Merging r243660:

------------------------------------------------------------------------
r243660 | Matthew.Arsenault | 2015-07-30 13:03:08 -0400 (Thu, 30 Jul 2015) | 9 lines

AMDGPU: Fix unreachable when emitting binary debug info

Copy implementation of applyFixup from AArch64 with AArch64 bits
ripped out.

Tests will be included with a later commit. Several other
problems must be fixed before binary debug info emission
will work.

------------------------------------------------------------------------

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_37@253229 91177308-0d34-0410-b5e6-96231b3b80d8

Author: tstellarAMD

lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp

@@ -71,12 +71,26 @@ void AMDGPUMCObjectWriter::writeObject(MCAssembler &Asm,
   }
 }
 
+static unsigned getFixupKindNumBytes(unsigned Kind) {
+  switch (Kind) {
+  case FK_Data_1:
+    return 1;
+  case FK_Data_2:
+    return 2;
+  case FK_Data_4:
+    return 4;
+  case FK_Data_8:
+    return 8;
+  default:
+    llvm_unreachable("Unknown fixup kind!");
+  }
+}
+
 void AMDGPUAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
                                   unsigned DataSize, uint64_t Value,
                                   bool IsPCRel) const {
 
   switch ((unsigned)Fixup.getKind()) {
-    default: llvm_unreachable("Unknown fixup kind");
     case AMDGPU::fixup_si_sopp_br: {
       uint16_t *Dst = (uint16_t*)(Data + Fixup.getOffset());
       *Dst = (Value - 4) / 4;
@@ -96,6 +110,24 @@ void AMDGPUAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
       *Dst = Value + 4;
       break;
     }
+    default: {
+      // FIXME: Copied from AArch64
+      unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
+      if (!Value)
+        return; // Doesn't change encoding.
+      MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
+
+      // Shift the value into position.
+      Value <<= Info.TargetOffset;
+
+      unsigned Offset = Fixup.getOffset();
+      assert(Offset + NumBytes <= DataSize && "Invalid fixup offset!");
+
+      // For each byte of the fragment that the fixup touches, mask in the
+      // bits from the fixup value.
+      for (unsigned i = 0; i != NumBytes; ++i)
+        Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff);
+    }
   }
 }