[llvm] r215938 - [MCJIT] Respect target endianness in RuntimeDyldMachO and RuntimeDyldChecker.

[Lang Hames]

Author: lhames
Date: Mon Aug 18 16:43:16 2014
New Revision: 215938

URL: http://llvm.org/viewvc/llvm-project?rev=215938&view=rev
Log:
[MCJIT] Respect target endianness in RuntimeDyldMachO and RuntimeDyldChecker.

This patch may address some of the issues described in http://llvm.org/PR20640.


Modified:
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp?rev=215938&r1=215937&r2=215938&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp Mon Aug 18 16:43:16 2014
@@ -705,7 +705,16 @@ uint64_t RuntimeDyldCheckerImpl::readMem
   assert(PtrSizedAddr == SrcAddr && "Linker memory pointer out-of-range.");
   uint8_t *Src = reinterpret_cast<uint8_t *>(PtrSizedAddr);
   uint64_t Result = 0;
-  memcpy(&Result, Src, Size);
+
+  // If host and target endianness match use memcpy, otherwise copy in reverse
+  // order.
+  if (getRTDyld().IsTargetLittleEndian == sys::IsLittleEndianHost)
+    memcpy(&Result, Src, Size);
+  else {
+    uint8_t *Dst = reinterpret_cast<uint8_t*>(&Result) + Size - 1;
+    for (unsigned i = 0; i < Size; ++i)
+      *Dst-- = *Src++;
+  }
   return Result;
 }
 

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp?rev=215938&r1=215937&r2=215938&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp Mon Aug 18 16:43:16 2014
@@ -110,11 +110,18 @@ void RuntimeDyldMachO::dumpRelocationToR
          << " Size: " << (1 << RE.Size) << "\n";
 }
 
-bool RuntimeDyldMachO::writeBytesUnaligned(uint8_t *Addr, uint64_t Value,
+bool RuntimeDyldMachO::writeBytesUnaligned(uint8_t *Dst, uint64_t Value,
                                            unsigned Size) {
-  for (unsigned i = 0; i < Size; ++i) {
-    *Addr++ = (uint8_t)Value;
-    Value >>= 8;
+
+
+  // If host and target endianness match use memcpy, otherwise copy in reverse
+  // order.
+  if (IsTargetLittleEndian == sys::IsLittleEndianHost)
+    memcpy(Dst, &Value, Size);
+  else {
+    uint8_t *Src = reinterpret_cast<uint8_t*>(&Value) + Size - 1;
+    for (unsigned i = 0; i < Size; ++i)
+      *Dst++ = *Src--;
   }
 
   return false;

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h?rev=215938&r1=215937&r2=215938&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.h Mon Aug 18 16:43:16 2014
@@ -119,7 +119,7 @@ public:
 
   /// Write the least significant 'Size' bytes in 'Value' out at the address
   /// pointed to by Addr. Check for overflow.
-  bool writeBytesUnaligned(uint8_t *Addr, uint64_t Value, unsigned Size);
+  bool writeBytesUnaligned(uint8_t *Dst, uint64_t Value, unsigned Size);
 
   SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }