Add support for detecting mismatched allocation/deallocation calls.

PR c++/90629 - Support for -Wmismatched-new-delete
PR middle-end/94527 - Add an __attribute__ that marks a function as freeing an object

gcc/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* builtins.c (access_ref::access_ref): Initialize new member.
	(compute_objsize): Use access_ref::deref.  Handle simple pointer
	assignment.
	(expand_builtin): Remove handling of the free built-in.
	(call_dealloc_argno): Same.
	(find_assignment_location): New function.
	(fndecl_alloc_p): Same.
	(gimple_call_alloc_p): Same.
	(call_dealloc_p): Same.
	(matching_alloc_calls_p): Same.
	(warn_dealloc_offset): Same.
	(maybe_emit_free_warning): Same.
	* builtins.h (struct access_ref): Declare new member.
	(maybe_emit_free_warning): Make extern.  Make use of access_ref.
	Handle -Wmismatched-new-delete.
	* calls.c (initialize_argument_information): Call
	maybe_emit_free_warning.
	* doc/extend.texi (attribute malloc): Update.
	* doc/invoke.texi (-Wfree-nonheap-object): Expand documentation.
	(-Wmismatched-new-delete): Document new option.
	(-Wmismatched-dealloc): Document new option.

gcc/c-family/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* c-attribs.c (handle_dealloc_attribute): New function.
	(handle_malloc_attribute): Handle argument forms of attribute.
	* c.opt (-Wmismatched-dealloc): New option.
	(-Wmismatched-new-delete): New option.

gcc/testsuite/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* g++.dg/asan/asan_test.cc: Fix a bug.
	* g++.dg/warn/delete-array-1.C: Add expected warning.
	* g++.old-deja/g++.other/delete2.C: Add expected warning.
	* g++.dg/warn/Wfree-nonheap-object-2.C: New test.
	* g++.dg/warn/Wfree-nonheap-object.C: New test.
	* g++.dg/warn/Wmismatched-new-delete.C: New test.
	* g++.dg/warn/Wmismatched-dealloc-2.C: New test.
	* g++.dg/warn/Wmismatched-dealloc.C: New test.
	* gcc.dg/Wmismatched-dealloc.c: New test.
	* gcc.dg/analyzer/malloc-1.c: Prune out expected warning.
	* gcc.dg/attr-malloc.c: New test.
	* gcc.dg/free-1.c: Adjust text of expected warning.
	* gcc.dg/free-2.c: Same.
	* gcc.dg/torture/pr71816.c: Prune out expected warning.
	* gcc.dg/tree-ssa/pr19831-2.c: Add an expected warning.
	* gcc.dg/Wfree-nonheap-object-2.c: New test.
	* gcc.dg/Wfree-nonheap-object-3.c: New test.
	* gcc.dg/Wfree-nonheap-object.c: New test.

libstdc++-v3/ChangeLog:

	* testsuite/ext/vstring/modifiers/clear/56166.cc: Suppress a false
	positive warning.

1 files changed, 279 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/Wfree-nonheap-object-2.c b/gcc/testsuite/gcc.dg/Wfree-nonheap-object-2.c
new file mode 100644
index 0000000..2b00d77
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wfree-nonheap-object-2.c
@@ -0,0 +1,279 @@
+/* PR ????? - No warning on attempts to access free object
+   Verify that attempting to reallocate unallocated objects referenced
+   either directly or through pointers is diagnosed.
+   { dg-do compile }
+   { dg-options "-O2 -Wall -Wfree-nonheap-object" }  */
+
+typedef __SIZE_TYPE__ size_t;
+
+extern void free (void*);
+extern void* alloca (size_t);
+extern void* realloc (void*, size_t);
+
+void sink (void*, ...);
+
+extern void* eparr[];
+extern char *eptr;
+
+extern size_t n;
+
+
+void nowarn_realloc (void *p, size_t n)
+{
+  char *q = realloc (p, n);
+  sink (q);
+
+  q = realloc (0, n);
+  sink (q);
+
+  q = realloc (q, n * 2);
+  sink (q);
+}
+
+/* Verify that calling realloc on a pointer to an unknown object minus
+   some nonzero offset isn't diagnosed, but a pointer plus a positive
+   offset is (a positive offset cannot point at the beginning).  */
+
+void test_realloc_offset (char *p1, char *p2, char *p3, size_t n, int i)
+{
+  char *q;
+  q = realloc (p1 - 1, n);
+  sink (q);
+
+  q = realloc (p2 + 1, n);    // { dg-warning "'realloc' called on pointer 'p2' with nonzero offset 1" }
+  sink (q);
+
+  q = realloc (p3 + i, n);
+  sink (q);
+}
+
+void warn_realloc_extern_arr (void)
+{
+  extern char ecarr[];        // { gg-message "declared here" }
+  char *p = ecarr;
+  char *q = realloc (p, n);   // { dg-warning "'realloc' called on unallocated object 'ecarr'" }
+  sink (q);
+}
+
+void warn_realloc_extern_arr_offset (int i)
+{
+  extern char ecarr[];
+  char *p = ecarr + i;
+  char *q = realloc (p, n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}
+
+
+void warn_realloc_string (int i)
+{
+  char *p, *q;
+  {
+    p = "123";
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+  {
+    p = "234" + 1;
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+  {
+    p = "123" + i;
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+}
+
+
+void warn_realloc_alloca (int n, int i)
+{
+  char *p, *q;
+  {
+    p = alloca (n);
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+  {
+    p = (char*)alloca (n + 1);
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+  {
+    p = (char*)alloca (n + 2) + i;
+    sink (p);
+    q = realloc (p, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+}
+
+
+void warn_realloc_local_arr (int i)
+{
+  char *q;
+  {
+    char a[4];
+    sink (a);
+    q = realloc (a, n);       // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char b[5];
+    sink (b);
+    q = realloc (b + 1, n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char c[6];
+    sink (c);
+    q = realloc (&c[2], n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char d[7];
+    sink (d);
+    q = realloc (&d[i], n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+}
+
+void warn_realloc_vla (int n1, int n2, int i)
+{
+  char *q;
+  {
+    char vla[n1];
+    sink (vla);
+    q = realloc (vla, n2);    // { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char vlb[n1 + 1];
+    sink (vlb);
+    q = realloc (vlb + 1, n2);// { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char vlc[n1 + 2];
+    sink (vlc);
+    q = realloc (&vlc[2], n2);// { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+
+  {
+    char vld[7];
+    sink (vld);
+    q = realloc (&vld[i], n2);// { dg-warning "\\\[-Wfree-nonheap-object" }
+    sink (q);
+  }
+}
+
+void nowarn_realloc_extern_ptrarr (void)
+{
+  char *q = realloc (*eparr, n);
+  sink (q);
+}
+
+void nowarn_realloc_extern_ptrarr_offset (int i)
+{
+  char *p = eparr[i];
+  char *q = realloc (p, n);
+  sink (q);
+}
+
+
+void warn_realloc_extern_ptrarr (void)
+{
+  char *q = realloc (eparr, n);  // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}
+
+void warn_realloc_extern_ptrarr_offset (int i)
+{
+  void *p = eparr + i;
+  void *q = realloc (p, n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}
+
+
+void nowarn_realloc_extern_ptr (void)
+{
+  char *q = realloc (eptr, n);
+  sink (q);
+}
+
+void nowarn_realloc_extern_ptr_offset (int i)
+{
+  char *p = eptr + i;
+  char *q = realloc (p, n);
+  sink (q);
+}
+
+
+void warn_realloc_extern_ptr_pos_offset (int i)
+{
+  if (i <= 0)
+    i = 1;
+
+  char *p = eptr + i;
+  char *q = realloc (p, n);   // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}
+
+
+void nowarn_realloc_parm_offset (char *p, int i)
+{
+  char *q = p + i;
+  q = realloc (q, n);
+  sink (q);
+}
+
+void nowarn_realloc_parm_neg_offset (char *p, int i)
+{
+  if (i >= 0)
+    i = -1;
+
+  char *q = p + i;
+  q = realloc (q, n);
+  sink (q);
+}
+
+void warn_realloc_parm_pos_offset (char *p, int i)
+{
+  if (i <= 0)
+    i = 1;
+
+  char *q = p + i;
+  q = realloc (q, n);         // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}
+
+void nowarn_realloc_deref_parm_pos_offset (void **p, int i)
+{
+  if (i <= 0)
+    i = 1;
+
+  // The offset is from p, not *p.
+  void *q = *(p + i);
+  q = realloc (q, n);
+  sink (q);
+}
+
+void warn_realloc_deref_parm_pos_offset (void **p, int i)
+{
+  if (i <= 0)
+    i = 1;
+
+  // Unlike in the function above the offset is from *p.
+  void *q = *p + i;
+  q = realloc (q, n);         // { dg-warning "\\\[-Wfree-nonheap-object" }
+  sink (q);
+}