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-rw-r--r--lib/CodeGen/CGStmt.cpp17
-rw-r--r--lib/CodeGen/CodeGenFunction.cpp103
-rw-r--r--lib/CodeGen/CodeGenFunction.h15
3 files changed, 91 insertions, 44 deletions
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 62e465d702..f58b579267 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -282,6 +282,7 @@ void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
EmitBranchThroughCleanup(getBasicBlockForLabel(S.getLabel()));
}
+
void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
// Emit initial switch which will be patched up later by
// EmitIndirectSwitches(). We need a default dest, so we use the
@@ -289,11 +290,17 @@ void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
llvm::Value *V = Builder.CreatePtrToInt(EmitScalarExpr(S.getTarget()),
llvm::Type::getInt32Ty(VMContext),
"addr");
- llvm::SwitchInst *I = Builder.CreateSwitch(V, Builder.GetInsertBlock());
- IndirectSwitches.push_back(I);
-
- // Clear the insertion point to indicate we are in unreachable code.
- Builder.ClearInsertionPoint();
+ llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
+
+
+ // Get the basic block for the indirect goto.
+ llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
+
+ // The first instruction in the block has to be the PHI for the switch dest,
+ // add an entry for this branch.
+ cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
+
+ EmitBranch(IndGotoBB);
}
void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 2d4dc455f2..5206f447f8 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -27,7 +27,8 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
: BlockFunction(cgm, *this, Builder), CGM(cgm),
Target(CGM.getContext().Target),
Builder(cgm.getModule().getContext()),
- DebugInfo(0), SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0),
+ DebugInfo(0), IndirectGotoSwitch(0),
+ SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0),
CXXThisDecl(0) {
LLVMIntTy = ConvertType(getContext().IntTy);
LLVMPointerWidth = Target.getPointerWidth(0);
@@ -111,9 +112,6 @@ void CodeGenFunction::EmitReturnBlock() {
}
void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
- // Finish emission of indirect switches.
- EmitIndirectSwitches();
-
assert(BreakContinueStack.empty() &&
"mismatched push/pop in break/continue stack!");
assert(BlockScopes.empty() &&
@@ -442,11 +440,6 @@ void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type,
CGM.ErrorUnsupported(S, Type, OmitOnError);
}
-unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) {
- // Use LabelIDs.size() as the new ID if one hasn't been assigned.
- return LabelIDs.insert(std::make_pair(L, LabelIDs.size()+1)).first->second;
-}
-
void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
if (DestPtr->getType() != BP)
@@ -471,33 +464,81 @@ void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
TypeInfo.second/8));
}
-void CodeGenFunction::EmitIndirectSwitches() {
- llvm::BasicBlock *Default;
-
- if (IndirectSwitches.empty())
- return;
+unsigned CodeGenFunction::GetIDForAddrOfLabel(const LabelStmt *L) {
+ // Use LabelIDs.size()+1 as the new ID if one hasn't been assigned.
+ unsigned &Entry = LabelIDs[L];
+ if (Entry) return Entry;
+
+ Entry = LabelIDs.size();
+
+ // If this is the first "address taken" of a label and the indirect goto has
+ // already been seen, add this to it.
+ if (IndirectGotoSwitch) {
+ // If this is the first address-taken label, set it as the default dest.
+ if (Entry == 1)
+ IndirectGotoSwitch->setSuccessor(0, getBasicBlockForLabel(L));
+ else {
+ // Otherwise add it to the switch as a new dest.
+ const llvm::IntegerType *Int32Ty = llvm::Type::getInt32Ty(VMContext);
+ IndirectGotoSwitch->addCase(llvm::ConstantInt::get(Int32Ty, Entry),
+ getBasicBlockForLabel(L));
+ }
+ }
+
+ return Entry;
+}
+llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
+ // If we already made the switch stmt for indirect goto, return its block.
+ if (IndirectGotoSwitch) return IndirectGotoSwitch->getParent();
+
+ EmitBlock(createBasicBlock("indirectgoto"));
+
+ // Create the PHI node that indirect gotos will add entries to.
+ llvm::Value *DestVal =
+ Builder.CreatePHI(llvm::Type::getInt32Ty(VMContext), "indirect.goto.dest");
+
+ // Create the switch instruction. For now, set the insert block to this block
+ // which will be fixed as labels are added.
+ IndirectGotoSwitch = Builder.CreateSwitch(DestVal, Builder.GetInsertBlock());
+
+ // Clear the insertion point to indicate we are in unreachable code.
+ Builder.ClearInsertionPoint();
+
+ // If we already have labels created, add them.
if (!LabelIDs.empty()) {
- Default = getBasicBlockForLabel(LabelIDs.begin()->first);
+ // Invert LabelID's so that the order is determinstic.
+ std::vector<const LabelStmt*> AddrTakenLabelsByID;
+ AddrTakenLabelsByID.resize(LabelIDs.size());
+
+ for (std::map<const LabelStmt*,unsigned>::iterator
+ LI = LabelIDs.begin(), LE = LabelIDs.end(); LI != LE; ++LI) {
+ assert(LI->second-1 < AddrTakenLabelsByID.size() &&
+ "Numbering inconsistent");
+ AddrTakenLabelsByID[LI->second-1] = LI->first;
+ }
+
+ // Set the default entry as the first block.
+ IndirectGotoSwitch->setSuccessor(0,
+ getBasicBlockForLabel(AddrTakenLabelsByID[0]));
+
+ const llvm::IntegerType *Int32Ty = llvm::Type::getInt32Ty(VMContext);
+
+ // FIXME: The iteration order of this is nondeterminstic!
+ for (unsigned i = 1, e = AddrTakenLabelsByID.size(); i != e; ++i)
+ IndirectGotoSwitch->addCase(llvm::ConstantInt::get(Int32Ty, i+1),
+ getBasicBlockForLabel(AddrTakenLabelsByID[i]));
} else {
- // No possible targets for indirect goto, just emit an infinite
- // loop.
- Default = createBasicBlock("indirectgoto.loop", CurFn);
- llvm::BranchInst::Create(Default, Default);
+ // Otherwise, create a dead block and set it as the default dest. This will
+ // be removed by the optimizers after the indirect goto is set up.
+ llvm::BasicBlock *Dummy = createBasicBlock("indgoto.dummy");
+ EmitBlock(Dummy);
+ IndirectGotoSwitch->setSuccessor(0, Dummy);
+ Builder.CreateUnreachable();
+ Builder.ClearInsertionPoint();
}
- for (std::vector<llvm::SwitchInst*>::iterator i = IndirectSwitches.begin(),
- e = IndirectSwitches.end(); i != e; ++i) {
- llvm::SwitchInst *I = *i;
-
- I->setSuccessor(0, Default);
- for (std::map<const LabelStmt*,unsigned>::iterator LI = LabelIDs.begin(),
- LE = LabelIDs.end(); LI != LE; ++LI) {
- I->addCase(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
- LI->second),
- getBasicBlockForLabel(LI->first));
- }
- }
+ return IndirectGotoSwitch->getParent();
}
llvm::Value *CodeGenFunction::GetVLASize(const VariableArrayType *VAT) {
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 42de9fb62e..722d002c19 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -189,10 +189,12 @@ private:
/// labels inside getIDForAddrOfLabel().
std::map<const LabelStmt*, unsigned> LabelIDs;
- /// IndirectSwitches - Record the list of switches for indirect
- /// gotos. Emission of the actual switching code needs to be delayed until all
- /// AddrLabelExprs have been seen.
- std::vector<llvm::SwitchInst*> IndirectSwitches;
+ /// IndirectGotoSwitch - The first time an indirect goto is seen we create a
+ /// block with the switch for the indirect gotos. Every time we see the
+ /// address of a label taken, we add the label to the indirect goto. Every
+ /// subsequent indirect goto is codegen'd as a jump to the
+ /// IndirectGotoSwitch's basic block.
+ llvm::SwitchInst *IndirectGotoSwitch;
/// LocalDeclMap - This keeps track of the LLVM allocas or globals for local C
/// decls.
@@ -555,6 +557,7 @@ public:
static unsigned getAccessedFieldNo(unsigned Idx, const llvm::Constant *Elts);
unsigned GetIDForAddrOfLabel(const LabelStmt *L);
+ llvm::BasicBlock *GetIndirectGotoBlock();
/// EmitMemSetToZero - Generate code to memset a value of the given type to 0.
void EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty);
@@ -1014,10 +1017,6 @@ public:
llvm::BasicBlock *FalseBlock);
private:
- /// EmitIndirectSwitches - Emit code for all of the switch
- /// instructions in IndirectSwitches.
- void EmitIndirectSwitches();
-
void EmitReturnOfRValue(RValue RV, QualType Ty);
/// ExpandTypeFromArgs - Reconstruct a structure of type \arg Ty
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-05-04 09:50:52 +0000