[PATCH] Implement variable-sized alloca instrumentation.

[Kostya Serebryany]

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:108
@@ -106,1 +107,3 @@
 
+const unsigned kAllocaRzSize = 32;
+const unsigned kAsanAllocaLeftMagic = 0xcacacacaU;
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static

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:541
@@ +540,3 @@
+      IRBuilder<> IRBRet(Ret);
+      IRBRet.CreateStore(ConstantInt::get(IRBRet.getInt32Ty(), 0),
+                         AllocaCall.LeftRzAddr);
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Constant::getNullValue

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:560
@@ +559,3 @@
+  // Calculate PartialRzMagic.
+  Value *calculatePartialRzMagic(Value *PartialSize, IRBuilder<> &IRB) {
+    PartialSize = IRB.CreateIntCast(PartialSize, IRB.getInt32Ty(),
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This deserves a comment: what exactly you are computing. 

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:584
@@ +583,3 @@
+
+  void handleDynamicAllocaCall(DynamicAllocaCall &AllocaCall) {
+    AllocaInst *AI = AllocaCall.AI;
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These new functions are probably too big and should be placed outside of the class decl. 

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:586
@@ +585,3 @@
+    AllocaInst *AI = AllocaCall.AI;
+    IRBuilder<> IRB(AI);
+
----------------
write a function-level comment with the expression you are computing

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:592
@@ +591,3 @@
+
+    Value *Zero = ConstantInt::get(IntptrTy, 0);
+    Value *AllocaRzSize = ConstantInt::get(IntptrTy, kAllocaRzSize);
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Constant::getNullValue

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Comment at: lib/Transforms/Instrumentation/AddressSanitizer.cpp:602
@@ +601,3 @@
+    unsigned ElementSize = ASan.DL->getTypeAllocSize(AI->getAllocatedType());
+    Value *OldSize = IRB.CreateMul(AI->getArraySize(),
+                                             ConstantInt::get(IntptrTy,
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two lines should be enough here

http://reviews.llvm.org/D6055