Subzero: Replace pointers to allocation functions in loads

src/IceASanInstrumentation.cpp

 //===- subzero/src/IceASanInstrumentation.cpp - ASan ------------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 345 matching lines @@
       InstCall::create(Context.getNode()->getCfg(), Instr->getNumArgs(),
                        Instr->getDest(), NewFunc, Instr->isTailcall());
   for (SizeT I = 0, Args = Instr->getNumArgs(); I < Args; ++I)
     NewCall->addArg(Instr->getArg(I));
   Context.insert(NewCall);
   Instr->setDeleted();
 }
 
 void ASanInstrumentation::instrumentLoad(LoweringContext &Context,
                                          InstLoad *Instr) {
+  Operand *Src = Instr->getSourceAddress();
+  auto *Reloc = llvm::dyn_cast<ConstantRelocatable>(Src);
+  if (Reloc != nullptr) {

[Jim Stichnoth, 2016/08/16 21:36:46]

if (auto *Reloc = llvm::dyn_cast<ConstantRelocatable>(Src)) {

[tlively, 2016/08/16 21:55:38]

Done.

+    std::string SrcName = Reloc->getName().toStringOrEmpty();
+    assert(!SrcName.empty());
+    StringMap::const_iterator SrcSub = FuncSubstitutions.find(SrcName);
+    if (SrcSub != FuncSubstitutions.end()) {
+      auto *NewSrc = ConstantRelocatable::create(
+          Ctx, Reloc->getType(),
+          RelocatableTuple(Reloc->getOffset(), RelocOffsetArray(0),
+                           Ctx->getGlobalString(SrcSub->second),
+                           Reloc->getEmitString()));
+      auto *NewLoad = InstLoad::create(Context.getNode()->getCfg(),
+                                       Instr->getDest(), NewSrc);
+      Instr->setDeleted();
+      Context.insert(NewLoad);
+      instrumentLoad(Context, NewLoad);

[Karl, 2016/08/16 21:38:43]

Do you need to recurse here? It looks like you just need to set Inst to NewLoad
and continue.

[tlively, 2016/08/16 21:55:38]

Done.

+      return;
+    }
+  }
   Constant *Func =
       Ctx->getConstantExternSym(Ctx->getGlobalString("__asan_check_load"));
   instrumentAccess(Context, Instr->getSourceAddress(),
                    typeWidthInBytes(Instr->getDest()->getType()), Func);
 }
 
 void ASanInstrumentation::instrumentStore(LoweringContext &Context,
                                           InstStore *Instr) {
   Constant *Func =
       Ctx->getConstantExternSym(Ctx->getGlobalString("__asan_check_store"));
@@ skipping 34 matching lines @@
                                 CheckFunc, NoTailCall);
   Call->addArg(Op);
   Call->addArg(ConstantInteger32::create(Ctx, IceType_i32, Size));
   // play games to insert the call before the access instruction
   InstList::iterator Next = Context.getNext();
   Context.setInsertPoint(Context.getCur());
   Context.insert(Call);
   Context.setNext(Next);
 }
 
-// TODO(tlively): Trace back load and store addresses to find their real offsets
+// TODO(tlively): Trace back load and store addresses to find their real

[Jim Stichnoth, 2016/08/16 21:36:46]

Why did this line change?

[tlively, 2016/08/16 21:55:38]

Done.

+// offsets
 bool ASanInstrumentation::isOkGlobalAccess(Operand *Op, SizeT Size) {
   auto *Reloc = llvm::dyn_cast<ConstantRelocatable>(Op);
   if (Reloc == nullptr)
     return false;
   RelocOffsetT Offset = Reloc->getOffset();
   GlobalSizeMap::iterator GlobalSize = GlobalSizes.find(Reloc->getName());
   return GlobalSize != GlobalSizes.end() && GlobalSize->second - Offset >= Size;
 }
 
 void ASanInstrumentation::instrumentRet(LoweringContext &Context, InstRet *) {
@@ skipping 23 matching lines @@
   Call->addArg(Ctx->getConstantSym(0, Ctx->getGlobalString(RzSizesName)));
 }
 
 // TODO(tlively): make this more efficient with swap idiom
 void ASanInstrumentation::finishFunc(Cfg *) {
   ICE_TLS_GET_FIELD(LocalVars)->clear();
   ICE_TLS_GET_FIELD(LocalDtors)->clear();
 }
 
 } // end of namespace Ice