| //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code to emit Stmt nodes as LLVM code. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CGDebugInfo.h" |
| #include "CodeGenModule.h" |
| #include "CodeGenFunction.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/Basic/PrettyStackTrace.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/InlineAsm.h" |
| #include "llvm/Intrinsics.h" |
| #include "llvm/Target/TargetData.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| //===----------------------------------------------------------------------===// |
| // Statement Emission |
| //===----------------------------------------------------------------------===// |
| |
| void CodeGenFunction::EmitStopPoint(const Stmt *S) { |
| if (CGDebugInfo *DI = getDebugInfo()) { |
| DI->setLocation(S->getLocStart()); |
| DI->EmitStopPoint(CurFn, Builder); |
| } |
| } |
| |
| void CodeGenFunction::EmitStmt(const Stmt *S) { |
| assert(S && "Null statement?"); |
| |
| // Check if we can handle this without bothering to generate an |
| // insert point or debug info. |
| if (EmitSimpleStmt(S)) |
| return; |
| |
| // Check if we are generating unreachable code. |
| if (!HaveInsertPoint()) { |
| // If so, and the statement doesn't contain a label, then we do not need to |
| // generate actual code. This is safe because (1) the current point is |
| // unreachable, so we don't need to execute the code, and (2) we've already |
| // handled the statements which update internal data structures (like the |
| // local variable map) which could be used by subsequent statements. |
| if (!ContainsLabel(S)) { |
| // Verify that any decl statements were handled as simple, they may be in |
| // scope of subsequent reachable statements. |
| assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!"); |
| return; |
| } |
| |
| // Otherwise, make a new block to hold the code. |
| EnsureInsertPoint(); |
| } |
| |
| // Generate a stoppoint if we are emitting debug info. |
| EmitStopPoint(S); |
| |
| switch (S->getStmtClass()) { |
| default: |
| // Must be an expression in a stmt context. Emit the value (to get |
| // side-effects) and ignore the result. |
| if (!isa<Expr>(S)) |
| ErrorUnsupported(S, "statement"); |
| |
| EmitAnyExpr(cast<Expr>(S), 0, false, true); |
| |
| // Expression emitters don't handle unreachable blocks yet, so look for one |
| // explicitly here. This handles the common case of a call to a noreturn |
| // function. |
| if (llvm::BasicBlock *CurBB = Builder.GetInsertBlock()) { |
| if (CurBB->empty() && CurBB->use_empty()) { |
| CurBB->eraseFromParent(); |
| Builder.ClearInsertionPoint(); |
| } |
| } |
| break; |
| case Stmt::IndirectGotoStmtClass: |
| EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break; |
| |
| case Stmt::IfStmtClass: EmitIfStmt(cast<IfStmt>(*S)); break; |
| case Stmt::WhileStmtClass: EmitWhileStmt(cast<WhileStmt>(*S)); break; |
| case Stmt::DoStmtClass: EmitDoStmt(cast<DoStmt>(*S)); break; |
| case Stmt::ForStmtClass: EmitForStmt(cast<ForStmt>(*S)); break; |
| |
| case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break; |
| |
| case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break; |
| case Stmt::AsmStmtClass: EmitAsmStmt(cast<AsmStmt>(*S)); break; |
| |
| case Stmt::ObjCAtTryStmtClass: |
| EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S)); |
| break; |
| case Stmt::ObjCAtCatchStmtClass: |
| assert(0 && "@catch statements should be handled by EmitObjCAtTryStmt"); |
| break; |
| case Stmt::ObjCAtFinallyStmtClass: |
| assert(0 && "@finally statements should be handled by EmitObjCAtTryStmt"); |
| break; |
| case Stmt::ObjCAtThrowStmtClass: |
| EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S)); |
| break; |
| case Stmt::ObjCAtSynchronizedStmtClass: |
| EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S)); |
| break; |
| case Stmt::ObjCForCollectionStmtClass: |
| EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S)); |
| break; |
| |
| case Stmt::CXXTryStmtClass: |
| EmitCXXTryStmt(cast<CXXTryStmt>(*S)); |
| break; |
| } |
| } |
| |
| bool CodeGenFunction::EmitSimpleStmt(const Stmt *S) { |
| switch (S->getStmtClass()) { |
| default: return false; |
| case Stmt::NullStmtClass: break; |
| case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break; |
| case Stmt::DeclStmtClass: EmitDeclStmt(cast<DeclStmt>(*S)); break; |
| case Stmt::LabelStmtClass: EmitLabelStmt(cast<LabelStmt>(*S)); break; |
| case Stmt::GotoStmtClass: EmitGotoStmt(cast<GotoStmt>(*S)); break; |
| case Stmt::BreakStmtClass: EmitBreakStmt(cast<BreakStmt>(*S)); break; |
| case Stmt::ContinueStmtClass: EmitContinueStmt(cast<ContinueStmt>(*S)); break; |
| case Stmt::DefaultStmtClass: EmitDefaultStmt(cast<DefaultStmt>(*S)); break; |
| case Stmt::CaseStmtClass: EmitCaseStmt(cast<CaseStmt>(*S)); break; |
| } |
| |
| return true; |
| } |
| |
| /// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true, |
| /// this captures the expression result of the last sub-statement and returns it |
| /// (for use by the statement expression extension). |
| RValue CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast, |
| llvm::Value *AggLoc, bool isAggVol) { |
| PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(), |
| "LLVM IR generation of compound statement ('{}')"); |
| |
| CGDebugInfo *DI = getDebugInfo(); |
| if (DI) { |
| DI->setLocation(S.getLBracLoc()); |
| DI->EmitRegionStart(CurFn, Builder); |
| } |
| |
| // Keep track of the current cleanup stack depth. |
| size_t CleanupStackDepth = CleanupEntries.size(); |
| bool OldDidCallStackSave = DidCallStackSave; |
| DidCallStackSave = false; |
| |
| for (CompoundStmt::const_body_iterator I = S.body_begin(), |
| E = S.body_end()-GetLast; I != E; ++I) |
| EmitStmt(*I); |
| |
| if (DI) { |
| DI->setLocation(S.getLBracLoc()); |
| DI->EmitRegionEnd(CurFn, Builder); |
| } |
| |
| RValue RV; |
| if (!GetLast) |
| RV = RValue::get(0); |
| else { |
| // We have to special case labels here. They are statements, but when put |
| // at the end of a statement expression, they yield the value of their |
| // subexpression. Handle this by walking through all labels we encounter, |
| // emitting them before we evaluate the subexpr. |
| const Stmt *LastStmt = S.body_back(); |
| while (const LabelStmt *LS = dyn_cast<LabelStmt>(LastStmt)) { |
| EmitLabel(*LS); |
| LastStmt = LS->getSubStmt(); |
| } |
| |
| EnsureInsertPoint(); |
| |
| RV = EmitAnyExpr(cast<Expr>(LastStmt), AggLoc); |
| } |
| |
| DidCallStackSave = OldDidCallStackSave; |
| |
| EmitCleanupBlocks(CleanupStackDepth); |
| |
| return RV; |
| } |
| |
| void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) { |
| llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator()); |
| |
| // If there is a cleanup stack, then we it isn't worth trying to |
| // simplify this block (we would need to remove it from the scope map |
| // and cleanup entry). |
| if (!CleanupEntries.empty()) |
| return; |
| |
| // Can only simplify direct branches. |
| if (!BI || !BI->isUnconditional()) |
| return; |
| |
| BB->replaceAllUsesWith(BI->getSuccessor(0)); |
| BI->eraseFromParent(); |
| BB->eraseFromParent(); |
| } |
| |
| void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) { |
| // Fall out of the current block (if necessary). |
| EmitBranch(BB); |
| |
| if (IsFinished && BB->use_empty()) { |
| delete BB; |
| return; |
| } |
| |
| // If necessary, associate the block with the cleanup stack size. |
| if (!CleanupEntries.empty()) { |
| // Check if the basic block has already been inserted. |
| BlockScopeMap::iterator I = BlockScopes.find(BB); |
| if (I != BlockScopes.end()) { |
| assert(I->second == CleanupEntries.size() - 1); |
| } else { |
| BlockScopes[BB] = CleanupEntries.size() - 1; |
| CleanupEntries.back().Blocks.push_back(BB); |
| } |
| } |
| |
| CurFn->getBasicBlockList().push_back(BB); |
| Builder.SetInsertPoint(BB); |
| } |
| |
| void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) { |
| // Emit a branch from the current block to the target one if this |
| // was a real block. If this was just a fall-through block after a |
| // terminator, don't emit it. |
| llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); |
| |
| if (!CurBB || CurBB->getTerminator()) { |
| // If there is no insert point or the previous block is already |
| // terminated, don't touch it. |
| } else { |
| // Otherwise, create a fall-through branch. |
| Builder.CreateBr(Target); |
| } |
| |
| Builder.ClearInsertionPoint(); |
| } |
| |
| void CodeGenFunction::EmitLabel(const LabelStmt &S) { |
| EmitBlock(getBasicBlockForLabel(&S)); |
| } |
| |
| |
| void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) { |
| EmitLabel(S); |
| EmitStmt(S.getSubStmt()); |
| } |
| |
| void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) { |
| // If this code is reachable then emit a stop point (if generating |
| // debug info). We have to do this ourselves because we are on the |
| // "simple" statement path. |
| if (HaveInsertPoint()) |
| EmitStopPoint(&S); |
| |
| EmitBranchThroughCleanup(getBasicBlockForLabel(S.getLabel())); |
| } |
| |
| |
| void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) { |
| // Ensure that we have an i8* for our PHI node. |
| llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()), |
| llvm::Type::getInt8PtrTy(VMContext), |
| "addr"); |
| 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) { |
| // C99 6.8.4.1: The first substatement is executed if the expression compares |
| // unequal to 0. The condition must be a scalar type. |
| |
| // If the condition constant folds and can be elided, try to avoid emitting |
| // the condition and the dead arm of the if/else. |
| if (int Cond = ConstantFoldsToSimpleInteger(S.getCond())) { |
| // Figure out which block (then or else) is executed. |
| const Stmt *Executed = S.getThen(), *Skipped = S.getElse(); |
| if (Cond == -1) // Condition false? |
| std::swap(Executed, Skipped); |
| |
| // If the skipped block has no labels in it, just emit the executed block. |
| // This avoids emitting dead code and simplifies the CFG substantially. |
| if (!ContainsLabel(Skipped)) { |
| if (Executed) |
| EmitStmt(Executed); |
| return; |
| } |
| } |
| |
| // Otherwise, the condition did not fold, or we couldn't elide it. Just emit |
| // the conditional branch. |
| llvm::BasicBlock *ThenBlock = createBasicBlock("if.then"); |
| llvm::BasicBlock *ContBlock = createBasicBlock("if.end"); |
| llvm::BasicBlock *ElseBlock = ContBlock; |
| if (S.getElse()) |
| ElseBlock = createBasicBlock("if.else"); |
| EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock); |
| |
| // Emit the 'then' code. |
| EmitBlock(ThenBlock); |
| EmitStmt(S.getThen()); |
| EmitBranch(ContBlock); |
| |
| // Emit the 'else' code if present. |
| if (const Stmt *Else = S.getElse()) { |
| EmitBlock(ElseBlock); |
| EmitStmt(Else); |
| EmitBranch(ContBlock); |
| } |
| |
| // Emit the continuation block for code after the if. |
| EmitBlock(ContBlock, true); |
| } |
| |
| void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) { |
| // Emit the header for the loop, insert it, which will create an uncond br to |
| // it. |
| llvm::BasicBlock *LoopHeader = createBasicBlock("while.cond"); |
| EmitBlock(LoopHeader); |
| |
| // Create an exit block for when the condition fails, create a block for the |
| // body of the loop. |
| llvm::BasicBlock *ExitBlock = createBasicBlock("while.end"); |
| llvm::BasicBlock *LoopBody = createBasicBlock("while.body"); |
| |
| // Store the blocks to use for break and continue. |
| BreakContinueStack.push_back(BreakContinue(ExitBlock, LoopHeader)); |
| |
| // Evaluate the conditional in the while header. C99 6.8.5.1: The |
| // evaluation of the controlling expression takes place before each |
| // execution of the loop body. |
| llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); |
| |
| // while(1) is common, avoid extra exit blocks. Be sure |
| // to correctly handle break/continue though. |
| bool EmitBoolCondBranch = true; |
| if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) |
| if (C->isOne()) |
| EmitBoolCondBranch = false; |
| |
| // As long as the condition is true, go to the loop body. |
| if (EmitBoolCondBranch) |
| Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock); |
| |
| // Emit the loop body. |
| EmitBlock(LoopBody); |
| EmitStmt(S.getBody()); |
| |
| BreakContinueStack.pop_back(); |
| |
| // Cycle to the condition. |
| EmitBranch(LoopHeader); |
| |
| // Emit the exit block. |
| EmitBlock(ExitBlock, true); |
| |
| // The LoopHeader typically is just a branch if we skipped emitting |
| // a branch, try to erase it. |
| if (!EmitBoolCondBranch) |
| SimplifyForwardingBlocks(LoopHeader); |
| } |
| |
| void CodeGenFunction::EmitDoStmt(const DoStmt &S) { |
| // Emit the body for the loop, insert it, which will create an uncond br to |
| // it. |
| llvm::BasicBlock *LoopBody = createBasicBlock("do.body"); |
| llvm::BasicBlock *AfterDo = createBasicBlock("do.end"); |
| EmitBlock(LoopBody); |
| |
| llvm::BasicBlock *DoCond = createBasicBlock("do.cond"); |
| |
| // Store the blocks to use for break and continue. |
| BreakContinueStack.push_back(BreakContinue(AfterDo, DoCond)); |
| |
| // Emit the body of the loop into the block. |
| EmitStmt(S.getBody()); |
| |
| BreakContinueStack.pop_back(); |
| |
| EmitBlock(DoCond); |
| |
| // C99 6.8.5.2: "The evaluation of the controlling expression takes place |
| // after each execution of the loop body." |
| |
| // Evaluate the conditional in the while header. |
| // C99 6.8.5p2/p4: The first substatement is executed if the expression |
| // compares unequal to 0. The condition must be a scalar type. |
| llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); |
| |
| // "do {} while (0)" is common in macros, avoid extra blocks. Be sure |
| // to correctly handle break/continue though. |
| bool EmitBoolCondBranch = true; |
| if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) |
| if (C->isZero()) |
| EmitBoolCondBranch = false; |
| |
| // As long as the condition is true, iterate the loop. |
| if (EmitBoolCondBranch) |
| Builder.CreateCondBr(BoolCondVal, LoopBody, AfterDo); |
| |
| // Emit the exit block. |
| EmitBlock(AfterDo); |
| |
| // The DoCond block typically is just a branch if we skipped |
| // emitting a branch, try to erase it. |
| if (!EmitBoolCondBranch) |
| SimplifyForwardingBlocks(DoCond); |
| } |
| |
| void CodeGenFunction::EmitForStmt(const ForStmt &S) { |
| // FIXME: What do we do if the increment (f.e.) contains a stmt expression, |
| // which contains a continue/break? |
| |
| // Evaluate the first part before the loop. |
| if (S.getInit()) |
| EmitStmt(S.getInit()); |
| |
| // Start the loop with a block that tests the condition. |
| llvm::BasicBlock *CondBlock = createBasicBlock("for.cond"); |
| llvm::BasicBlock *AfterFor = createBasicBlock("for.end"); |
| |
| EmitBlock(CondBlock); |
| |
| // Evaluate the condition if present. If not, treat it as a |
| // non-zero-constant according to 6.8.5.3p2, aka, true. |
| if (S.getCond()) { |
| // As long as the condition is true, iterate the loop. |
| llvm::BasicBlock *ForBody = createBasicBlock("for.body"); |
| |
| // C99 6.8.5p2/p4: The first substatement is executed if the expression |
| // compares unequal to 0. The condition must be a scalar type. |
| EmitBranchOnBoolExpr(S.getCond(), ForBody, AfterFor); |
| |
| EmitBlock(ForBody); |
| } else { |
| // Treat it as a non-zero constant. Don't even create a new block for the |
| // body, just fall into it. |
| } |
| |
| // If the for loop doesn't have an increment we can just use the |
| // condition as the continue block. |
| llvm::BasicBlock *ContinueBlock; |
| if (S.getInc()) |
| ContinueBlock = createBasicBlock("for.inc"); |
| else |
| ContinueBlock = CondBlock; |
| |
| // Store the blocks to use for break and continue. |
| BreakContinueStack.push_back(BreakContinue(AfterFor, ContinueBlock)); |
| |
| // If the condition is true, execute the body of the for stmt. |
| CGDebugInfo *DI = getDebugInfo(); |
| if (DI) { |
| DI->setLocation(S.getSourceRange().getBegin()); |
| DI->EmitRegionStart(CurFn, Builder); |
| } |
| EmitStmt(S.getBody()); |
| |
| BreakContinueStack.pop_back(); |
| |
| // If there is an increment, emit it next. |
| if (S.getInc()) { |
| EmitBlock(ContinueBlock); |
| EmitStmt(S.getInc()); |
| } |
| |
| // Finally, branch back up to the condition for the next iteration. |
| EmitBranch(CondBlock); |
| if (DI) { |
| DI->setLocation(S.getSourceRange().getEnd()); |
| DI->EmitRegionEnd(CurFn, Builder); |
| } |
| |
| // Emit the fall-through block. |
| EmitBlock(AfterFor, true); |
| } |
| |
| void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) { |
| if (RV.isScalar()) { |
| Builder.CreateStore(RV.getScalarVal(), ReturnValue); |
| } else if (RV.isAggregate()) { |
| EmitAggregateCopy(ReturnValue, RV.getAggregateAddr(), Ty); |
| } else { |
| StoreComplexToAddr(RV.getComplexVal(), ReturnValue, false); |
| } |
| EmitBranchThroughCleanup(ReturnBlock); |
| } |
| |
| /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand |
| /// if the function returns void, or may be missing one if the function returns |
| /// non-void. Fun stuff :). |
| void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) { |
| // Emit the result value, even if unused, to evalute the side effects. |
| const Expr *RV = S.getRetValue(); |
| |
| // FIXME: Clean this up by using an LValue for ReturnTemp, |
| // EmitStoreThroughLValue, and EmitAnyExpr. |
| if (!ReturnValue) { |
| // Make sure not to return anything, but evaluate the expression |
| // for side effects. |
| if (RV) |
| EmitAnyExpr(RV); |
| } else if (RV == 0) { |
| // Do nothing (return value is left uninitialized) |
| } else if (FnRetTy->isReferenceType()) { |
| // If this function returns a reference, take the address of the expression |
| // rather than the value. |
| Builder.CreateStore(EmitLValue(RV).getAddress(), ReturnValue); |
| } else if (!hasAggregateLLVMType(RV->getType())) { |
| Builder.CreateStore(EmitScalarExpr(RV), ReturnValue); |
| } else if (RV->getType()->isAnyComplexType()) { |
| EmitComplexExprIntoAddr(RV, ReturnValue, false); |
| } else { |
| EmitAggExpr(RV, ReturnValue, false); |
| } |
| |
| EmitBranchThroughCleanup(ReturnBlock); |
| } |
| |
| void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) { |
| // As long as debug info is modeled with instructions, we have to ensure we |
| // have a place to insert here and write the stop point here. |
| if (getDebugInfo()) { |
| EnsureInsertPoint(); |
| EmitStopPoint(&S); |
| } |
| |
| for (DeclStmt::const_decl_iterator I = S.decl_begin(), E = S.decl_end(); |
| I != E; ++I) |
| EmitDecl(**I); |
| } |
| |
| void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) { |
| assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!"); |
| |
| // If this code is reachable then emit a stop point (if generating |
| // debug info). We have to do this ourselves because we are on the |
| // "simple" statement path. |
| if (HaveInsertPoint()) |
| EmitStopPoint(&S); |
| |
| llvm::BasicBlock *Block = BreakContinueStack.back().BreakBlock; |
| EmitBranchThroughCleanup(Block); |
| } |
| |
| void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) { |
| assert(!BreakContinueStack.empty() && "continue stmt not in a loop!"); |
| |
| // If this code is reachable then emit a stop point (if generating |
| // debug info). We have to do this ourselves because we are on the |
| // "simple" statement path. |
| if (HaveInsertPoint()) |
| EmitStopPoint(&S); |
| |
| llvm::BasicBlock *Block = BreakContinueStack.back().ContinueBlock; |
| EmitBranchThroughCleanup(Block); |
| } |
| |
| /// EmitCaseStmtRange - If case statement range is not too big then |
| /// add multiple cases to switch instruction, one for each value within |
| /// the range. If range is too big then emit "if" condition check. |
| void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) { |
| assert(S.getRHS() && "Expected RHS value in CaseStmt"); |
| |
| llvm::APSInt LHS = S.getLHS()->EvaluateAsInt(getContext()); |
| llvm::APSInt RHS = S.getRHS()->EvaluateAsInt(getContext()); |
| |
| // Emit the code for this case. We do this first to make sure it is |
| // properly chained from our predecessor before generating the |
| // switch machinery to enter this block. |
| EmitBlock(createBasicBlock("sw.bb")); |
| llvm::BasicBlock *CaseDest = Builder.GetInsertBlock(); |
| EmitStmt(S.getSubStmt()); |
| |
| // If range is empty, do nothing. |
| if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS)) |
| return; |
| |
| llvm::APInt Range = RHS - LHS; |
| // FIXME: parameters such as this should not be hardcoded. |
| if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) { |
| // Range is small enough to add multiple switch instruction cases. |
| for (unsigned i = 0, e = Range.getZExtValue() + 1; i != e; ++i) { |
| SwitchInsn->addCase(llvm::ConstantInt::get(VMContext, LHS), CaseDest); |
| LHS++; |
| } |
| return; |
| } |
| |
| // The range is too big. Emit "if" condition into a new block, |
| // making sure to save and restore the current insertion point. |
| llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock(); |
| |
| // Push this test onto the chain of range checks (which terminates |
| // in the default basic block). The switch's default will be changed |
| // to the top of this chain after switch emission is complete. |
| llvm::BasicBlock *FalseDest = CaseRangeBlock; |
| CaseRangeBlock = createBasicBlock("sw.caserange"); |
| |
| CurFn->getBasicBlockList().push_back(CaseRangeBlock); |
| Builder.SetInsertPoint(CaseRangeBlock); |
| |
| // Emit range check. |
| llvm::Value *Diff = |
| Builder.CreateSub(SwitchInsn->getCondition(), |
| llvm::ConstantInt::get(VMContext, LHS), "tmp"); |
| llvm::Value *Cond = |
| Builder.CreateICmpULE(Diff, |
| llvm::ConstantInt::get(VMContext, Range), "tmp"); |
| Builder.CreateCondBr(Cond, CaseDest, FalseDest); |
| |
| // Restore the appropriate insertion point. |
| if (RestoreBB) |
| Builder.SetInsertPoint(RestoreBB); |
| else |
| Builder.ClearInsertionPoint(); |
| } |
| |
| void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) { |
| if (S.getRHS()) { |
| EmitCaseStmtRange(S); |
| return; |
| } |
| |
| EmitBlock(createBasicBlock("sw.bb")); |
| llvm::BasicBlock *CaseDest = Builder.GetInsertBlock(); |
| llvm::APSInt CaseVal = S.getLHS()->EvaluateAsInt(getContext()); |
| SwitchInsn->addCase(llvm::ConstantInt::get(VMContext, CaseVal), CaseDest); |
| |
| // Recursively emitting the statement is acceptable, but is not wonderful for |
| // code where we have many case statements nested together, i.e.: |
| // case 1: |
| // case 2: |
| // case 3: etc. |
| // Handling this recursively will create a new block for each case statement |
| // that falls through to the next case which is IR intensive. It also causes |
| // deep recursion which can run into stack depth limitations. Handle |
| // sequential non-range case statements specially. |
| const CaseStmt *CurCase = &S; |
| const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt()); |
| |
| // Otherwise, iteratively add consequtive cases to this switch stmt. |
| while (NextCase && NextCase->getRHS() == 0) { |
| CurCase = NextCase; |
| CaseVal = CurCase->getLHS()->EvaluateAsInt(getContext()); |
| SwitchInsn->addCase(llvm::ConstantInt::get(VMContext, CaseVal), CaseDest); |
| |
| NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt()); |
| } |
| |
| // Normal default recursion for non-cases. |
| EmitStmt(CurCase->getSubStmt()); |
| } |
| |
| void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) { |
| llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest(); |
| assert(DefaultBlock->empty() && |
| "EmitDefaultStmt: Default block already defined?"); |
| EmitBlock(DefaultBlock); |
| EmitStmt(S.getSubStmt()); |
| } |
| |
| void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) { |
| llvm::Value *CondV = EmitScalarExpr(S.getCond()); |
| |
| // Handle nested switch statements. |
| llvm::SwitchInst *SavedSwitchInsn = SwitchInsn; |
| llvm::BasicBlock *SavedCRBlock = CaseRangeBlock; |
| |
| // Create basic block to hold stuff that comes after switch |
| // statement. We also need to create a default block now so that |
| // explicit case ranges tests can have a place to jump to on |
| // failure. |
| llvm::BasicBlock *NextBlock = createBasicBlock("sw.epilog"); |
| llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default"); |
| SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock); |
| CaseRangeBlock = DefaultBlock; |
| |
| // Clear the insertion point to indicate we are in unreachable code. |
| Builder.ClearInsertionPoint(); |
| |
| // All break statements jump to NextBlock. If BreakContinueStack is non empty |
| // then reuse last ContinueBlock. |
| llvm::BasicBlock *ContinueBlock = 0; |
| if (!BreakContinueStack.empty()) |
| ContinueBlock = BreakContinueStack.back().ContinueBlock; |
| |
| // Ensure any vlas created between there and here, are undone |
| BreakContinueStack.push_back(BreakContinue(NextBlock, ContinueBlock)); |
| |
| // Emit switch body. |
| EmitStmt(S.getBody()); |
| |
| BreakContinueStack.pop_back(); |
| |
| // Update the default block in case explicit case range tests have |
| // been chained on top. |
| SwitchInsn->setSuccessor(0, CaseRangeBlock); |
| |
| // If a default was never emitted then reroute any jumps to it and |
| // discard. |
| if (!DefaultBlock->getParent()) { |
| DefaultBlock->replaceAllUsesWith(NextBlock); |
| delete DefaultBlock; |
| } |
| |
| // Emit continuation. |
| EmitBlock(NextBlock, true); |
| |
| SwitchInsn = SavedSwitchInsn; |
| CaseRangeBlock = SavedCRBlock; |
| } |
| |
| static std::string |
| SimplifyConstraint(const char *Constraint, const TargetInfo &Target, |
| llvm::SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=0) { |
| std::string Result; |
| |
| while (*Constraint) { |
| switch (*Constraint) { |
| default: |
| Result += Target.convertConstraint(*Constraint); |
| break; |
| // Ignore these |
| case '*': |
| case '?': |
| case '!': |
| break; |
| case 'g': |
| Result += "imr"; |
| break; |
| case '[': { |
| assert(OutCons && |
| "Must pass output names to constraints with a symbolic name"); |
| unsigned Index; |
| bool result = Target.resolveSymbolicName(Constraint, |
| &(*OutCons)[0], |
| OutCons->size(), Index); |
| assert(result && "Could not resolve symbolic name"); result=result; |
| Result += llvm::utostr(Index); |
| break; |
| } |
| } |
| |
| Constraint++; |
| } |
| |
| return Result; |
| } |
| |
| llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S, |
| const TargetInfo::ConstraintInfo &Info, |
| const Expr *InputExpr, |
| std::string &ConstraintStr) { |
| llvm::Value *Arg; |
| if (Info.allowsRegister() || !Info.allowsMemory()) { |
| const llvm::Type *Ty = ConvertType(InputExpr->getType()); |
| |
| if (Ty->isSingleValueType()) { |
| Arg = EmitScalarExpr(InputExpr); |
| } else { |
| InputExpr = InputExpr->IgnoreParenNoopCasts(getContext()); |
| LValue Dest = EmitLValue(InputExpr); |
| |
| uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty); |
| if (Size <= 64 && llvm::isPowerOf2_64(Size)) { |
| Ty = llvm::IntegerType::get(VMContext, Size); |
| Ty = llvm::PointerType::getUnqual(Ty); |
| |
| Arg = Builder.CreateLoad(Builder.CreateBitCast(Dest.getAddress(), Ty)); |
| } else { |
| Arg = Dest.getAddress(); |
| ConstraintStr += '*'; |
| } |
| } |
| } else { |
| InputExpr = InputExpr->IgnoreParenNoopCasts(getContext()); |
| LValue Dest = EmitLValue(InputExpr); |
| Arg = Dest.getAddress(); |
| ConstraintStr += '*'; |
| } |
| |
| return Arg; |
| } |
| |
| void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { |
| // Analyze the asm string to decompose it into its pieces. We know that Sema |
| // has already done this, so it is guaranteed to be successful. |
| llvm::SmallVector<AsmStmt::AsmStringPiece, 4> Pieces; |
| unsigned DiagOffs; |
| S.AnalyzeAsmString(Pieces, getContext(), DiagOffs); |
| |
| // Assemble the pieces into the final asm string. |
| std::string AsmString; |
| for (unsigned i = 0, e = Pieces.size(); i != e; ++i) { |
| if (Pieces[i].isString()) |
| AsmString += Pieces[i].getString(); |
| else if (Pieces[i].getModifier() == '\0') |
| AsmString += '$' + llvm::utostr(Pieces[i].getOperandNo()); |
| else |
| AsmString += "${" + llvm::utostr(Pieces[i].getOperandNo()) + ':' + |
| Pieces[i].getModifier() + '}'; |
| } |
| |
| // Get all the output and input constraints together. |
| llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; |
| llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; |
| |
| for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { |
| TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), |
| S.getOutputName(i)); |
| bool result = Target.validateOutputConstraint(Info); |
| assert(result && "Failed to parse output constraint"); result=result; |
| OutputConstraintInfos.push_back(Info); |
| } |
| |
| for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { |
| TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), |
| S.getInputName(i)); |
| bool result = Target.validateInputConstraint(OutputConstraintInfos.data(), |
| S.getNumOutputs(), |
| Info); result=result; |
| assert(result && "Failed to parse input constraint"); |
| InputConstraintInfos.push_back(Info); |
| } |
| |
| std::string Constraints; |
| |
| std::vector<LValue> ResultRegDests; |
| std::vector<QualType> ResultRegQualTys; |
| std::vector<const llvm::Type *> ResultRegTypes; |
| std::vector<const llvm::Type *> ResultTruncRegTypes; |
| std::vector<const llvm::Type*> ArgTypes; |
| std::vector<llvm::Value*> Args; |
| |
| // Keep track of inout constraints. |
| std::string InOutConstraints; |
| std::vector<llvm::Value*> InOutArgs; |
| std::vector<const llvm::Type*> InOutArgTypes; |
| |
| for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { |
| TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i]; |
| |
| // Simplify the output constraint. |
| std::string OutputConstraint(S.getOutputConstraint(i)); |
| OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1, Target); |
| |
| const Expr *OutExpr = S.getOutputExpr(i); |
| OutExpr = OutExpr->IgnoreParenNoopCasts(getContext()); |
| |
| LValue Dest = EmitLValue(OutExpr); |
| if (!Constraints.empty()) |
| Constraints += ','; |
| |
| // If this is a register output, then make the inline asm return it |
| // by-value. If this is a memory result, return the value by-reference. |
| if (!Info.allowsMemory() && !hasAggregateLLVMType(OutExpr->getType())) { |
| Constraints += "=" + OutputConstraint; |
| ResultRegQualTys.push_back(OutExpr->getType()); |
| ResultRegDests.push_back(Dest); |
| ResultRegTypes.push_back(ConvertTypeForMem(OutExpr->getType())); |
| ResultTruncRegTypes.push_back(ResultRegTypes.back()); |
| |
| // If this output is tied to an input, and if the input is larger, then |
| // we need to set the actual result type of the inline asm node to be the |
| // same as the input type. |
| if (Info.hasMatchingInput()) { |
| unsigned InputNo; |
| for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) { |
| TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo]; |
| if (Input.hasTiedOperand() && |
| Input.getTiedOperand() == i) |
| break; |
| } |
| assert(InputNo != S.getNumInputs() && "Didn't find matching input!"); |
| |
| QualType InputTy = S.getInputExpr(InputNo)->getType(); |
| QualType OutputTy = OutExpr->getType(); |
| |
| uint64_t InputSize = getContext().getTypeSize(InputTy); |
| if (getContext().getTypeSize(OutputTy) < InputSize) { |
| // Form the asm to return the value as a larger integer type. |
| ResultRegTypes.back() = llvm::IntegerType::get(VMContext, (unsigned)InputSize); |
| } |
| } |
| } else { |
| ArgTypes.push_back(Dest.getAddress()->getType()); |
| Args.push_back(Dest.getAddress()); |
| Constraints += "=*"; |
| Constraints += OutputConstraint; |
| } |
| |
| if (Info.isReadWrite()) { |
| InOutConstraints += ','; |
| |
| const Expr *InputExpr = S.getOutputExpr(i); |
| llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, InOutConstraints); |
| |
| if (Info.allowsRegister()) |
| InOutConstraints += llvm::utostr(i); |
| else |
| InOutConstraints += OutputConstraint; |
| |
| InOutArgTypes.push_back(Arg->getType()); |
| InOutArgs.push_back(Arg); |
| } |
| } |
| |
| unsigned NumConstraints = S.getNumOutputs() + S.getNumInputs(); |
| |
| for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { |
| const Expr *InputExpr = S.getInputExpr(i); |
| |
| TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; |
| |
| if (!Constraints.empty()) |
| Constraints += ','; |
| |
| // Simplify the input constraint. |
| std::string InputConstraint(S.getInputConstraint(i)); |
| InputConstraint = SimplifyConstraint(InputConstraint.c_str(), Target, |
| &OutputConstraintInfos); |
| |
| llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, Constraints); |
| |
| // If this input argument is tied to a larger output result, extend the |
| // input to be the same size as the output. The LLVM backend wants to see |
| // the input and output of a matching constraint be the same size. Note |
| // that GCC does not define what the top bits are here. We use zext because |
| // that is usually cheaper, but LLVM IR should really get an anyext someday. |
| if (Info.hasTiedOperand()) { |
| unsigned Output = Info.getTiedOperand(); |
| QualType OutputTy = S.getOutputExpr(Output)->getType(); |
| QualType InputTy = InputExpr->getType(); |
| |
| if (getContext().getTypeSize(OutputTy) > |
| getContext().getTypeSize(InputTy)) { |
| // Use ptrtoint as appropriate so that we can do our extension. |
| if (isa<llvm::PointerType>(Arg->getType())) |
| Arg = Builder.CreatePtrToInt(Arg, |
| llvm::IntegerType::get(VMContext, LLVMPointerWidth)); |
| unsigned OutputSize = (unsigned)getContext().getTypeSize(OutputTy); |
| Arg = Builder.CreateZExt(Arg, llvm::IntegerType::get(VMContext, OutputSize)); |
| } |
| } |
| |
| |
| ArgTypes.push_back(Arg->getType()); |
| Args.push_back(Arg); |
| Constraints += InputConstraint; |
| } |
| |
| // Append the "input" part of inout constraints last. |
| for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) { |
| ArgTypes.push_back(InOutArgTypes[i]); |
| Args.push_back(InOutArgs[i]); |
| } |
| Constraints += InOutConstraints; |
| |
| // Clobbers |
| for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) { |
| std::string Clobber(S.getClobber(i)->getStrData(), |
| S.getClobber(i)->getByteLength()); |
| |
| Clobber = Target.getNormalizedGCCRegisterName(Clobber.c_str()); |
| |
| if (i != 0 || NumConstraints != 0) |
| Constraints += ','; |
| |
| Constraints += "~{"; |
| Constraints += Clobber; |
| Constraints += '}'; |
| } |
| |
| // Add machine specific clobbers |
| std::string MachineClobbers = Target.getClobbers(); |
| if (!MachineClobbers.empty()) { |
| if (!Constraints.empty()) |
| Constraints += ','; |
| Constraints += MachineClobbers; |
| } |
| |
| const llvm::Type *ResultType; |
| if (ResultRegTypes.empty()) |
| ResultType = llvm::Type::getVoidTy(VMContext); |
| else if (ResultRegTypes.size() == 1) |
| ResultType = ResultRegTypes[0]; |
| else |
| ResultType = llvm::StructType::get(VMContext, ResultRegTypes); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(ResultType, ArgTypes, false); |
| |
| llvm::InlineAsm *IA = |
| llvm::InlineAsm::get(FTy, AsmString, Constraints, |
| S.isVolatile() || S.getNumOutputs() == 0); |
| llvm::CallInst *Result = Builder.CreateCall(IA, Args.begin(), Args.end()); |
| Result->addAttribute(~0, llvm::Attribute::NoUnwind); |
| |
| |
| // Extract all of the register value results from the asm. |
| std::vector<llvm::Value*> RegResults; |
| if (ResultRegTypes.size() == 1) { |
| RegResults.push_back(Result); |
| } else { |
| for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) { |
| llvm::Value *Tmp = Builder.CreateExtractValue(Result, i, "asmresult"); |
| RegResults.push_back(Tmp); |
| } |
| } |
| |
| for (unsigned i = 0, e = RegResults.size(); i != e; ++i) { |
| llvm::Value *Tmp = RegResults[i]; |
| |
| // If the result type of the LLVM IR asm doesn't match the result type of |
| // the expression, do the conversion. |
| if (ResultRegTypes[i] != ResultTruncRegTypes[i]) { |
| const llvm::Type *TruncTy = ResultTruncRegTypes[i]; |
| // Truncate the integer result to the right size, note that |
| // ResultTruncRegTypes can be a pointer. |
| uint64_t ResSize = CGM.getTargetData().getTypeSizeInBits(TruncTy); |
| Tmp = Builder.CreateTrunc(Tmp, llvm::IntegerType::get(VMContext, (unsigned)ResSize)); |
| |
| if (Tmp->getType() != TruncTy) { |
| assert(isa<llvm::PointerType>(TruncTy)); |
| Tmp = Builder.CreateIntToPtr(Tmp, TruncTy); |
| } |
| } |
| |
| EmitStoreThroughLValue(RValue::get(Tmp), ResultRegDests[i], |
| ResultRegQualTys[i]); |
| } |
| } |