/doc/invoke.texi
+++ gcc/gcc/doc/invoke.texi
@@ -266,7 +266,7 @@ Objective-C and Objective-C++ Dialects}.
-Wredundant-decls -Wno-return-local-addr @gol
-Wreturn-type -Wsequence-point -Wshadow -Wno-shadow-ivar @gol
-Wsign-compare -Wsign-conversion -Wfloat-conversion @gol
--Wsizeof-pointer-memaccess @gol
+-Wsizeof-pointer-memaccess @gol -Wsizeof-array-argument @gol
-Wstack-protector -Wstack-usage=@var{len} -Wstrict-aliasing @gol
-Wstrict-aliasing=n @gol -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
-Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol
@@ -4662,6 +4662,13 @@ but a pointer, and suggests a possible fix, or about
@code{memcpy (&foo, ptr, sizeof (&foo));}. This warning is enabled by
@option{-Wall}.
+@item -Wsizeof-array-argument
+@opindex Wsizeof-array-argument
+@opindex Wno-sizeof-array-argument
+Warn when the @code{sizeof} operator is applied to a parameter that is
+declared as an array in a function definition. This warning is enabled by
+default for C and C++ programs.
+
@item -Waddress
@opindex Waddress
@opindex Wno-address
diff --git gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess1.c
gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess1.c
index 2a5f419..8e829d6 100644
--- gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess1.c
+++ gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess1.c
@@ -1,6 +1,6 @@
/* Test -Wsizeof-pointer-memaccess warnings. */
/* { dg-do compile } */
-/* { dg-options "-Wall" } */
+/* { dg-options "-Wall -Wno-sizeof-array-argument" } */
typedef __SIZE_TYPE__ size_t;
#ifdef __cplusplus
diff --git gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess2.c
gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess2.c
index 73cdf0e..fe17a70 100644
--- gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess2.c
+++ gcc/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess2.c
@@ -1,6 +1,6 @@
/* Test -Wsizeof-pointer-memaccess warnings. */
/* { dg-do compile } */
-/* { dg-options "-Wall -O2" } */
+/* { dg-options "-Wall -O2 -Wno-sizeof-array-argument" } */
#define bos(ptr) __builtin_object_size (ptr, 1)
#define bos0(ptr) __builtin_object_size (ptr, 0)
diff --git gcc/gcc/testsuite/c-c++-common/sizeof-array-argument.c
gcc/gcc/testsuite/c-c++-common/sizeof-array-argument.c
index e69de29..d22212e 100644
--- gcc/gcc/testsuite/c-c++-common/sizeof-array-argument.c
+++ gcc/gcc/testsuite/c-c++-common/sizeof-array-argument.c
@@ -0,0 +1,86 @@
+/* PR c/6940 */
+/* { dg-do compile } */
+
+/* Test -Wsizeof-array-argument warning. */
+
+int
+fn1 (int a[])
+{
+ return sizeof a; /* { dg-warning "on array function parameter" } */
+}
+
+int
+fn2 (int x, int b[3])
+{
+ return x + sizeof b; /* { dg-warning "on array function parameter" } */
+}
+
+int
+fn3 (int *p)
+{
+ return sizeof p;
+}
+
+int fn4 (int *p);
+int
+fn4 (int p[])
+{
+ return sizeof p; /* { dg-warning "on array function parameter" } */
+}
+
+int fn5 (int x[]);
+int
+fn5 (int *x)
+{
+ return sizeof x;
+}
+
+#ifndef __cplusplus
+/* C++ doesn't know VLA unspec. */
+int fn6 (int x[*]);
+int
+fn6 (int x[])
+{
+ return sizeof x; /* { dg-warning "on array function parameter" "" { target c
} } */
+}
+#endif
+
+int
+fn7 (int x[][2])
+{
+ return sizeof x; /* { dg-warning "on array function parameter" } */
+}
+
+int
+fn8 (char *x[])
+{
+ return sizeof x; /* { dg-warning "on array function parameter" } */
+}
+
+int
+fn9 (char **x)
+{
+ return sizeof x;
+}
+
+#ifndef __cplusplus
+int
+fn10 (int a, char x[static sizeof a])
+{
+ return sizeof x; /* { dg-warning "on array function parameter" "" { target c
} } */
+}
+
+int
+fn11 (a)
+ char a[];
+{
+ return sizeof a; /* { dg-warning "on array function parameter" "" { target c
} } */
+}
+
+int
+fn12 (a)
+ char *a;
+{
+ return sizeof a;
+}
+#endif
diff --git gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess1.C
gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess1.C
index 6cb3980..8b5c33e 100644
--- gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess1.C
+++ gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess1.C
@@ -1,6 +1,6 @@
// Test -Wsizeof-pointer-memaccess warnings.
// { dg-do compile }
-// { dg-options "-Wall" }
+// { dg-options "-Wall -Wno-sizeof-array-argument" }
// Test just twice, once with -O0 non-fortified, once with -O2 fortified.
// { dg-skip-if "" { *-*-* } { "*" } { "-O0" "-O2" } }
// { dg-skip-if "" { *-*-* } { "-flto" } { "" } }
diff --git gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess2.C
gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess2.C
index 9e2805d..0e99568 100644
--- gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess2.C
+++ gcc/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess2.C
@@ -1,6 +1,6 @@
// Test -Wsizeof-pointer-memaccess warnings.
// { dg-do compile }
-// { dg-options "-Wall" }
+// { dg-options "-Wall -Wno-sizeof-array-argument" }
// Test just twice, once with -O0 non-fortified, once with -O2 fortified.
// { dg-skip-if "" { *-*-* } { "*" } { "-O0" "-O2" } }
// { dg-skip-if "" { *-*-* } { "-flto" } { "" } }
diff --git gcc/gcc/testsuite/g++.dg/warn/Wsizeof-pointer-memaccess-1.C
gcc/gcc/testsuite/g++.dg/warn/Wsizeof-pointer-memaccess-1.C
index e2ba876..798cb6d 100644
--- gcc/gcc/testsuite/g++.dg/warn/Wsizeof-pointer-memaccess-1.C
+++ gcc/gcc/testsuite/g++.dg/warn/Wsizeof-pointer-memaccess-1.C
@@ -1,6 +1,6 @@
// Test -Wsizeof-pointer-memaccess warnings.
// { dg-do compile }
-// { dg-options "-Wall" }
+// { dg-options "-Wall -Wno-sizeof-array-argument" }
typedef __SIZE_TYPE__ size_t;
extern "C" void *memset (void *, int, size_t);
diff --git gcc/gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess1.c
gcc/gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess1.c
index b683be7..66be5a5 100644
--- gcc/gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess1.c
+++ gcc/gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess1.c
@@ -1,6 +1,6 @@
/* Test -Wsizeof-pointer-memaccess warnings. */
/* { dg-do compile } */
-/* { dg-options "-Wall" } */
+/* { dg-options "-Wall -Wno-sizeof-array-argument" } */
typedef __SIZE_TYPE__ size_t;
extern void bzero (void *, size_t);
diff --git gcc/gcc/testsuite/gcc.dg/torture/Wsizeof-pointer-memaccess1.c
gcc/gcc/testsuite/gcc.dg/torture/Wsizeof-pointer-memaccess1.c
index 8d01bc6..a82f4ef 100644
--- gcc/gcc/testsuite/gcc.dg/torture/Wsizeof-pointer-memaccess1.c
+++ gcc/gcc/testsuite/gcc.dg/torture/Wsizeof-pointer-memaccess1.c
@@ -1,6 +1,6 @@
/* Test -Wsizeof-pointer-memaccess warnings. */
/* { dg-do compile } */
-/* { dg-options "-Wall" } */
+/* { dg-options "-Wall -Wno-sizeof-array-argument" } */
/* Test just twice, once with -O0 non-fortified, once with -O2 fortified. */
/* { dg-skip-if "" { *-*-* } { "*" } { "-O0" "-O2" } } */
/* { dg-skip-if "" { *-*-* } { "-flto" } { "" } } */
diff --git gcc/gcc/testsuite/gcc.dg/vla-5.c gcc/gcc/testsuite/gcc.dg/vla-5.c
index f5256c4..2c253b5 100644
--- gcc/gcc/testsuite/gcc.dg/vla-5.c
+++ gcc/gcc/testsuite/gcc.dg/vla-5.c
@@ -13,12 +13,12 @@ void foo4(int j, int a[j]) {
int foo5(int a, int b[*][*], int c[static sizeof(*b)]);
int foo5(int a, int b[10][10], int c[400]) {
- return sizeof (c);
+ return sizeof (c); /* { dg-warning "on array function parameter" } */
}
int foo6(int a, int b[*][*], int c[static sizeof(*b)]);
int foo6(int a, int b[a][a], int c[sizeof(*b)]) {
- return sizeof (c);
+ return sizeof (c); /* { dg-warning "on array function parameter" } */
}
void foo7(__typeof__ (int (*)(int o[*])) i);
diff --git gcc/libgomp/testsuite/libgomp.c/appendix-a/a.29.1.c
gcc/libgomp/testsuite/libgomp.c/appendix-a/a.29.1.c
index 6f0f65f..4843212 100644
--- gcc/libgomp/testsuite/libgomp.c/appendix-a/a.29.1.c
+++ gcc/libgomp/testsuite/libgomp.c/appendix-a/a.29.1.c
@@ -11,8 +11,8 @@ f (int n, int B[n][n], int C[])
E[1][1] = 4;
#pragma omp parallel firstprivate(B, C, D, E)
{
- assert (sizeof (B) == sizeof (int (*)[n]));
- assert (sizeof (C) == sizeof (int *));
+ assert (sizeof (B) == sizeof (int (*)[n])); /* { dg-warning "on array
function parameter" } */
+ assert (sizeof (C) == sizeof (int *)); /* { dg-warning "on array function
parameter" } */
assert (sizeof (D) == 4 * sizeof (int));
assert (sizeof (E) == n * n * sizeof (int));
/* Private B and C have values of original B and C. */
Marek
