4 files changed, 40 insertions, 35 deletions

diff --git a/include/llvm/CodeGen/JITCodeEmitter.h b/include/llvm/CodeGen/JITCodeEmitter.h
index c3f95b4198..180783a4d6 100644
--- a/include/llvm/CodeGen/JITCodeEmitter.h
+++ b/include/llvm/CodeGen/JITCodeEmitter.h
@@ -19,6 +19,7 @@
 
 #include <string>
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/CodeGen/MachineCodeEmitter.h"
 
 using namespace std;
@@ -161,17 +162,26 @@ public:
   /// alignment (saturated to BufferEnd of course).
   void emitAlignment(unsigned Alignment) {
     if (Alignment == 0) Alignment = 1;
+    uint8_t *NewPtr = (uint8_t*)RoundUpToAlignment((uintptr_t)CurBufferPtr,
+                                                   Alignment);
+    CurBufferPtr = std::min(NewPtr, BufferEnd);
+  }
 
-    if(Alignment <= (uintptr_t)(BufferEnd-CurBufferPtr)) {
-      // Move the current buffer ptr up to the specified alignment.
-      CurBufferPtr =
-        (uint8_t*)(((uintptr_t)CurBufferPtr+Alignment-1) &
-                   ~(uintptr_t)(Alignment-1));
-    } else {
+  /// emitAlignmentWithFill - Similar to emitAlignment, except that the
+  /// extra bytes are filled with the provided byte.
+  void emitAlignmentWithFill(unsigned Alignment, uint8_t Fill) {
+    if (Alignment == 0) Alignment = 1;
+    uint8_t *NewPtr = (uint8_t*)RoundUpToAlignment((uintptr_t)CurBufferPtr,
+                                                   Alignment);
+    // Fail if we don't have room.
+    if (NewPtr > BufferEnd) {
       CurBufferPtr = BufferEnd;
+      return;
+    }
+    while (CurBufferPtr < NewPtr) {
+      *CurBufferPtr++ = Fill;
     }
   }
-  
 
   /// emitULEB128Bytes - This callback is invoked when a ULEB128 needs to be
   /// written to the output stream.
diff --git a/include/llvm/Support/Dwarf.h b/include/llvm/Support/Dwarf.h
index 55838b8144..bfccc522b9 100644
--- a/include/llvm/Support/Dwarf.h
+++ b/include/llvm/Support/Dwarf.h
@@ -449,6 +449,7 @@ enum dwarf_constants {
 
   // Call frame instruction encodings
   DW_CFA_extended = 0x00,
+  DW_CFA_nop = 0x00,
   DW_CFA_advance_loc = 0x40,
   DW_CFA_offset = 0x80,
   DW_CFA_restore = 0xc0,
diff --git a/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
index c661168487..a3a050635f 100644
--- a/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
@@ -396,20 +396,10 @@ unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
                         TargetAsmInfo::getULEB128Size(SizeSites) + 
                         SizeSites + SizeActions + SizeTypes;
 
-  unsigned TotalSize = sizeof(int8_t) + // LPStart format
-                       sizeof(int8_t) + // TType format
-                       TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
-                       TypeOffset;
-
-  unsigned SizeAlign = (4 - TotalSize) & 3;
-
   // Begin the exception table.
-  JCE->emitAlignment(4);
-  for (unsigned i = 0; i != SizeAlign; ++i) {
-    JCE->emitByte(0);
-    // Asm->EOL("Padding");
-  }
-  
+  JCE->emitAlignmentWithFill(4, 0);
+  // Asm->EOL("Padding");
+
   unsigned char* DwarfExceptionTable = (unsigned char*)JCE->getCurrentPCValue();
 
   // Emit the header.
@@ -496,8 +486,8 @@ unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
     JCE->emitULEB128Bytes(TypeID);
     //Asm->EOL("Filter TypeInfo index");
   }
-  
-  JCE->emitAlignment(4);
+
+  JCE->emitAlignmentWithFill(4, 0);
 
   return DwarfExceptionTable;
 }
@@ -546,11 +536,12 @@ JITDwarfEmitter::EmitCommonEHFrame(const Function* Personality) const {
   std::vector<MachineMove> Moves;
   RI->getInitialFrameState(Moves);
   EmitFrameMoves(0, Moves);
-  JCE->emitAlignment(PointerSize);
-  
-  JCE->emitInt32At((uintptr_t*)StartCommonPtr, 
-              (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() - 
-                          FrameCommonBeginPtr));
+
+  JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
+
+  JCE->emitInt32At((uintptr_t*)StartCommonPtr,
+                   (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
+                               FrameCommonBeginPtr));
 
   return StartCommonPtr;
 }
@@ -590,14 +581,14 @@ JITDwarfEmitter::EmitEHFrame(const Function* Personality,
   // Indicate locations of function specific  callee saved registers in
   // frame.
   EmitFrameMoves((intptr_t)StartFunction, MMI->getFrameMoves());
-      
-  JCE->emitAlignment(PointerSize);
-  
+
+  JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
+
   // Indicate the size of the table
-  JCE->emitInt32At((uintptr_t*)StartEHPtr, 
-              (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() - 
-                          StartEHPtr));
-  
+  JCE->emitInt32At((uintptr_t*)StartEHPtr,
+                   (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
+                               StartEHPtr));
+
   // Double zeroes for the unwind runtime
   if (PointerSize == 8) {
     JCE->emitInt64(0);
@@ -606,7 +597,6 @@ JITDwarfEmitter::EmitEHFrame(const Function* Personality,
     JCE->emitInt32(0);
     JCE->emitInt32(0);
   }
-
   
   return StartEHPtr;
 }
diff --git a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
index f40e67d90c..57dd45813e 100644
--- a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
+++ b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
@@ -650,6 +650,10 @@ sys::MemoryBlock DefaultJITMemoryManager::allocateNewSlab(size_t size) {
   }
   LastSlab = B;
   ++NumSlabs;
+  // Initialize the slab to garbage when debugging.
+  if (PoisonMemory) {
+    memset(B.base(), 0xCD, B.size());
+  }
   return B;
 }