[X86_64] Fix empty field error in vaarg of C++. #101639
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@llvm/pr-subscribers-clang-codegen @llvm/pr-subscribers-backend-x86 Author: Longsheng Mou (CoTinker) ChangesSuch struct types: For such structures, Lo is NoClass and Hi is Integer/SSE. And when this structure argument is passed, the high part is passed at offset 8 in memory. So we should do special handling for these types in EmitVAArg.Fix #79790 and #86371. Full diff: https://github.com/llvm/llvm-project/pull/101639.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/Targets/X86.cpp b/clang/lib/CodeGen/Targets/X86.cpp
index 26ff4e4ac0a3b..c7e84f70ae15f 100644
--- a/clang/lib/CodeGen/Targets/X86.cpp
+++ b/clang/lib/CodeGen/Targets/X86.cpp
@@ -3124,26 +3124,40 @@ RValue X86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 1));
RegAddr = Tmp.withElementType(LTy);
- } else if (neededInt) {
- RegAddr = Address(CGF.Builder.CreateGEP(CGF.Int8Ty, RegSaveArea, gp_offset),
- LTy, CharUnits::fromQuantity(8));
-
+ } else if (neededInt || neededSSE == 1) {
// Copy to a temporary if necessary to ensure the appropriate alignment.
auto TInfo = getContext().getTypeInfoInChars(Ty);
uint64_t TySize = TInfo.Width.getQuantity();
CharUnits TyAlign = TInfo.Align;
+ llvm::Value *GpOrFpOffset = neededInt ? gp_offset : fp_offset;
+ uint64_t Alignment = neededInt ? 8 : 16;
+ if (auto Offset = AI.getDirectOffset()) {
+ Address Tmp = CGF.CreateMemTemp(Ty);
+ llvm::Type *TyHi = AI.getCoerceToType();
+ llvm::Value *Addr =
+ CGF.Builder.CreateGEP(CGF.Int8Ty, RegSaveArea, GpOrFpOffset);
+ llvm::Value *Src = CGF.Builder.CreateAlignedLoad(TyHi, Addr, TyAlign);
+ llvm::Value *PtrOffset = llvm::ConstantInt::get(CGF.Int32Ty, Offset);
+ Address Dst = Address(
+ CGF.Builder.CreateGEP(CGF.Int8Ty, Tmp.getBasePointer(), PtrOffset),
+ LTy, TyAlign);
+ CGF.Builder.CreateStore(Src, Dst);
+ RegAddr = Tmp.withElementType(LTy);
+ } else {
+ RegAddr =
+ Address(CGF.Builder.CreateGEP(CGF.Int8Ty, RegSaveArea, GpOrFpOffset),
+ LTy, CharUnits::fromQuantity(Alignment));
+ }
+
// Copy into a temporary if the type is more aligned than the
// register save area.
- if (TyAlign.getQuantity() > 8) {
+ if (neededInt && TyAlign.getQuantity() > 8) {
Address Tmp = CGF.CreateMemTemp(Ty);
CGF.Builder.CreateMemCpy(Tmp, RegAddr, TySize, false);
RegAddr = Tmp;
}
- } else if (neededSSE == 1) {
- RegAddr = Address(CGF.Builder.CreateGEP(CGF.Int8Ty, RegSaveArea, fp_offset),
- LTy, CharUnits::fromQuantity(16));
} else {
assert(neededSSE == 2 && "Invalid number of needed registers!");
// SSE registers are spaced 16 bytes apart in the register save
diff --git a/clang/test/CodeGenCXX/x86_64-vaarg.cpp b/clang/test/CodeGenCXX/x86_64-vaarg.cpp
index c4616a97e2055..1703b74ad10a2 100644
--- a/clang/test/CodeGenCXX/x86_64-vaarg.cpp
+++ b/clang/test/CodeGenCXX/x86_64-vaarg.cpp
@@ -29,6 +29,7 @@ typedef struct {
// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_S1:%.*]], align 8
// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
// CHECK-NEXT: [[LIST:%.*]] = alloca [1 x %struct.__va_list_tag], align 16
+// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_S1]], align 8
// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4
// CHECK-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[ARRAYDECAY]])
@@ -41,8 +42,11 @@ typedef struct {
// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 3
// CHECK-NEXT: [[REG_SAVE_AREA:%.*]] = load ptr, ptr [[TMP0]], align 16
// CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[REG_SAVE_AREA]], i32 [[FP_OFFSET]]
-// CHECK-NEXT: [[TMP2:%.*]] = add i32 [[FP_OFFSET]], 16
-// CHECK-NEXT: store i32 [[TMP2]], ptr [[FP_OFFSET_P]], align 4
+// CHECK-NEXT: [[TMP2:%.*]] = load double, ptr [[TMP1]], align 8
+// CHECK-NEXT: [[TMP3:%.*]] = getelementptr i8, ptr [[TMP]], i32 8
+// CHECK-NEXT: store double [[TMP2]], ptr [[TMP3]], align 8
+// CHECK-NEXT: [[TMP4:%.*]] = add i32 [[FP_OFFSET]], 16
+// CHECK-NEXT: store i32 [[TMP4]], ptr [[FP_OFFSET_P]], align 4
// CHECK-NEXT: br label [[VAARG_END:%.*]]
// CHECK: vaarg.in_mem:
// CHECK-NEXT: [[OVERFLOW_ARG_AREA_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 2
@@ -51,14 +55,209 @@ typedef struct {
// CHECK-NEXT: store ptr [[OVERFLOW_ARG_AREA_NEXT]], ptr [[OVERFLOW_ARG_AREA_P]], align 8
// CHECK-NEXT: br label [[VAARG_END]]
// CHECK: vaarg.end:
-// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP1]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
+// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 [[RETVAL]], ptr align 8 [[VAARG_ADDR]], i64 16, i1 false)
-// CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
-// CHECK-NEXT: [[TMP4:%.*]] = load double, ptr [[TMP3]], align 8
-// CHECK-NEXT: ret double [[TMP4]]
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
+// CHECK-NEXT: [[TMP6:%.*]] = load double, ptr [[TMP5]], align 8
+// CHECK-NEXT: ret double [[TMP6]]
//
s1 f(int z, ...) {
__builtin_va_list list;
__builtin_va_start(list, z);
return __builtin_va_arg(list, s1);
}
+
+typedef struct {
+ struct{} a[5];
+ float b;
+ float c;
+} s2;
+
+// CHECK-LABEL: @_Z2f2iz(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_S2:%.*]], align 4
+// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT: [[LIST:%.*]] = alloca [1 x %struct.__va_list_tag], align 16
+// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_S2]], align 4
+// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[ARRAYDECAY]])
+// CHECK-NEXT: [[ARRAYDECAY1:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: [[FP_OFFSET_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG:%.*]], ptr [[ARRAYDECAY1]], i32 0, i32 1
+// CHECK-NEXT: [[FP_OFFSET:%.*]] = load i32, ptr [[FP_OFFSET_P]], align 4
+// CHECK-NEXT: [[FITS_IN_FP:%.*]] = icmp ule i32 [[FP_OFFSET]], 160
+// CHECK-NEXT: br i1 [[FITS_IN_FP]], label [[VAARG_IN_REG:%.*]], label [[VAARG_IN_MEM:%.*]]
+// CHECK: vaarg.in_reg:
+// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 3
+// CHECK-NEXT: [[REG_SAVE_AREA:%.*]] = load ptr, ptr [[TMP0]], align 16
+// CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[REG_SAVE_AREA]], i32 [[FP_OFFSET]]
+// CHECK-NEXT: [[TMP2:%.*]] = load <2 x float>, ptr [[TMP1]], align 4
+// CHECK-NEXT: [[TMP3:%.*]] = getelementptr i8, ptr [[TMP]], i32 8
+// CHECK-NEXT: store <2 x float> [[TMP2]], ptr [[TMP3]], align 4
+// CHECK-NEXT: [[TMP4:%.*]] = add i32 [[FP_OFFSET]], 16
+// CHECK-NEXT: store i32 [[TMP4]], ptr [[FP_OFFSET_P]], align 4
+// CHECK-NEXT: br label [[VAARG_END:%.*]]
+// CHECK: vaarg.in_mem:
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 2
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA:%.*]] = load ptr, ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_NEXT:%.*]] = getelementptr i8, ptr [[OVERFLOW_ARG_AREA]], i32 16
+// CHECK-NEXT: store ptr [[OVERFLOW_ARG_AREA_NEXT]], ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: br label [[VAARG_END]]
+// CHECK: vaarg.end:
+// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[RETVAL]], ptr align 4 [[VAARG_ADDR]], i64 16, i1 false)
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
+// CHECK-NEXT: [[TMP6:%.*]] = load <2 x float>, ptr [[TMP5]], align 4
+// CHECK-NEXT: ret <2 x float> [[TMP6]]
+//
+s2 f2(int z, ...) {
+ __builtin_va_list list;
+ __builtin_va_start(list, z);
+ return __builtin_va_arg(list, s2);
+}
+
+typedef struct {
+ struct{} a;
+ long long b;
+} s3;
+
+// CHECK-LABEL: @_Z2f3iz(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_S3:%.*]], align 8
+// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT: [[LIST:%.*]] = alloca [1 x %struct.__va_list_tag], align 16
+// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_S3]], align 8
+// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[ARRAYDECAY]])
+// CHECK-NEXT: [[ARRAYDECAY1:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: [[GP_OFFSET_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG:%.*]], ptr [[ARRAYDECAY1]], i32 0, i32 0
+// CHECK-NEXT: [[GP_OFFSET:%.*]] = load i32, ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: [[FITS_IN_GP:%.*]] = icmp ule i32 [[GP_OFFSET]], 40
+// CHECK-NEXT: br i1 [[FITS_IN_GP]], label [[VAARG_IN_REG:%.*]], label [[VAARG_IN_MEM:%.*]]
+// CHECK: vaarg.in_reg:
+// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 3
+// CHECK-NEXT: [[REG_SAVE_AREA:%.*]] = load ptr, ptr [[TMP0]], align 16
+// CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[REG_SAVE_AREA]], i32 [[GP_OFFSET]]
+// CHECK-NEXT: [[TMP2:%.*]] = load i64, ptr [[TMP1]], align 8
+// CHECK-NEXT: [[TMP3:%.*]] = getelementptr i8, ptr [[TMP]], i32 8
+// CHECK-NEXT: store i64 [[TMP2]], ptr [[TMP3]], align 8
+// CHECK-NEXT: [[TMP4:%.*]] = add i32 [[GP_OFFSET]], 8
+// CHECK-NEXT: store i32 [[TMP4]], ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: br label [[VAARG_END:%.*]]
+// CHECK: vaarg.in_mem:
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 2
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA:%.*]] = load ptr, ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_NEXT:%.*]] = getelementptr i8, ptr [[OVERFLOW_ARG_AREA]], i32 16
+// CHECK-NEXT: store ptr [[OVERFLOW_ARG_AREA_NEXT]], ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: br label [[VAARG_END]]
+// CHECK: vaarg.end:
+// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 [[RETVAL]], ptr align 8 [[VAARG_ADDR]], i64 16, i1 false)
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
+// CHECK-NEXT: [[TMP6:%.*]] = load i64, ptr [[TMP5]], align 8
+// CHECK-NEXT: ret i64 [[TMP6]]
+//
+s3 f3(int z, ...) {
+ __builtin_va_list list;
+ __builtin_va_start(list, z);
+ return __builtin_va_arg(list, s3);
+}
+
+typedef struct {
+ struct{} a[7];
+ short b;
+ int c;
+} s4;
+
+// CHECK-LABEL: @_Z2f4iz(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_S4:%.*]], align 4
+// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT: [[LIST:%.*]] = alloca [1 x %struct.__va_list_tag], align 16
+// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_S4]], align 4
+// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[ARRAYDECAY]])
+// CHECK-NEXT: [[ARRAYDECAY1:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: [[GP_OFFSET_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG:%.*]], ptr [[ARRAYDECAY1]], i32 0, i32 0
+// CHECK-NEXT: [[GP_OFFSET:%.*]] = load i32, ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: [[FITS_IN_GP:%.*]] = icmp ule i32 [[GP_OFFSET]], 40
+// CHECK-NEXT: br i1 [[FITS_IN_GP]], label [[VAARG_IN_REG:%.*]], label [[VAARG_IN_MEM:%.*]]
+// CHECK: vaarg.in_reg:
+// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 3
+// CHECK-NEXT: [[REG_SAVE_AREA:%.*]] = load ptr, ptr [[TMP0]], align 16
+// CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[REG_SAVE_AREA]], i32 [[GP_OFFSET]]
+// CHECK-NEXT: [[TMP2:%.*]] = load i64, ptr [[TMP1]], align 4
+// CHECK-NEXT: [[TMP3:%.*]] = getelementptr i8, ptr [[TMP]], i32 8
+// CHECK-NEXT: store i64 [[TMP2]], ptr [[TMP3]], align 4
+// CHECK-NEXT: [[TMP4:%.*]] = add i32 [[GP_OFFSET]], 8
+// CHECK-NEXT: store i32 [[TMP4]], ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: br label [[VAARG_END:%.*]]
+// CHECK: vaarg.in_mem:
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 2
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA:%.*]] = load ptr, ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_NEXT:%.*]] = getelementptr i8, ptr [[OVERFLOW_ARG_AREA]], i32 16
+// CHECK-NEXT: store ptr [[OVERFLOW_ARG_AREA_NEXT]], ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: br label [[VAARG_END]]
+// CHECK: vaarg.end:
+// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[RETVAL]], ptr align 4 [[VAARG_ADDR]], i64 16, i1 false)
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
+// CHECK-NEXT: [[TMP6:%.*]] = load i64, ptr [[TMP5]], align 4
+// CHECK-NEXT: ret i64 [[TMP6]]
+//
+s4 f4(int z, ...) {
+ __builtin_va_list list;
+ __builtin_va_start(list, z);
+ return __builtin_va_arg(list, s4);
+}
+
+typedef struct {
+ struct{} a[5];
+ float b;
+ int c;
+} s5;
+
+// CHECK-LABEL: @_Z2f5iz(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_S5:%.*]], align 4
+// CHECK-NEXT: [[Z_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT: [[LIST:%.*]] = alloca [1 x %struct.__va_list_tag], align 16
+// CHECK-NEXT: [[TMP:%.*]] = alloca [[STRUCT_S5]], align 4
+// CHECK-NEXT: store i32 [[Z:%.*]], ptr [[Z_ADDR]], align 4
+// CHECK-NEXT: [[ARRAYDECAY:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: call void @llvm.va_start.p0(ptr [[ARRAYDECAY]])
+// CHECK-NEXT: [[ARRAYDECAY1:%.*]] = getelementptr inbounds [1 x %struct.__va_list_tag], ptr [[LIST]], i64 0, i64 0
+// CHECK-NEXT: [[GP_OFFSET_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG:%.*]], ptr [[ARRAYDECAY1]], i32 0, i32 0
+// CHECK-NEXT: [[GP_OFFSET:%.*]] = load i32, ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: [[FITS_IN_GP:%.*]] = icmp ule i32 [[GP_OFFSET]], 40
+// CHECK-NEXT: br i1 [[FITS_IN_GP]], label [[VAARG_IN_REG:%.*]], label [[VAARG_IN_MEM:%.*]]
+// CHECK: vaarg.in_reg:
+// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 3
+// CHECK-NEXT: [[REG_SAVE_AREA:%.*]] = load ptr, ptr [[TMP0]], align 16
+// CHECK-NEXT: [[TMP1:%.*]] = getelementptr i8, ptr [[REG_SAVE_AREA]], i32 [[GP_OFFSET]]
+// CHECK-NEXT: [[TMP2:%.*]] = load i64, ptr [[TMP1]], align 4
+// CHECK-NEXT: [[TMP3:%.*]] = getelementptr i8, ptr [[TMP]], i32 8
+// CHECK-NEXT: store i64 [[TMP2]], ptr [[TMP3]], align 4
+// CHECK-NEXT: [[TMP4:%.*]] = add i32 [[GP_OFFSET]], 8
+// CHECK-NEXT: store i32 [[TMP4]], ptr [[GP_OFFSET_P]], align 16
+// CHECK-NEXT: br label [[VAARG_END:%.*]]
+// CHECK: vaarg.in_mem:
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_P:%.*]] = getelementptr inbounds [[STRUCT___VA_LIST_TAG]], ptr [[ARRAYDECAY1]], i32 0, i32 2
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA:%.*]] = load ptr, ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: [[OVERFLOW_ARG_AREA_NEXT:%.*]] = getelementptr i8, ptr [[OVERFLOW_ARG_AREA]], i32 16
+// CHECK-NEXT: store ptr [[OVERFLOW_ARG_AREA_NEXT]], ptr [[OVERFLOW_ARG_AREA_P]], align 8
+// CHECK-NEXT: br label [[VAARG_END]]
+// CHECK: vaarg.end:
+// CHECK-NEXT: [[VAARG_ADDR:%.*]] = phi ptr [ [[TMP]], [[VAARG_IN_REG]] ], [ [[OVERFLOW_ARG_AREA]], [[VAARG_IN_MEM]] ]
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[RETVAL]], ptr align 4 [[VAARG_ADDR]], i64 16, i1 false)
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[RETVAL]], i64 8
+// CHECK-NEXT: [[TMP6:%.*]] = load i64, ptr [[TMP5]], align 4
+// CHECK-NEXT: ret i64 [[TMP6]]
+//
+s5 f5(int z, ...) {
+ __builtin_va_list list;
+ __builtin_va_start(list, z);
+ return __builtin_va_arg(list, s5);
+}
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Ping~ |
clang/lib/CodeGen/Targets/X86.cpp
Outdated
| // Copy into a temporary if the type is more aligned than the | ||
| // register save area. | ||
| if (TyAlign.getQuantity() > 8) { | ||
| if (neededInt && TyAlign.getQuantity() > 8) { |
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Can we refactor the code so it's clear we never create two temporaries for the same va_arg? Use an else-if instead of a separate if.
It looks it's possible that we end up reading past the end of the register save area for something like:
struct {
long long b;
struct{} a;
};
Can you also fix that while you're here? (Not sure that actually has any visible effect, but better to be on the safe side.)
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I am glad to fix it.
CoTinker
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clang/lib/CodeGen/Targets/X86.cpp
Outdated
| // ``` | ||
| // struct { | ||
| // long long a; | ||
| // int b; |
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This example doesn't seem right; the size of the register save area has to be a multiple of 8.
Given that, we can simplify the "RegSize" to just neededInt ? neededInt * 8 : 16, I think?
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Yeah, you're right.
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SSE size is 8 and SSEUp is 8?
Consider such structure：
struct {
double a;
struct {} b;
}
Maybe RegSize = neededInt ? neededInt * 8 : 8, I think?
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The relevant "size" here is the size of the slots in the register save area. Which is 16 bytes for fp registers.
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Such struct types:
```
struct {
struct{} a;
long long b;
};
stuct {
struct{} a;
double b;
};
```
For such structures, Lo is NoClass and Hi is Integer/SSE. And when
this structure argument is passed, the high part is passed at
offset 8 in memory. So we should do special handling for these types
in EmitVAArg.
Fix edge cases that may reading past the end of the register save area.
Such as:
```
struct {
long long a;
struct {} b;
};
```
|
Thanks. |
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Such struct types:
For such structures, Lo is NoClass and Hi is Integer/SSE. And when this structure argument is passed, the high part is passed at offset 8 in memory. So we should do special handling for these types in EmitVAArg.Fix #79790 and fix #86371.