[gcc r13-6707] tree-optimization/109123 - run -Wuse-afer-free only early

[gcc r13-6707] tree-optimization/109123 - run -Wuse-afer-free only early

[Richard Biener]

https://gcc.gnu.org/g:0a07bfad12530bca5dc5188057ad910198780dbc

commit r13-6707-g0a07bfad12530bca5dc5188057ad910198780dbc
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Mar 15 09:12:33 2023 +0100

    tree-optimization/109123 - run -Wuse-afer-free only early
    
    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 an issue in c-c++-common/Wuse-after-free-6.c
    and causes the name of the unused pointer to appear in the diagnostic
    for extra cases in gcc.dg/Wuse-after-free-2.c
    
            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.
            * gcc.dg/Wuse-after-free-2.c: Amend expected diagnostic with
            the name of the pointer.
            * c-c++-common/Wuse-after-free-6.c: Un-XFAIL case.

Diff:
---
 gcc/gimple-ssa-warn-access.cc                   | 28 ++++++++---------
 gcc/testsuite/c-c++-common/Wuse-after-free-6.c  |  2 +-
 gcc/testsuite/gcc.dg/Wuse-after-free-2.c        |  8 ++---
 gcc/testsuite/gcc.dg/Wuse-after-free-pr109123.c | 41 +++++++++++++++++++++++++
 4 files changed, 60 insertions(+), 19 deletions(-)

diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
index fbb9b10fa75..88d44690ade 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;
@@ -4303,19 +4304,18 @@ 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/gcc.dg/Wuse-after-free-2.c b/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
index ebc051690db..ac174fdd104 100644
--- a/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
+++ b/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
@@ -76,7 +76,7 @@ void warn_cond_2_cst (char *p, int i)
   char *r = i ? p + 1 : p + 2;
 
   free (p);         // { dg-message "call to 'free'" }
-  sink (r);         // { dg-warning "pointer used after 'free'" }
+  sink (r);         // { dg-warning "pointer 'r' used after 'free'" }
 }
 
 void warn_cond_2_var (char *p, int i, int j)
@@ -84,7 +84,7 @@ void warn_cond_2_var (char *p, int i, int j)
   char *r = i ? p + i : p + j;
 
   free (p);         // { dg-message "call to 'free'" }
-  sink (r);         // { dg-warning "pointer used after 'free'" }
+  sink (r);         // { dg-warning "pointer 'r' used after 'free'" }
 }
 
 void warn_cond_3_var (char *p0, int i, int j)
@@ -92,7 +92,7 @@ void warn_cond_3_var (char *p0, int i, int j)
   char *r = i < 0 ? p0 - i : 0 < i ? p0 + j : p0 + i + j;
 
   free (p0);        // { dg-message "call to 'free'" }
-  sink (r + 1);     // { dg-warning "pointer used after 'free'" }
+  sink (r + 1);     // { dg-warning "pointer 'r' used after 'free'" }
 }
 
 int warn_cond_4 (char *p0, char *q0, int i)
@@ -100,7 +100,7 @@ int warn_cond_4 (char *p0, char *q0, int i)
   char *r = i < -1 ? p0 - 2 : i < 0 ? p0 - 1 : 1 < i ? p0 + 2 : p0 + 1;
 
   free (p0);        // { dg-message "call to 'free'" }
-  return *r;        // { dg-warning "pointer used after 'free'" }
+  return *r;        // { dg-warning "pointer 'r' used after 'free'" }
 }
 
 int warn_cond_loop (char *p)
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;
+}