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c: Less warnings for parameters declared as arrays [PR98536]

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To avoid false positivies, tune the warnings for parameters declared
as arrays with size expressions.  Do not warn when more bounds are
specified in the declaration than before.

	PR c/98536

gcc/c-family/:
	* c-warn.cc (warn_parm_array_mismatch): Do not warn if more
	bounds are specified.

gcc/testsuite:
	* gcc.dg/Wvla-parameter-4.c: Adapt test.
	* gcc.dg/attr-access-2.c: Adapt test.
This commit is contained in:
Martin Uecker 2023-04-13 19:35:15 +02:00
parent 54be338589
commit 39f413fc4b
3 changed files with 3 additions and 32 deletions
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20
gcc/c-family/c-warn.cc
View file

@ -3599,23 +3599,13 @@ warn_parm_array_mismatch (location_t origloc, tree fndecl, tree newparms)
continue;
}
if (newunspec != curunspec)
if (newunspec > curunspec)
{
location_t warnloc = newloc, noteloc = origloc;
const char *warnparmstr = newparmstr.c_str ();
const char *noteparmstr = curparmstr.c_str ();
unsigned warnunspec = newunspec, noteunspec = curunspec;
if (newunspec < curunspec)
{
/* If the new declaration has fewer unspecified bounds
point the warning to the previous declaration to make
it clear that that's the one to change. Otherwise,
point it to the new decl. */
std::swap (warnloc, noteloc);
std::swap (warnparmstr, noteparmstr);
std::swap (warnunspec, noteunspec);
}
if (warning_n (warnloc, OPT_Wvla_parameter, warnunspec,
"argument %u of type %s declared with "
"%u unspecified variable bound",
@ -3643,14 +3633,10 @@ warn_parm_array_mismatch (location_t origloc, tree fndecl, tree newparms)
}
/* Iterate over the lists of VLA variable bounds, comparing each
pair for equality, and diagnosing mismatches. The case of
the lists having different lengths is handled above so at
this point they do . */
for (tree newvbl = newa->size, curvbl = cura->size; newvbl;
pair for equality, and diagnosing mismatches. */
for (tree newvbl = newa->size, curvbl = cura->size; newvbl && curvbl;
newvbl = TREE_CHAIN (newvbl), curvbl = TREE_CHAIN (curvbl))
{
gcc_assert (curvbl);
tree newpos = TREE_PURPOSE (newvbl);
tree curpos = TREE_PURPOSE (curvbl);

5
gcc/testsuite/gcc.dg/Wvla-parameter-4.c
View file

@ -12,11 +12,6 @@ typedef int IA3[3];
/* Verify the warning points to the declaration with more unspecified
bounds, guiding the user to specify them rather than making them all
unspecified. */
void* f_pIA3ax (IA3 *x[*]); // { dg-warning "argument 1 of type 'int \\\(\\\*\\\[\\\*]\\\)\\\[3]' .aka '\[^\n\r\}\]+'. declared with 1 unspecified variable bound" }
void* f_pIA3ax (IA3 *x[*]);
void* f_pIA3ax (IA3 *x[n]); // { dg-message "subsequently declared as 'int \\\(\\\*\\\[n]\\\)\\\[3]' with 0 unspecified variable bounds" "note" }
void* f_pIA3ax (IA3 *x[n]) { return x; }
void* f_pIA3an (IA3 *x[n]); // { dg-message "previously declared as 'int \\\(\\\*\\\[n]\\\)\\\[3]' with 0 unspecified variable bounds" "note" }
void* f_pIA3an (IA3 *x[n]);

10
gcc/testsuite/gcc.dg/attr-access-2.c
View file

@ -60,16 +60,6 @@ RW (2, 1) void f10 (int n, char a[n]) // { dg-warning "attribute 'access *\\\(
// { dg-warning "argument 2 of type 'char\\\[n]' declared as a variable length array" "" { target *-*-* } .-1 }
{ (void)&n; (void)&a; }
/* The following is diagnosed to point out declarations with the T[*]
form in headers where specifying the bound is just as important as
in the definition (to detect bugs). */
void f11 (int, char[*]); // { dg-warning "argument 2 of type 'char\\\[\\\*\\\]' declared with 1 unspecified variable bound" }
void f11 (int m, char a[m]); // { dg-message "subsequently declared as 'char\\\[m]' with 0 unspecified variable bounds" "note" }
RW (2, 1) void f11 (int n, char arr[n]) // { dg-message "subsequently declared as 'char\\\[n]' with 0 unspecified variable bounds" "note" }
{ (void)&n; (void)&arr; }
/* Verify that redeclaring a function with attribute access applying
to an array parameter of any form is not diagnosed. */
void f12__ (int, int[]) RW (2, 1);