[PATCH] D11190: unwind: Fix libc++abi and libgcc build.

[Logan Chien]

logan created this revision.
logan added reviewers: rengolin, joerg, danalbert, asl, compnerd.
logan added a subscriber: cfe-commits.

To build libc++abi without libunwind, we should make sure that all
function calls to _Unwind_{Get,Set}{GR,IP}() are inlined as function
calls to _Unwind_VRS_{Get,Set}().  Otherwise, libc++abi.so will fail to
link since libgcc does not provide these symbol at all.

The commit reverts the changes in r228903, which breaks libc++abi/libgcc
build since then.

http://reviews.llvm.org/D11190

Files:
  include/unwind.h
  src/UnwindLevel1.c

Index: src/UnwindLevel1.c
===================================================================
--- src/UnwindLevel1.c
+++ src/UnwindLevel1.c
@@ -496,39 +496,4 @@
   unw_set_reg(cursor, UNW_REG_IP, value);
 }
 
-#else
-
-_LIBUNWIND_EXPORT uintptr_t
-_Unwind_GetGR(struct _Unwind_Context *context, int index) {
-  uintptr_t value = 0;
-  _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
-  _LIBUNWIND_TRACE_API("_Unwind_GetGR(context=%p, reg=%d) => 0x%" PRIx64 "\n",
-                       (void *)context, index, (uint64_t)value);
-  return value;
-}
-
-_LIBUNWIND_EXPORT void _Unwind_SetGR(struct _Unwind_Context *context, int index,
-                                     uintptr_t value) {
-  _LIBUNWIND_TRACE_API("_Unwind_SetGR(context=%p, reg=%d, value=0x%0"PRIx64")\n",
-                       (void *)context, index, (uint64_t)value);
-  _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
-}
-
-_LIBUNWIND_EXPORT uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
-  // remove the thumb-bit before returning
-  uintptr_t value = _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
-  _LIBUNWIND_TRACE_API("_Unwind_GetIP(context=%p) => 0x%" PRIx64 "\n",
-                       (void *)context, (uint64_t)value);
-  return value;
-}
-
-_LIBUNWIND_EXPORT void _Unwind_SetIP(struct _Unwind_Context *context,
-                                     uintptr_t value) {
-  _LIBUNWIND_TRACE_API("_Unwind_SetIP(context=%p, value=0x%0" PRIx64 ")\n",
-                       (void *)context, (uint64_t)value);
-  uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
-  _Unwind_SetGR(context, 15, value | thumb_bit);
-}
-
 #endif // !LIBCXXABI_ARM_EHABI
-
Index: include/unwind.h
===================================================================
--- include/unwind.h
+++ include/unwind.h
@@ -204,12 +204,47 @@
                 _Unwind_VRS_DataRepresentation representation);
 #endif
 
+#if !LIBCXXABI_ARM_EHABI
+
 extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
 extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
                           uintptr_t new_value);
 extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
 extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t new_value);
 
+#else  // LIBCXXABI_ARM_EHABI
+
+// These are de facto helper functions for ARM, which delegate the function
+// calls to _Unwind_VRS_Get/Set().  These are not a part of ARM EHABI
+// specification, thus these function MUST be inlined.  Please don't replace
+// these with the "extern" functin declaration; otherwise, the program
+// including this <unwind.h> header won't be ABI compatible and will result in
+// link error when we are linking the program with libgcc.
+
+static __inline__ uintptr_t _Unwind_GetGR(struct _Unwind_Context *context,
+                                          int index) {
+  uintptr_t value = 0;
+  _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
+  return value;
+}
+
+static __inline__ void _Unwind_SetGR(struct _Unwind_Context *context,
+                                     int index, uintptr_t value) {
+  _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
+}
+
+static __inline__ uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
+  // remove the thumb-bit before returning
+  return _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
+}
+
+static __inline__ void _Unwind_SetIP(struct _Unwind_Context *context,
+                                     uintptr_t value) {
+  uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
+  _Unwind_SetGR(context, 15, value | thumb_bit);
+}
+#endif  // LIBCXXABI_ARM_EHABI
+
 extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
 extern uintptr_t
     _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);


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