Treat the user defined stack protect guard, __stack_chk_guard, as an
internal C/C++ symbol and declare __stack_chk_guard as a size_t variable
if size_t has the same size as pointer. If a user defined variable name
is the same as the stack protect guard, use the predefined stack protect
guard declaration and apply its visibility attribute to the internal
__stack_chk_guard symbol.
gcc/
PR c/121911
* targhooks.cc (default_stack_protect_guard): Use size_type_node
if it has the same size as ptr_type_node.
* varasm.cc (mark_stack_protect_guard_decl_local): New.
* varasm.h (mark_stack_protect_guard_decl_local): Likewise.
gcc/c-family/
PR c/121911
* c-attribs.cc (handle_visibility_attribute): Call
mark_stack_protect_guard_decl_local as local for non-default
visibility.
gcc/c/
PR c/121911
* c-decl.cc (grokdeclarator): If the variable name is the same
as the stack protect guard, use the stack protect guard decl.
gcc/cp/
PR c/121911
* decl.cc (grokdeclarator): If the variable name is the same as
the stack protect guard, use the stack protect guard decl.
gcc/testsuite/
PR c/121911
* g++.target/i386/ssp-global-hidden-1.C: New test.
* g++.target/i386/ssp-global-hidden-2.C: Likewise.
* gcc.target/i386/ssp-global-hidden-1.c: Likewise.
* gcc.target/i386/ssp-global-hidden-2.c: Likewise.
Signed-off-by: H.J. Lu <[email protected]>
---
gcc/c-family/c-attribs.cc | 5 +++
gcc/c/c-decl.cc | 16 +++++++
gcc/cp/decl.cc | 15 +++++++
gcc/targhooks.cc | 7 ++-
.../g++.target/i386/ssp-global-hidden-1.C | 45 +++++++++++++++++++
.../g++.target/i386/ssp-global-hidden-2.C | 19 ++++++++
.../gcc.target/i386/ssp-global-hidden-1.c | 45 +++++++++++++++++++
.../gcc.target/i386/ssp-global-hidden-2.c | 19 ++++++++
gcc/varasm.cc | 12 +++++
gcc/varasm.h | 1 +
10 files changed, 183 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.target/i386/ssp-global-hidden-1.C
create mode 100644 gcc/testsuite/g++.target/i386/ssp-global-hidden-2.C
create mode 100644 gcc/testsuite/gcc.target/i386/ssp-global-hidden-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/ssp-global-hidden-2.c
diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index 1e3a94ed949..8d76e81bf98 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -3652,6 +3652,11 @@ handle_visibility_attribute (tree *node, tree name, tree
args,
DECL_VISIBILITY (decl) = vis;
DECL_VISIBILITY_SPECIFIED (decl) = 1;
+ /* Mark the symbol of DECL for non-default visibility as local if it
+ is the stack protect guard decl. */
+ if (flag_stack_protect && vis != VISIBILITY_DEFAULT)
+ mark_stack_protect_guard_decl_local (decl);
+
/* Go ahead and attach the attribute to the node as well. This is needed
so we can determine whether we have VISIBILITY_DEFAULT because the
visibility was not specified, or because it was explicitly overridden
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index b122e82bfc4..89885593acc 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -8106,6 +8106,22 @@ grokdeclarator (const struct c_declarator *declarator,
else
{
/* It's a variable. */
+
+ if (flag_stack_protect)
+ {
+ /* If the variable name is the same as the stack protect
+ guard, use the stack protect guard decl. */
+ tree guard_decl = targetm.stack_protect_guard ();
+ if (guard_decl && VAR_P (guard_decl))
+ {
+ const char *stack_protect_guard_name
+ = IDENTIFIER_POINTER (DECL_NAME (guard_decl));
+ if (strcmp (stack_protect_guard_name,
+ IDENTIFIER_POINTER (declarator->u.id.id)) == 0)
+ return guard_decl;
+ }
+ }
+
/* An uninitialized decl with `extern' is a reference. */
int extern_ref = !initialized && storage_class == csc_extern;
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index a6a98426ed9..2e6e935bcc9 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -16233,6 +16233,21 @@ grokdeclarator (const cp_declarator *declarator,
{
/* It's a variable. */
+ if (flag_stack_protect && dname && identifier_p (dname))
+ {
+ /* If the variable name is the same as the stack protect
+ guard, use the stack protect guard decl. */
+ tree guard_decl = targetm.stack_protect_guard ();
+ if (guard_decl && VAR_P (guard_decl))
+ {
+ const char *stack_protect_guard_name
+ = IDENTIFIER_POINTER (DECL_NAME (guard_decl));
+ if (strcmp (stack_protect_guard_name,
+ IDENTIFIER_POINTER (unqualified_id)) == 0)
+ return guard_decl;
+ }
+ }
+
/* An uninitialized decl with `extern' is a reference. */
decl = grokvardecl (type, dname, unqualified_id,
declspecs,
diff --git a/gcc/targhooks.cc b/gcc/targhooks.cc
index 947e39aedc1..fc24a6fd488 100644
--- a/gcc/targhooks.cc
+++ b/gcc/targhooks.cc
@@ -924,9 +924,14 @@ default_stack_protect_guard (void)
{
rtx x;
+ /* __stack_chk_guard is treated as an internal C/C++ symbol. Use
+ size_type_node if it has the same size as ptr_type_node since
+ __stack_chk_guard can be initialized as an integer. */
t = build_decl (UNKNOWN_LOCATION,
VAR_DECL, get_identifier ("__stack_chk_guard"),
- ptr_type_node);
+ (TYPE_PRECISION (size_type_node)
+ == TYPE_PRECISION (ptr_type_node)
+ ? size_type_node : ptr_type_node));
TREE_STATIC (t) = 1;
TREE_PUBLIC (t) = 1;
DECL_EXTERNAL (t) = 1;
diff --git a/gcc/testsuite/g++.target/i386/ssp-global-hidden-1.C
b/gcc/testsuite/g++.target/i386/ssp-global-hidden-1.C
new file mode 100644
index 00000000000..2f7a554ccbd
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/ssp-global-hidden-1.C
@@ -0,0 +1,45 @@
+/* { dg-do run { target { fstack_protector && fpic } } } */
+/* { dg-options "-O2 -fPIC -fstack-protector-all
-mstack-protector-guard=global -save-temps" } */
+
+#include <stdlib.h>
+#include <stddef.h>
+
+__attribute__ ((visibility ("hidden")))
+#ifdef __LP64__
+const size_t __stack_chk_guard = 0x2d853605a4d9a09cUL;
+#else
+const size_t __stack_chk_guard = 0xdd2cc927UL;
+#endif
+
+extern "C" void
+__stack_chk_fail (void)
+{
+ exit (0); /* pass */
+}
+
+__attribute__ ((noipa))
+void
+smash (char *p, int i)
+{
+ p[i] = 42;
+}
+
+int
+main (void)
+{
+ char foo[255];
+
+ /* smash stack */
+ for (int i = 0; i <= 400; i++)
+ smash (foo, i);
+
+ return 1;
+}
+
+/* { dg-final { scan-hidden "__stack_chk_guard" } } */
+/* { dg-final { scan-assembler "__stack_chk_guard\\(%rip\\)" { target { ! ia32
} } } } */
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOTPCREL" { target { !
ia32 } } } } */
+ /* { dg-final { scan-assembler ".quad 3280087301477736604" { target {
lp64 } } } } */
+/* { dg-final { scan-assembler "__stack_chk_guard@GOTOFF" { target ia32 } } }
*/
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOT\\(" { target ia32 }
} } */
+ /* { dg-final { scan-assembler ".long -584267481" { target { ! lp64 }
} } } */
diff --git a/gcc/testsuite/g++.target/i386/ssp-global-hidden-2.C
b/gcc/testsuite/g++.target/i386/ssp-global-hidden-2.C
new file mode 100644
index 00000000000..845cf550eb9
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/ssp-global-hidden-2.C
@@ -0,0 +1,19 @@
+/* { dg-do compile { target { fstack_protector && fpic } } } */
+/* { dg-options "-O2 -fPIC -fstack-protector-all
-mstack-protector-guard=global" } */
+
+#include <stddef.h>
+
+__attribute__ ((visibility ("hidden")))
+extern const size_t __stack_chk_guard;
+
+void
+smash (char *p, int i)
+{
+ p[i] = 42;
+}
+
+/* { dg-final { scan-hidden "__stack_chk_guard" } } */
+/* { dg-final { scan-assembler "__stack_chk_guard\\(%rip\\)" { target { ! ia32
} } } } */
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOTPCREL" { target { !
ia32 } } } } */
+/* { dg-final { scan-assembler "__stack_chk_guard@GOTOFF" { target ia32 } } }
*/
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOT\\(" { target ia32 }
} } */
diff --git a/gcc/testsuite/gcc.target/i386/ssp-global-hidden-1.c
b/gcc/testsuite/gcc.target/i386/ssp-global-hidden-1.c
new file mode 100644
index 00000000000..cf6af3971d7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/ssp-global-hidden-1.c
@@ -0,0 +1,45 @@
+/* { dg-do run { target { fstack_protector && fpic } } } */
+/* { dg-options "-O2 -fPIC -fstack-protector-all
-mstack-protector-guard=global -save-temps" } */
+
+#include <stdlib.h>
+#include <stddef.h>
+
+__attribute__ ((visibility ("hidden")))
+#ifdef __LP64__
+const size_t __stack_chk_guard = 0x2d853605a4d9a09cUL;
+#else
+const size_t __stack_chk_guard = 0xdd2cc927UL;
+#endif
+
+void
+__stack_chk_fail (void)
+{
+ exit (0); /* pass */
+}
+
+__attribute__ ((noipa))
+void
+smash (char *p, int i)
+{
+ p[i] = 42;
+}
+
+int
+main (void)
+{
+ char foo[255];
+
+ /* smash stack */
+ for (int i = 0; i <= 400; i++)
+ smash (foo, i);
+
+ return 1;
+}
+
+/* { dg-final { scan-hidden "__stack_chk_guard" } } */
+/* { dg-final { scan-assembler "__stack_chk_guard\\(%rip\\)" { target { ! ia32
} } } } */
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOTPCREL" { target { !
ia32 } } } } */
+ /* { dg-final { scan-assembler ".quad 3280087301477736604" { target {
lp64 } } } } */
+/* { dg-final { scan-assembler "__stack_chk_guard@GOTOFF" { target ia32 } } }
*/
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOT\\(" { target ia32 }
} } */
+ /* { dg-final { scan-assembler ".long -584267481" { target { ! lp64 }
} } } */
diff --git a/gcc/testsuite/gcc.target/i386/ssp-global-hidden-2.c
b/gcc/testsuite/gcc.target/i386/ssp-global-hidden-2.c
new file mode 100644
index 00000000000..845cf550eb9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/ssp-global-hidden-2.c
@@ -0,0 +1,19 @@
+/* { dg-do compile { target { fstack_protector && fpic } } } */
+/* { dg-options "-O2 -fPIC -fstack-protector-all
-mstack-protector-guard=global" } */
+
+#include <stddef.h>
+
+__attribute__ ((visibility ("hidden")))
+extern const size_t __stack_chk_guard;
+
+void
+smash (char *p, int i)
+{
+ p[i] = 42;
+}
+
+/* { dg-final { scan-hidden "__stack_chk_guard" } } */
+/* { dg-final { scan-assembler "__stack_chk_guard\\(%rip\\)" { target { ! ia32
} } } } */
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOTPCREL" { target { !
ia32 } } } } */
+/* { dg-final { scan-assembler "__stack_chk_guard@GOTOFF" { target ia32 } } }
*/
+/* { dg-final { scan-assembler-not "__stack_chk_guard@GOT\\(" { target ia32 }
} } */
diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 0d78f5b384f..5b54293dc1e 100644
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -2920,6 +2920,18 @@ mark_decl_referenced (tree decl)
which do not need to be marked. */
}
+/* Mark the symbol of DECL as local if it is the stack protect guard
+ decl. */
+
+void
+mark_stack_protect_guard_decl_local (tree decl)
+{
+ if (decl != targetm.stack_protect_guard ())
+ return;
+ rtx symbol = DECL_RTL (decl);
+ symbol = XEXP (symbol, 0);
+ SYMBOL_REF_FLAGS (symbol) |= SYMBOL_FLAG_LOCAL;
+}
/* Output to FILE (an assembly file) a reference to NAME. If NAME
starts with a *, the rest of NAME is output verbatim. Otherwise
diff --git a/gcc/varasm.h b/gcc/varasm.h
index fc31c1bbf65..33171999496 100644
--- a/gcc/varasm.h
+++ b/gcc/varasm.h
@@ -41,6 +41,7 @@ extern void process_pending_assemble_externals (void);
extern bool decl_replaceable_p (tree, bool);
extern bool decl_binds_to_current_def_p (const_tree);
extern enum tls_model decl_default_tls_model (const_tree);
+extern void mark_stack_protect_guard_decl_local (tree);
/* Declare DECL to be a weak symbol. */
extern void declare_weak (tree);
--
2.51.0
