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Re: [Qemu-devel] gcc auto-omit-frame-pointer vs msvc longjmp
2011/10/24 Bob Breuer <breuerr@mc.net>:
> Kai Tietz wrote:
>> Hi,
>>
>> For trunk-version I have a tentative patch for this issue. ?On 4.6.x
>> and older branches this doesn't work, as here we can't differenciate
>> that easy between ms- and sysv-abi.
>>
>> But could somebody give this patch a try?
>>
>> Regards,
>> Kai
>>
>> ChangeLog
>>
>> ? ? ? ? * config/i386/i386.c (ix86_frame_pointer_required): Enforce use of
>> ? ? ? ? frame-pointer for 32-bit ms-abi, if setjmp is used.
>>
>> Index: i386.c
>> ===================================================================
>> --- i386.c ? ? ?(revision 180099)
>> +++ i386.c ? ? ?(working copy)
>> @@ -8391,6 +8391,10 @@
>> ? ?if (SUBTARGET_FRAME_POINTER_REQUIRED)
>> ? ? ?return true;
>>
>> + ?/* For older 32-bit runtimes setjmp requires valid frame-pointer. ?*/
>> + ?if (TARGET_32BIT_MS_ABI && cfun->calls_setjmp)
>> + ? ?return true;
>> +
>> ? ?/* In ix86_option_override_internal, TARGET_OMIT_LEAF_FRAME_POINTER
>> ? ? ? turns off the frame pointer by default. ?Turn it back on now if
>> ? ? ? we've not got a leaf function. ?*/
>>
>
> For a gcc 4.7 snapshot, this does fix the longjmp problem that I
> encountered. ?So aside from specifying -fno-omit-frame-pointer for
> affected files, what can be done for 4.6?
>
> Bob
Well, for 4.6.x (or older) we just can use the mingw32.h header in
gcc/config/i386/ and define here a subtarget-macro to indicate that.
The only incompatible point here might be for Wine using the
linux-compiler to build Windows related code.
A possible patch for 4.6 gcc versions I attached to this mail.
Regards,
Kai
Index: mingw32.h
===================================================================
--- mingw32.h (revision 180393)
+++ mingw32.h (working copy)
@@ -239,3 +239,8 @@
/* We should find a way to not have to update this manually. */
#define LIBGCJ_SONAME "libgcj" /*LIBGCC_EH_EXTN*/ "-12.dll"
+/* For 32-bit Windows we need valid frame-pointer for function using
+ setjmp. */
+#define SUBTARGET_SETJMP_NEED_FRAME_POINTER \
+ (!TARGET_64BIT && cfun->calls_setjmp)
+
Index: i386.c
===================================================================
--- i386.c (revision 180393)
+++ i386.c (working copy)
@@ -8741,6 +8741,12 @@
if (SUBTARGET_FRAME_POINTER_REQUIRED)
return true;
+#ifdef SUBTARGET_SETJMP_NEED_FRAME_POINTER
+ /* For older 32-bit runtimes setjmp requires valid frame-pointer. */
+ if (SUBTARGET_SETJMP_NEED_FRAME_POINTER)
+ return true;
+#endif
+
/* In ix86_option_override_internal, TARGET_OMIT_LEAF_FRAME_POINTER
turns off the frame pointer by default. Turn it back on now if
we've not got a leaf function. */