Re: [PATCH] PR target/80556

[Iain Sandoe <iain@codesourcery.com>]

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> On 18 Sep 2017, at 22:08, Simon Wright <simon@pushface.org> wrote:
> 
> On 18 Sep 2017, at 21:09, Iain Sandoe <iain@codesourcery.com> wrote:
>> 

>>> If I propose this alternative patch, should it be a new post, or should I continue this thread?
>> 
>> thanks for the patch.
>> 
>> The basic idea seems sound - as a workaround (as noted in comment #20 in the PR, we should really rationalise the libgcc/crts stuff to reflect the modern world, but these things take time...).
>> 
>> The patch as you have it would apply to every version of Darwin.
>> 
>> AFAICT from the published sources, i386 Darwin should be able to work with the libgcc unwinder (and all earlier Darwin *have* to) - so I’ve proposed a modified patch in the PR that makes the changes specific to m64 x86 and doesn’t make any alteration for PPC and/or Darwin < 10.
> 
> That sounds like the right thing to do. I hadn't considered the older hardware/os issues (I only have kit back to macOS 10.11, Darwin 15).

So here’s the revised version with the comments slightly updated, checked Darwin10,15,16 x86_64 and i386 in progress,
OK if i386 succeeds?

Iain Sandoe
CodeSourcery / Mentor Embedded / Siemens

gcc/

2017-09-xx Iain Sandoe <iain@codesourcery.com>

	PR target/80556
	* config/i386/darwin.h (REAL_LIB_SPEC): New; put libSystem ahead of libgcc_eh
	for m64.
	* config/i386/darwin64.h: Likewise.



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diff --git a/gcc/config/i386/darwin.h b/gcc/config/i386/darwin.h
index fccaf7e..321ed27 100644
--- a/gcc/config/i386/darwin.h
+++ b/gcc/config/i386/darwin.h
@@ -39,6 +39,32 @@ along with GCC; see the file COPYING3.  If not see
 #endif
 #endif
 
+/* WORKAROUND pr80556:
+   For x86_64 Darwin10 and later, the unwinder is in libunwind (redirected
+   from libSystem).  This doesn't use the keymgr (see keymgr.c) and therefore
+   the calls that libgcc makes to obtain the KEYMGR_GCC3_DW2_OBJ_LIST are not
+   updated to include new images, and might not even be valid for a single
+   image.
+   Therefore, for 64b exes at least, we must use the libunwind implementation,
+   even when static-libgcc is specified.  We put libSystem first so that
+   unwinder symbols are satisfied from there. */
+#undef REAL_LIBGCC_SPEC
+#define REAL_LIBGCC_SPEC						   \
+   "%{static-libgcc|static: 						   \
+      %{m64:%:version-compare(>= 10.6 mmacosx-version-min= -lSystem)}	   \
+        -lgcc_eh -lgcc;							   \
+      shared-libgcc|fexceptions|fgnu-runtime:				   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_s.10.4)	   \
+       %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5)   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_ext.10.4)	   \
+       %:version-compare(>= 10.5 mmacosx-version-min= -lgcc_ext.10.5)	   \
+       -lgcc ;								   \
+      :%:version-compare(>< 10.3.9 10.5 mmacosx-version-min= -lgcc_s.10.4) \
+       %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5)   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_ext.10.4)	   \
+       %:version-compare(>= 10.5 mmacosx-version-min= -lgcc_ext.10.5)	   \
+       -lgcc }"
+
 /* Size of the Obj-C jump buffer.  */
 #define OBJC_JBLEN ((TARGET_64BIT) ? ((9 * 2) + 3 + 16) : (18))
 
diff --git a/gcc/config/i386/darwin64.h b/gcc/config/i386/darwin64.h
index f2982ed..32cb789 100644
--- a/gcc/config/i386/darwin64.h
+++ b/gcc/config/i386/darwin64.h
@@ -21,6 +21,32 @@ along with GCC; see the file COPYING3.  If not see
 #undef  DARWIN_ARCH_SPEC
 #define DARWIN_ARCH_SPEC "%{m32:i386;:x86_64}"
 
+/* WORKAROUND pr80556:
+   For x86_64 Darwin10 and later, the unwinder is in libunwind (redirected
+   from libSystem).  This doesn't use the keymgr (see keymgr.c) and therefore
+   the calls that libgcc makes to obtain the KEYMGR_GCC3_DW2_OBJ_LIST are not
+   updated to include new images, and might not even be valid for a single
+   image.
+   Therefore, for 64b exes at least, we must use the libunwind implementation,
+   even when static-libgcc is specified.  We put libSystem first so that
+   unwinder symbols are satisfied from there. */
+#undef REAL_LIBGCC_SPEC
+#define REAL_LIBGCC_SPEC						   \
+   "%{static-libgcc|static: 						   \
+      %{!m32:%:version-compare(>= 10.6 mmacosx-version-min= -lSystem)}	   \
+        -lgcc_eh -lgcc;							   \
+      shared-libgcc|fexceptions|fgnu-runtime:				   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_s.10.4)	   \
+       %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5)   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_ext.10.4)	   \
+       %:version-compare(>= 10.5 mmacosx-version-min= -lgcc_ext.10.5)	   \
+       -lgcc ;								   \
+      :%:version-compare(>< 10.3.9 10.5 mmacosx-version-min= -lgcc_s.10.4) \
+       %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5)   \
+       %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_ext.10.4)	   \
+       %:version-compare(>= 10.5 mmacosx-version-min= -lgcc_ext.10.5)	   \
+       -lgcc }"
+
 #undef  DARWIN_SUBARCH_SPEC
 #define DARWIN_SUBARCH_SPEC DARWIN_ARCH_SPEC
 

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