[clang] [CIR] Emit CIR builtins: coroAlloc, coroBegin, and coroSize (PR #164180)
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Sun Oct 19 14:11:54 PDT 2025
https://github.com/Andres-Salamanca created https://github.com/llvm/llvm-project/pull/164180
This PR adds support for emitting the builtins coroAlloc, coroBegin, and coroSize.
>From 3e24f4b1e5b1d15f34e38755ebe7c44ec09b9fba Mon Sep 17 00:00:00 2001
From: Andres Salamanca <andrealebarbaritos at gmail.com>
Date: Sun, 19 Oct 2025 16:03:51 -0500
Subject: [PATCH] [CIR] Emit CIR builtins: coroAlloc, coroBegin, and coroSize
---
clang/include/clang/CIR/MissingFeatures.h | 4 +-
clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp | 14 ++--
clang/lib/CIR/CodeGen/CIRGenCoroutine.cpp | 81 ++++++++++++++++++++++-
clang/lib/CIR/CodeGen/CIRGenFunction.h | 3 +
clang/lib/CIR/CodeGen/CIRGenModule.h | 2 +
clang/test/CIR/CodeGen/coro-task.cpp | 19 +++++-
6 files changed, 112 insertions(+), 11 deletions(-)
diff --git a/clang/include/clang/CIR/MissingFeatures.h b/clang/include/clang/CIR/MissingFeatures.h
index 090cf35c2d279..7956ba797f837 100644
--- a/clang/include/clang/CIR/MissingFeatures.h
+++ b/clang/include/clang/CIR/MissingFeatures.h
@@ -149,11 +149,9 @@ struct MissingFeatures {
static bool zeroSizeRecordMembers() { return false; }
// Coroutines
- static bool coroAllocBuiltinCall() { return false; }
- static bool coroBeginBuiltinCall() { return false; }
static bool coroEndBuiltinCall() { return false; }
- static bool coroSizeBuiltinCall() { return false; }
static bool coroutineFrame() { return false; }
+ static bool emitBodyAndFallthrough() { return false; }
// Various handling of deferred processing in CIRGenModule.
static bool cgmRelease() { return false; }
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index ea31871806bd7..92ede62cac630 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -449,10 +449,16 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
}
case Builtin::BI__builtin_coro_free:
case Builtin::BI__builtin_coro_size: {
- cgm.errorNYI(e->getSourceRange(),
- "BI__builtin_coro_free, BI__builtin_coro_size NYI");
- assert(!cir::MissingFeatures::coroSizeBuiltinCall());
- return getUndefRValue(e->getType());
+ GlobalDecl gd{fd};
+ mlir::Type ty = cgm.getTypes().getFunctionType(
+ cgm.getTypes().arrangeGlobalDeclaration(gd));
+ const auto *nd = cast<NamedDecl>(gd.getDecl());
+ cir::FuncOp fnOp =
+ cgm.getOrCreateCIRFunction(nd->getName(), ty, gd, /*ForVTable=*/false,
+ /*DontDefer=*/false);
+ fnOp.setBuiltin(true);
+ return emitCall(e->getCallee()->getType(), CIRGenCallee::forDirect(fnOp), e,
+ returnValue);
}
}
diff --git a/clang/lib/CIR/CodeGen/CIRGenCoroutine.cpp b/clang/lib/CIR/CodeGen/CIRGenCoroutine.cpp
index c25cce4ab33b3..86b4e43ea2998 100644
--- a/clang/lib/CIR/CodeGen/CIRGenCoroutine.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenCoroutine.cpp
@@ -15,6 +15,7 @@
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CIR/Dialect/IR/CIRTypes.h"
+#include "clang/CIR/MissingFeatures.h"
using namespace clang;
using namespace clang::CIRGen;
@@ -23,6 +24,9 @@ struct clang::CIRGen::CGCoroData {
// Stores the __builtin_coro_id emitted in the function so that we can supply
// it as the first argument to other builtins.
cir::CallOp coroId = nullptr;
+
+ // Stores the result of __builtin_coro_begin call.
+ mlir::Value coroBegin = nullptr;
};
// Defining these here allows to keep CGCoroData private to this file.
@@ -63,6 +67,48 @@ cir::CallOp CIRGenFunction::emitCoroIDBuiltinCall(mlir::Location loc,
nullPtr, nullPtr, nullPtr});
}
+cir::CallOp CIRGenFunction::emitCoroAllocBuiltinCall(mlir::Location loc) {
+ cir::BoolType boolTy = builder.getBoolTy();
+ cir::IntType int32Ty = builder.getUInt32Ty();
+
+ mlir::Operation *builtin = cgm.getGlobalValue(cgm.builtinCoroAlloc);
+
+ cir::FuncOp fnOp;
+ if (!builtin) {
+ fnOp = cgm.createCIRBuiltinFunction(loc, cgm.builtinCoroAlloc,
+ cir::FuncType::get({int32Ty}, boolTy),
+ /*FD=*/nullptr);
+ assert(fnOp && "should always succeed");
+ } else {
+ fnOp = cast<cir::FuncOp>(builtin);
+ }
+
+ return builder.createCallOp(
+ loc, fnOp, mlir::ValueRange{curCoro.data->coroId.getResult()});
+}
+
+cir::CallOp
+CIRGenFunction::emitCoroBeginBuiltinCall(mlir::Location loc,
+ mlir::Value coroframeAddr) {
+ cir::IntType int32Ty = builder.getUInt32Ty();
+ mlir::Operation *builtin = cgm.getGlobalValue(cgm.builtinCoroBegin);
+
+ cir::FuncOp fnOp;
+ if (!builtin) {
+ fnOp = cgm.createCIRBuiltinFunction(
+ loc, cgm.builtinCoroBegin,
+ cir::FuncType::get({int32Ty, VoidPtrTy}, VoidPtrTy),
+ /*FD=*/nullptr);
+ assert(fnOp && "should always succeed");
+ } else {
+ fnOp = cast<cir::FuncOp>(builtin);
+ }
+
+ return builder.createCallOp(
+ loc, fnOp,
+ mlir::ValueRange{curCoro.data->coroId.getResult(), coroframeAddr});
+}
+
mlir::LogicalResult
CIRGenFunction::emitCoroutineBody(const CoroutineBodyStmt &s) {
mlir::Location openCurlyLoc = getLoc(s.getBeginLoc());
@@ -73,10 +119,39 @@ CIRGenFunction::emitCoroutineBody(const CoroutineBodyStmt &s) {
cir::CallOp coroId = emitCoroIDBuiltinCall(openCurlyLoc, nullPtrCst);
createCoroData(*this, curCoro, coroId);
- assert(!cir::MissingFeatures::coroAllocBuiltinCall());
-
- assert(!cir::MissingFeatures::coroBeginBuiltinCall());
+ // Backend is allowed to elide memory allocations, to help it, emit
+ // auto mem = coro.alloc() ? 0 : ... allocation code ...;
+ cir::CallOp coroAlloc = emitCoroAllocBuiltinCall(openCurlyLoc);
+
+ // Initialize address of coroutine frame to null
+ CanQualType astVoidPtrTy = cgm.getASTContext().VoidPtrTy;
+ mlir::Type allocaTy = convertTypeForMem(astVoidPtrTy);
+ Address coroFrame =
+ createTempAlloca(allocaTy, getContext().getTypeAlignInChars(astVoidPtrTy),
+ openCurlyLoc, "__coro_frame_addr",
+ /*ArraySize=*/nullptr);
+
+ mlir::Value storeAddr = coroFrame.getPointer();
+ builder.CIRBaseBuilderTy::createStore(openCurlyLoc, nullPtrCst, storeAddr);
+ cir::IfOp::create(
+ builder, openCurlyLoc, coroAlloc.getResult(),
+ /*withElseRegion=*/false,
+ /*thenBuilder=*/[&](mlir::OpBuilder &b, mlir::Location loc) {
+ builder.CIRBaseBuilderTy::createStore(
+ loc, emitScalarExpr(s.getAllocate()), storeAddr);
+ builder.create<cir::YieldOp>(loc);
+ });
+ curCoro.data->coroBegin =
+ emitCoroBeginBuiltinCall(
+ openCurlyLoc,
+ builder.create<cir::LoadOp>(openCurlyLoc, allocaTy, storeAddr))
+ .getResult();
+
+ // Handle allocation failure if 'ReturnStmtOnAllocFailure' was provided.
+ if (s.getReturnStmtOnAllocFailure())
+ cgm.errorNYI("NYI");
assert(!cir::MissingFeatures::generateDebugInfo());
+ assert(!cir::MissingFeatures::emitBodyAndFallthrough());
return mlir::success();
}
diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.h b/clang/lib/CIR/CodeGen/CIRGenFunction.h
index 3c36f5c697118..f3ef54892bcae 100644
--- a/clang/lib/CIR/CodeGen/CIRGenFunction.h
+++ b/clang/lib/CIR/CodeGen/CIRGenFunction.h
@@ -1252,6 +1252,9 @@ class CIRGenFunction : public CIRGenTypeCache {
mlir::LogicalResult emitCoroutineBody(const CoroutineBodyStmt &s);
cir::CallOp emitCoroEndBuiltinCall(mlir::Location loc, mlir::Value nullPtr);
cir::CallOp emitCoroIDBuiltinCall(mlir::Location loc, mlir::Value nullPtr);
+ cir::CallOp emitCoroAllocBuiltinCall(mlir::Location loc);
+ cir::CallOp emitCoroBeginBuiltinCall(mlir::Location loc,
+ mlir::Value coroframeAddr);
void emitDestroy(Address addr, QualType type, Destroyer *destroyer);
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.h b/clang/lib/CIR/CodeGen/CIRGenModule.h
index 1fc116d98a858..186913d1bac9d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.h
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.h
@@ -496,6 +496,8 @@ class CIRGenModule : public CIRGenTypeCache {
bool assumeConvergent = false);
static constexpr const char *builtinCoroId = "__builtin_coro_id";
+ static constexpr const char *builtinCoroAlloc = "__builtin_coro_alloc";
+ static constexpr const char *builtinCoroBegin = "__builtin_coro_begin";
/// Given a builtin id for a function like "__builtin_fabsf", return a
/// Function* for "fabsf".
diff --git a/clang/test/CIR/CodeGen/coro-task.cpp b/clang/test/CIR/CodeGen/coro-task.cpp
index 1fc7d77be2bce..265325f82d7f7 100644
--- a/clang/test/CIR/CodeGen/coro-task.cpp
+++ b/clang/test/CIR/CodeGen/coro-task.cpp
@@ -106,6 +106,9 @@ co_invoke_fn co_invoke;
// CIR-NEXT: cir.global external @_ZN5folly4coro9co_invokeE = #cir.zero : !rec_folly3A3Acoro3A3Aco_invoke_fn
// CIR: cir.func builtin private @__builtin_coro_id(!u32i, !cir.ptr<!void>, !cir.ptr<!void>, !cir.ptr<!void>) -> !u32i
+// CIR: cir.func builtin private @__builtin_coro_alloc(!u32i) -> !cir.bool
+// CIR: cir.func builtin private @__builtin_coro_size() -> !u64i
+// CIR: cir.func builtin private @__builtin_coro_begin(!u32i, !cir.ptr<!void>) -> !cir.ptr<!void>
using VoidTask = folly::coro::Task<void>;
@@ -114,10 +117,24 @@ VoidTask silly_task() {
}
// CIR: cir.func coroutine dso_local @_Z10silly_taskv() -> ![[VoidTask]]
-// CHECK: %[[#VoidTaskAddr:]] = cir.alloca ![[VoidTask]], {{.*}}, ["__retval"]
+// CIR: %[[VoidTaskAddr:.*]] = cir.alloca ![[VoidTask]], {{.*}}, ["__retval"]
+// CIR: %[[SavedFrameAddr:.*]] = cir.alloca !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>, ["__coro_frame_addr"]
// Get coroutine id with __builtin_coro_id.
// CIR: %[[NullPtr:.*]] = cir.const #cir.ptr<null> : !cir.ptr<!void>
// CIR: %[[Align:.*]] = cir.const #cir.int<16> : !u32i
// CIR: %[[CoroId:.*]] = cir.call @__builtin_coro_id(%[[Align]], %[[NullPtr]], %[[NullPtr]], %[[NullPtr]])
+
+// Perform allocation calling operator 'new' depending on __builtin_coro_alloc and
+// call __builtin_coro_begin for the final coroutine frame address.
+
+// CIR: %[[ShouldAlloc:.*]] = cir.call @__builtin_coro_alloc(%[[CoroId]]) : (!u32i) -> !cir.bool
+// CIR: cir.store{{.*}} %[[NullPtr]], %[[SavedFrameAddr]] : !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>
+// CIR: cir.if %[[ShouldAlloc]] {
+// CIR: %[[CoroSize:.*]] = cir.call @__builtin_coro_size() : () -> !u64i
+// CIR: %[[AllocAddr:.*]] = cir.call @_Znwm(%[[CoroSize]]) : (!u64i) -> !cir.ptr<!void>
+// CIR: cir.store{{.*}} %[[AllocAddr]], %[[SavedFrameAddr]] : !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>
+// CIR: }
+// CIR: %[[Load0:.*]] = cir.load{{.*}} %[[SavedFrameAddr]] : !cir.ptr<!cir.ptr<!void>>, !cir.ptr<!void>
+// CIR: %[[CoroFrameAddr:.*]] = cir.call @__builtin_coro_begin(%[[CoroId]], %[[Load0]])
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