diff options
Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGStmt.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGStmt.cpp | 1676 |
1 files changed, 1676 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGStmt.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGStmt.cpp new file mode 100644 index 0000000..bf42dcb --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGStmt.cpp @@ -0,0 +1,1676 @@ +//===--- 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 "TargetInfo.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()) { + SourceLocation Loc; + if (isa<DeclStmt>(S)) + Loc = S->getLocEnd(); + else + Loc = S->getLocStart(); + DI->EmitLocation(Builder, Loc); + } +} + +void CodeGenFunction::EmitStmt(const Stmt *S) { + assert(S && "Null statement?"); + + // These statements have their own debug info handling. + 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()) { + case Stmt::NoStmtClass: + case Stmt::CXXCatchStmtClass: + case Stmt::SEHExceptStmtClass: + case Stmt::SEHFinallyStmtClass: + case Stmt::MSDependentExistsStmtClass: + llvm_unreachable("invalid statement class to emit generically"); + case Stmt::NullStmtClass: + case Stmt::CompoundStmtClass: + case Stmt::DeclStmtClass: + case Stmt::LabelStmtClass: + case Stmt::GotoStmtClass: + case Stmt::BreakStmtClass: + case Stmt::ContinueStmtClass: + case Stmt::DefaultStmtClass: + case Stmt::CaseStmtClass: + llvm_unreachable("should have emitted these statements as simple"); + +#define STMT(Type, Base) +#define ABSTRACT_STMT(Op) +#define EXPR(Type, Base) \ + case Stmt::Type##Class: +#include "clang/AST/StmtNodes.inc" + { + // Remember the block we came in on. + llvm::BasicBlock *incoming = Builder.GetInsertBlock(); + assert(incoming && "expression emission must have an insertion point"); + + EmitIgnoredExpr(cast<Expr>(S)); + + llvm::BasicBlock *outgoing = Builder.GetInsertBlock(); + assert(outgoing && "expression emission cleared block!"); + + // The expression emitters assume (reasonably!) that the insertion + // point is always set. To maintain that, the call-emission code + // for noreturn functions has to enter a new block with no + // predecessors. We want to kill that block and mark the current + // insertion point unreachable in the common case of a call like + // "exit();". Since expression emission doesn't otherwise create + // blocks with no predecessors, we can just test for that. + // However, we must be careful not to do this to our incoming + // block, because *statement* emission does sometimes create + // reachable blocks which will have no predecessors until later in + // the function. This occurs with, e.g., labels that are not + // reachable by fallthrough. + if (incoming != outgoing && outgoing->use_empty()) { + outgoing->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: + llvm_unreachable( + "@catch statements should be handled by EmitObjCAtTryStmt"); + case Stmt::ObjCAtFinallyStmtClass: + llvm_unreachable( + "@finally statements should be handled by EmitObjCAtTryStmt"); + 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::ObjCAutoreleasePoolStmtClass: + EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S)); + break; + + case Stmt::CXXTryStmtClass: + EmitCXXTryStmt(cast<CXXTryStmt>(*S)); + break; + case Stmt::CXXForRangeStmtClass: + EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S)); + case Stmt::SEHTryStmtClass: + // FIXME Not yet implemented + 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, + AggValueSlot AggSlot) { + PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(), + "LLVM IR generation of compound statement ('{}')"); + + // Keep track of the current cleanup stack depth, including debug scopes. + LexicalScope Scope(*this, S.getSourceRange()); + + for (CompoundStmt::const_body_iterator I = S.body_begin(), + E = S.body_end()-GetLast; I != E; ++I) + EmitStmt(*I); + + 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->getDecl()); + LastStmt = LS->getSubStmt(); + } + + EnsureInsertPoint(); + + RV = EmitAnyExpr(cast<Expr>(LastStmt), AggSlot); + } + + 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 (!EHStack.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) { + llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + + // Fall out of the current block (if necessary). + EmitBranch(BB); + + if (IsFinished && BB->use_empty()) { + delete BB; + return; + } + + // Place the block after the current block, if possible, or else at + // the end of the function. + if (CurBB && CurBB->getParent()) + CurFn->getBasicBlockList().insertAfter(CurBB, BB); + else + 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::EmitBlockAfterUses(llvm::BasicBlock *block) { + bool inserted = false; + for (llvm::BasicBlock::use_iterator + i = block->use_begin(), e = block->use_end(); i != e; ++i) { + if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(*i)) { + CurFn->getBasicBlockList().insertAfter(insn->getParent(), block); + inserted = true; + break; + } + } + + if (!inserted) + CurFn->getBasicBlockList().push_back(block); + + Builder.SetInsertPoint(block); +} + +CodeGenFunction::JumpDest +CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) { + JumpDest &Dest = LabelMap[D]; + if (Dest.isValid()) return Dest; + + // Create, but don't insert, the new block. + Dest = JumpDest(createBasicBlock(D->getName()), + EHScopeStack::stable_iterator::invalid(), + NextCleanupDestIndex++); + return Dest; +} + +void CodeGenFunction::EmitLabel(const LabelDecl *D) { + JumpDest &Dest = LabelMap[D]; + + // If we didn't need a forward reference to this label, just go + // ahead and create a destination at the current scope. + if (!Dest.isValid()) { + Dest = getJumpDestInCurrentScope(D->getName()); + + // Otherwise, we need to give this label a target depth and remove + // it from the branch-fixups list. + } else { + assert(!Dest.getScopeDepth().isValid() && "already emitted label!"); + Dest = JumpDest(Dest.getBlock(), + EHStack.stable_begin(), + Dest.getDestIndex()); + + ResolveBranchFixups(Dest.getBlock()); + } + + EmitBlock(Dest.getBlock()); +} + + +void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) { + EmitLabel(S.getDecl()); + 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(getJumpDestForLabel(S.getLabel())); +} + + +void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) { + if (const LabelDecl *Target = S.getConstantTarget()) { + EmitBranchThroughCleanup(getJumpDestForLabel(Target)); + return; + } + + // Ensure that we have an i8* for our PHI node. + llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()), + Int8PtrTy, "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. + RunCleanupsScope ConditionScope(*this); + + if (S.getConditionVariable()) + EmitAutoVarDecl(*S.getConditionVariable()); + + // If the condition constant folds and can be elided, try to avoid emitting + // the condition and the dead arm of the if/else. + bool CondConstant; + if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant)) { + // Figure out which block (then or else) is executed. + const Stmt *Executed = S.getThen(); + const Stmt *Skipped = S.getElse(); + if (!CondConstant) // 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) { + RunCleanupsScope ExecutedScope(*this); + 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); + { + RunCleanupsScope ThenScope(*this); + EmitStmt(S.getThen()); + } + EmitBranch(ContBlock); + + // Emit the 'else' code if present. + if (const Stmt *Else = S.getElse()) { + // There is no need to emit line number for unconditional branch. + if (getDebugInfo()) + Builder.SetCurrentDebugLocation(llvm::DebugLoc()); + EmitBlock(ElseBlock); + { + RunCleanupsScope ElseScope(*this); + EmitStmt(Else); + } + // There is no need to emit line number for unconditional branch. + if (getDebugInfo()) + Builder.SetCurrentDebugLocation(llvm::DebugLoc()); + 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, which will also become + // the continue target. + JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond"); + EmitBlock(LoopHeader.getBlock()); + + // Create an exit block for when the condition fails, which will + // also become the break target. + JumpDest LoopExit = getJumpDestInCurrentScope("while.end"); + + // Store the blocks to use for break and continue. + BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader)); + + // C++ [stmt.while]p2: + // When the condition of a while statement is a declaration, the + // scope of the variable that is declared extends from its point + // of declaration (3.3.2) to the end of the while statement. + // [...] + // The object created in a condition is destroyed and created + // with each iteration of the loop. + RunCleanupsScope ConditionScope(*this); + + if (S.getConditionVariable()) + EmitAutoVarDecl(*S.getConditionVariable()); + + // 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. + llvm::BasicBlock *LoopBody = createBasicBlock("while.body"); + if (EmitBoolCondBranch) { + llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); + if (ConditionScope.requiresCleanups()) + ExitBlock = createBasicBlock("while.exit"); + + Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock); + + if (ExitBlock != LoopExit.getBlock()) { + EmitBlock(ExitBlock); + EmitBranchThroughCleanup(LoopExit); + } + } + + // Emit the loop body. We have to emit this in a cleanup scope + // because it might be a singleton DeclStmt. + { + RunCleanupsScope BodyScope(*this); + EmitBlock(LoopBody); + EmitStmt(S.getBody()); + } + + BreakContinueStack.pop_back(); + + // Immediately force cleanup. + ConditionScope.ForceCleanup(); + + // Branch to the loop header again. + EmitBranch(LoopHeader.getBlock()); + + // Emit the exit block. + EmitBlock(LoopExit.getBlock(), true); + + // The LoopHeader typically is just a branch if we skipped emitting + // a branch, try to erase it. + if (!EmitBoolCondBranch) + SimplifyForwardingBlocks(LoopHeader.getBlock()); +} + +void CodeGenFunction::EmitDoStmt(const DoStmt &S) { + JumpDest LoopExit = getJumpDestInCurrentScope("do.end"); + JumpDest LoopCond = getJumpDestInCurrentScope("do.cond"); + + // Store the blocks to use for break and continue. + BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond)); + + // Emit the body of the loop. + llvm::BasicBlock *LoopBody = createBasicBlock("do.body"); + EmitBlock(LoopBody); + { + RunCleanupsScope BodyScope(*this); + EmitStmt(S.getBody()); + } + + BreakContinueStack.pop_back(); + + EmitBlock(LoopCond.getBlock()); + + // 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, LoopExit.getBlock()); + + // Emit the exit block. + EmitBlock(LoopExit.getBlock()); + + // The DoCond block typically is just a branch if we skipped + // emitting a branch, try to erase it. + if (!EmitBoolCondBranch) + SimplifyForwardingBlocks(LoopCond.getBlock()); +} + +void CodeGenFunction::EmitForStmt(const ForStmt &S) { + JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); + + RunCleanupsScope ForScope(*this); + + CGDebugInfo *DI = getDebugInfo(); + if (DI) + DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin()); + + // Evaluate the first part before the loop. + if (S.getInit()) + EmitStmt(S.getInit()); + + // Start the loop with a block that tests the condition. + // If there's an increment, the continue scope will be overwritten + // later. + JumpDest Continue = getJumpDestInCurrentScope("for.cond"); + llvm::BasicBlock *CondBlock = Continue.getBlock(); + EmitBlock(CondBlock); + + // Create a cleanup scope for the condition variable cleanups. + RunCleanupsScope ConditionScope(*this); + + llvm::Value *BoolCondVal = 0; + if (S.getCond()) { + // If the for statement has a condition scope, emit the local variable + // declaration. + llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); + if (S.getConditionVariable()) { + EmitAutoVarDecl(*S.getConditionVariable()); + } + + // If there are any cleanups between here and the loop-exit scope, + // create a block to stage a loop exit along. + if (ForScope.requiresCleanups()) + ExitBlock = createBasicBlock("for.cond.cleanup"); + + // 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. + BoolCondVal = EvaluateExprAsBool(S.getCond()); + Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock); + + if (ExitBlock != LoopExit.getBlock()) { + EmitBlock(ExitBlock); + EmitBranchThroughCleanup(LoopExit); + } + + 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. Otherwise we'll need to create + // a block for it (in the current scope, i.e. in the scope of the + // condition), and that we will become our continue block. + if (S.getInc()) + Continue = getJumpDestInCurrentScope("for.inc"); + + // Store the blocks to use for break and continue. + BreakContinueStack.push_back(BreakContinue(LoopExit, Continue)); + + { + // Create a separate cleanup scope for the body, in case it is not + // a compound statement. + RunCleanupsScope BodyScope(*this); + EmitStmt(S.getBody()); + } + + // If there is an increment, emit it next. + if (S.getInc()) { + EmitBlock(Continue.getBlock()); + EmitStmt(S.getInc()); + } + + BreakContinueStack.pop_back(); + + ConditionScope.ForceCleanup(); + EmitBranch(CondBlock); + + ForScope.ForceCleanup(); + + if (DI) + DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd()); + + // Emit the fall-through block. + EmitBlock(LoopExit.getBlock(), true); +} + +void CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S) { + JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); + + RunCleanupsScope ForScope(*this); + + CGDebugInfo *DI = getDebugInfo(); + if (DI) + DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin()); + + // Evaluate the first pieces before the loop. + EmitStmt(S.getRangeStmt()); + EmitStmt(S.getBeginEndStmt()); + + // Start the loop with a block that tests the condition. + // If there's an increment, the continue scope will be overwritten + // later. + llvm::BasicBlock *CondBlock = createBasicBlock("for.cond"); + EmitBlock(CondBlock); + + // If there are any cleanups between here and the loop-exit scope, + // create a block to stage a loop exit along. + llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); + if (ForScope.requiresCleanups()) + ExitBlock = createBasicBlock("for.cond.cleanup"); + + // The loop body, consisting of the specified body and the loop variable. + llvm::BasicBlock *ForBody = createBasicBlock("for.body"); + + // The body is executed if the expression, contextually converted + // to bool, is true. + llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); + Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock); + + if (ExitBlock != LoopExit.getBlock()) { + EmitBlock(ExitBlock); + EmitBranchThroughCleanup(LoopExit); + } + + EmitBlock(ForBody); + + // Create a block for the increment. In case of a 'continue', we jump there. + JumpDest Continue = getJumpDestInCurrentScope("for.inc"); + + // Store the blocks to use for break and continue. + BreakContinueStack.push_back(BreakContinue(LoopExit, Continue)); + + { + // Create a separate cleanup scope for the loop variable and body. + RunCleanupsScope BodyScope(*this); + EmitStmt(S.getLoopVarStmt()); + EmitStmt(S.getBody()); + } + + // If there is an increment, emit it next. + EmitBlock(Continue.getBlock()); + EmitStmt(S.getInc()); + + BreakContinueStack.pop_back(); + + EmitBranch(CondBlock); + + ForScope.ForceCleanup(); + + if (DI) + DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd()); + + // Emit the fall-through block. + EmitBlock(LoopExit.getBlock(), 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 (S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable() && + !Target.useGlobalsForAutomaticVariables()) { + // Apply the named return value optimization for this return statement, + // which means doing nothing: the appropriate result has already been + // constructed into the NRVO variable. + + // If there is an NRVO flag for this variable, set it to 1 into indicate + // that the cleanup code should not destroy the variable. + if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()]) + Builder.CreateStore(Builder.getTrue(), NRVOFlag); + } else 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. + RValue Result = EmitReferenceBindingToExpr(RV, /*InitializedDecl=*/0); + Builder.CreateStore(Result.getScalarVal(), ReturnValue); + } else if (!hasAggregateLLVMType(RV->getType())) { + Builder.CreateStore(EmitScalarExpr(RV), ReturnValue); + } else if (RV->getType()->isAnyComplexType()) { + EmitComplexExprIntoAddr(RV, ReturnValue, false); + } else { + CharUnits Alignment = getContext().getTypeAlignInChars(RV->getType()); + EmitAggExpr(RV, AggValueSlot::forAddr(ReturnValue, Alignment, Qualifiers(), + AggValueSlot::IsDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased)); + } + + 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 (HaveInsertPoint()) + 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); + + JumpDest 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); + + JumpDest 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()->EvaluateKnownConstInt(getContext()); + llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(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(Builder.getInt(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(), Builder.getInt(LHS)); + llvm::Value *Cond = + Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds"); + 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 there is no enclosing switch instance that we're aware of, then this + // case statement and its block can be elided. This situation only happens + // when we've constant-folded the switch, are emitting the constant case, + // and part of the constant case includes another case statement. For + // instance: switch (4) { case 4: do { case 5: } while (1); } + if (!SwitchInsn) { + EmitStmt(S.getSubStmt()); + return; + } + + // Handle case ranges. + if (S.getRHS()) { + EmitCaseStmtRange(S); + return; + } + + llvm::ConstantInt *CaseVal = + Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext())); + + // If the body of the case is just a 'break', and if there was no fallthrough, + // try to not emit an empty block. + if ((CGM.getCodeGenOpts().OptimizationLevel > 0) && isa<BreakStmt>(S.getSubStmt())) { + JumpDest Block = BreakContinueStack.back().BreakBlock; + + // Only do this optimization if there are no cleanups that need emitting. + if (isObviouslyBranchWithoutCleanups(Block)) { + SwitchInsn->addCase(CaseVal, Block.getBlock()); + + // If there was a fallthrough into this case, make sure to redirect it to + // the end of the switch as well. + if (Builder.GetInsertBlock()) { + Builder.CreateBr(Block.getBlock()); + Builder.ClearInsertionPoint(); + } + return; + } + } + + EmitBlock(createBasicBlock("sw.bb")); + llvm::BasicBlock *CaseDest = Builder.GetInsertBlock(); + SwitchInsn->addCase(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 consecutive cases to this switch stmt. + while (NextCase && NextCase->getRHS() == 0) { + CurCase = NextCase; + llvm::ConstantInt *CaseVal = + Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext())); + SwitchInsn->addCase(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()); +} + +/// CollectStatementsForCase - Given the body of a 'switch' statement and a +/// constant value that is being switched on, see if we can dead code eliminate +/// the body of the switch to a simple series of statements to emit. Basically, +/// on a switch (5) we want to find these statements: +/// case 5: +/// printf(...); <-- +/// ++i; <-- +/// break; +/// +/// and add them to the ResultStmts vector. If it is unsafe to do this +/// transformation (for example, one of the elided statements contains a label +/// that might be jumped to), return CSFC_Failure. If we handled it and 'S' +/// should include statements after it (e.g. the printf() line is a substmt of +/// the case) then return CSFC_FallThrough. If we handled it and found a break +/// statement, then return CSFC_Success. +/// +/// If Case is non-null, then we are looking for the specified case, checking +/// that nothing we jump over contains labels. If Case is null, then we found +/// the case and are looking for the break. +/// +/// If the recursive walk actually finds our Case, then we set FoundCase to +/// true. +/// +enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success }; +static CSFC_Result CollectStatementsForCase(const Stmt *S, + const SwitchCase *Case, + bool &FoundCase, + SmallVectorImpl<const Stmt*> &ResultStmts) { + // If this is a null statement, just succeed. + if (S == 0) + return Case ? CSFC_Success : CSFC_FallThrough; + + // If this is the switchcase (case 4: or default) that we're looking for, then + // we're in business. Just add the substatement. + if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) { + if (S == Case) { + FoundCase = true; + return CollectStatementsForCase(SC->getSubStmt(), 0, FoundCase, + ResultStmts); + } + + // Otherwise, this is some other case or default statement, just ignore it. + return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase, + ResultStmts); + } + + // If we are in the live part of the code and we found our break statement, + // return a success! + if (Case == 0 && isa<BreakStmt>(S)) + return CSFC_Success; + + // If this is a switch statement, then it might contain the SwitchCase, the + // break, or neither. + if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { + // Handle this as two cases: we might be looking for the SwitchCase (if so + // the skipped statements must be skippable) or we might already have it. + CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end(); + if (Case) { + // Keep track of whether we see a skipped declaration. The code could be + // using the declaration even if it is skipped, so we can't optimize out + // the decl if the kept statements might refer to it. + bool HadSkippedDecl = false; + + // If we're looking for the case, just see if we can skip each of the + // substatements. + for (; Case && I != E; ++I) { + HadSkippedDecl |= isa<DeclStmt>(*I); + + switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) { + case CSFC_Failure: return CSFC_Failure; + case CSFC_Success: + // A successful result means that either 1) that the statement doesn't + // have the case and is skippable, or 2) does contain the case value + // and also contains the break to exit the switch. In the later case, + // we just verify the rest of the statements are elidable. + if (FoundCase) { + // If we found the case and skipped declarations, we can't do the + // optimization. + if (HadSkippedDecl) + return CSFC_Failure; + + for (++I; I != E; ++I) + if (CodeGenFunction::ContainsLabel(*I, true)) + return CSFC_Failure; + return CSFC_Success; + } + break; + case CSFC_FallThrough: + // If we have a fallthrough condition, then we must have found the + // case started to include statements. Consider the rest of the + // statements in the compound statement as candidates for inclusion. + assert(FoundCase && "Didn't find case but returned fallthrough?"); + // We recursively found Case, so we're not looking for it anymore. + Case = 0; + + // If we found the case and skipped declarations, we can't do the + // optimization. + if (HadSkippedDecl) + return CSFC_Failure; + break; + } + } + } + + // If we have statements in our range, then we know that the statements are + // live and need to be added to the set of statements we're tracking. + for (; I != E; ++I) { + switch (CollectStatementsForCase(*I, 0, FoundCase, ResultStmts)) { + case CSFC_Failure: return CSFC_Failure; + case CSFC_FallThrough: + // A fallthrough result means that the statement was simple and just + // included in ResultStmt, keep adding them afterwards. + break; + case CSFC_Success: + // A successful result means that we found the break statement and + // stopped statement inclusion. We just ensure that any leftover stmts + // are skippable and return success ourselves. + for (++I; I != E; ++I) + if (CodeGenFunction::ContainsLabel(*I, true)) + return CSFC_Failure; + return CSFC_Success; + } + } + + return Case ? CSFC_Success : CSFC_FallThrough; + } + + // Okay, this is some other statement that we don't handle explicitly, like a + // for statement or increment etc. If we are skipping over this statement, + // just verify it doesn't have labels, which would make it invalid to elide. + if (Case) { + if (CodeGenFunction::ContainsLabel(S, true)) + return CSFC_Failure; + return CSFC_Success; + } + + // Otherwise, we want to include this statement. Everything is cool with that + // so long as it doesn't contain a break out of the switch we're in. + if (CodeGenFunction::containsBreak(S)) return CSFC_Failure; + + // Otherwise, everything is great. Include the statement and tell the caller + // that we fall through and include the next statement as well. + ResultStmts.push_back(S); + return CSFC_FallThrough; +} + +/// FindCaseStatementsForValue - Find the case statement being jumped to and +/// then invoke CollectStatementsForCase to find the list of statements to emit +/// for a switch on constant. See the comment above CollectStatementsForCase +/// for more details. +static bool FindCaseStatementsForValue(const SwitchStmt &S, + const llvm::APInt &ConstantCondValue, + SmallVectorImpl<const Stmt*> &ResultStmts, + ASTContext &C) { + // First step, find the switch case that is being branched to. We can do this + // efficiently by scanning the SwitchCase list. + const SwitchCase *Case = S.getSwitchCaseList(); + const DefaultStmt *DefaultCase = 0; + + for (; Case; Case = Case->getNextSwitchCase()) { + // It's either a default or case. Just remember the default statement in + // case we're not jumping to any numbered cases. + if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) { + DefaultCase = DS; + continue; + } + + // Check to see if this case is the one we're looking for. + const CaseStmt *CS = cast<CaseStmt>(Case); + // Don't handle case ranges yet. + if (CS->getRHS()) return false; + + // If we found our case, remember it as 'case'. + if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue) + break; + } + + // If we didn't find a matching case, we use a default if it exists, or we + // elide the whole switch body! + if (Case == 0) { + // It is safe to elide the body of the switch if it doesn't contain labels + // etc. If it is safe, return successfully with an empty ResultStmts list. + if (DefaultCase == 0) + return !CodeGenFunction::ContainsLabel(&S); + Case = DefaultCase; + } + + // Ok, we know which case is being jumped to, try to collect all the + // statements that follow it. This can fail for a variety of reasons. Also, + // check to see that the recursive walk actually found our case statement. + // Insane cases like this can fail to find it in the recursive walk since we + // don't handle every stmt kind: + // switch (4) { + // while (1) { + // case 4: ... + bool FoundCase = false; + return CollectStatementsForCase(S.getBody(), Case, FoundCase, + ResultStmts) != CSFC_Failure && + FoundCase; +} + +void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) { + JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog"); + + RunCleanupsScope ConditionScope(*this); + + if (S.getConditionVariable()) + EmitAutoVarDecl(*S.getConditionVariable()); + + // Handle nested switch statements. + llvm::SwitchInst *SavedSwitchInsn = SwitchInsn; + llvm::BasicBlock *SavedCRBlock = CaseRangeBlock; + + // See if we can constant fold the condition of the switch and therefore only + // emit the live case statement (if any) of the switch. + llvm::APInt ConstantCondValue; + if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) { + SmallVector<const Stmt*, 4> CaseStmts; + if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts, + getContext())) { + RunCleanupsScope ExecutedScope(*this); + + // At this point, we are no longer "within" a switch instance, so + // we can temporarily enforce this to ensure that any embedded case + // statements are not emitted. + SwitchInsn = 0; + + // Okay, we can dead code eliminate everything except this case. Emit the + // specified series of statements and we're good. + for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i) + EmitStmt(CaseStmts[i]); + + // Now we want to restore the saved switch instance so that nested + // switches continue to function properly + SwitchInsn = SavedSwitchInsn; + + return; + } + } + + llvm::Value *CondV = EmitScalarExpr(S.getCond()); + + // 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 *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. + JumpDest OuterContinue; + if (!BreakContinueStack.empty()) + OuterContinue = BreakContinueStack.back().ContinueBlock; + + BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue)); + + // 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->setDefaultDest(CaseRangeBlock); + + // If a default was never emitted: + if (!DefaultBlock->getParent()) { + // If we have cleanups, emit the default block so that there's a + // place to jump through the cleanups from. + if (ConditionScope.requiresCleanups()) { + EmitBlock(DefaultBlock); + + // Otherwise, just forward the default block to the switch end. + } else { + DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock()); + delete DefaultBlock; + } + } + + ConditionScope.ForceCleanup(); + + // Emit continuation. + EmitBlock(SwitchExit.getBlock(), true); + + SwitchInsn = SavedSwitchInsn; + CaseRangeBlock = SavedCRBlock; +} + +static std::string +SimplifyConstraint(const char *Constraint, const TargetInfo &Target, + SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=0) { + std::string Result; + + while (*Constraint) { + switch (*Constraint) { + default: + Result += Target.convertConstraint(Constraint); + break; + // Ignore these + case '*': + case '?': + case '!': + case '=': // Will see this and the following in mult-alt constraints. + case '+': + break; + case ',': + Result += "|"; + 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"); (void)result; + Result += llvm::utostr(Index); + break; + } + } + + Constraint++; + } + + return Result; +} + +/// AddVariableConstraints - Look at AsmExpr and if it is a variable declared +/// as using a particular register add that as a constraint that will be used +/// in this asm stmt. +static std::string +AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr, + const TargetInfo &Target, CodeGenModule &CGM, + const AsmStmt &Stmt) { + const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr); + if (!AsmDeclRef) + return Constraint; + const ValueDecl &Value = *AsmDeclRef->getDecl(); + const VarDecl *Variable = dyn_cast<VarDecl>(&Value); + if (!Variable) + return Constraint; + if (Variable->getStorageClass() != SC_Register) + return Constraint; + AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>(); + if (!Attr) + return Constraint; + StringRef Register = Attr->getLabel(); + assert(Target.isValidGCCRegisterName(Register)); + // We're using validateOutputConstraint here because we only care if + // this is a register constraint. + TargetInfo::ConstraintInfo Info(Constraint, ""); + if (Target.validateOutputConstraint(Info) && + !Info.allowsRegister()) { + CGM.ErrorUnsupported(&Stmt, "__asm__"); + return Constraint; + } + // Canonicalize the register here before returning it. + Register = Target.getNormalizedGCCRegisterName(Register); + return "{" + Register.str() + "}"; +} + +llvm::Value* +CodeGenFunction::EmitAsmInputLValue(const AsmStmt &S, + const TargetInfo::ConstraintInfo &Info, + LValue InputValue, QualType InputType, + std::string &ConstraintStr) { + llvm::Value *Arg; + if (Info.allowsRegister() || !Info.allowsMemory()) { + if (!CodeGenFunction::hasAggregateLLVMType(InputType)) { + Arg = EmitLoadOfLValue(InputValue).getScalarVal(); + } else { + llvm::Type *Ty = ConvertType(InputType); + uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty); + if (Size <= 64 && llvm::isPowerOf2_64(Size)) { + Ty = llvm::IntegerType::get(getLLVMContext(), Size); + Ty = llvm::PointerType::getUnqual(Ty); + + Arg = Builder.CreateLoad(Builder.CreateBitCast(InputValue.getAddress(), + Ty)); + } else { + Arg = InputValue.getAddress(); + ConstraintStr += '*'; + } + } + } else { + Arg = InputValue.getAddress(); + ConstraintStr += '*'; + } + + return Arg; +} + +llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S, + const TargetInfo::ConstraintInfo &Info, + const Expr *InputExpr, + std::string &ConstraintStr) { + if (Info.allowsRegister() || !Info.allowsMemory()) + if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType())) + return EmitScalarExpr(InputExpr); + + InputExpr = InputExpr->IgnoreParenNoopCasts(getContext()); + LValue Dest = EmitLValue(InputExpr); + return EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), ConstraintStr); +} + +/// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline +/// asm call instruction. The !srcloc MDNode contains a list of constant +/// integers which are the source locations of the start of each line in the +/// asm. +static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str, + CodeGenFunction &CGF) { + SmallVector<llvm::Value *, 8> Locs; + // Add the location of the first line to the MDNode. + Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty, + Str->getLocStart().getRawEncoding())); + StringRef StrVal = Str->getString(); + if (!StrVal.empty()) { + const SourceManager &SM = CGF.CGM.getContext().getSourceManager(); + const LangOptions &LangOpts = CGF.CGM.getLangOpts(); + + // Add the location of the start of each subsequent line of the asm to the + // MDNode. + for (unsigned i = 0, e = StrVal.size()-1; i != e; ++i) { + if (StrVal[i] != '\n') continue; + SourceLocation LineLoc = Str->getLocationOfByte(i+1, SM, LangOpts, + CGF.Target); + Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty, + LineLoc.getRawEncoding())); + } + } + + return llvm::MDNode::get(CGF.getLLVMContext(), Locs); +} + +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. + 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. + SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; + 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 IsValid = Target.validateOutputConstraint(Info); (void)IsValid; + assert(IsValid && "Failed to parse output constraint"); + OutputConstraintInfos.push_back(Info); + } + + for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { + TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), + S.getInputName(i)); + bool IsValid = Target.validateInputConstraint(OutputConstraintInfos.data(), + S.getNumOutputs(), Info); + assert(IsValid && "Failed to parse input constraint"); (void)IsValid; + InputConstraintInfos.push_back(Info); + } + + std::string Constraints; + + std::vector<LValue> ResultRegDests; + std::vector<QualType> ResultRegQualTys; + std::vector<llvm::Type *> ResultRegTypes; + std::vector<llvm::Type *> ResultTruncRegTypes; + std::vector<llvm::Type*> ArgTypes; + std::vector<llvm::Value*> Args; + + // Keep track of inout constraints. + std::string InOutConstraints; + std::vector<llvm::Value*> InOutArgs; + std::vector<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()); + + OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr, + Target, CGM, S); + + 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 OutputType = OutExpr->getType(); + + uint64_t InputSize = getContext().getTypeSize(InputTy); + if (getContext().getTypeSize(OutputType) < InputSize) { + // Form the asm to return the value as a larger integer or fp type. + ResultRegTypes.back() = ConvertType(InputTy); + } + } + if (llvm::Type* AdjTy = + getTargetHooks().adjustInlineAsmType(*this, OutputConstraint, + ResultRegTypes.back())) + ResultRegTypes.back() = AdjTy; + } 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 = EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), + InOutConstraints); + + if (llvm::Type* AdjTy = + getTargetHooks().adjustInlineAsmType(*this, OutputConstraint, + Arg->getType())) + Arg = Builder.CreateBitCast(Arg, AdjTy); + + 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); + + InputConstraint = + AddVariableConstraints(InputConstraint, + *InputExpr->IgnoreParenNoopCasts(getContext()), + Target, CGM, S); + + 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 OutputType = S.getOutputExpr(Output)->getType(); + QualType InputTy = InputExpr->getType(); + + if (getContext().getTypeSize(OutputType) > + getContext().getTypeSize(InputTy)) { + // Use ptrtoint as appropriate so that we can do our extension. + if (isa<llvm::PointerType>(Arg->getType())) + Arg = Builder.CreatePtrToInt(Arg, IntPtrTy); + llvm::Type *OutputTy = ConvertType(OutputType); + if (isa<llvm::IntegerType>(OutputTy)) + Arg = Builder.CreateZExt(Arg, OutputTy); + else if (isa<llvm::PointerType>(OutputTy)) + Arg = Builder.CreateZExt(Arg, IntPtrTy); + else { + assert(OutputTy->isFloatingPointTy() && "Unexpected output type"); + Arg = Builder.CreateFPExt(Arg, OutputTy); + } + } + } + if (llvm::Type* AdjTy = + getTargetHooks().adjustInlineAsmType(*this, InputConstraint, + Arg->getType())) + Arg = Builder.CreateBitCast(Arg, AdjTy); + + 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++) { + StringRef Clobber = S.getClobber(i)->getString(); + + if (Clobber != "memory" && Clobber != "cc") + Clobber = Target.getNormalizedGCCRegisterName(Clobber); + + 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; + } + + llvm::Type *ResultType; + if (ResultRegTypes.empty()) + ResultType = VoidTy; + else if (ResultRegTypes.size() == 1) + ResultType = ResultRegTypes[0]; + else + ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes); + + 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); + Result->addAttribute(~0, llvm::Attribute::NoUnwind); + + // Slap the source location of the inline asm into a !srcloc metadata on the + // call. + Result->setMetadata("srcloc", getAsmSrcLocInfo(S.getAsmString(), *this)); + + // 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]) { + llvm::Type *TruncTy = ResultTruncRegTypes[i]; + + // Truncate the integer result to the right size, note that TruncTy can be + // a pointer. + if (TruncTy->isFloatingPointTy()) + Tmp = Builder.CreateFPTrunc(Tmp, TruncTy); + else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) { + uint64_t ResSize = CGM.getTargetData().getTypeSizeInBits(TruncTy); + Tmp = Builder.CreateTrunc(Tmp, + llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize)); + Tmp = Builder.CreateIntToPtr(Tmp, TruncTy); + } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) { + uint64_t TmpSize =CGM.getTargetData().getTypeSizeInBits(Tmp->getType()); + Tmp = Builder.CreatePtrToInt(Tmp, + llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize)); + Tmp = Builder.CreateTrunc(Tmp, TruncTy); + } else if (TruncTy->isIntegerTy()) { + Tmp = Builder.CreateTrunc(Tmp, TruncTy); + } else if (TruncTy->isVectorTy()) { + Tmp = Builder.CreateBitCast(Tmp, TruncTy); + } + } + + EmitStoreThroughLValue(RValue::get(Tmp), ResultRegDests[i]); + } +} |
