[patch i386]: Unbreak bootstrap for x64 SEH enabled target
Hello,
by recent changes gcc begun to move code into the prologue region.
This is for x64 SEH an issue, as here the table-information for
prologue is limited to 255 bytes size. So we need to avoid moving
additional code into prologue. To achieve this we mark all standard
and xmm registers as prologue-used at the end of prologue. Also we
need to emit a memory blockage.
ChangeLog
2011-10-12 Kai Tietz kti...@redhat.com
* config/i386/i386.c (ix86_expand_prologue): Mark
for TARGET_SEH all sse/integer registers as prologue-used.
Tested for x86_64-w64-mingw32. Ok for apply?
Regards,
Kai
Index: i386.c
===
--- i386.c (revision 179824)
+++ i386.c (working copy)
@@ -10356,7 +10356,24 @@
Further, prevent alloca modifications to the stack pointer from being
combined with prologue modifications. */
if (TARGET_SEH)
-emit_insn (gen_prologue_use (stack_pointer_rtx));
+{
+ int i;
+
+ /* Due limited size of prologue-code size of 255 bytes,
+ we need to prevent scheduler to sink instructions into
+ prologue code. Therefore we mark all standard, sse, fpu,
+ and the pc registers as prologue-used to prevent this.
+ Also an memory-blockage is necessary. */
+ emit_insn (gen_memory_blockage ());
+
+ for (i = 0; i = 7; i++)
+{
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, AX_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, R8_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM0_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM8_REG + i)));
+ }
+}
}
/* Emit code to restore REG using a POP insn. */
Re: [patch i386]: Unbreak bootstrap for x64 SEH enabled target
On 10/12/2011 12:07 AM, Kai Tietz wrote:
Hello,
by recent changes gcc begun to move code into the prologue region.
This is for x64 SEH an issue, as here the table-information for
prologue is limited to 255 bytes size. So we need to avoid moving
additional code into prologue. To achieve this we mark all standard
and xmm registers as prologue-used at the end of prologue. Also we
need to emit a memory blockage.
ChangeLog
2011-10-12 Kai Tietz kti...@redhat.com
* config/i386/i386.c (ix86_expand_prologue): Mark
for TARGET_SEH all sse/integer registers as prologue-used.
Tested for x86_64-w64-mingw32. Ok for apply?
Regards,
Kai
Index: i386.c
===
--- i386.c (revision 179824)
+++ i386.c (working copy)
@@ -10356,7 +10356,24 @@
Further, prevent alloca modifications to the stack pointer from being
combined with prologue modifications. */
if (TARGET_SEH)
-emit_insn (gen_prologue_use (stack_pointer_rtx));
+{
+ int i;
+
+ /* Due limited size of prologue-code size of 255 bytes,
+ we need to prevent scheduler to sink instructions into
+ prologue code. Therefore we mark all standard, sse, fpu,
+ and the pc registers as prologue-used to prevent this.
+ Also an memory-blockage is necessary. */
+ emit_insn (gen_memory_blockage ());
+
+ for (i = 0; i = 7; i++)
+{
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, AX_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, R8_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM0_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM8_REG + i)));
+ }
+}
This is overkill. We simply need to disable shrink-wrapping for SEH.
The easiest way to do that is to add !TARGET_SEH (and a comment) to
the simple_return pattern predicate.
r~
Re: [patch i386]: Unbreak bootstrap for x64 SEH enabled target
2011/10/12 Richard Henderson r...@redhat.com:
On 10/12/2011 12:07 AM, Kai Tietz wrote:
Hello,
by recent changes gcc begun to move code into the prologue region.
This is for x64 SEH an issue, as here the table-information for
prologue is limited to 255 bytes size. So we need to avoid moving
additional code into prologue. To achieve this we mark all standard
and xmm registers as prologue-used at the end of prologue. Also we
need to emit a memory blockage.
ChangeLog
2011-10-12 Kai Tietz kti...@redhat.com
* config/i386/i386.c (ix86_expand_prologue): Mark
for TARGET_SEH all sse/integer registers as prologue-used.
Tested for x86_64-w64-mingw32. Ok for apply?
Regards,
Kai
Index: i386.c
===
--- i386.c (revision 179824)
+++ i386.c (working copy)
@@ -10356,7 +10356,24 @@
Further, prevent alloca modifications to the stack pointer from being
combined with prologue modifications. */
if (TARGET_SEH)
- emit_insn (gen_prologue_use (stack_pointer_rtx));
+ {
+ int i;
+
+ /* Due limited size of prologue-code size of 255 bytes,
+ we need to prevent scheduler to sink instructions into
+ prologue code. Therefore we mark all standard, sse, fpu,
+ and the pc registers as prologue-used to prevent this.
+ Also an memory-blockage is necessary. */
+ emit_insn (gen_memory_blockage ());
+
+ for (i = 0; i = 7; i++)
+ {
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, AX_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (Pmode, R8_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM0_REG + i)));
+ emit_insn (gen_prologue_use (gen_rtx_REG (TImode, XMM8_REG + i)));
+ }
+ }
This is overkill. We simply need to disable shrink-wrapping for SEH.
The easiest way to do that is to add !TARGET_SEH (and a comment) to
the simple_return pattern predicate.
r~
Thanks, this is indeed more simple. I wasn't aware that enamed
return_simple expand also enables shrink-wrapping into prologue.
Patch tested for x86_64-w64-mingw32. Ok?
Regards,
Kai
Index: i386.md
===
--- i386.md (revision 179824)
+++ i386.md (working copy)
@@ -11708,9 +11708,13 @@
}
})
+;; We need to disable this for TARGET_SEH, as otherwise
+;; shrink-wrapped prologue gets enabled too. This might exceed
+;; the maximum size of prologue in unwind information.
+
(define_expand simple_return
[(simple_return)]
-
+ !TARGET_SEH
{
if (crtl-args.pops_args)
{
Re: [patch i386]: Unbreak bootstrap for x64 SEH enabled target
On 10/12/2011 09:54 AM, Kai Tietz wrote: +;; We need to disable this for TARGET_SEH, as otherwise +;; shrink-wrapped prologue gets enabled too. This might exceed +;; the maximum size of prologue in unwind information. + (define_expand simple_return [(simple_return)] - + !TARGET_SEH Ok. r~
