From: Joseph Myers <joseph@codesourcery.com>
Date: Sat, 18 Apr 2009 22:34:10 +0000 (+0100)
Subject: re PR c/22367 (constraints on '&' not fully implemented)
X-Git-Tag: releases/gcc-4.5.0~6420
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b4b70360f735644f8df105d2057023135367168;p=thirdparty%2Fgcc.git

re PR c/22367 (constraints on '&' not fully implemented)

	PR c/22367
	* c-typeck.c (build_unary_op): Check for taking address of
	expression of type void.

testsuite:
	* gcc.dg/lvalue-6.c, gcc.dg/lvalue-7.c: New tests.

From-SVN: r146332
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e1507651c2b5..4035b2c90ebc 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-04-18  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/22367
+	* c-typeck.c (build_unary_op): Check for taking address of
+	expression of type void.
+
 2009-04-18  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/35210
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 001ea1a5aec3..bacfdc0e8493 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -3346,6 +3346,15 @@ build_unary_op (location_t location,
     case ADDR_EXPR:
       /* Note that this operation never does default_conversion.  */
 
+      /* The operand of unary '&' must be an lvalue (which excludes
+	 expressions of type void), or, in C99, the result of a [] or
+	 unary '*' operator.  */
+      if (VOID_TYPE_P (TREE_TYPE (arg))
+	  && TYPE_QUALS (TREE_TYPE (arg)) == TYPE_UNQUALIFIED
+	  && (TREE_CODE (arg) != INDIRECT_REF
+	      || !flag_isoc99))
+	pedwarn (location, 0, "taking address of expression of type %<void%>");
+
       /* Let &* cancel out to simplify resulting code.  */
       if (TREE_CODE (arg) == INDIRECT_REF)
 	{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0ccc20a22468..a2b0bb043c3c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-04-18  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/22367
+	* gcc.dg/lvalue-6.c, gcc.dg/lvalue-7.c: New tests.
+
 2009-04-18  Joseph Myers  <joseph@codesourcery.com>
 
 	* gcc.dg/cpp/include5.c: New test.
diff --git a/gcc/testsuite/gcc.dg/lvalue-6.c b/gcc/testsuite/gcc.dg/lvalue-6.c
new file mode 100644
index 000000000000..af69de4df4c8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lvalue-6.c
@@ -0,0 +1,17 @@
+/* Test constraints on unary '&': PR 22367.  */
+
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990 -pedantic-errors" } */
+
+extern void v;
+void f1 (void) { &v; } /* { dg-error "taking address of expression of type 'void'" } */
+
+extern void *pv;
+void f2 (void) { &*pv; } /* { dg-warning "dereferencing" } */
+/* { dg-error "taking address of expression of type 'void'" "C90 only error" { target *-*-* } 10 } */
+
+extern const void cv;
+void f3 (void) { &cv; }
+
+extern const void *pcv;
+void f4 (void) { &*pcv; } /* { dg-warning "dereferencing" } */
diff --git a/gcc/testsuite/gcc.dg/lvalue-7.c b/gcc/testsuite/gcc.dg/lvalue-7.c
new file mode 100644
index 000000000000..37964e1cd763
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lvalue-7.c
@@ -0,0 +1,16 @@
+/* Test constraints on unary '&': PR 22367.  */
+
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+extern void v;
+void f1 (void) { &v; } /* { dg-error "taking address of expression of type 'void'" } */
+
+extern void *pv;
+void f2 (void) { &*pv; } /* { dg-warning "dereferencing" } */
+
+extern const void cv;
+void f3 (void) { &cv; }
+
+extern const void *pcv;
+void f4 (void) { &*pcv; } /* { dg-warning "dereferencing" } */