V2 [PATCH 2/2] Warn used and not used symbols in section with the same name
H.J. Lu
hjl.tools@gmail.com
Fri Dec 4 16:17:23 GMT 2020
When SECTION_RETAIN is used, issue a warning when a symbol without used
attribute and a symbol with used attribute are placed in the section with
the same name, like
int __attribute__((used,section(".data.foo"))) foo2 = 2;
int __attribute__((section(".data.foo"))) foo1 = 1;
since assembler will put them in different sections with the same section
name.
gcc/
PR target/98146
* varasm.c (switch_to_section): Warn when a symbol without used
attribute and a symbol with used attribute are placed in the
section with the same name.
gcc/testsuite/
PR target/98146
* c-c++-common/attr-used-5.c: Updated.
* c-c++-common/attr-used-6.c: Likewise.
* c-c++-common/attr-used-7.c: Likewise.
* c-c++-common/attr-used-8.c: Likewise.
* c-c++-common/attr-used-9.c: Likewise.
---
gcc/testsuite/c-c++-common/attr-used-5.c | 1 +
gcc/testsuite/c-c++-common/attr-used-6.c | 1 +
gcc/testsuite/c-c++-common/attr-used-7.c | 1 +
gcc/testsuite/c-c++-common/attr-used-8.c | 1 +
gcc/testsuite/c-c++-common/attr-used-9.c | 28 ++++++++++++++++++++++++
gcc/varasm.c | 22 ++++++++++++++++---
6 files changed, 51 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/attr-used-9.c
diff --git a/gcc/testsuite/c-c++-common/attr-used-5.c b/gcc/testsuite/c-c++-common/attr-used-5.c
index 9fc0d3834e9..38ca8ef83f3 100644
--- a/gcc/testsuite/c-c++-common/attr-used-5.c
+++ b/gcc/testsuite/c-c++-common/attr-used-5.c
@@ -10,6 +10,7 @@ extern struct dtv_slotinfo_list *list;
static int __attribute__ ((section ("__libc_freeres_fn")))
free_slotinfo (struct dtv_slotinfo_list **elemp)
+/* { dg-warning "'.*' without 'used' attribute and '.*' with 'used' attribute are placed in a section with the same name" "" { target *-*-* } .-1 } */
{
if (!free_slotinfo (&(*elemp)->next))
return 0;
diff --git a/gcc/testsuite/c-c++-common/attr-used-6.c b/gcc/testsuite/c-c++-common/attr-used-6.c
index 0cb82ade5a9..a4800f6d0f1 100644
--- a/gcc/testsuite/c-c++-common/attr-used-6.c
+++ b/gcc/testsuite/c-c++-common/attr-used-6.c
@@ -18,6 +18,7 @@ free_slotinfo (struct dtv_slotinfo_list **elemp)
__attribute__ ((section ("__libc_freeres_fn")))
void free_mem (void)
+/* { dg-warning "'.*' without 'used' attribute and '.*' with 'used' attribute are placed in a section with the same name" "" { target *-*-* } .-1 } */
{
free_slotinfo (&list);
}
diff --git a/gcc/testsuite/c-c++-common/attr-used-7.c b/gcc/testsuite/c-c++-common/attr-used-7.c
index fba2706ffc1..39923cdde33 100644
--- a/gcc/testsuite/c-c++-common/attr-used-7.c
+++ b/gcc/testsuite/c-c++-common/attr-used-7.c
@@ -3,6 +3,7 @@
int __attribute__((used,section(".data.foo"))) foo2 = 2;
int __attribute__((section(".data.foo"))) foo1 = 1;
+/* { dg-warning "'.*' without 'used' attribute and '.*' with 'used' attribute are placed in a section with the same name" "" { target *-*-* } .-1 } */
/* { dg-final { scan-assembler ".data.foo,\"aw\"" { target R_flag_in_section } } } */
/* { dg-final { scan-assembler ".data.foo,\"awR\"" { target R_flag_in_section } } } */
diff --git a/gcc/testsuite/c-c++-common/attr-used-8.c b/gcc/testsuite/c-c++-common/attr-used-8.c
index 4da4aabe573..032cdd20901 100644
--- a/gcc/testsuite/c-c++-common/attr-used-8.c
+++ b/gcc/testsuite/c-c++-common/attr-used-8.c
@@ -2,6 +2,7 @@
/* { dg-options "-Wall -O2" } */
int __attribute__((section(".data.foo"))) foo1 = 1;
+/* { dg-warning "'.*' without 'used' attribute and '.*' with 'used' attribute are placed in a section with the same name" "" { target *-*-* } .-1 } */
int __attribute__((used,section(".data.foo"))) foo2 = 2;
/* { dg-final { scan-assembler ".data.foo,\"aw\"" { target R_flag_in_section } } } */
diff --git a/gcc/testsuite/c-c++-common/attr-used-9.c b/gcc/testsuite/c-c++-common/attr-used-9.c
new file mode 100644
index 00000000000..502c768c813
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-used-9.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wall -O2" } */
+
+struct dtv_slotinfo_list
+{
+ struct dtv_slotinfo_list *next;
+};
+
+extern struct dtv_slotinfo_list *list;
+
+static int __attribute__ ((used, section ("__libc_freeres_fn")))
+free_slotinfo (struct dtv_slotinfo_list **elemp)
+{
+ if (!free_slotinfo (&(*elemp)->next))
+ return 0;
+ return 1;
+}
+
+__attribute__ ((section ("__libc_freeres_fn")))
+static void free_mem (void)
+/* { dg-warning "defined but not used" "" { target *-*-* } .-1 } */
+{
+ free_slotinfo (&list);
+}
+
+/* { dg-final { scan-assembler-not "__libc_freeres_fn,\"ax\"" } }*/
+/* { dg-final { scan-assembler-not "__libc_freeres_fn\n" } } */
+/* { dg-final { scan-assembler "__libc_freeres_fn,\"axR\"" { target R_flag_in_section } } } */
diff --git a/gcc/varasm.c b/gcc/varasm.c
index c85d39813ec..025e0fb32fe 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -7731,11 +7731,27 @@ switch_to_section (section *new_section, tree decl)
{
/* If the SECTION_RETAIN bit doesn't match, switch to a new
section. */
+ tree used_decl, no_used_decl;
+
if (DECL_PRESERVE_P (decl))
- new_section->common.flags |= SECTION_RETAIN;
+ {
+ new_section->common.flags |= SECTION_RETAIN;
+ used_decl = decl;
+ no_used_decl = new_section->named.decl;
+ }
else
- new_section->common.flags &= ~(SECTION_RETAIN
- | SECTION_DECLARED);
+ {
+ new_section->common.flags &= ~(SECTION_RETAIN
+ | SECTION_DECLARED);
+ used_decl = new_section->named.decl;
+ no_used_decl = decl;
+ }
+ warning (OPT_Wattributes,
+ "%+qD without %<used%> attribute and %qD with "
+ "%<used%> attribute are placed in a section with "
+ "the same name", no_used_decl, used_decl);
+ inform (DECL_SOURCE_LOCATION (used_decl),
+ "%qD was declared here", used_decl);
}
else
return;
--
2.28.0
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