Hi,
This patch is to fix the problem described here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
I follow Ian's suggestion and set
ix86_tls_descriptor_calls_expanded_in_cfun in
tls_global_dynamic_64_<mode> and tls_local_dynamic_base_64_<mode>.
Although 32bit doesn't have the problem,
ix86_tls_descriptor_calls_expanded_in_cfun is also set for
tls_global_dynamic_32 and tls_local_dynamic_base_32 to make
ix86_tls_descriptor_calls_expanded_in_cfun setting consistent across
32bits and 64bits.
If ix86_current_function_calls_tls_descriptor is set, we know that
there is tls expanded call in current function. Update
crtl->preferred_stack_boundary and crtl->stack_alignment_needed to be
no less than PREFERED_STACK_ALIGNMENT at the start of
ix86_compute_frame_layout. We don't do the update in
legitimize_tls_address in cfgexpand stage, which is too early because
according to the comments before
ix86_current_function_calls_tls_descriptor, tls call may be optimized
away. ix86_compute_frame_layout is the latest place to do the update.
bootstrap on x86_64-linux-gnu is ok. regression test is going on. Ok
for trunk if tests pass?
Thanks,
Wei.
gcc/ChangeLog:
2014-03-07 Wei Mi <w...@google.com>
* config/i386/i386.c (ix86_compute_frame_layout): Update
preferred_stack_boundary when there is tls expanded call.
* config/i386/i386.md: Set
ix86_tls_descriptor_calls_expanded_in_cfun.
gcc/testsuite/ChangeLog:
2014-03-07 Wei Mi <w...@google.com>
* g++.dg/pr58066.C: New test.
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 208410)
+++ gcc/config/i386/i386.c (working copy)
@@ -9504,6 +9504,19 @@ ix86_compute_frame_layout (struct ix86_f
crtl->preferred_stack_boundary = 128;
crtl->stack_alignment_needed = 128;
}
+ /* For 64-bit target, preferred_stack_boundary is never updated for call
+ expanded from tls descriptor. Update it here. We don't update it in
+ expand stage because according to the comments before
+ ix86_current_function_calls_tls_descriptor, tls calls may be optimized
+ away. */
+ else if (TARGET_64BIT
+ && ix86_current_function_calls_tls_descriptor
+ && crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
+ {
+ crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
+ if (crtl->stack_alignment_needed < PREFERRED_STACK_BOUNDARY)
+ crtl->stack_alignment_needed = PREFERRED_STACK_BOUNDARY;
+ }
gcc_assert (!size || stack_alignment_needed);
gcc_assert (preferred_alignment >= STACK_BOUNDARY / BITS_PER_UNIT);
Index: gcc/config/i386/i386.md
===================================================================
--- gcc/config/i386/i386.md (revision 208410)
+++ gcc/config/i386/i386.md (working copy)
@@ -12891,7 +12891,11 @@
UNSPEC_TLS_GD))
(clobber (match_scratch:SI 4))
(clobber (match_scratch:SI 5))
- (clobber (reg:CC FLAGS_REG))])])
+ (clobber (reg:CC FLAGS_REG))])]
+ ""
+{
+ ix86_tls_descriptor_calls_expanded_in_cfun = true;
+})
(define_insn "*tls_global_dynamic_64_<mode>"
[(set (match_operand:P 0 "register_operand" "=a")
@@ -12946,7 +12950,10 @@
(const_int 0)))
(unspec:P [(match_operand 1 "tls_symbolic_operand")]
UNSPEC_TLS_GD)])]
- "TARGET_64BIT")
+ "TARGET_64BIT"
+{
+ ix86_tls_descriptor_calls_expanded_in_cfun = true;
+})
(define_insn "*tls_local_dynamic_base_32_gnu"
[(set (match_operand:SI 0 "register_operand" "=a")
@@ -12982,7 +12989,11 @@
UNSPEC_TLS_LD_BASE))
(clobber (match_scratch:SI 3))
(clobber (match_scratch:SI 4))
- (clobber (reg:CC FLAGS_REG))])])
+ (clobber (reg:CC FLAGS_REG))])]
+ ""
+{
+ ix86_tls_descriptor_calls_expanded_in_cfun = true;
+})
(define_insn "*tls_local_dynamic_base_64_<mode>"
[(set (match_operand:P 0 "register_operand" "=a")
@@ -13029,7 +13040,10 @@
(mem:QI (match_operand 1))
(const_int 0)))
(unspec:P [(const_int 0)] UNSPEC_TLS_LD_BASE)])]
- "TARGET_64BIT")
+ "TARGET_64BIT"
+{
+ ix86_tls_descriptor_calls_expanded_in_cfun = true;
+})
;; Local dynamic of a single variable is a lose. Show combine how
;; to convert that back to global dynamic.
Index: gcc/testsuite/g++.dg/pr58066.C
===================================================================
--- gcc/testsuite/g++.dg/pr58066.C (revision 0)
+++ gcc/testsuite/g++.dg/pr58066.C (revision 0)
@@ -0,0 +1,12 @@
+/* { dg-do compile { target {{ i?86-*-* x86_64-*-* } && lp64 } } } */
+/* { dg-options "-fPIC -O2 -m64" } */
+
+/* Check whether the stack frame starting address of tls expanded call
+ in __cxa_get_globals() is 16bytes aligned. */
+static __thread char ccc;
+extern "C" void* __cxa_get_globals() throw()
+{
+ return &ccc;
+}
+
+/* { dg-final { scan-assembler ".cfi_def_cfa_offset 16" } } */
