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Re: [PATCH] PR target/65248: Copy relocation against protected symbol doesn't work

On Thu, Mar 05, 2015 at 05:31:51PM -0800, H.J. Lu wrote:
> Protected data symbol means that it can't be pre-emptied.  It doesn't mean
> its address won't be external.  This is true for pointer to protected
> function.  With copy relocation, address of protected data defined in the
> shared library may also be external.  We only know that for sure at
> run-time.  TARGET_BINDS_LOCAL_P should return false on protected data
> symbol.  OK for trunk?
> 
> Thanks.
> 
> H.J.
> ---
> 	PR target/65248
> 	* output.h (default_binds_local_p_2): New.
> 	* varasm.c (default_binds_local_p_2): Renamed to ...
> 	(default_binds_local_p_3): This.  Don't return true on protected
> 	data symbol if protected data may be external.
> 	(default_binds_local_p): Use default_binds_local_p_3.
> 	(default_binds_local_p_1): Likewise.
> 	(default_binds_local_p_2): New.
> 	* config/i386/i386.c (TARGET_BINDS_LOCAL_P): Replace
> 	darwin_binds_local_p with default_binds_local_p_2.

Here is the updated patch with testcases.  Tested on Linux/x86.  OK
for trunk?

Thanks.


H.J.
----
gcc/

	PR target/65248
	* output.h (default_binds_local_p_2): New.
	* varasm.c (default_binds_local_p_2): Renamed to ...
	(default_binds_local_p_3): This.  Don't return true on protected
	data symbol if protected data may be external.
	(default_binds_local_p): Use default_binds_local_p_3.
	(default_binds_local_p_1): Likewise.
	(default_binds_local_p_2): New.
	* config/i386/i386.c (TARGET_BINDS_LOCAL_P): Replace
	darwin_binds_local_p with default_binds_local_p_2.

gcc/testsuite/

	PR target/65248
	* gcc.target/i386/pr65248-1.c: New file.
	* gcc.target/i386/pr65248-2.c: Likewise.
	* gcc.target/i386/pr65248-3.c: Likewise.
	* gcc.target/i386/pr65248-4.c: Likewise.
---
 gcc/config/i386/i386.c                    |  3 +++
 gcc/output.h                              |  1 +
 gcc/testsuite/gcc.target/i386/pr65248-1.c | 17 +++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr65248-2.c | 17 +++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr65248-3.c | 17 +++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr65248-4.c | 17 +++++++++++++++++
 gcc/varasm.c                              | 18 +++++++++++++++---
 7 files changed, 87 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr65248-1.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr65248-2.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr65248-3.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr65248-4.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index ab8f03a..41a487a 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -51878,6 +51878,9 @@ ix86_initialize_bounds (tree var, tree lb, tree ub, tree *stmts)
 #if TARGET_MACHO
 #undef TARGET_BINDS_LOCAL_P
 #define TARGET_BINDS_LOCAL_P darwin_binds_local_p
+#else
+#undef TARGET_BINDS_LOCAL_P
+#define TARGET_BINDS_LOCAL_P default_binds_local_p_2
 #endif
 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
 #undef TARGET_BINDS_LOCAL_P
diff --git a/gcc/output.h b/gcc/output.h
index 217d979..53e47d0 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -586,6 +586,7 @@ extern void default_asm_output_anchor (rtx);
 extern bool default_use_anchors_for_symbol_p (const_rtx);
 extern bool default_binds_local_p (const_tree);
 extern bool default_binds_local_p_1 (const_tree, int);
+extern bool default_binds_local_p_2 (const_tree);
 extern void default_globalize_label (FILE *, const char *);
 extern void default_globalize_decl_name (FILE *, tree);
 extern void default_emit_unwind_label (FILE *, tree, int, int);
diff --git a/gcc/testsuite/gcc.target/i386/pr65248-1.c b/gcc/testsuite/gcc.target/i386/pr65248-1.c
new file mode 100644
index 0000000..7b0d2af
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr65248-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fpic" } */
+
+/* Common symbol with -fpic.  */
+__attribute__((visibility("protected")))
+int xxx;
+
+int
+foo ()
+{
+  return xxx;
+}
+
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx\\(%rip\\), %eax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "xxx@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx@GOTOFF\\(%\[^,\]*\\), %eax" { target ia32 } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]xxx@GOT\\(%\[^,\]*\\), %eax" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr65248-2.c b/gcc/testsuite/gcc.target/i386/pr65248-2.c
new file mode 100644
index 0000000..78efa34
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr65248-2.c
@@ -0,0 +1,17 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fpic" } */
+
+/* Weak common symbol with -fpic.  */
+__attribute__((weak, visibility("protected")))
+int xxx;
+
+int
+foo ()
+{
+  return xxx;
+}
+
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx\\(%rip\\), %eax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "xxx@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx@GOTOFF\\(%\[^,\]*\\), %eax" { target ia32 } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]xxx@GOT\\(%\[^,\]*\\), %eax" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr65248-3.c b/gcc/testsuite/gcc.target/i386/pr65248-3.c
new file mode 100644
index 0000000..a126a26
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr65248-3.c
@@ -0,0 +1,17 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fpic" } */
+
+/* Initialized symbol with -fpic.  */
+__attribute__((visibility("protected")))
+int xxx = -1;
+
+int
+foo ()
+{
+  return xxx;
+}
+
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx\\(%rip\\), %eax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "xxx@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx@GOTOFF\\(%\[^,\]*\\), %eax" { target ia32 } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]xxx@GOT\\(%\[^,\]*\\), %eax" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr65248-4.c b/gcc/testsuite/gcc.target/i386/pr65248-4.c
new file mode 100644
index 0000000..ab730f7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr65248-4.c
@@ -0,0 +1,17 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-O2 -fpic" } */
+
+/* Weak initialized symbol with -fpic.  */
+__attribute__((weak, visibility("protected")))
+int xxx = -1;
+
+int
+foo ()
+{
+  return xxx;
+}
+
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx\\(%rip\\), %eax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "xxx@GOTPCREL" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "movl\[ \t\]xxx@GOTOFF\\(%\[^,\]*\\), %eax" { target ia32 } } } */
+/* { dg-final { scan-assembler "movl\[ \t\]xxx@GOT\\(%\[^,\]*\\), %eax" { target ia32 } } } */
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 8173207..87ac646 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -6803,7 +6803,8 @@ resolution_local_p (enum ld_plugin_symbol_resolution resolution)
 }
 
 static bool
-default_binds_local_p_2 (const_tree exp, bool shlib, bool weak_dominate)
+default_binds_local_p_3 (const_tree exp, bool shlib, bool weak_dominate,
+			 bool extern_protected_data)
 {
   /* A non-decl is an entry in the constant pool.  */
   if (!DECL_P (exp))
@@ -6849,6 +6850,9 @@ default_binds_local_p_2 (const_tree exp, bool shlib, bool weak_dominate)
      or if we have a definition for the symbol.  We cannot infer visibility
      for undefined symbols.  */
   if (DECL_VISIBILITY (exp) != VISIBILITY_DEFAULT
+      && (TREE_CODE (exp) == FUNCTION_DECL
+	  || !extern_protected_data
+	  || DECL_VISIBILITY (exp) != VISIBILITY_PROTECTED)
       && (DECL_VISIBILITY_SPECIFIED (exp) || defined_locally))
     return true;
 
@@ -6884,13 +6888,21 @@ default_binds_local_p_2 (const_tree exp, bool shlib, bool weak_dominate)
 bool
 default_binds_local_p (const_tree exp)
 {
-  return default_binds_local_p_2 (exp, flag_shlib != 0, true);
+  return default_binds_local_p_3 (exp, flag_shlib != 0, true, false);
+}
+
+/* Similar to default_binds_local_p, but protected data may be
+   external.  */
+bool
+default_binds_local_p_2 (const_tree exp)
+{
+  return default_binds_local_p_3 (exp, flag_shlib != 0, true, true);
 }
 
 bool
 default_binds_local_p_1 (const_tree exp, int shlib)
 {
-  return default_binds_local_p_2 (exp, shlib != 0, false);
+  return default_binds_local_p_3 (exp, shlib != 0, false, false);
 }
 
 /* Return true when references to DECL must bind to current definition in
-- 
1.9.3
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