From 01248e671100fbd6eac6bc3646096dc75ec885d1 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Fri, 21 Aug 2009 21:03:57 +0000
Subject: Fix a bug where the DWARF emitter in the JIT was not initializing
 alignment bytes.  libgcc doesn't seem to mind, but if you pass this DWARF to
 GDB, it doesn't like it.

Also make the JIT memory manager to initialize it's memory to garbage in debug
mode, so that it's easier to find bugs like these in the future.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79674 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp  | 46 +++++++++++-----------------
 lib/ExecutionEngine/JIT/JITMemoryManager.cpp |  4 +++
 2 files changed, 22 insertions(+), 28 deletions(-)

(limited to 'lib')

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;
 }
 
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