Hi,
unfortunately there are some more issues with -Waddress-of-packed-member, that
show that my previous
patch was not yet complete.
That is a bogus warning, in C and C++ (see addition in test case 1), and a
couple of missing warnings
in C++ (test case 2).
The latter warning regressions were accidentally introduced by my previous
patch, sorry.
As a side note, the generic tree for an expression like struct.array is folded
differently by
C and C++ FE. While C folds that to &struct.array, C++ folds it to
struct.array, without the
ADDR_EXPR. That might help to explain why this needs to be done in this
slightly confusing way.
Fixed the warning regression, and added some more test cases.
Bootstrapped and reg-tested on x86_64-pc-linux-gnu.
Is it OK for trunk?
Thanks
Bernd.
2019-01-22 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR c/88928
* c-warn.c (check_address_or_pointer_of_packed_member): Handle the case
when rhs is of array type correctly. Fix handling of nested structures.
testsuite:
2019-01-22 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR c/88928
* c-c++-common/Waddress-of-packed-member-1.c: Extended test case.
* c-c++-common/Waddress-of-packed-member-2.c: New test case.
Index: gcc/c-family/c-warn.c
===================================================================
--- gcc/c-family/c-warn.c (revision 268119)
+++ gcc/c-family/c-warn.c (working copy)
@@ -2796,6 +2796,10 @@ check_address_or_pointer_of_packed_membe
if (context)
break;
}
+ if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE)
+ rvalue = false;
+ if (rvalue)
+ return NULL_TREE;
rhs = TREE_OPERAND (rhs, 0);
}
Index: gcc/testsuite/c-c++-common/Waddress-of-packed-member-1.c
===================================================================
--- gcc/testsuite/c-c++-common/Waddress-of-packed-member-1.c (revision 268119)
+++ gcc/testsuite/c-c++-common/Waddress-of-packed-member-1.c (working copy)
@@ -6,6 +6,7 @@ struct t {
int b;
int *c;
int d[10];
+ int *e[1];
} __attribute__((packed));
struct t t0;
@@ -40,6 +41,7 @@ void foo (void)
i1 = t10[0].c; /* { dg-bogus "may result in an unaligned pointer value" } */
u1 = (__UINTPTR_TYPE__) &t0; /* { dg-bogus "may result in an unaligned pointer value" } */
u1 = (__UINTPTR_TYPE__) t1; /* { dg-bogus "may result in an unaligned pointer value" } */
+ i1 = t10[0].e[0]; /* { dg-bogus "may result in an unaligned pointer value" } */
t2 = (struct t**) t10; /* { dg-warning "may result in an unaligned pointer value" } */
t2 = (struct t**) t100; /* { dg-warning "may result in an unaligned pointer value" } */
t2 = (struct t**) t1; /* { dg-warning "may result in an unaligned pointer value" } */
@@ -52,4 +54,6 @@ void foo (void)
i1 = t0.d; /* { dg-warning "may result in an unaligned pointer value" } */
i1 = t1->d; /* { dg-warning "may result in an unaligned pointer value" } */
i1 = t10[0].d; /* { dg-warning "may result in an unaligned pointer value" } */
+ i1 = (int*) &t10[0].e[0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i1 = (int*) t10[0].e; /* { dg-warning "may result in an unaligned pointer value" } */
}
Index: gcc/testsuite/c-c++-common/Waddress-of-packed-member-2.c
===================================================================
--- gcc/testsuite/c-c++-common/Waddress-of-packed-member-2.c (revision 0)
+++ gcc/testsuite/c-c++-common/Waddress-of-packed-member-2.c (working copy)
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-Waddress-of-packed-member" } */
+
+struct r {
+ int a[10];
+ int b[10][10];
+};
+
+struct s {
+ char c;
+ struct r p;
+} __attribute__((packed));
+
+struct t {
+ char c;
+ struct r p __attribute__((packed));
+ struct r u;
+};
+
+struct s s0;
+struct t t0;
+int *i0;
+
+void foo (void)
+{
+ i0 = s0.p.a; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = t0.p.a; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = s0.p.b[0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = t0.p.b[0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = &s0.p.a[0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = &t0.p.a[0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = &s0.p.b[0][0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = &t0.p.b[0][0]; /* { dg-warning "may result in an unaligned pointer value" } */
+ i0 = t0.u.a; /* { dg-bogus "may result in an unaligned pointer value" } */
+ i0 = t0.u.b[0]; /* { dg-bogus "may result in an unaligned pointer value" } */
+ i0 = &t0.u.a[0]; /* { dg-bogus "may result in an unaligned pointer value" } */
+ i0 = &t0.u.b[0][0]; /* { dg-bogus "may result in an unaligned pointer value" } */
+}
