Coverage Report

Created: 2020-11-24 06:42

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/AST/Interp/ByteCodeStmtGen.cpp
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//===--- ByteCodeStmtGen.cpp - Code generator for expressions ---*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "ByteCodeStmtGen.h"
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#include "ByteCodeEmitter.h"
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#include "ByteCodeGenError.h"
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#include "Context.h"
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#include "Function.h"
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#include "PrimType.h"
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#include "Program.h"
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#include "State.h"
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#include "clang/Basic/LLVM.h"
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using namespace clang;
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using namespace clang::interp;
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namespace clang {
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namespace interp {
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/// Scope managing label targets.
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template <class Emitter> class LabelScope {
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public:
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  virtual ~LabelScope() {  }
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protected:
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  LabelScope(ByteCodeStmtGen<Emitter> *Ctx) : Ctx(Ctx) {}
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  /// ByteCodeStmtGen instance.
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  ByteCodeStmtGen<Emitter> *Ctx;
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};
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/// Sets the context for break/continue statements.
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template <class Emitter> class LoopScope final : public LabelScope<Emitter> {
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public:
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  using LabelTy = typename ByteCodeStmtGen<Emitter>::LabelTy;
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  using OptLabelTy = typename ByteCodeStmtGen<Emitter>::OptLabelTy;
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  LoopScope(ByteCodeStmtGen<Emitter> *Ctx, LabelTy BreakLabel,
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            LabelTy ContinueLabel)
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      : LabelScope<Emitter>(Ctx), OldBreakLabel(Ctx->BreakLabel),
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        OldContinueLabel(Ctx->ContinueLabel) {
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    this->Ctx->BreakLabel = BreakLabel;
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    this->Ctx->ContinueLabel = ContinueLabel;
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  }
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  ~LoopScope() {
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    this->Ctx->BreakLabel = OldBreakLabel;
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    this->Ctx->ContinueLabel = OldContinueLabel;
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  }
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private:
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  OptLabelTy OldBreakLabel;
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  OptLabelTy OldContinueLabel;
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};
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// Sets the context for a switch scope, mapping labels.
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template <class Emitter> class SwitchScope final : public LabelScope<Emitter> {
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public:
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  using LabelTy = typename ByteCodeStmtGen<Emitter>::LabelTy;
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  using OptLabelTy = typename ByteCodeStmtGen<Emitter>::OptLabelTy;
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  using CaseMap = typename ByteCodeStmtGen<Emitter>::CaseMap;
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  SwitchScope(ByteCodeStmtGen<Emitter> *Ctx, CaseMap &&CaseLabels,
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              LabelTy BreakLabel, OptLabelTy DefaultLabel)
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      : LabelScope<Emitter>(Ctx), OldBreakLabel(Ctx->BreakLabel),
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        OldDefaultLabel(this->Ctx->DefaultLabel),
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        OldCaseLabels(std::move(this->Ctx->CaseLabels)) {
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    this->Ctx->BreakLabel = BreakLabel;
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    this->Ctx->DefaultLabel = DefaultLabel;
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    this->Ctx->CaseLabels = std::move(CaseLabels);
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  }
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  ~SwitchScope() {
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    this->Ctx->BreakLabel = OldBreakLabel;
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    this->Ctx->DefaultLabel = OldDefaultLabel;
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    this->Ctx->CaseLabels = std::move(OldCaseLabels);
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  }
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private:
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  OptLabelTy OldBreakLabel;
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  OptLabelTy OldDefaultLabel;
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  CaseMap OldCaseLabels;
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};
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} // namespace interp
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} // namespace clang
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitFunc(const FunctionDecl *F) {
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  // Classify the return type.
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  ReturnType = this->classify(F->getReturnType());
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  // Set up fields and context if a constructor.
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  if (auto *MD = dyn_cast<CXXMethodDecl>(F))
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    return this->bail(MD);
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  if (auto *Body = F->getBody())
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    if (!visitStmt(Body))
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      return false;
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  // Emit a guard return to protect against a code path missing one.
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  if (F->getReturnType()->isVoidType())
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    return this->emitRetVoid(SourceInfo{});
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  else
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    return this->emitNoRet(SourceInfo{});
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitStmt(const Stmt *S) {
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  switch (S->getStmtClass()) {
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  case Stmt::CompoundStmtClass:
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    return visitCompoundStmt(cast<CompoundStmt>(S));
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  case Stmt::DeclStmtClass:
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    return visitDeclStmt(cast<DeclStmt>(S));
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  case Stmt::ReturnStmtClass:
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    return visitReturnStmt(cast<ReturnStmt>(S));
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  case Stmt::IfStmtClass:
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    return visitIfStmt(cast<IfStmt>(S));
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  case Stmt::NullStmtClass:
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    return true;
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  default: {
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    if (auto *Exp = dyn_cast<Expr>(S))
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      return this->discard(Exp);
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    return this->bail(S);
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  }
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  }
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitCompoundStmt(
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    const CompoundStmt *CompoundStmt) {
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  BlockScope<Emitter> Scope(this);
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  for (auto *InnerStmt : CompoundStmt->body())
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    if (!visitStmt(InnerStmt))
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      return false;
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  return true;
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitDeclStmt(const DeclStmt *DS) {
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  for (auto *D : DS->decls()) {
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    // Variable declarator.
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    if (auto *VD = dyn_cast<VarDecl>(D)) {
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      if (!visitVarDecl(VD))
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        return false;
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      continue;
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    }
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    // Decomposition declarator.
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    if (auto *DD = dyn_cast<DecompositionDecl>(D)) {
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      return this->bail(DD);
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    }
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  }
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  return true;
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitReturnStmt(const ReturnStmt *RS) {
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  if (const Expr *RE = RS->getRetValue()) {
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    ExprScope<Emitter> RetScope(this);
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    if (ReturnType) {
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      // Primitive types are simply returned.
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      if (!this->visit(RE))
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        return false;
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      this->emitCleanup();
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      return this->emitRet(*ReturnType, RS);
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    } else {
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      // RVO - construct the value in the return location.
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      auto ReturnLocation = [this, RE] { return this->emitGetParamPtr(0, RE); };
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      if (!this->visitInitializer(RE, ReturnLocation))
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        return false;
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      this->emitCleanup();
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      return this->emitRetVoid(RS);
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    }
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  } else {
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    this->emitCleanup();
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    if (!this->emitRetVoid(RS))
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      return false;
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    return true;
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  }
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitIfStmt(const IfStmt *IS) {
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  BlockScope<Emitter> IfScope(this);
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  if (auto *CondInit = IS->getInit())
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    if (!visitStmt(IS->getInit()))
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      return false;
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  if (const DeclStmt *CondDecl = IS->getConditionVariableDeclStmt())
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    if (!visitDeclStmt(CondDecl))
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      return false;
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  if (!this->visitBool(IS->getCond()))
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    return false;
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  if (const Stmt *Else = IS->getElse()) {
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    LabelTy LabelElse = this->getLabel();
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    LabelTy LabelEnd = this->getLabel();
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    if (!this->jumpFalse(LabelElse))
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      return false;
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    if (!visitStmt(IS->getThen()))
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      return false;
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    if (!this->jump(LabelEnd))
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      return false;
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    this->emitLabel(LabelElse);
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    if (!visitStmt(Else))
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      return false;
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    this->emitLabel(LabelEnd);
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  } else {
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    LabelTy LabelEnd = this->getLabel();
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    if (!this->jumpFalse(LabelEnd))
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      return false;
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    if (!visitStmt(IS->getThen()))
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      return false;
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    this->emitLabel(LabelEnd);
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  }
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  return true;
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}
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template <class Emitter>
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bool ByteCodeStmtGen<Emitter>::visitVarDecl(const VarDecl *VD) {
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  auto DT = VD->getType();
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  if (!VD->hasLocalStorage()) {
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    // No code generation required.
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    return true;
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  }
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  // Integers, pointers, primitives.
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  if (Optional<PrimType> T = this->classify(DT)) {
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    auto Off = this->allocateLocalPrimitive(VD, *T, DT.isConstQualified());
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    // Compile the initialiser in its own scope.
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    {
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      ExprScope<Emitter> Scope(this);
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      if (!this->visit(VD->getInit()))
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        return false;
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    }
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    // Set the value.
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    return this->emitSetLocal(*T, Off, VD);
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  } else {
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    // Composite types - allocate storage and initialize it.
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    if (auto Off = this->allocateLocal(VD)) {
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      return this->visitLocalInitializer(VD->getInit(), *Off);
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    } else {
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      return this->bail(VD);
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    }
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  }
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}
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namespace clang {
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namespace interp {
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template class ByteCodeStmtGen<ByteCodeEmitter>;
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} // namespace interp
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} // namespace clang