[clang] a96c14e - [Clang] Always forward sret parameters to musttail calls
Oliver Stannard via cfe-commits
cfe-commits at lists.llvm.org
Fri Oct 25 01:35:01 PDT 2024
Author: Kiran
Date: 2024-10-25T09:34:08+01:00
New Revision: a96c14eeb8fcb1a141c0f55ed5d28dd7f1f3e38e
URL: https://github.com/llvm/llvm-project/commit/a96c14eeb8fcb1a141c0f55ed5d28dd7f1f3e38e
DIFF: https://github.com/llvm/llvm-project/commit/a96c14eeb8fcb1a141c0f55ed5d28dd7f1f3e38e.diff
LOG: [Clang] Always forward sret parameters to musttail calls
If a call using the musttail attribute returns it's value through an
sret argument pointer, we must forward an incoming sret pointer to it,
instead of creating a new alloca. This is always possible because the
musttail attribute requires the caller and callee to have the same
argument and return types.
Added:
clang/test/CodeGen/musttail-sret.cpp
Modified:
clang/lib/CodeGen/CGCall.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 5f50ab6f34ff8d..1949b4ceb7f204 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -5112,7 +5112,11 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
RawAddress SRetAlloca = RawAddress::invalid();
llvm::Value *UnusedReturnSizePtr = nullptr;
if (RetAI.isIndirect() || RetAI.isInAlloca() || RetAI.isCoerceAndExpand()) {
- if (IsVirtualFunctionPointerThunk && RetAI.isIndirect()) {
+ // For virtual function pointer thunks and musttail calls, we must always
+ // forward an incoming SRet pointer to the callee, because a local alloca
+ // would be de-allocated before the call. These cases both guarantee that
+ // there will be an incoming SRet argument of the correct type.
+ if ((IsVirtualFunctionPointerThunk || IsMustTail) && RetAI.isIndirect()) {
SRetPtr = makeNaturalAddressForPointer(CurFn->arg_begin() +
IRFunctionArgs.getSRetArgNo(),
RetTy, CharUnits::fromQuantity(1));
diff --git a/clang/test/CodeGen/musttail-sret.cpp b/clang/test/CodeGen/musttail-sret.cpp
new file mode 100644
index 00000000000000..ca67c218cd67f6
--- /dev/null
+++ b/clang/test/CodeGen/musttail-sret.cpp
@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -triple=arm %s -emit-llvm -O3 -o - | FileCheck %s --check-prefix=CHECK-ARM
+// RUN: %clang_cc1 -triple=arm64 %s -emit-llvm -O3 -o - | FileCheck %s --check-prefix=CHECK-ARM64
+// RUN: %clang_cc1 -triple=i686 %s -emit-llvm -O3 -o - | FileCheck %s --check-prefix=CHECK-X86
+// RUN: %clang_cc1 -triple=x86_64 %s -emit-llvm -O3 -o - | FileCheck %s --check-prefix=CHECK-X64
+
+// Sret tests
+struct Big {
+ int a, b, c, d, e, f, g, h;
+};
+
+struct Big F1(signed short P0);
+
+struct Big F2(signed short P0) {
+ signed short P1 = 20391;
+ [[clang::musttail]] return F1(P1);
+}
+
+// CHECK-NOT: alloca
+// CHECK-ARM: musttail call arm_aapcscc void @_Z2F1s(ptr dead_on_unwind writable sret(%struct.Big) align 4 %agg.result, i16 noundef signext 20391)
+// CHECK-ARM64: musttail call void @_Z2F1s(ptr dead_on_unwind writable sret(%struct.Big) align 4 %agg.result, i16 noundef 20391)
+// CHECK-X86: musttail call void @_Z2F1s(ptr dead_on_unwind writable sret(%struct.Big) align 4 %agg.result, i16 noundef signext 20391)
+// CHECK-X64: musttail call void @_Z2F1s(ptr dead_on_unwind writable sret(%struct.Big) align 4 %agg.result, i16 noundef signext 20391)
+
+struct ReallyBig {
+ int a[100];
+};
+
+// Indirect sret tests
+// Function pointer for testing indirect musttail call.
+struct FunctionPointers {
+ ReallyBig (*F3)(int, int, int, int, float, double);
+ ReallyBig (*F4)(int, int, int, char, float, double);
+};
+
+struct ReallyBig F3(int P0, int P1, int P2, int P3, float P4, double P5);
+struct ReallyBig F4(int P0, int P1, int P2, char P3, float P4, double P5);
+
+static struct FunctionPointers FP = {F3, F4};
+
+struct ReallyBig F5 (int P0, int P1, int P2, int P3, float P4, double P5) {
+ [[clang::musttail]] return FP.F3(P0, P1, P2, P3, P4, P5);
+}
+
+// CHECK-NOT: alloca
+// CHECK-ARM: musttail call arm_aapcscc void @_Z2F3iiiifd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i32 noundef %P3, float noundef %P4, double noundef %P5)
+// CHECK-ARM64: musttail call void @_Z2F3iiiifd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i32 noundef %P3, float noundef %P4, double noundef %P5)
+// CHECK-X86: musttail call void @_Z2F3iiiifd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i32 noundef %P3, float noundef %P4, double noundef %P5)
+// CHECK-X64: musttail call void @_Z2F3iiiifd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i32 noundef %P3, float noundef %P4, double noundef %P5)
+
+struct ReallyBig F6 (int P0, int P1, int P2, char P3, float P4, double P5) {
+ [[clang::musttail]] return FP.F4(P0, P1, P2, P3, P4, P5);
+}
+
+// Complex and BitInt. Special cases for sret.
+// CHECK-NOT: alloca
+// CHECK-ARM: musttail call arm_aapcscc void @_Z2F4iiicfd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i8 noundef signext %P3, float noundef %P4, double noundef %P5)
+// CHECK-ARM64: musttail call void @_Z2F4iiicfd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i8 noundef %P3, float noundef %P4, double noundef %P5)
+// CHECK-X86: musttail call void @_Z2F4iiicfd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i8 noundef signext %P3, float noundef %P4, double noundef %P5)
+// CHECK-X64: musttail call void @_Z2F4iiicfd(ptr dead_on_unwind writable sret(%struct.ReallyBig) align 4 %agg.result, i32 noundef %P0, i32 noundef %P1, i32 noundef %P2, i8 noundef signext %P3, float noundef %P4, double noundef %P5)
+
+double _Complex F7(signed short P0);
+
+double _Complex F8(signed short P0) {
+ signed short P1 = 20391;
+ [[clang::musttail]] return F7(P1);
+}
+
+// CHECK-NOT: alloca
+// CHECK-ARM: musttail call arm_aapcscc void @_Z2F7s(ptr dead_on_unwind writable sret({ double, double }) align 8 %agg.result, i16 noundef signext 20391)
+// CHECK-ARM64: musttail call noundef { double, double } @_Z2F7s(i16 noundef 20391)
+// CHECK-X86: musttail call void @_Z2F7s(ptr dead_on_unwind writable sret({ double, double }) align 4 %agg.result, i16 noundef signext 20391)
+// CHECK-X64: musttail call noundef { double, double } @_Z2F7s(i16 noundef signext 20391)
+
+signed _BitInt(100) F9(float P0, float P1, double P2, char P3);
+
+signed _BitInt(100) F10(float P0, float P1, double P2, char P3) {
+ [[clang::musttail]] return F9(P0, P1, P2, P3);
+}
+
+// CHECK-NOT: alloca
+// CHECK-ARM: musttail call arm_aapcscc void @_Z2F9ffdc(ptr dead_on_unwind writable sret(i128) align 8 %agg.result, float noundef %P0, float noundef %P1, double noundef %P2, i8 noundef signext %P3)
+// CHECK-ARM64: musttail call noundef i100 @_Z2F9ffdc(float noundef %P0, float noundef %P1, double noundef %P2, i8 noundef %P3)
+// CHECK-X86: musttail call void @_Z2F9ffdc(ptr dead_on_unwind writable sret(i128) align 4 %agg.result, float noundef %P0, float noundef %P1, double noundef %P2, i8 noundef signext %P3)
+// CHECK-X64: musttail call noundef { i64, i64 } @_Z2F9ffdc(float noundef %P0, float noundef %P1, double noundef %P2, i8 noundef signext %P3)
\ No newline at end of file
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