[coroutines] Add support for coroutines with non-scalar parameters
Summary:
Simple types like int are handled by LLVM Coroutines just fine.
But for non-scalar parameters we need to create copies of those parameters in the coroutine frame and make all uses of those parameters to refer to parameter copies.
Reviewers: rsmith, EricWF, GorNishanov
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D33507
llvm-svn: 303803
diff --git a/clang/lib/CodeGen/CGCoroutine.cpp b/clang/lib/CodeGen/CGCoroutine.cpp
index 9eb47b7..c468c1b 100644
--- a/clang/lib/CodeGen/CGCoroutine.cpp
+++ b/clang/lib/CodeGen/CGCoroutine.cpp
@@ -15,6 +15,7 @@
#include "CodeGenFunction.h"
#include "llvm/ADT/ScopeExit.h"
#include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtVisitor.h"
using namespace clang;
using namespace CodeGen;
@@ -239,7 +240,67 @@
EmitBranchThroughCleanup(CurCoro.Data->FinalJD);
}
-// For WinEH exception representation backend need to know what funclet coro.end
+// Hunts for the parameter reference in the parameter copy/move declaration.
+namespace {
+struct GetParamRef : public StmtVisitor<GetParamRef> {
+public:
+ DeclRefExpr *Expr = nullptr;
+ GetParamRef() {}
+ void VisitDeclRefExpr(DeclRefExpr *E) {
+ assert(Expr == nullptr && "multilple declref in param move");
+ Expr = E;
+ }
+ void VisitStmt(Stmt *S) {
+ for (auto *C : S->children()) {
+ if (C)
+ Visit(C);
+ }
+ }
+};
+}
+
+// This class replaces references to parameters to their copies by changing
+// the addresses in CGF.LocalDeclMap and restoring back the original values in
+// its destructor.
+
+namespace {
+ struct ParamReferenceReplacerRAII {
+ CodeGenFunction::DeclMapTy SavedLocals;
+ CodeGenFunction::DeclMapTy& LocalDeclMap;
+
+ ParamReferenceReplacerRAII(CodeGenFunction::DeclMapTy &LocalDeclMap)
+ : LocalDeclMap(LocalDeclMap) {}
+
+ void addCopy(DeclStmt const *PM) {
+ // Figure out what param it refers to.
+
+ assert(PM->isSingleDecl());
+ VarDecl const*VD = static_cast<VarDecl const*>(PM->getSingleDecl());
+ Expr const *InitExpr = VD->getInit();
+ GetParamRef Visitor;
+ Visitor.Visit(const_cast<Expr*>(InitExpr));
+ assert(Visitor.Expr);
+ auto *DREOrig = cast<DeclRefExpr>(Visitor.Expr);
+ auto *PD = DREOrig->getDecl();
+
+ auto it = LocalDeclMap.find(PD);
+ assert(it != LocalDeclMap.end() && "parameter is not found");
+ SavedLocals.insert({ PD, it->second });
+
+ auto copyIt = LocalDeclMap.find(VD);
+ assert(copyIt != LocalDeclMap.end() && "parameter copy is not found");
+ it->second = copyIt->getSecond();
+ }
+
+ ~ParamReferenceReplacerRAII() {
+ for (auto&& SavedLocal : SavedLocals) {
+ LocalDeclMap.insert({SavedLocal.first, SavedLocal.second});
+ }
+ }
+ };
+}
+
+// For WinEH exception representation backend needs to know what funclet coro.end
// belongs to. That information is passed in a funclet bundle.
static SmallVector<llvm::OperandBundleDef, 1>
getBundlesForCoroEnd(CodeGenFunction &CGF) {
@@ -462,21 +523,38 @@
CurCoro.Data->CleanupJD = getJumpDestInCurrentScope(RetBB);
{
+ ParamReferenceReplacerRAII ParamReplacer(LocalDeclMap);
CodeGenFunction::RunCleanupsScope ResumeScope(*this);
EHStack.pushCleanup<CallCoroDelete>(NormalAndEHCleanup, S.getDeallocate());
+ // Create parameter copies. We do it before creating a promise, since an
+ // evolution of coroutine TS may allow promise constructor to observe
+ // parameter copies.
+ for (auto *PM : S.getParamMoves()) {
+ EmitStmt(PM);
+ ParamReplacer.addCopy(cast<DeclStmt>(PM));
+ // TODO: if(CoroParam(...)) need to surround ctor and dtor
+ // for the copy, so that llvm can elide it if the copy is
+ // not needed.
+ }
+
EmitStmt(S.getPromiseDeclStmt());
+ Address PromiseAddr = GetAddrOfLocalVar(S.getPromiseDecl());
+ auto *PromiseAddrVoidPtr =
+ new llvm::BitCastInst(PromiseAddr.getPointer(), VoidPtrTy, "", CoroId);
+ // Update CoroId to refer to the promise. We could not do it earlier because
+ // promise local variable was not emitted yet.
+ CoroId->setArgOperand(1, PromiseAddrVoidPtr);
+
// Now we have the promise, initialize the GRO
GroManager.EmitGroInit();
+
EHStack.pushCleanup<CallCoroEnd>(EHCleanup);
- CurCoro.Data->FinalJD = getJumpDestInCurrentScope(FinalBB);
-
- // FIXME: Emit param moves.
-
CurCoro.Data->CurrentAwaitKind = AwaitKind::Init;
EmitStmt(S.getInitSuspendStmt());
+ CurCoro.Data->FinalJD = getJumpDestInCurrentScope(FinalBB);
CurCoro.Data->CurrentAwaitKind = AwaitKind::Normal;
@@ -577,5 +655,6 @@
// deletion of the coroutine frame.
if (CurCoro.Data)
CurCoro.Data->LastCoroFree = Call;
- } return RValue::get(Call);
+ }
+ return RValue::get(Call);
}