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CoroutinesCodeGenerator.cpp
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/******************************************************************************
*
* C++ Insights, copyright (C) by Andreas Fertig
* Distributed under an MIT license. See LICENSE for details
*
****************************************************************************/
#include <iterator>
#include <optional>
#include <vector>
#include "CodeGenerator.h"
#include "DPrint.h"
#include "Insights.h"
#include "InsightsHelpers.h"
#include "NumberIterator.h"
//-----------------------------------------------------------------------------
namespace clang::insights {
void SkipNamePrefix(bool b);
#define SKIP_NAME_PREFIX_FOR_SCOPE \
if(FinalAction __fa{[] { SkipNamePrefix(false); }}; SkipNamePrefix(true), false) { \
} else
#define SCOPED_VAR_TOGGLE(var) \
if(FinalAction __fa{[&] { var != var; }}; (var != var), false) { \
} else
//-----------------------------------------------------------------------------
constexpr std::string_view CORO_FRAME_NAME{"__f"sv};
const std::string CORO_FRAME_ACCESS{StrCat(CORO_FRAME_NAME, "->"sv)};
const std::string CORO_FRAME_ACCESS_THIS{StrCat(CORO_FRAME_ACCESS, kwInternalThis)};
const std::string SUSPEND_INDEX_NAME{BuildInternalVarName("suspend_index"sv)};
const std::string INITIAL_AWAIT_SUSPEND_CALLED_NAME{BuildInternalVarName("initial_await_suspend_called"sv)};
const std::string RESUME_LABEL_PREFIX{BuildInternalVarName("resume"sv)};
const std::string FINAL_SUSPEND_NAME{BuildInternalVarName("final_suspend"sv)};
//-----------------------------------------------------------------------------
namespace asthelpers {
auto* mkLabelDecl(std::string_view name)
{
auto& ctx = GetGlobalAST();
return LabelDecl::Create(const_cast<ASTContext&>(ctx), ctx.getTranslationUnitDecl(), {}, &ctx.Idents.get(name));
}
auto* mkLabelStmt(std::string_view name)
{
return new(GetGlobalAST()) LabelStmt({}, mkLabelDecl(name), nullptr);
}
CompoundStmt* mkCompoundStmt(ArrayRef<Stmt*> bodyStmts, SourceLocation beginLoc = {}, SourceLocation endLoc = {})
{
return CompoundStmt::Create(GetGlobalAST(),
bodyStmts,
#if IS_CLANG_NEWER_THAN(14)
FPOptionsOverride{},
#endif
beginLoc,
endLoc);
}
auto* mkIfStmt(Expr* condition, ArrayRef<Stmt*> bodyStmts)
{
return IfStmt::Create(GetGlobalAST(),
{},
IfStatementKind::Ordinary,
nullptr,
nullptr,
condition,
{},
{},
mkCompoundStmt(bodyStmts),
{},
/*else*/ nullptr);
}
auto* mkUnaryOperator(Expr* stmt, UnaryOperatorKind kind, QualType type)
{
return UnaryOperator::Create(GetGlobalAST(), stmt, kind, type, VK_PRValue, OK_Ordinary, {}, false, {});
}
auto* mkNotIfStmt(Expr* stmt, ArrayRef<Stmt*> bodyStmts)
{
auto* opNot = mkUnaryOperator(stmt, UO_LNot, stmt->getType());
return mkIfStmt(opNot, bodyStmts);
}
auto* mkIntegerLiteral32(uint64_t value)
{
auto& ctx = GetGlobalAST();
llvm::APInt v{32, value, true};
return IntegerLiteral::Create(ctx, v, ctx.IntTy, {});
}
auto* mkBoolLiteral(bool value)
{
auto& ctx = GetGlobalAST();
return new(ctx) CXXBoolLiteralExpr(value, ctx.BoolTy, {});
}
auto* mkMemberExpr(Expr* expr, ValueDecl* vd, bool isArrow = true)
{
return MemberExpr::CreateImplicit(GetGlobalAST(), expr, isArrow, vd, vd->getType(), VK_LValue, OK_Ordinary);
}
auto* mkBinaryOperator(Expr* lhs, Expr* rhs, BinaryOperator::Opcode opc, QualType resType)
{
return BinaryOperator::Create(GetGlobalAST(), lhs, rhs, opc, resType, VK_LValue, OK_Ordinary, {}, {});
}
auto* mkAssign(DeclRefExpr* declRef, FieldDecl* field, Expr* assignExpr)
{
auto* me = mkMemberExpr(declRef, field);
return mkBinaryOperator(me, assignExpr, BO_Assign, field->getType());
}
auto* mkGotoStmt(std::string_view labelName)
{
return new(GetGlobalAST()) GotoStmt(asthelpers::mkLabelDecl(labelName), {}, {});
}
using params_vector = std::vector<std::pair<std::string_view, QualType>>;
auto* mkFunctionDeclBase(std::string_view name,
QualType returnType,
const params_vector& parameters,
DeclContext* declCtx)
{
auto& ctx = GetGlobalAST();
SmallVector<QualType, 8> argTypes{};
for(const auto& [_, type] : parameters) {
argTypes.push_back(type);
}
FunctionDecl* fdd = FunctionDecl::Create(
const_cast<ASTContext&>(ctx),
declCtx,
{},
{},
&ctx.Idents.get(name),
ctx.getFunctionType(returnType, ArrayRef<QualType>{argTypes}, FunctionProtoType::ExtProtoInfo{}),
nullptr,
SC_None, // SC_Static,
false,
false,
false,
ConstexprSpecKind::Unspecified,
nullptr);
fdd->setImplicit(true);
SmallVector<ParmVarDecl*, 16> paramVarDecls{};
for(const auto& [name, type] : parameters) {
ParmVarDecl* param = ParmVarDecl::Create(
const_cast<ASTContext&>(ctx), fdd, {}, {}, &ctx.Idents.get(name), type, nullptr, SC_None, nullptr);
param->setScopeInfo(0, 0);
paramVarDecls.push_back(param);
}
fdd->setParams(paramVarDecls);
return fdd;
}
auto* mkFunctionDecl(std::string_view name, QualType returnType, const params_vector& parameters)
{
return mkFunctionDeclBase(name, returnType, parameters, GetGlobalAST().getTranslationUnitDecl());
}
auto* mkStdFunctionDecl(std::string_view name, QualType returnType, const params_vector& parameters)
{
auto& ctx = GetGlobalAST();
NamespaceDecl* stdNs = NamespaceDecl::Create(
const_cast<ASTContext&>(ctx), ctx.getTranslationUnitDecl(), false, {}, {}, &ctx.Idents.get("std"), nullptr);
return mkFunctionDeclBase(name, returnType, parameters, stdNs);
}
auto* mkDeclRefExpr(ValueDecl* vd)
{
return DeclRefExpr::Create(GetGlobalAST(),
NestedNameSpecifierLoc{},
SourceLocation{},
vd,
false,
SourceLocation{},
vd->getType(),
VK_LValue,
nullptr,
nullptr,
NOUR_None);
}
auto* mkCallExpr(FunctionDecl* fd, QualType retType, const std::vector<Expr*>& params)
{
auto* fdDref = asthelpers::mkDeclRefExpr(fd);
return CallExpr::Create(GetGlobalAST(), fdDref, params, retType, VK_LValue, {}, {});
}
auto* mkMemberCallExpr(MemberExpr* memExpr, QualType retType /*, const std::vector<Expr*>& params*/)
{
return CXXMemberCallExpr::Create(GetGlobalAST(), memExpr, /*params*/ {}, retType, VK_LValue, {}, {});
}
auto* mkReturnStmt(Expr* stmt = nullptr)
{
return ReturnStmt::Create(GetGlobalAST(), {}, stmt, nullptr);
}
auto* mkCaseStmt(int value, Stmt* stmt)
{
auto* il = asthelpers::mkIntegerLiteral32(value);
auto* caseStmt = CaseStmt::Create(GetGlobalAST(), il, nullptr, {}, {}, {});
caseStmt->setSubStmt(stmt);
return caseStmt;
}
auto* mkVarDecl(std::string_view name, QualType type)
{
auto& ctx = GetGlobalAST();
return VarDecl::Create(const_cast<ASTContext&>(ctx),
ctx.getTranslationUnitDecl(),
{},
{},
&ctx.Idents.get(name),
type,
nullptr,
SC_None);
}
auto* mkNullStmt()
{
static auto* nstmt = new(GetGlobalAST()) NullStmt({}, false);
return nstmt;
}
auto* mkInsightsComment(std::string_view comment)
{
return new(GetGlobalAST()) CppInsightsCommentStmt{comment};
}
auto* mkFunctionReference(FunctionDecl* fd)
{
auto* dref = asthelpers::mkDeclRefExpr(fd);
return asthelpers::mkUnaryOperator(dref, UO_AddrOf, fd->getType());
}
auto* mkCXXRecordDecl(std::string_view name)
{
auto& ctx = GetGlobalAST();
return CXXRecordDecl::Create(
ctx, TTK_Struct, ctx.getTranslationUnitDecl(), {}, {}, &ctx.Idents.get(name), nullptr, false);
}
} // namespace asthelpers
using decl_vector_t = std::vector<const VarDecl*>;
using this_vector_t = std::vector<const CXXThisExpr*>;
using recordDecl_vector_t = std::vector<const CXXRecordDecl*>;
//-----------------------------------------------------------------------------
struct DeclsHolder
{
decl_vector_t mMoveDecls{};
decl_vector_t mDecls{};
recordDecl_vector_t mEmptyRecordDecls{};
recordDecl_vector_t mRecordDecls{};
this_vector_t mThisExprs{};
int mSuspendsCount{};
bool EmulateEmpty{true};
void push_back(const VarDecl* vd)
{
void AddToVarNamePrefixMap(const VarDecl* vd, std::string_view name);
mMoveDecls.push_back(vd);
AddToVarNamePrefixMap(vd, CORO_FRAME_ACCESS);
}
void JoinDeclsAndMoveDecls()
{
mDecls.insert(mDecls.end(), mMoveDecls.begin(), mMoveDecls.end());
mMoveDecls.clear();
}
/// Traverse the whole CoroutineBodyStmt to find all appearing \c VarDecl. These need to be rerouted to the
/// coroutine frame and hence prefixed by something like __f->. For that reason we only look for \c VarDecls
/// directly appearing in the body, \c CallExpr will be skipped.
void FindAllVarDecls(const Stmt* stmt)
{
RETURN_IF(nullptr == stmt);
// Take this expressions to rewrite access when the coroutine is a class method.
if(const auto* thisExpr = dyn_cast_or_null<CXXThisExpr>(stmt)) {
mThisExprs.push_back(thisExpr);
} else if(const auto* declStmt = dyn_cast_or_null<DeclStmt>(stmt)) {
if(declStmt->isSingleDecl()) {
const auto* singleDecl = declStmt->getSingleDecl();
if(const auto* vd = dyn_cast_or_null<VarDecl>(singleDecl)) {
push_back(vd);
return;
} else if(const auto* recordDecl = dyn_cast_or_null<CXXRecordDecl>(singleDecl)) {
mRecordDecls.push_back(recordDecl);
}
}
}
for(const auto* child : stmt->children()) {
FindAllVarDecls(child);
}
}
const decl_vector_t& GetDecls() const
{
if(EmulateEmpty) {
static const decl_vector_t mEmptyDecls{};
return mEmptyDecls;
}
return mDecls;
}
bool ContainsDecl(const Decl* decl) const { return Contains(GetDecls(), decl); }
};
//-----------------------------------------------------------------------------
static DeclsHolder mDeclsHolder{};
//-----------------------------------------------------------------------------
QualType CoroutinesCodeGenerator::GetFramePointerType() const
{
return GetGlobalAST().getPointerType(GetFrameType());
}
//-----------------------------------------------------------------------------
CoroutinesCodeGenerator::~CoroutinesCodeGenerator()
{
RETURN_IF(not(mASTData.mFrameType and mASTData.mDoInsertInDtor));
mASTData.mFrameType->completeDefinition();
OutputFormatHelper ofm{};
// Using the "normal" CodeGenerator here as this is only about inserting the made up coroutine-frame.
void ClearVarNamePrefix();
ClearVarNamePrefix();
CodeGenerator codeGenerator{ofm};
codeGenerator.InsertArg(mASTData.mFrameType);
// Insert the made-up struct before the function declaration
mOutputFormatHelper.InsertAt(mPosBeforeFunc, ofm);
}
//-----------------------------------------------------------------------------
///! A helper type to have a container for ArrayRef
struct StmtsContainer
{
std::vector<Stmt*> mStmts{};
StmtsContainer() = default;
StmtsContainer(std::initializer_list<const Stmt*> stmts)
{
for(const auto& stmt : stmts) {
Add(stmt);
}
}
void Add(const Stmt* stmt)
{
if(stmt) {
mStmts.push_back(const_cast<Stmt*>(stmt));
}
}
operator ArrayRef<Stmt*>() { return mStmts; }
};
//-----------------------------------------------------------------------------
FieldDecl* CoroutinesCodeGenerator::AddField(std::string_view name, QualType type)
{
if(nullptr == mASTData.mFrameType) {
return nullptr;
}
auto& ctx = GetGlobalAST();
auto* fieldDecl = FieldDecl::Create(
ctx, mASTData.mFrameType, {}, {}, &ctx.Idents.get(name), type, nullptr, nullptr, false, ICIS_NoInit);
fieldDecl->setAccess(AS_public);
mASTData.mFrameType->addDecl(fieldDecl);
return fieldDecl;
}
//-----------------------------------------------------------------------------
static void ReplaceAll(std::string& str, std::string_view from, std::string_view to)
{
size_t start_pos = 0;
while((start_pos = str.find(from, start_pos)) != std::string::npos) {
str.replace(start_pos, from.length(), to);
start_pos += to.length(); // Handles case where 'to' is a substring of 'from'
}
}
//-----------------------------------------------------------------------------
static auto* CreateFunctionDecl(std::string funcName, asthelpers::params_vector params)
{
const std::string coroFsmName{BuildInternalVarName(funcName)};
return asthelpers::mkFunctionDecl(coroFsmName, GetGlobalAST().VoidTy, params);
}
//-----------------------------------------------------------------------------
static void SetFunctionBody(FunctionDecl* fd, StmtsContainer& bodyStmts)
{
fd->setBody(asthelpers::mkCompoundStmt(bodyStmts));
}
//-----------------------------------------------------------------------------
void CoroutinesCodeGenerator::InsertCoroutine(const FunctionDecl& fd, const CoroutineBodyStmt* stmt)
{
mOutputFormatHelper.OpenScope();
const auto* promiseDecl = stmt->getPromiseDecl();
mDeclsHolder.push_back(promiseDecl);
auto& ctx = GetGlobalAST();
mFSMName = [&] {
OutputFormatHelper ofm{};
CodeGenerator codeGenerator{ofm};
// Coroutines can be templates and then we end up with the same FSM name but different template parameters.
// XXX: This will fail with NTTP's like 3.14
if(const auto* args = fd.getTemplateSpecializationArgs()) {
ofm.Append('_');
OnceFalse needsUnderscore{};
for(const auto& arg : args->asArray()) {
if(needsUnderscore) {
ofm.Append('_');
}
codeGenerator.InsertTemplateArg(arg);
}
}
auto& str = ofm.GetString();
ReplaceAll(str, "<"sv, ""sv);
ReplaceAll(str, ":"sv, ""sv);
ReplaceAll(str, ">"sv, ""sv);
ReplaceAll(str, ","sv, ""sv);
ReplaceAll(str, " "sv, ""sv);
if(fd.isOverloadedOperator()) {
return StrCat(MakeLineColumnName(ctx.getSourceManager(), stmt->getBeginLoc(), "operator_"sv), str);
} else {
return StrCat(GetName(fd), str);
}
}();
mFrameName = BuildInternalVarName(StrCat(mFSMName, "Frame"sv));
// Insert a made up struct which holds the "captured" parameters stored in the coroutine frame
mASTData.mFrameType = asthelpers::mkCXXRecordDecl(mFrameName);
mASTData.mFrameType->startDefinition();
// A "normal" struct has itself attached as a Decl. To make everything work do the same thing here
auto* selfDecl = asthelpers::mkCXXRecordDecl(mFrameName);
selfDecl->setAccess(AS_public);
mASTData.mFrameType->addDecl(selfDecl);
auto* frameAccess = asthelpers::mkVarDecl(CORO_FRAME_NAME, GetFrameType());
mASTData.mFrameAccessDeclRef = asthelpers::mkDeclRefExpr(frameAccess);
// The coroutine frame starts with two function pointers to the resume and destroy function. See:
// https://gcc.gnu.org/legacy-ml/gcc-patches/2020-01/msg01096.html and https://llvm.org/docs/Coroutines.html#id72
// "Coroutine Representation"
auto* resumeFnFd =
asthelpers::mkFunctionDecl(hlpResumeFn, ctx.VoidTy, {{CORO_FRAME_NAME, ctx.getPointerType(GetFrameType())}});
auto resumeFnType = ctx.getPointerType(resumeFnFd->getType());
mASTData.mResumeFnField = AddField(hlpResumeFn, resumeFnType);
auto* destroyFnFd =
asthelpers::mkFunctionDecl(hlpDestroyFn, ctx.VoidTy, {{CORO_FRAME_NAME, ctx.getPointerType(GetFrameType())}});
auto destroyFnType = ctx.getPointerType(destroyFnFd->getType());
mASTData.mDestroyFnField = AddField(hlpDestroyFn, destroyFnType);
SKIP_NAME_PREFIX_FOR_SCOPE
{
mASTData.mPromiseField = AddField(GetName(*promiseDecl), promiseDecl->getType());
// add the suspend index variable
mASTData.mSuspendIndexField = AddField(SUSPEND_INDEX_NAME, ctx.IntTy);
mASTData.mSuspendIndexAccess =
asthelpers::mkMemberExpr(mASTData.mFrameAccessDeclRef, mASTData.mSuspendIndexField);
// https://timsong-cpp.github.io/cppwp/n4861/dcl.fct.def.coroutine#5.3
mASTData.mInitialAwaitResumeCalledField = AddField(INITIAL_AWAIT_SUSPEND_CALLED_NAME, ctx.BoolTy);
mASTData.mInitialAwaitResumeCalledAccess =
asthelpers::mkMemberExpr(mASTData.mFrameAccessDeclRef, mASTData.mInitialAwaitResumeCalledField);
}
for(auto* param : stmt->getParamMoves()) {
if(const auto* declStmt = dyn_cast_or_null<DeclStmt>(param)) {
if(const auto* varDecl = dyn_cast_or_null<VarDecl>(declStmt->getSingleDecl())) {
// For the captured parameters we need to find the ParmVarDecl instead of the newly created VarDecl
if(const auto* declRef = FindDeclRef(varDecl->getAnyInitializer())) {
varDecl = dyn_cast<ParmVarDecl>(declRef->getDecl());
}
mDeclsHolder.push_back(varDecl);
}
}
}
// Allocated the made up frame
mOutputFormatHelper.AppendCommentNewLine("Allocate the frame including the promise"sv);
auto* coroFrameVar = asthelpers::mkVarDecl(CORO_FRAME_NAME, GetFramePointerType());
CXXReinterpretCastExpr* reicast =
CXXReinterpretCastExpr::Create(ctx,
GetFramePointerType(),
VK_LValue,
CK_BitCast,
stmt->getAllocate(),
nullptr,
ctx.getTrivialTypeSourceInfo(GetFramePointerType()),
{},
{},
{});
coroFrameVar->setInit(reicast);
InsertArg(coroFrameVar);
// P0057R8: [dcl.fct.def.coroutine] p8: get_return_object_on_allocation_failure indicates that new may return a
// nullptr. In this case return get_return_object_on_allocation_failure.
if(stmt->getReturnStmtOnAllocFailure()) {
auto* nptr = new(ctx) CXXNullPtrLiteralExpr({});
auto* bop = asthelpers::mkBinaryOperator(nptr, mASTData.mFrameAccessDeclRef, BO_EQ, ctx.BoolTy);
// Create an IfStmt.
StmtsContainer bodyStmts{stmt->getReturnStmtOnAllocFailure()};
auto* ifStmt = asthelpers::mkIfStmt(bop, bodyStmts);
mOutputFormatHelper.AppendNewLine();
InsertArg(ifStmt);
}
// set initial suspend count to zero.
auto* setSuspendIndexToZero = asthelpers::mkAssign(
mASTData.mFrameAccessDeclRef, mASTData.mSuspendIndexField, asthelpers::mkIntegerLiteral32(0));
InsertArgWithNull(setSuspendIndexToZero);
// https://timsong-cpp.github.io/cppwp/n4861/dcl.fct.def.coroutine#5.3
auto* initializeInitialAwaitResume = asthelpers::mkAssign(
mASTData.mFrameAccessDeclRef, mASTData.mInitialAwaitResumeCalledField, asthelpers::mkBoolLiteral(false));
InsertArgWithNull(initializeInitialAwaitResume);
// Move the parameters first
for(auto* param : stmt->getParamMoves()) {
if(const auto* declStmt = dyn_cast_or_null<DeclStmt>(param)) {
if(const auto* varDecl = dyn_cast_or_null<VarDecl>(declStmt->getSingleDecl())) {
const auto varName = GetName(*varDecl);
mOutputFormatHelper.AppendNewLine(CORO_FRAME_ACCESS,
varName,
" = "sv,
"std::forward<"sv,
GetName(varDecl->getType()),
">("sv,
varName,
");"sv);
}
}
}
mDeclsHolder.FindAllVarDecls(stmt->getBody());
// cache the entries. At least in a co_return co_await + co_await we see the operands multiple times
llvm::DenseMap<const Stmt*, bool> exprs{};
// -1 because of the final suspend which needs no label
auto FindAllSuspends = [&](const Stmt* stmt, auto& self) {
if(nullptr == stmt) {
return 0;
}
int count = 0;
if(isa<CoroutineSuspendExpr>(stmt)) {
if(not Contains(exprs, stmt)) {
++count;
exprs.insert(std::make_pair(stmt, true));
}
}
for(const auto* child : stmt->children()) {
count += self(child, self);
}
return count;
};
mSuspendsCounter = FindAllSuspends(fd.getBody(), FindAllSuspends) - 1;
SCOPED_VAR_TOGGLE(mDeclsHolder.EmulateEmpty)
{
for(const auto* thisExpr : mDeclsHolder.mThisExprs) {
mOutputFormatHelper.AppendNewLine(CORO_FRAME_ACCESS_THIS, " = this;"sv);
}
// Now call the promise ctor, as it may access some of the parameters it comes at this point.
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendCommentNewLine("Construct the promise."sv);
// XXX: Can the promise have parameters?
auto* me = asthelpers::mkMemberExpr(mASTData.mFrameAccessDeclRef, mASTData.mPromiseField);
auto* asRef = asthelpers::mkUnaryOperator(me, UO_AddrOf, mASTData.mPromiseField->getType());
CXXNewExpr* newFrame =
CXXNewExpr::Create(ctx,
false,
nullptr,
nullptr,
true,
false,
{asRef},
SourceRange{},
Optional<Expr*>{},
CXXNewExpr::ListInit,
new(ctx) InitListExpr{{}},
ctx.getPointerType(mASTData.mPromiseField->getType()),
ctx.getTrivialTypeSourceInfo(ctx.getPointerType(mASTData.mPromiseField->getType())),
SourceRange{},
SourceRange{});
InsertArgWithNull(newFrame);
// Add parameters from the original function to the list
mDeclsHolder.JoinDeclsAndMoveDecls();
}
// P0057R8: [dcl.fct.def.coroutine] p5: before initial_suspend and at tops 1
#if not IS_CLANG_NEWER_THAN(14)
mOutputFormatHelper.AppendNewLine();
InsertArg(stmt->getResultDecl());
#endif
// Make a call the the made up state machine function for the initial suspend
mOutputFormatHelper.AppendNewLine();
// [dcl.fct.def.coroutine]
mOutputFormatHelper.AppendCommentNewLine("Forward declare the resume and destroy function."sv);
auto* fsmFuncDecl = CreateFunctionDecl(StrCat(mFSMName, "Resume"sv), {{CORO_FRAME_NAME, GetFramePointerType()}});
InsertArg(fsmFuncDecl);
auto* deallocFuncDecl =
CreateFunctionDecl(StrCat(mFSMName, "Destroy"sv), {{CORO_FRAME_NAME, GetFramePointerType()}});
InsertArg(deallocFuncDecl);
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendCommentNewLine("Assign the resume and destroy function pointers."sv);
auto* assignResumeFn = asthelpers::mkAssign(
mASTData.mFrameAccessDeclRef, mASTData.mResumeFnField, asthelpers::mkFunctionReference(fsmFuncDecl));
InsertArgWithNull(assignResumeFn);
auto* assignDestroyFn = asthelpers::mkAssign(
mASTData.mFrameAccessDeclRef, mASTData.mDestroyFnField, asthelpers::mkFunctionReference(deallocFuncDecl));
InsertArgWithNull(assignDestroyFn);
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendCommentNewLine(
R"A(Call the made up function with the coroutine body for initial suspend.
This function will be called subsequently by coroutine_handle<>::resume()
which calls __builtin_coro_resume(__handle_))A"sv);
auto* callCoroFSM = asthelpers::mkCallExpr(fsmFuncDecl, fsmFuncDecl->getType(), {mASTData.mFrameAccessDeclRef});
InsertArgWithNull(callCoroFSM);
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendNewLine();
// XXX: The getReturnStmt may contain more as just __coro_gro pre Clang 15
SKIP_NAME_PREFIX_FOR_SCOPE
{
#if IS_CLANG_NEWER_THAN(14)
InsertArg(stmt->getReturnStmt());
#else
DeclsHolder tmpDeclsHolder{};
tmpDeclsHolder.FindAllVarDecls(stmt->getResultDecl());
if(tmpDeclsHolder.mMoveDecls.size() > 0) {
const auto* retVd = tmpDeclsHolder.mMoveDecls.at(0);
auto* coroReturnDref = asthelpers::mkDeclRefExpr(const_cast<VarDecl*>(retVd));
auto* returnStmt = asthelpers::mkReturnStmt(coroReturnDref);
InsertArg(returnStmt);
}
#endif
}
mOutputFormatHelper.AppendSemiNewLine();
mOutputFormatHelper.CloseScope(OutputFormatHelper::NoNewLineBefore::Yes);
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendNewLine();
// add contents of the original function to the body of our made up function
StmtsContainer fsmFuncBodyStmts{stmt};
mOutputFormatHelper.AppendCommentNewLine("This function invoked by coroutine_handle<>::resume()"sv);
SetFunctionBody(fsmFuncDecl, fsmFuncBodyStmts);
InsertArg(fsmFuncDecl);
mASTData.mDoInsertInDtor = true; // As we have a coroutine insert the frame when this object goes out of scope.
#if 0 // Preserve for later. Technically the destructor for the entire frame that's made up below takes care of
// everything.
// A destructor is only present, if they promise_type or one of its members is non-trivially destructible.
if(auto* dtor = mASTData.mPromiseField->getType()->getAsCXXRecordDecl()->getDestructor()) {
deallocFuncBodyStmts.Add(asthelpers::mkInsightsComment("Deallocating the coroutine promise type"sv));
auto* promiseAccess = asthelpers::mkMemberExpr(mASTData.mFrameAccessDeclRef, mASTData.mPromiseField);
auto* deallocPromise = asthelpers::mkMemberExpr(promiseAccess, dtor, false);
auto* dtorCall = asthelpers::mkMemberCallExpr(deallocPromise, dtor->getType());
deallocFuncBodyStmts.Add(dtorCall);
} else {
deallocFuncBodyStmts.Add(
asthelpers::mkInsightsComment("promise_type is trivially destructible, no dtor required."sv));
}
#endif
// This code isn't really there but it is the easiest and cleanest way to visualize the destruction of all member in
// the frame.
// The deallocation function: https://devblogs.microsoft.com/oldnewthing/20210331-00/?p=105028
mOutputFormatHelper.AppendNewLine();
mOutputFormatHelper.AppendCommentNewLine("This function invoked by coroutine_handle<>::destroy()"sv);
StmtsContainer deallocFuncBodyStmts{asthelpers::mkInsightsComment("destroy all variables with dtors"sv)};
auto* dtorFuncDecl = asthelpers::mkFunctionDecl(
StrCat("~"sv, GetName(*mASTData.mFrameType)), ctx.VoidTy, {{CORO_FRAME_NAME, GetFramePointerType()}});
auto* deallocPromise = asthelpers::mkMemberExpr(mASTData.mFrameAccessDeclRef, dtorFuncDecl);
auto* dtorCall = asthelpers::mkMemberCallExpr(deallocPromise, GetFrameType());
deallocFuncBodyStmts.Add(dtorCall);
deallocFuncBodyStmts.Add(asthelpers::mkInsightsComment("Deallocating the coroutine frame"sv));
deallocFuncBodyStmts.Add(stmt->getDeallocate());
SetFunctionBody(deallocFuncDecl, deallocFuncBodyStmts);
InsertArg(deallocFuncDecl);
}
//-----------------------------------------------------------------------------
void CoroutinesCodeGenerator::InsertArg(const CoroutineBodyStmt* stmt)
{
auto& ctx = GetGlobalAST();
// insert a made up switch for continuing a resume
SwitchStmt* sstmt = SwitchStmt::Create(ctx, nullptr, nullptr, mASTData.mSuspendIndexAccess, {}, {});
// insert 0 with break for consistency
auto* initialSuspendCase = asthelpers::mkCaseStmt(0, new(ctx) BreakStmt(SourceLocation{}));
StmtsContainer switchBodyStmts{initialSuspendCase};
for(const auto& i : NumberIterator{mSuspendsCounter}) {
switchBodyStmts.Add(asthelpers::mkCaseStmt(i + 1, asthelpers::mkGotoStmt(BuildResumeLabelName(i + 1))));
}
auto* switchBody = asthelpers::mkCompoundStmt(switchBodyStmts);
sstmt->setBody(switchBody);
StmtsContainer funcBodyStmts{asthelpers::mkInsightsComment("Create a switch to get to the correct resume point"sv),
sstmt,
stmt->getInitSuspendStmt()};
// insert the init suspend expr
mState = eState::InitialSuspend;
for(const auto* recordDeclDecl : mDeclsHolder.mRecordDecls) {
mASTData.mFrameType->addDecl(const_cast<CXXRecordDecl*>(recordDeclDecl));
}
SKIP_NAME_PREFIX_FOR_SCOPE
{
for(const auto* thisExpr : mDeclsHolder.mThisExprs) {
AddField(kwInternalThis, thisExpr->getType());
}
SCOPED_VAR_TOGGLE(mDeclsHolder.EmulateEmpty)
{
for(const auto& promiseType{stmt->getPromiseDecl()->getType()}; const auto* varDecl : mDeclsHolder.mDecls) {
// skip the promise-type, as we inserted that earlier to be sure about the order
if(promiseType != varDecl->getType()) {
AddField(GetName(*varDecl), varDecl->getType());
}
}
}
}
mInsertVarDecl = false;
mSupressRecordDecls = true;
for(const auto* c : stmt->children()) {
// Process only CompoundStmt's
if(not isa<CompoundStmt>(c)) {
break;
}
for(const auto* c : c->children()) {
funcBodyStmts.Add(c);
}
}
// InsertArg(stmt->getFallthroughHandler());
auto* gotoFinalSuspend = asthelpers::mkGotoStmt(FINAL_SUSPEND_NAME);
funcBodyStmts.Add(gotoFinalSuspend);
auto* body = [&]() -> Stmt* {
auto* tryBody = asthelpers::mkCompoundStmt(funcBodyStmts);
// First open the try-catch block, as we get an error when jumping across such blocks with goto
if(const auto* exceptionHandler = stmt->getExceptionHandler()) {
// If we encounter an exceptionbefore inital_suspend's await_suspend was called we re-throw the
// exception.
auto* throwExpr = new(ctx) CXXThrowExpr(nullptr, {}, {}, false);
auto* ifStmt = asthelpers::mkNotIfStmt(mASTData.mInitialAwaitResumeCalledAccess, throwExpr);
StmtsContainer catchBodyStmts{ifStmt, exceptionHandler};
auto* catchAll = new(ctx) CXXCatchStmt({}, nullptr, asthelpers::mkCompoundStmt(catchBodyStmts));
return CXXTryStmt::Create(ctx, {}, tryBody, {catchAll});
}
return tryBody;
}();
InsertArg(body);
mOutputFormatHelper.AppendNewLine();
auto* finalSuspendLabel = asthelpers::mkLabelStmt(FINAL_SUSPEND_NAME);
InsertArg(finalSuspendLabel);
mState = eState::FinalSuspend;
InsertArg(stmt->getFinalSuspendStmt());
// disable prefixing names and types
mInsertVarDecl = true;
mDeclsHolder.EmulateEmpty = true;
mDeclsHolder.mDecls.clear();
}
//-----------------------------------------------------------------------------
void CoroutinesCodeGenerator::InsertArg(const CXXRecordDecl* stmt)
{
if(not mSupressRecordDecls) {
CodeGenerator::InsertArg(stmt);
}
}
//-----------------------------------------------------------------------------
/// This is here to filter out a void cast of a co_await / co_yield expr.
void CoroutinesCodeGenerator::InsertArg(const CStyleCastExpr* stmt)
{
// treat a case where a co_await / co_yield is casted to void:
// \code
// (void)(co_await i);
// \endcode
auto findChilds = [](const Stmt* s, int n, auto f, int i = 0) -> const CoroutineSuspendExpr* {
if(i > n) {
return nullptr;
}
for(const auto* c : s->children()) {
if(const auto* corSus = dyn_cast_or_null<CoroutineSuspendExpr>(c)) {
return corSus;
}
return f(c, n, f, ++i);
}
return nullptr;
};
if(const auto* corSus = findChilds(stmt->getSubExpr(), 3, findChilds)) {
InsertArg(corSus);
return;
}
CodeGenerator::InsertArg(stmt);
}
//-----------------------------------------------------------------------------
// We seem to need this, to peal of some static_casts in a CoroutineSuspendExpr.
void CoroutinesCodeGenerator::InsertArg(const ImplicitCastExpr* stmt)
{
if(mSupressCasts) {
InsertArg(stmt->getSubExpr());
} else {
CodeGenerator::InsertArg(stmt);
}
}
//-----------------------------------------------------------------------------
// A special hack to avoid having calls to __builtin_coro_frame() which are what Clang does but don't show that it
// is about the promise type.
void CoroutinesCodeGenerator::InsertArg(const CallExpr* stmt)
{
if(const auto* callee = dyn_cast_or_null<DeclRefExpr>(stmt->getCallee()->IgnoreCasts())) {
if(GetPlainName(*callee) == "__builtin_coro_frame"sv) {
auto& ctx = GetGlobalAST();
CXXStaticCastExpr* toVoid = CXXStaticCastExpr::Create(ctx,
ctx.VoidPtrTy,
VK_LValue,
CK_BitCast,
mASTData.mFrameAccessDeclRef,
nullptr,
ctx.getTrivialTypeSourceInfo(ctx.VoidPtrTy),
{},
{},
{},
{});
CodeGenerator::InsertArg(toVoid);
return;
}
}
CodeGenerator::InsertArg(stmt);
}
//-----------------------------------------------------------------------------
static std::optional<std::string> FindValue(llvm::DenseMap<const Expr*, std::string>& map, const Expr* key)
{
if(const auto& s = map.find(key); s != map.end()) {
return s->second;
}
return {};
}
//-----------------------------------------------------------------------------
void CoroutinesCodeGenerator::InsertArg(const OpaqueValueExpr* stmt)
{
const auto* sourceExpr = stmt->getSourceExpr();
if(const auto& s = FindValue(mOpaqueValues, sourceExpr)) {
mOutputFormatHelper.Append(s.value());
} else {
// Needs to be internal because a user can create the same type and it gets put into the stack frame
std::string name{BuildInternalVarName(
MakeLineColumnName(GetGlobalAST().getSourceManager(), stmt->getBeginLoc(), "suspend_"sv))};
auto lookupName{StrCat(CORO_FRAME_ACCESS, name)};
// The initial_suspend and final_suspend expressions carry the same location info. If we hit such a case,
// make up another name.
// Below is a std::find_if. However, the same code looks unreadable with std::find_if
for(const auto& [k, v] : mOpaqueValues) {
if(v == lookupName) {
name += "_1"sv;
break;
}
}
const auto accessName{StrCat(CORO_FRAME_ACCESS, name)};
mOpaqueValues.insert(std::make_pair(sourceExpr, accessName));
OutputFormatHelper ofm{};
CoroutinesCodeGenerator codeGenerator{ofm, mPosBeforeFunc, mFSMName, mSuspendsCount, mASTData};
auto* promiseField = AddField(name, stmt->getType());
BinaryOperator* assignPromiseSuspend =
asthelpers::mkAssign(mASTData.mFrameAccessDeclRef, promiseField, stmt->getSourceExpr());
codeGenerator.InsertArg(assignPromiseSuspend);
ofm.AppendSemiNewLine();