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Revert "IRGen: fix alignment for tail allocated arrays with elements which have a large alignment" #14656

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Revert "IRGen: fix alignment for tail allocated arrays with elements which have a large alignment" #14656

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22 changes: 9 additions & 13 deletions lib/IRGen/GenClass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -739,10 +739,9 @@ static llvm::Value *stackPromote(IRGenFunction &IGF,
return Alloca.getAddress();
}

std::pair<llvm::Value *, llvm::Value *>
irgen::appendSizeForTailAllocatedArrays(IRGenFunction &IGF,
llvm::Value *size, llvm::Value *alignMask,
TailArraysRef TailArrays) {
llvm::Value *irgen::appendSizeForTailAllocatedArrays(IRGenFunction &IGF,
llvm::Value *size,
TailArraysRef TailArrays) {
for (const auto &TailArray : TailArrays) {
SILType ElemTy = TailArray.first;
llvm::Value *Count = TailArray.second;
Expand All @@ -751,17 +750,16 @@ irgen::appendSizeForTailAllocatedArrays(IRGenFunction &IGF,

// Align up to the tail-allocated array.
llvm::Value *ElemStride = ElemTI.getStride(IGF, ElemTy);
llvm::Value *ElemAlignMask = ElemTI.getAlignmentMask(IGF, ElemTy);
size = IGF.Builder.CreateAdd(size, ElemAlignMask);
llvm::Value *InvertedMask = IGF.Builder.CreateNot(ElemAlignMask);
llvm::Value *AlignMask = ElemTI.getAlignmentMask(IGF, ElemTy);
size = IGF.Builder.CreateAdd(size, AlignMask);
llvm::Value *InvertedMask = IGF.Builder.CreateNot(AlignMask);
size = IGF.Builder.CreateAnd(size, InvertedMask);

// Add the size of the tail allocated array.
llvm::Value *AllocSize = IGF.Builder.CreateMul(ElemStride, Count);
size = IGF.Builder.CreateAdd(size, AllocSize);
alignMask = IGF.Builder.CreateOr(alignMask, ElemAlignMask);
}
return {size, alignMask};
return size;
}


Expand Down Expand Up @@ -802,8 +800,7 @@ llvm::Value *irgen::emitClassAllocation(IRGenFunction &IGF, SILType selfType,
val = IGF.emitInitStackObjectCall(metadata, val, "reference.new");
} else {
// Allocate the object on the heap.
std::tie(size, alignMask)
= appendSizeForTailAllocatedArrays(IGF, size, alignMask, TailArrays);
size = appendSizeForTailAllocatedArrays(IGF, size, TailArrays);
val = IGF.emitAllocObjectCall(metadata, size, alignMask, "reference.new");
StackAllocSize = -1;
}
Expand All @@ -826,8 +823,7 @@ llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF,
= emitClassResilientInstanceSizeAndAlignMask(IGF,
selfType.getClassOrBoundGenericClass(),
metadata);
std::tie(size, alignMask)
= appendSizeForTailAllocatedArrays(IGF, size, alignMask, TailArrays);
size = appendSizeForTailAllocatedArrays(IGF, size, TailArrays);

llvm::Value *val = IGF.emitAllocObjectCall(metadata, size, alignMask,
"reference.new");
Expand Down
10 changes: 4 additions & 6 deletions lib/IRGen/GenClass.h
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Expand Up @@ -95,12 +95,10 @@ namespace irgen {
typedef llvm::ArrayRef<std::pair<SILType, llvm::Value *>> TailArraysRef;

/// Adds the size for tail allocated arrays to \p size and returns the new
/// size value. Also updades the alignment mask to represent the alignment of
/// the largest element.
std::pair<llvm::Value *, llvm::Value *>
appendSizeForTailAllocatedArrays(IRGenFunction &IGF,
llvm::Value *size, llvm::Value *alignMask,
TailArraysRef TailArrays);
/// size value.
llvm::Value *appendSizeForTailAllocatedArrays(IRGenFunction &IGF,
llvm::Value *size,
TailArraysRef TailArrays);

/// Emit an allocation of a class.
/// The \p StackAllocSize is an in- and out-parameter. The passed value
Expand Down
12 changes: 3 additions & 9 deletions test/IRGen/tail_alloc.sil
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Expand Up @@ -95,8 +95,7 @@ bb0(%c1 : $Builtin.Word, %c2 : $Builtin.Word):
// CHECK-NEXT: [[S3:%[0-9]+]] = and i64 [[S1]], [[S2]]
// CHECK-NEXT: [[S4:%[0-9]+]] = mul i64 %stride, %0
// CHECK-NEXT: [[S5:%[0-9]+]] = add i64 [[S3]], [[S4]]
// CHECK-NEXT: [[A:%[0-9]+]] = or i64 7, %flags.alignmentMask
// CHECK: call noalias %swift.refcounted* @swift_allocObject(%swift.type* %{{[0-9]+}}, i64 [[S5]], i64 [[A]])
// CHECK: call noalias %swift.refcounted* @swift_allocObject(%swift.type* %{{[0-9]+}}, i64 [[S5]], i64 7)
// CHECK: ret
sil @alloc_generic : $@convention(thin) <T> (Builtin.Word, @thick T.Type) -> @owned TestClass {
bb0(%0 : $Builtin.Word, %1 : $@thick T.Type):
Expand All @@ -111,15 +110,10 @@ bb0(%0 : $Builtin.Word, %1 : $@thick T.Type):
// CHECK-NEXT: [[INT_PTR:%[0-9]+]] = bitcast i8* [[SIZE_ADDR]] to i32*
// CHECK-NEXT: [[SIZE:%[0-9]+]] = load i32, i32* [[INT_PTR]]
// CHECK-NEXT: [[SIZE64:%[0-9]+]] = zext i32 [[SIZE]] to i64
// CHECK-NEXT: [[ALIGN_ADDR:%[0-9]+]] = getelementptr inbounds i8, i8* [[BYTE_PTR]], i32 52
// CHECK-NEXT: [[SHORT_PTR:%[0-9]+]] = bitcast i8* [[ALIGN_ADDR]] to i16*
// CHECK-NEXT: [[ALIGN:%[0-9]+]] = load i16, i16* [[SHORT_PTR]]
// CHECK-NEXT: [[ALIGN64:%[0-9]+]] = zext i16 [[ALIGN]] to i64
// CHECK-NEXT: [[ALIGN_TMP:%[0-9]+]] = add i64 [[SIZE64]], 3
// CHECK: [[ALIGN_TMP:%[0-9]+]] = add i64 [[SIZE64]], 3
// CHECK-NEXT: [[ALIGNED:%[0-9]+]] = and i64 [[ALIGN_TMP]], -4
// CHECK-NEXT: [[TOTAL_SIZE:%[0-9]+]] = add i64 [[ALIGNED]], 12
// CHECK-NEXT: [[TOTAL_ALIGN:%[0-9]+]] = or i64 [[ALIGN64]], 3
// CHECK-NEXT: [[O:%[0-9]+]] = call noalias %swift.refcounted* @swift_allocObject(%swift.type* %0, i64 [[TOTAL_SIZE]], i64 [[TOTAL_ALIGN]])
// CHECK-NEXT: [[O:%[0-9]+]] = call noalias %swift.refcounted* @swift_allocObject(%swift.type* %0, i64 [[TOTAL_SIZE]], i64 {{.*}})
// CHECK-NEXT: [[O2:%[0-9]+]] = bitcast %swift.refcounted* [[O]] to %{{.*TestClassC}}*
// CHECK-NEXT: ret %{{.*TestClassC}}* [[O2]]
sil @alloc_dynamic : $@convention(thin) (@thick TestClass.Type) -> @owned TestClass {
Expand Down