AutoUpgrade: upgrade from scalar TBAA format to struct-path aware TBAA format.

We treat TBAA tags as struct-path aware TBAA format when the first operand
is a MDNode and the tag has 3 or more operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191593 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/AutoUpgrade.h

@@ -19,6 +19,7 @@ namespace llvm {
   class GlobalVariable;
   class Function;
   class CallInst;
+  class Instruction;
 
   /// This is a more granular function that simply checks an intrinsic function
   /// for upgrading, and returns true if it requires upgrading. It may return
@@ -39,6 +40,10 @@ namespace llvm {
   /// This checks for global variables which should be upgraded. It returns true
   /// if it requires upgrading.
   bool UpgradeGlobalVariable(GlobalVariable *GV);
+
+  /// If the TBAA tag for the given instruction uses the scalar TBAA format,
+  /// we upgrade it to the struct-path aware TBAA format.
+  void UpgradeInstWithTBAATag(Instruction *I);
 } // End llvm namespace
 
 #endif

lib/AsmParser/LLParser.cpp

@@ -19,6 +19,7 @@
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/ValueSymbolTable.h"
@@ -65,6 +66,9 @@ bool LLParser::ValidateEndOfModule() {
     ForwardRefInstMetadata.clear();
   }
 
+  for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
+    UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
+
   // Handle any function attribute group forward references.
   for (std::map<Value*, std::vector<unsigned> >::iterator
          I = ForwardRefAttrGroups.begin(), E = ForwardRefAttrGroups.end();
@@ -1427,6 +1431,9 @@ bool LLParser::ParseInstructionMetadata(Instruction *Inst,
       }
     }
 
+    if (MDK == LLVMContext::MD_tbaa)
+      InstsWithTBAATag.push_back(Inst);
+
     // If this is the end of the list, we're done.
   } while (EatIfPresent(lltok::comma));
   return false;

lib/AsmParser/LLParser.h

@@ -107,6 +107,8 @@ namespace llvm {
     };
     DenseMap<Instruction*, std::vector<MDRef> > ForwardRefInstMetadata;
 
+    SmallVector<Instruction*, 64> InstsWithTBAATag;
+
     // Type resolution handling data structures.  The location is set when we
     // have processed a use of the type but not a definition yet.
     StringMap<std::pair<Type*, LocTy> > NamedTypes;

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -17,6 +17,7 @@
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/OperandTraits.h"
 #include "llvm/IR/Operator.h"
@@ -2123,6 +2124,8 @@ bool BitcodeReader::ParseMetadataAttachment() {
           return Error("Invalid metadata kind ID");
         Value *Node = MDValueList.getValueFwdRef(Record[i+1]);
         Inst->setMetadata(I->second, cast<MDNode>(Node));
+        if (I->second == LLVMContext::MD_tbaa)
+          InstsWithTBAATag.push_back(Inst);
       }
       break;
     }
@@ -3134,6 +3137,9 @@ bool BitcodeReader::MaterializeModule(Module *M, std::string *ErrInfo) {
   }
   std::vector<std::pair<Function*, Function*> >().swap(UpgradedIntrinsics);
 
+  for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
+    UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
+
   return false;
 }
 

lib/Bitcode/Reader/BitcodeReader.h

@@ -144,6 +144,8 @@ class BitcodeReader : public GVMaterializer {
   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
   std::vector<std::pair<Function*, unsigned> > FunctionPrefixes;
 
+  SmallVector<Instruction*, 64> InstsWithTBAATag;
+
   /// MAttributes - The set of attributes by index.  Index zero in the
   /// file is for null, and is thus not represented here.  As such all indices
   /// are off by one.

lib/IR/AutoUpgrade.cpp

@@ -391,3 +391,30 @@ void llvm::UpgradeCallsToIntrinsic(Function* F) {
   }
 }
 
+void llvm::UpgradeInstWithTBAATag(Instruction *I) {
+  MDNode *MD = I->getMetadata(LLVMContext::MD_tbaa);
+  assert(MD && "UpgradeInstWithTBAATag should have a TBAA tag");
+  // Check if the tag uses struct-path aware TBAA format.
+  if (isa<MDNode>(MD->getOperand(0)) && MD->getNumOperands() >= 3)
+    return;
+
+  if (MD->getNumOperands() == 3) {
+    Value *Elts[] = {
+      MD->getOperand(0),
+      MD->getOperand(1)
+    };
+    MDNode *ScalarType = MDNode::get(I->getContext(), Elts);
+    // Create a MDNode <ScalarType, ScalarType, offset 0, const>
+    Value *Elts2[] = {
+      ScalarType, ScalarType,
+      Constant::getNullValue(Type::getInt64Ty(I->getContext())),
+      MD->getOperand(2)
+    };
+    I->setMetadata(LLVMContext::MD_tbaa, MDNode::get(I->getContext(), Elts2));
+  } else {
+    // Create a MDNode <MD, MD, offset 0>
+    Value *Elts[] = {MD, MD,
+      Constant::getNullValue(Type::getInt64Ty(I->getContext()))};
+    I->setMetadata(LLVMContext::MD_tbaa, MDNode::get(I->getContext(), Elts));
+  }
+}

test/Bitcode/upgrade-tbaa.ll

@@ -0,0 +1,23 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+; Function Attrs: nounwind
+define void @_Z4testPiPf(i32* nocapture %pI, float* nocapture %pF) #0 {
+entry:
+  store i32 0, i32* %pI, align 4, !tbaa !{metadata !"int", metadata !0}
+  ; CHECK: store i32 0, i32* %pI, align 4, !tbaa [[TAG_INT:!.*]]
+  store float 1.000000e+00, float* %pF, align 4, !tbaa !2
+  ; CHECK: store float 1.000000e+00, float* %pF, align 4, !tbaa [[TAG_FLOAT:!.*]]
+  ret void
+}
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!0 = metadata !{metadata !"omnipotent char", metadata !1}
+!1 = metadata !{metadata !"Simple C/C++ TBAA"}
+!2 = metadata !{metadata !"float", metadata !0}
+
+; CHECK: [[TAG_INT]] = metadata !{metadata [[TYPE_INT:!.*]], metadata [[TYPE_INT]], i64 0}
+; CHECK: [[TYPE_INT]] = metadata !{metadata !"int", metadata [[TYPE_CHAR:!.*]]}
+; CHECK: [[TYPE_CHAR]] = metadata !{metadata !"omnipotent char", metadata !{{.*}}
+; CHECK: [[TAG_FLOAT]] = metadata !{metadata [[TYPE_FLOAT:!.*]], metadata [[TYPE_FLOAT]], i64 0}
+; CHECK: [[TYPE_FLOAT]] = metadata !{metadata !"float", metadata [[TYPE_CHAR]]}