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[Clang] Use private address space for builtin_alloca return type for …
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…OpenCL (llvm#95750)

The __builtin_alloca was returning a flat pointer with no address space
when compiled using openCL1.2 or below but worked fine with openCL2.0
and above. This accounts to the fact that later uses the concept of
generic address space which supports cast to other address space(i.e to
private address space which is used for stack allocation) .

But, in actuality, as it returns pointer to the stack, it should be
pointing to private address space irrespective of openCL version becuase
builtin_alloca allocates stack memory used for current function in which
it is called. Thus,it requires redefintion of the builtin function with
appropraite return pointer to private address space.
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@vg0204
vg0204 authored Jul 26, 2024
1 parent 35dfe80 commit d65f037
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15 changes: 15 additions & 0 deletions clang/lib/Sema/SemaChecking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1477,6 +1477,18 @@ static bool BuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall,
return false;
}

// In OpenCL, __builtin_alloca_* should return a pointer to address space
// that corresponds to the stack address space i.e private address space.
static void builtinAllocaAddrSpace(Sema &S, CallExpr *TheCall) {
QualType RT = TheCall->getType();
assert((RT->isPointerType() && !(RT->getPointeeType().hasAddressSpace())) &&
"__builtin_alloca has invalid address space");

RT = RT->getPointeeType();
RT = S.Context.getAddrSpaceQualType(RT, LangAS::opencl_private);
TheCall->setType(S.Context.getPointerType(RT));
}

namespace {
enum PointerAuthOpKind {
PAO_Strip,
Expand Down Expand Up @@ -2214,6 +2226,9 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
case Builtin::BI__builtin_alloca_uninitialized:
Diag(TheCall->getBeginLoc(), diag::warn_alloca)
<< TheCall->getDirectCallee();
if (getLangOpts().OpenCL) {
builtinAllocaAddrSpace(*this, TheCall);
}
break;
case Builtin::BI__arithmetic_fence:
if (BuiltinArithmeticFence(TheCall))
Expand Down
141 changes: 141 additions & 0 deletions clang/test/CodeGenOpenCL/builtins-alloca.cl
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@@ -0,0 +1,141 @@
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
// RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -cl-std=CL1.2 \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=OPENCL %s
// RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -cl-std=CL2.0 \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=OPENCL %s
// RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -cl-std=CL3.0 \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=OPENCL %s
// RUN: %clang_cc1 %s -O0 -triple amdgcn-amd-amdhsa -cl-std=CL3.0 -cl-ext=+__opencl_c_generic_address_space \
// RUN: -emit-llvm -o - | FileCheck --check-prefixes=OPENCL %s

// OPENCL-LABEL: define dso_local void @test1_builtin_alloca(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0:[0-9]+]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[MUL:%.*]] = mul i64 [[CONV]], 4
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[MUL]], align 8, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR]], align 4
// OPENCL-NEXT: ret void
//
void test1_builtin_alloca(unsigned n) {
__private float* alloc_ptr = (__private float*)__builtin_alloca(n*sizeof(int));
}

// OPENCL-LABEL: define dso_local void @test1_builtin_alloca_uninitialized(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_UNINITIALIZED:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[MUL:%.*]] = mul i64 [[CONV]], 4
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[MUL]], align 8, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_UNINITIALIZED]], align 4
// OPENCL-NEXT: ret void
//
void test1_builtin_alloca_uninitialized(unsigned n) {
__private float* alloc_ptr_uninitialized = (__private float*)__builtin_alloca_uninitialized(n*sizeof(int));
}

// OPENCL-LABEL: define dso_local void @test1_builtin_alloca_with_align(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_ALIGN:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[MUL:%.*]] = mul i64 [[CONV]], 4
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[MUL]], align 1, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_ALIGN]], align 4
// OPENCL-NEXT: ret void
//
void test1_builtin_alloca_with_align(unsigned n) {
__private float* alloc_ptr_align = (__private float*)__builtin_alloca_with_align((n*sizeof(int)), 8);
}

// OPENCL-LABEL: define dso_local void @test1_builtin_alloca_with_align_uninitialized(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_ALIGN_UNINITIALIZED:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[MUL:%.*]] = mul i64 [[CONV]], 4
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[MUL]], align 1, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_ALIGN_UNINITIALIZED]], align 4
// OPENCL-NEXT: ret void
//
void test1_builtin_alloca_with_align_uninitialized(unsigned n) {
__private float* alloc_ptr_align_uninitialized = (__private float*)__builtin_alloca_with_align_uninitialized((n*sizeof(int)), 8);
}

// OPENCL-LABEL: define dso_local void @test2_builtin_alloca(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[CONV]], align 8, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR]], align 4
// OPENCL-NEXT: ret void
//
void test2_builtin_alloca(unsigned n) {
__private void *alloc_ptr = __builtin_alloca(n);
}

// OPENCL-LABEL: define dso_local void @test2_builtin_alloca_uninitialized(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_UNINITIALIZED:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[CONV]], align 8, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_UNINITIALIZED]], align 4
// OPENCL-NEXT: ret void
//
void test2_builtin_alloca_uninitialized(unsigned n) {
__private void *alloc_ptr_uninitialized = __builtin_alloca_uninitialized(n);
}

// OPENCL-LABEL: define dso_local void @test2_builtin_alloca_with_align(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_ALIGN:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[CONV]], align 1, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_ALIGN]], align 4
// OPENCL-NEXT: ret void
//
void test2_builtin_alloca_with_align(unsigned n) {
__private void *alloc_ptr_align = __builtin_alloca_with_align(n, 8);
}

// OPENCL-LABEL: define dso_local void @test2_builtin_alloca_with_align_uninitialized(
// OPENCL-SAME: i32 noundef [[N:%.*]]) #[[ATTR0]] {
// OPENCL-NEXT: [[ENTRY:.*:]]
// OPENCL-NEXT: [[N_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
// OPENCL-NEXT: [[ALLOC_PTR_ALIGN_UNINITIALIZED:%.*]] = alloca ptr addrspace(5), align 4, addrspace(5)
// OPENCL-NEXT: store i32 [[N]], ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[TMP0:%.*]] = load i32, ptr addrspace(5) [[N_ADDR]], align 4
// OPENCL-NEXT: [[CONV:%.*]] = zext i32 [[TMP0]] to i64
// OPENCL-NEXT: [[TMP1:%.*]] = alloca i8, i64 [[CONV]], align 1, addrspace(5)
// OPENCL-NEXT: store ptr addrspace(5) [[TMP1]], ptr addrspace(5) [[ALLOC_PTR_ALIGN_UNINITIALIZED]], align 4
// OPENCL-NEXT: ret void
//
void test2_builtin_alloca_with_align_uninitialized(unsigned n) {
__private void *alloc_ptr_align_uninitialized = __builtin_alloca_with_align_uninitialized(n, 8);
}

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