Author: Billy Laws Date: 2024-03-11T14:29:51-07:00 New Revision: 89d543227a324d9925c68caf5d75c8c1e46c02a4
URL: https://github.com/llvm/llvm-project/commit/89d543227a324d9925c68caf5d75c8c1e46c02a4 DIFF: https://github.com/llvm/llvm-project/commit/89d543227a324d9925c68caf5d75c8c1e46c02a4.diff LOG: [AArch64] Skip over shadow space for ARM64EC entry thunk variadic calls (#80994) When in an entry thunk the x64 SP is passed in x4 but this cannot be directly passed through since x64 varargs calls have a 32 byte shadow store at SP followed by the in-stack parameters. ARM64EC varargs calls on the other hand expect x4 to point to the first in-stack parameter. Added: Modified: llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp llvm/lib/Target/AArch64/AArch64CallingConvention.td llvm/test/CodeGen/AArch64/arm64ec-entry-thunks.ll Removed: ################################################################################ diff --git a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp index 91b4f18c73c935..03d641d04413ef 100644 --- a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp +++ b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp @@ -117,8 +117,8 @@ void AArch64Arm64ECCallLowering::getThunkType(FunctionType *FT, getThunkArgTypes(FT, AttrList, TT, Out, Arm64ArgTypes, X64ArgTypes, HasSretPtr); - Arm64Ty = FunctionType::get(Arm64RetTy, Arm64ArgTypes, - TT == ThunkType::Entry && FT->isVarArg()); + Arm64Ty = FunctionType::get(Arm64RetTy, Arm64ArgTypes, false); + X64Ty = FunctionType::get(X64RetTy, X64ArgTypes, false); } @@ -156,13 +156,13 @@ void AArch64Arm64ECCallLowering::getThunkArgTypes( X64ArgTypes.push_back(I64Ty); } + // x4 + Arm64ArgTypes.push_back(PtrTy); + X64ArgTypes.push_back(PtrTy); + // x5 + Arm64ArgTypes.push_back(I64Ty); if (TT != ThunkType::Entry) { - // x4 - Arm64ArgTypes.push_back(PtrTy); - X64ArgTypes.push_back(PtrTy); - // x5 - Arm64ArgTypes.push_back(I64Ty); - // FIXME: x5 isn't actually passed/used by the x64 side; revisit once we + // FIXME: x5 isn't actually used by the x64 side; revisit once we // have proper isel for varargs X64ArgTypes.push_back(I64Ty); } @@ -471,10 +471,11 @@ Function *AArch64Arm64ECCallLowering::buildEntryThunk(Function *F) { bool TransformDirectToSRet = X64RetType->isVoidTy() && !RetTy->isVoidTy(); unsigned ThunkArgOffset = TransformDirectToSRet ? 2 : 1; + unsigned PassthroughArgSize = F->isVarArg() ? 5 : Thunk->arg_size(); // Translate arguments to call. SmallVector<Value *> Args; - for (unsigned i = ThunkArgOffset, e = Thunk->arg_size(); i != e; ++i) { + for (unsigned i = ThunkArgOffset, e = PassthroughArgSize; i != e; ++i) { Value *Arg = Thunk->getArg(i); Type *ArgTy = Arm64Ty->getParamType(i - ThunkArgOffset); if (ArgTy->isArrayTy() || ArgTy->isStructTy() || @@ -491,6 +492,22 @@ Function *AArch64Arm64ECCallLowering::buildEntryThunk(Function *F) { Args.push_back(Arg); } + if (F->isVarArg()) { + // The 5th argument to variadic entry thunks is used to model the x64 sp + // which is passed to the thunk in x4, this can be passed to the callee as + // the variadic argument start address after skipping over the 32 byte + // shadow store. + + // The EC thunk CC will assign any argument marked as InReg to x4. + Thunk->addParamAttr(5, Attribute::InReg); + Value *Arg = Thunk->getArg(5); + Arg = IRB.CreatePtrAdd(Arg, IRB.getInt64(0x20)); + Args.push_back(Arg); + + // Pass in a zero variadic argument size (in x5). + Args.push_back(IRB.getInt64(0)); + } + // Call the function passed to the thunk. Value *Callee = Thunk->getArg(0); Callee = IRB.CreateBitCast(Callee, PtrTy); diff --git a/llvm/lib/Target/AArch64/AArch64CallingConvention.td b/llvm/lib/Target/AArch64/AArch64CallingConvention.td index 78ea4a5180f703..8e67f0f5c8815f 100644 --- a/llvm/lib/Target/AArch64/AArch64CallingConvention.td +++ b/llvm/lib/Target/AArch64/AArch64CallingConvention.td @@ -213,6 +213,9 @@ def CC_AArch64_Arm64EC_VarArg : CallingConv<[ // address is passed in X9. let Entry = 1 in def CC_AArch64_Arm64EC_Thunk : CallingConv<[ + // ARM64EC-specific: the InReg attribute can be used to access the x64 sp passed into entry thunks in x4 from the IR. + CCIfInReg<CCIfType<[i64], CCAssignToReg<[X4]>>>, + // Byval aggregates are passed by pointer CCIfByVal<CCPassIndirect<i64>>, diff --git a/llvm/test/CodeGen/AArch64/arm64ec-entry-thunks.ll b/llvm/test/CodeGen/AArch64/arm64ec-entry-thunks.ll index 0083818def1514..bb9ba05f7a2724 100644 --- a/llvm/test/CodeGen/AArch64/arm64ec-entry-thunks.ll +++ b/llvm/test/CodeGen/AArch64/arm64ec-entry-thunks.ll @@ -147,7 +147,7 @@ define void @has_varargs(...) nounwind { ; CHECK-NEXT: add x29, sp, #160 ; CHECK-NEXT: .seh_add_fp 160 ; CHECK-NEXT: .seh_endprologue -; CHECK-NEXT: mov x4, sp +; CHECK-NEXT: add x4, x4, #32 ; CHECK-NEXT: mov x5, xzr ; CHECK-NEXT: blr x9 ; CHECK-NEXT: adrp x8, __os_arm64x_dispatch_ret _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
