diff mbox series

[2/2] tree-optimization/109123 - run -Wuse-afer-free only early

Message ID 20230315105003.D4D1F3857437@sourceware.org
State Accepted
Headers
Series [1/2] Avoid random stmt order result in pass_waccess::use_after_inval_p |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Richard Biener March 15, 2023, 10:49 a.m. UTC 
  The following switches the -Wuse-after-free diagnostics from emitted
during the late access warning passes to the early access warning
passes to make sure we run before passes performing code motion run
which are the source of a lot of false positives on use-after-free
not involving memory operations.

The patch also fixes issues in c-c++-common/Wuse-after-free-6.c and
g++.dg/warn/Wuse-after-free3.C.

Bootstrapped and tested on x86_64-unknown-linux-gnu (without 1/2
sofar, but its testcase XFAILed).

OK?

Thanks,
Richard.

	PR tree-optimization/109123
	* gimple-ssa-warn-access.cc (pass_waccess::warn_invalid_pointer):
	Do not emit -Wuse-after-free late.
	(pass_waccess::check_call): Always check call pointer uses.

	* gcc.dg/Wuse-after-free-pr109123.c: New testcase.
	* c-c++-common/Wuse-after-free-6.c: Un-XFAIL case.
	* g++.dg/warn/Wuse-after-free3.C: Remove expected duplicate
	diagnostic.
---
 gcc/gimple-ssa-warn-access.cc                 | 28 ++++++-------
 .../c-c++-common/Wuse-after-free-6.c          |  2 +-
 gcc/testsuite/g++.dg/warn/Wuse-after-free3.C  |  3 +-
 .../gcc.dg/Wuse-after-free-pr109123.c         | 41 +++++++++++++++++++
 4 files changed, 57 insertions(+), 17 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/Wuse-after-free-pr109123.c
diff mbox series

Patch

diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
index a8ad7a6df65..d0809d321ea 100644
--- a/gcc/gimple-ssa-warn-access.cc
+++ b/gcc/gimple-ssa-warn-access.cc
@@ -3907,7 +3907,8 @@  pass_waccess::warn_invalid_pointer (tree ref, gimple *use_stmt,
 
   if (is_gimple_call (inval_stmt))
     {
-      if ((equality && warn_use_after_free < 3)
+      if (!m_early_checks_p
+	  || (equality && warn_use_after_free < 3)
 	  || (maybe && warn_use_after_free < 2)
 	  || warning_suppressed_p (use_stmt, OPT_Wuse_after_free))
 	return;
@@ -4300,19 +4301,18 @@  pass_waccess::check_call (gcall *stmt)
   if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
     check_builtin (stmt);
 
-  if (!m_early_checks_p)
-    if (tree callee = gimple_call_fndecl (stmt))
-      {
-	/* Check for uses of the pointer passed to either a standard
-	   or a user-defined deallocation function.  */
-	unsigned argno = fndecl_dealloc_argno (callee);
-	if (argno < (unsigned) call_nargs (stmt))
-	  {
-	    tree arg = call_arg (stmt, argno);
-	    if (TREE_CODE (arg) == SSA_NAME)
-	      check_pointer_uses (stmt, arg);
-	  }
-      }
+  if (tree callee = gimple_call_fndecl (stmt))
+    {
+      /* Check for uses of the pointer passed to either a standard
+	 or a user-defined deallocation function.  */
+      unsigned argno = fndecl_dealloc_argno (callee);
+      if (argno < (unsigned) call_nargs (stmt))
+	{
+	  tree arg = call_arg (stmt, argno);
+	  if (TREE_CODE (arg) == SSA_NAME)
+	    check_pointer_uses (stmt, arg);
+	}
+    }
 
   check_call_access (stmt);
   check_call_dangling (stmt);
diff --git a/gcc/testsuite/c-c++-common/Wuse-after-free-6.c b/gcc/testsuite/c-c++-common/Wuse-after-free-6.c
index 581b1a0a024..0c17a2545f4 100644
--- a/gcc/testsuite/c-c++-common/Wuse-after-free-6.c
+++ b/gcc/testsuite/c-c++-common/Wuse-after-free-6.c
@@ -53,7 +53,7 @@  void* warn_cond_return_after_free (void *p, int c)
   free (p);
   // PHI handling not fully implemented.
   if (c)
-    return p;       // { dg-warning "pointer 'p' may be used" "pr??????" { xfail *-*-* } }
+    return p;       // { dg-warning "pointer 'p' may be used" }
   return 0;
 }
 
diff --git a/gcc/testsuite/g++.dg/warn/Wuse-after-free3.C b/gcc/testsuite/g++.dg/warn/Wuse-after-free3.C
index 1862ac8b09d..e5b157865bf 100644
--- a/gcc/testsuite/g++.dg/warn/Wuse-after-free3.C
+++ b/gcc/testsuite/g++.dg/warn/Wuse-after-free3.C
@@ -1,7 +1,6 @@ 
 // PR target/104213
 // { dg-do compile }
 // { dg-options "-Wuse-after-free" }
-// FIXME: We should not output the warning twice.
 
 struct A
 {
@@ -13,4 +12,4 @@  A::~A ()
 {
   operator delete (this);
   f (); // { dg-warning "used after" }
-} // { dg-warning "used after" }
+}
diff --git a/gcc/testsuite/gcc.dg/Wuse-after-free-pr109123.c b/gcc/testsuite/gcc.dg/Wuse-after-free-pr109123.c
new file mode 100644
index 00000000000..ece066dd28b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wuse-after-free-pr109123.c
@@ -0,0 +1,41 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+
+typedef long unsigned int size_t;
+extern void *realloc (void *__ptr, size_t __size)
+     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__warn_unused_result__)) __attribute__ ((__alloc_size__ (2)));
+struct vector_objective; 
+typedef struct vector_objective vector_objective;
+struct vector_objective { double *_begin; double *_end; double *_capacity; };
+static inline size_t vector_objective_size(const vector_objective * v) { 
+    return v->_end - v->_begin;  /* { dg-bogus "used after" } */
+}
+static inline size_t vector_objective_capacity(const vector_objective * v) {
+    return v->_capacity - v->_begin;
+}
+static inline void vector_objective_reserve(vector_objective * v, size_t n) {
+    size_t old_capacity = vector_objective_capacity(v);
+    size_t old_size = vector_objective_size(v);
+    if (n > old_capacity) {
+        v->_begin = realloc(v->_begin, sizeof(double) * n);
+        v->_end = v->_begin + old_size;
+        v->_capacity = v->_begin + n;
+    }
+}
+static inline void vector_objective_push_back(vector_objective * v, double x) {
+    if (v->_end == v->_capacity)
+        vector_objective_reserve (v, (vector_objective_capacity (v) == 0) ? 8 : 2 * vector_objective_capacity (v));
+    *(v->_end) = x;
+    v->_end++;
+}
+
+typedef struct {
+    vector_objective xy;
+} eaf_polygon_t;
+
+int
+rectangle_add(eaf_polygon_t * regions, double lx)
+{
+  vector_objective_push_back(&regions->xy, lx);
+  return 0;
+}