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analyzer: fix zero-fill of calloc 

It turned out that the analyzer wasn't treating calloc regions
as zero-filled, due to binding_cluster::fill_region getting an
unknown value for the byte_size_size_sval, and thus
get_or_create_repeated_svalue returning an unknown_svalue, which
was then used to fill the region.

Fixed thusly.

gcc/analyzer/ChangeLog:
	* region-model-impl-calls.cc (region_model::impl_call_calloc): Use
	a sized_region when calling zero_fill_region.

gcc/testsuite/ChangeLog:
	* gcc.dg/analyzer/calloc-1.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>
This commit is contained in:
David Malcolm 2022-02-03 11:15:48 -05:00
parent 5a668ec033
commit 23b2cb628e
2 changed files with 30 additions and 1 deletions
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4
gcc/analyzer/region-model-impl-calls.cc
View File

@ -373,7 +373,9 @@ region_model::impl_call_calloc (const call_details &cd)
nmemb_sval, size_sval);
const region *new_reg
= create_region_for_heap_alloc (prod_sval, cd.get_ctxt ());
zero_fill_region (new_reg);
const region *sized_reg
= m_mgr->get_sized_region (new_reg, NULL_TREE, prod_sval);
zero_fill_region (sized_reg);
if (cd.get_lhs_type ())
{
const svalue *ptr_sval

27
gcc/testsuite/gcc.dg/analyzer/calloc-1.c Normal file
View File

@ -0,0 +1,27 @@
#include "analyzer-decls.h"
typedef __SIZE_TYPE__ size_t;
#define NULL ((void *)0)
extern void *calloc (size_t __nmemb, size_t __size)
__attribute__ ((__nothrow__ , __leaf__))
__attribute__ ((__malloc__))
__attribute__ ((__alloc_size__ (1, 2))) ;
char *test_1 (size_t sz)
{
char *p;
p = calloc (1, 3);
if (!p)
return NULL;
__analyzer_dump_capacity (p); /* { dg-warning "capacity: '\\(\[^\n\r\]*\\)3'" } */
__analyzer_eval (p[0] == 0); /* { dg-warning "TRUE" } */
__analyzer_eval (p[1] == 0); /* { dg-warning "TRUE" } */
__analyzer_eval (p[2] == 0); /* { dg-warning "TRUE" } */
return p;
}