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+//===--- EvalEmitter.h - Instruction emitter for the VM ---------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines the instruction emitters.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_INTERP_EVALEMITTER_H
+#define LLVM_CLANG_AST_INTERP_EVALEMITTER_H
+
+#include "ByteCodeGenError.h"
+#include "Context.h"
+#include "InterpStack.h"
+#include "InterpState.h"
+#include "PrimType.h"
+#include "Program.h"
+#include "Source.h"
+#include "llvm/Support/Error.h"
+
+namespace clang {
+class FunctionDecl;
+namespace interp {
+class Context;
+class Function;
+class InterpState;
+class Program;
+class SourceInfo;
+enum Opcode : uint32_t;
+
+/// An emitter which evaluates opcodes as they are emitted.
+class EvalEmitter : public SourceMapper {
+public:
+ using LabelTy = uint32_t;
+ using AddrTy = uintptr_t;
+ using Local = Scope::Local;
+
+ llvm::Expected<bool> interpretExpr(const Expr *E);
+ llvm::Expected<bool> interpretDecl(const VarDecl *VD);
+
+protected:
+ EvalEmitter(Context &Ctx, Program &P, State &Parent, InterpStack &Stk,
+ APValue &Result);
+
+ virtual ~EvalEmitter() {}
+
+ /// Define a label.
+ void emitLabel(LabelTy Label);
+ /// Create a label.
+ LabelTy getLabel();
+
+ /// Methods implemented by the compiler.
+ virtual bool visitExpr(const Expr *E) = 0;
+ virtual bool visitDecl(const VarDecl *VD) = 0;
+
+ bool bail(const Stmt *S) { return bail(S->getBeginLoc()); }
+ bool bail(const Decl *D) { return bail(D->getBeginLoc()); }
+ bool bail(const SourceLocation &Loc);
+
+ /// Emits jumps.
+ bool jumpTrue(const LabelTy &Label);
+ bool jumpFalse(const LabelTy &Label);
+ bool jump(const LabelTy &Label);
+ bool fallthrough(const LabelTy &Label);
+
+ /// Callback for registering a local.
+ Local createLocal(Descriptor *D);
+
+ /// Returns the source location of the current opcode.
+ SourceInfo getSource(Function *F, CodePtr PC) const override {
+ return F ? F->getSource(PC) : CurrentSource;
+ }
+
+ /// Parameter indices.
+ llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
+ /// Local descriptors.
+ llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
+
+private:
+ /// Current compilation context.
+ Context &Ctx;
+ /// Current program.
+ Program &P;
+ /// Callee evaluation state.
+ InterpState S;
+ /// Location to write the result to.
+ APValue &Result;
+
+ /// Temporaries which require storage.
+ llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Locals;
+
+ // The emitter always tracks the current instruction and sets OpPC to a token
+ // value which is mapped to the location of the opcode being evaluated.
+ CodePtr OpPC;
+ /// Location of a failure.
+ llvm::Optional<SourceLocation> BailLocation;
+ /// Location of the current instruction.
+ SourceInfo CurrentSource;
+
+ /// Next label ID to generate - first label is 1.
+ LabelTy NextLabel = 1;
+ /// Label being executed - 0 is the entry label.
+ LabelTy CurrentLabel = 0;
+ /// Active block which should be executed.
+ LabelTy ActiveLabel = 0;
+
+ /// Since expressions can only jump forward, predicated execution is
+ /// used to deal with if-else statements.
+ bool isActive() { return CurrentLabel == ActiveLabel; }
+
+ /// Helper to invoke a method.
+ bool ExecuteCall(Function *F, Pointer &&This, const SourceInfo &Info);
+ /// Helper to emit a diagnostic on a missing method.
+ bool ExecuteNoCall(const FunctionDecl *F, const SourceInfo &Info);
+
+protected:
+#define GET_EVAL_PROTO
+#include "Opcodes.inc"
+#undef GET_EVAL_PROTO
+};
+
+} // namespace interp
+} // namespace clang
+
+#endif