Fix the data layout mangling specification for 'i686-pc-macho'

Use 'o' for the mangling specification instead of 'e'. This fixes an
error in the backend caused by a mismatch between the data layouts
generated by the backend and the frontend.

rdar://problem/64168540

Author: ahatanaka

clang/lib/Basic/Targets/X86.h

@@ -358,7 +358,10 @@ class LLVM_LIBRARY_VISIBILITY X86_32TargetInfo : public X86TargetInfo {
     LongDoubleWidth = 96;
     LongDoubleAlign = 32;
     SuitableAlign = 128;
-    resetDataLayout("e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-"
+    resetDataLayout(Triple.isOSBinFormatMachO() ?
+                    "e-m:o-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-"
+                    "f80:32-n8:16:32-S128" :
+                    "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-"
                     "f80:32-n8:16:32-S128");
     SizeType = UnsignedInt;
     PtrDiffType = SignedInt;

clang/test/CodeGen/target-data.c

@@ -14,6 +14,10 @@
 // RUN:     FileCheck --check-prefix=I686-CYGWIN %s
 // I686-CYGWIN: target datalayout = "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:32-n8:16:32-a:0:32-S32"
 
+// RUN: %clang_cc1 -triple i686-pc-macho -emit-llvm -o - %s | \
+// RUN:     FileCheck --check-prefix=I686-MACHO %s
+// I686-MACHO: target datalayout = "e-m:o-p:32:32-p270:32:32-p271:32:32-p272:64:64-f64:32:64-f80:32-n8:16:32-S128"
+
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | \
 // RUN:     FileCheck --check-prefix=X86_64 %s
 // X86_64: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"