Warn used and not used symbols in section with the same name

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.

diff --git a/gcc/testsuite/c-c++-common/attr-used-5.c b/gcc/testsuite/c-c++-common/attr-used-5.c
index 9fc0d3834e9399331fdfebfca89a0f5757713067..ba59326e4523510a8544a379f3b69526283b7288 100644 (file)
--- 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 R_flag_in_section } .-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 0cb82ade5a9554c6e37155193e358fa9b80158a1..5d20f875bf0f1640160e8238c8661ae72815d5ed 100644 (file)
--- 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 R_flag_in_section } .-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 fba2706ffc10d3047adab6b598ff5c38361d42d0..75576bcabe5af20ef796eafdabecd16a493b4016 100644 (file)
--- 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 R_flag_in_section } .-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 4da4aabe573cbd3ce76844542450f5528e383066..e4982db1044be7c759739267a771736892630b3a 100644 (file)
--- 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 R_flag_in_section } .-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/varasm.c b/gcc/varasm.c
index cfec870e067747a9475fe566fa34c76abe1bf30f..a1a8d3bd73e698e983ab5a0bde5ec03c13a9533c 100644 (file)
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -7765,11 +7765,27 @@ 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;