[llvm] [WebAssembly] Implement addrspacecast to funcref (PR #166820)
Demetrius Kanios via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 4 09:53:07 PST 2025
https://github.com/QuantumSegfault updated https://github.com/llvm/llvm-project/pull/166820
>From 237533c393f3668d3129415bf8f1376af8759441 Mon Sep 17 00:00:00 2001
From: Demetrius Kanios <demetrius at kanios.net>
Date: Thu, 6 Nov 2025 10:28:45 -0800
Subject: [PATCH 1/3] Implement addrspacecast 0 -> 20
---
.../WebAssembly/WebAssemblyISelLowering.cpp | 58 +++++++++++++++++++
.../WebAssembly/WebAssemblyISelLowering.h | 1 +
.../Target/WebAssembly/WebAssemblyInstrRef.td | 7 ++-
.../WebAssembly/addrspacecast-funcref.ll | 55 ++++++++++++++++++
4 files changed, 120 insertions(+), 1 deletion(-)
create mode 100644 llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index af322982d5355..782b878350b42 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -409,6 +409,10 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
setOperationAction(ISD::INTRINSIC_W_CHAIN, MVT::Other, Custom);
setOperationAction(ISD::INTRINSIC_VOID, MVT::Other, Custom);
+ // Allow converting function ptrs in address space 0 to WASM funcref (address
+ // space 20)
+ setOperationAction(ISD::ADDRSPACECAST, MVT::funcref, Custom);
+
setMaxAtomicSizeInBitsSupported(64);
// Always convert switches to br_tables unless there is only one case, which
@@ -1733,6 +1737,8 @@ SDValue WebAssemblyTargetLowering::LowerOperation(SDValue Op,
return LowerMUL_LOHI(Op, DAG);
case ISD::UADDO:
return LowerUADDO(Op, DAG);
+ case ISD::ADDRSPACECAST:
+ return LowerADDRSPACECAST(Op, DAG);
}
}
@@ -1876,6 +1882,58 @@ SDValue WebAssemblyTargetLowering::LowerUADDO(SDValue Op,
return DAG.getMergeValues(Ops, DL);
}
+SDValue WebAssemblyTargetLowering::LowerADDRSPACECAST(SDValue Op,
+ SelectionDAG &DAG) const {
+ SDLoc DL(Op);
+
+ AddrSpaceCastSDNode *ACN = cast<AddrSpaceCastSDNode>(Op.getNode());
+
+ if (ACN->getSrcAddressSpace() !=
+ WebAssembly::WasmAddressSpace::WASM_ADDRESS_SPACE_DEFAULT ||
+ ACN->getDestAddressSpace() !=
+ WebAssembly::WasmAddressSpace::WASM_ADDRESS_SPACE_FUNCREF)
+ return Op;
+
+ if (ACN->getValueType(0) != MVT::funcref) {
+ reportFatalInternalError("Cannot addrspacecast to funcref addrspace with "
+ "results other than MVT::funcref");
+ }
+
+ SDValue Src = ACN->getOperand(0);
+
+ // Lower addrspacecasts of direct/constant function ptrs to ref.func
+ if (auto *GA = dyn_cast<GlobalAddressSDNode>(
+ Src->getOpcode() == WebAssemblyISD::Wrapper ? Src->getOperand(0)
+ : Src)) {
+ auto *GV = GA->getGlobal();
+
+ if (const Function *F = dyn_cast<Function>(GV)) {
+ SDValue FnAddress = DAG.getTargetGlobalAddress(F, DL, MVT::i32);
+
+ SDValue RefFuncNode =
+ DAG.getNode(WebAssemblyISD::REF_FUNC, DL, MVT::funcref, FnAddress);
+ return RefFuncNode;
+ }
+ }
+
+ // Lower everything else to a table.get from the indirect function table
+ const MachineFunction &MF = DAG.getMachineFunction();
+
+ MVT PtrVT = getPointerTy(MF.getDataLayout());
+
+ MCSymbolWasm *Table =
+ WebAssembly::getOrCreateFunctionTableSymbol(MF.getContext(), Subtarget);
+ SDValue TableSym = DAG.getMCSymbol(Table, PtrVT);
+
+ SDValue TableSlot = Op.getOperand(0);
+
+ SDValue Result(DAG.getMachineNode(WebAssembly::TABLE_GET_FUNCREF, DL,
+ MVT::funcref, TableSym, TableSlot),
+ 0);
+
+ return Result;
+}
+
SDValue WebAssemblyTargetLowering::Replace128Op(SDNode *N,
SelectionDAG &DAG) const {
assert(Subtarget->hasWideArithmetic());
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
index f7052989b3c75..c3cca072f1958 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
@@ -121,6 +121,7 @@ class WebAssemblyTargetLowering final : public TargetLowering {
SDValue LowerMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
SDValue Replace128Op(SDNode *N, SelectionDAG &DAG) const;
SDValue LowerUADDO(SDValue Op, SelectionDAG &DAG) const;
+ SDValue LowerADDRSPACECAST(SDValue Op, SelectionDAG &DAG) const;
// Custom DAG combine hooks
SDValue
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrRef.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrRef.td
index 304c4f3fcb028..2589ab758638c 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrRef.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrRef.td
@@ -11,6 +11,11 @@
///
//===----------------------------------------------------------------------===//
+def WebAssemblyRefFunc_t : SDTypeProfile<1, 1, [SDTCisVT<0, funcref>, SDTCisPtrTy<1>]>;
+def WebAssemblyRefFunc :
+ SDNode<"WebAssemblyISD::REF_FUNC", WebAssemblyRefFunc_t,
+ []>;
+
multiclass REF_I<WebAssemblyRegClass rc, ValueType vt, string ht> {
defm REF_NULL_#rc : I<(outs rc:$dst), (ins),
(outs), (ins),
@@ -42,7 +47,7 @@ defm REF_TEST_FUNCREF : I<(outs I32:$res), (ins TypeIndex:$type, FUNCREF:$ref),
Requires<[HasGC]>;
defm REF_FUNC : I<(outs FUNCREF:$res), (ins function32_op:$func),
- (outs), (ins function32_op:$func), [],
+ (outs), (ins function32_op:$func), [(set FUNCREF:$res, (WebAssemblyRefFunc tglobaladdr:$func))],
"ref.func\t$func", "ref.func $func", 0xd2>,
Requires<[HasReferenceTypes]>;
diff --git a/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
new file mode 100644
index 0000000000000..1ae676f1c99c8
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
@@ -0,0 +1,55 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc -mtriple=wasm32-unknown-unknown -mattr=+reference-types < %s | FileCheck -check-prefixes=CHECK,WASM32 %s
+; RUN: llc -mtriple=wasm64-unknown-unknown -mattr=+reference-types < %s | FileCheck -check-prefixes=CHECK,WASM64 %s
+
+%funcref = type ptr addrspace(20) ;; addrspace 20 is nonintegral
+
+declare void @foo();
+
+ at global_var = local_unnamed_addr global i32 undef
+
+define %funcref @cast_const_funcptr() {
+; CHECK-LABEL: cast_const_funcptr:
+; CHECK: .functype cast_const_funcptr () -> (funcref)
+; CHECK-NEXT: # %bb.0:
+; CHECK-NEXT: ref.func foo
+; CHECK-NEXT: # fallthrough-return
+ %result = addrspacecast ptr @foo to ptr addrspace(20)
+ ret %funcref %result
+}
+
+define %funcref @cast_const_not_funcptr() {
+; WASM32-LABEL: cast_const_not_funcptr:
+; WASM32: .functype cast_const_not_funcptr () -> (funcref)
+; WASM32-NEXT: # %bb.0:
+; WASM32-NEXT: i32.const global_var
+; WASM32-NEXT: table.get __indirect_function_table
+; WASM32-NEXT: # fallthrough-return
+;
+; WASM64-LABEL: cast_const_not_funcptr:
+; WASM64: .functype cast_const_not_funcptr () -> (funcref)
+; WASM64-NEXT: # %bb.0:
+; WASM64-NEXT: i64.const global_var
+; WASM64-NEXT: table.get __indirect_function_table
+; WASM64-NEXT: # fallthrough-return
+ %result = addrspacecast ptr @global_var to ptr addrspace(20)
+ ret %funcref %result
+}
+
+define %funcref @cast_param_funcptr(ptr %funcptr) {
+; WASM32-LABEL: cast_param_funcptr:
+; WASM32: .functype cast_param_funcptr (i32) -> (funcref)
+; WASM32-NEXT: # %bb.0:
+; WASM32-NEXT: local.get 0
+; WASM32-NEXT: table.get __indirect_function_table
+; WASM32-NEXT: # fallthrough-return
+;
+; WASM64-LABEL: cast_param_funcptr:
+; WASM64: .functype cast_param_funcptr (i64) -> (funcref)
+; WASM64-NEXT: # %bb.0:
+; WASM64-NEXT: local.get 0
+; WASM64-NEXT: table.get __indirect_function_table
+; WASM64-NEXT: # fallthrough-return
+ %result = addrspacecast ptr %funcptr to ptr addrspace(20)
+ ret %funcref %result
+}
>From b8d4767ee3b4a20c8d361e120a44b44a9fc820e6 Mon Sep 17 00:00:00 2001
From: Demetrius Kanios <demetrius at kanios.net>
Date: Thu, 6 Nov 2025 10:37:38 -0800
Subject: [PATCH 2/3] Replace undef in test
---
llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
index 1ae676f1c99c8..a7dfdd08d9030 100644
--- a/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
+++ b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
@@ -6,7 +6,7 @@
declare void @foo();
- at global_var = local_unnamed_addr global i32 undef
+ at global_var = local_unnamed_addr global i32 0
define %funcref @cast_const_funcptr() {
; CHECK-LABEL: cast_const_funcptr:
>From ae52e7a149b18c0e8923a70c150f85aa74619c9f Mon Sep 17 00:00:00 2001
From: Demetrius Kanios <demetrius at kanios.net>
Date: Thu, 4 Dec 2025 09:52:56 -0800
Subject: [PATCH 3/3] Minor touchups
---
llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp | 4 ++--
llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll | 6 +++---
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 782b878350b42..d30b54535c4b0 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -409,7 +409,7 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
setOperationAction(ISD::INTRINSIC_W_CHAIN, MVT::Other, Custom);
setOperationAction(ISD::INTRINSIC_VOID, MVT::Other, Custom);
- // Allow converting function ptrs in address space 0 to WASM funcref (address
+ // Allow converting function ptrs in address space 0 to Wasm funcref (address
// space 20)
setOperationAction(ISD::ADDRSPACECAST, MVT::funcref, Custom);
@@ -1892,7 +1892,7 @@ SDValue WebAssemblyTargetLowering::LowerADDRSPACECAST(SDValue Op,
WebAssembly::WasmAddressSpace::WASM_ADDRESS_SPACE_DEFAULT ||
ACN->getDestAddressSpace() !=
WebAssembly::WasmAddressSpace::WASM_ADDRESS_SPACE_FUNCREF)
- return Op;
+ return SDValue();
if (ACN->getValueType(0) != MVT::funcref) {
reportFatalInternalError("Cannot addrspacecast to funcref addrspace with "
diff --git a/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
index a7dfdd08d9030..f0a5989a4c811 100644
--- a/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
+++ b/llvm/test/CodeGen/WebAssembly/addrspacecast-funcref.ll
@@ -14,7 +14,7 @@ define %funcref @cast_const_funcptr() {
; CHECK-NEXT: # %bb.0:
; CHECK-NEXT: ref.func foo
; CHECK-NEXT: # fallthrough-return
- %result = addrspacecast ptr @foo to ptr addrspace(20)
+ %result = addrspacecast ptr @foo to %funcref
ret %funcref %result
}
@@ -32,7 +32,7 @@ define %funcref @cast_const_not_funcptr() {
; WASM64-NEXT: i64.const global_var
; WASM64-NEXT: table.get __indirect_function_table
; WASM64-NEXT: # fallthrough-return
- %result = addrspacecast ptr @global_var to ptr addrspace(20)
+ %result = addrspacecast ptr @global_var to %funcref
ret %funcref %result
}
@@ -50,6 +50,6 @@ define %funcref @cast_param_funcptr(ptr %funcptr) {
; WASM64-NEXT: local.get 0
; WASM64-NEXT: table.get __indirect_function_table
; WASM64-NEXT: # fallthrough-return
- %result = addrspacecast ptr %funcptr to ptr addrspace(20)
+ %result = addrspacecast ptr %funcptr to %funcref
ret %funcref %result
}
More information about the llvm-commits
mailing list