[llvm] 7ed2f70 - [HLSL] Set visibility of cbuffer global variables to internal (#200312)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 8 19:05:32 PDT 2026
Author: Helena Kotas
Date: 2026-06-08T19:05:26-07:00
New Revision: 7ed2f70f6c5b3849017f0eb38c521cc5d42040a2
URL: https://github.com/llvm/llvm-project/commit/7ed2f70f6c5b3849017f0eb38c521cc5d42040a2
DIFF: https://github.com/llvm/llvm-project/commit/7ed2f70f6c5b3849017f0eb38c521cc5d42040a2.diff
LOG: [HLSL] Set visibility of cbuffer global variables to internal (#200312)
Global variables for all resources except `cbuffer` are already emitted
with internal linkage (since #166844). This change adds internal linkage
to the `cbuffer` handle globals as well.
One problem is that the `cbuffer` handle globals appears unused between
Clang CodeGen and `{DXIL|SPIRV}CBufferAccess` pass, which replaces
individual `cbuffer` constant globals with accesses through the
`cbuffer` handle globals. Before this pass runs, the unused globals
could get optimized away in `GlobalOptPass` with `-O3`.
To solve this, the `cbuffer` handle globals are added to the
`@llvm.compiler.used` list to make sure they stay in the module until
the `{DXIL|SPRIV}CBufferAccess` pass, which then removes them from the
list.
Added:
llvm/test/CodeGen/DirectX/cbuffer_global_elim.ll
llvm/test/CodeGen/SPIRV/cbuffer_global_elim.ll
Modified:
clang/lib/CodeGen/CGHLSLRuntime.cpp
clang/test/CodeGenHLSL/ArrayAssignable.hlsl
clang/test/CodeGenHLSL/ArrayAssignable.logicalptr.hlsl
clang/test/CodeGenHLSL/cbuffer-matrix-layout-keyword.hlsl
clang/test/CodeGenHLSL/resources/cbuffer-empty-struct-array.hlsl
clang/test/CodeGenHLSL/resources/cbuffer.hlsl
clang/test/CodeGenHLSL/resources/cbuffer_and_namespaces.hlsl
clang/test/CodeGenHLSL/resources/cbuffer_with_packoffset.hlsl
clang/test/CodeGenHLSL/resources/cbuffer_with_static_global_and_function.hlsl
clang/test/CodeGenHLSL/resources/default_cbuffer.hlsl
clang/test/CodeGenHLSL/resources/default_cbuffer_with_layout.hlsl
llvm/include/llvm/Frontend/HLSL/CBuffer.h
llvm/lib/Frontend/HLSL/CBuffer.cpp
llvm/lib/Target/DirectX/DXILCBufferAccess.cpp
llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index 33d76cbda494a..262a2d8dabf5d 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -45,6 +45,7 @@
#include "llvm/Support/Alignment.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <cstdint>
#include <optional>
@@ -531,11 +532,18 @@ void CGHLSLRuntime::addBuffer(const HLSLBufferDecl *BufDecl) {
llvm::Type *LayoutTy = convertHLSLSpecificType(ResHandleTy, OffsetInfo);
llvm::GlobalVariable *BufGV = new GlobalVariable(
LayoutTy, /*isConstant*/ false,
- GlobalValue::LinkageTypes::ExternalLinkage, PoisonValue::get(LayoutTy),
+ GlobalValue::LinkageTypes::InternalLinkage, PoisonValue::get(LayoutTy),
llvm::formatv("{0}{1}", BufDecl->getName(),
BufDecl->isCBuffer() ? ".cb" : ".tb"),
GlobalValue::NotThreadLocal);
- CGM.getModule().insertGlobalVariable(BufGV);
+
+ llvm::Module &M = CGM.getModule();
+ M.insertGlobalVariable(BufGV);
+
+ // Add the global variable to the compiler used list so it does not
+ // get optimized away by GlobalOptPass before it reaches
+ // {DXIL|SPIRV}CBufferAccess pass.
+ llvm::appendToCompilerUsed(M, {BufGV});
// Add globals for constant buffer elements and create metadata nodes
emitBufferGlobalsAndMetadata(BufDecl, BufGV, OffsetInfo);
diff --git a/clang/test/CodeGenHLSL/ArrayAssignable.hlsl b/clang/test/CodeGenHLSL/ArrayAssignable.hlsl
index 36d44b26d81bb..2ff42120a3d18 100644
--- a/clang/test/CodeGenHLSL/ArrayAssignable.hlsl
+++ b/clang/test/CodeGenHLSL/ArrayAssignable.hlsl
@@ -7,7 +7,7 @@ struct S {
// CHECK: [[CBLayout:%.*]] = type <{ <{ [1 x <{ float, target("dx.Padding", 12) }>], float }>, target("dx.Padding", 12), [2 x <4 x i32>], <{ [1 x <{ <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }>, target("dx.Padding", 12) }>], <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }> }>, target("dx.Padding", 12), <{ [1 x <{ %S, target("dx.Padding", 8) }>], %S }> }>
-// CHECK: @CBArrays.cb = global target("dx.CBuffer", [[CBLayout]])
+// CHECK: @CBArrays.cb = internal global target("dx.CBuffer", [[CBLayout]])
// CHECK: @c1 = external hidden addrspace(2) global <{ [1 x <{ float, target("dx.Padding", 12) }>], float }>, align 4
// CHECK: @c2 = external hidden addrspace(2) global [2 x <4 x i32>], align 4
// CHECK: @c3 = external hidden addrspace(2) global <{ [1 x <{ <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }>, target("dx.Padding", 12) }>], <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }> }>, align 4
diff --git a/clang/test/CodeGenHLSL/ArrayAssignable.logicalptr.hlsl b/clang/test/CodeGenHLSL/ArrayAssignable.logicalptr.hlsl
index e5fa7e62f739d..cda023b16f891 100644
--- a/clang/test/CodeGenHLSL/ArrayAssignable.logicalptr.hlsl
+++ b/clang/test/CodeGenHLSL/ArrayAssignable.logicalptr.hlsl
@@ -15,14 +15,14 @@ cbuffer CBArrays : register(b0) {
}
// CHECK-DXIL: [[CBLayout:%.*]] = type <{ <{ [1 x <{ float, target("dx.Padding", 12) }>], float }>, target("dx.Padding", 12), [2 x <4 x i32>], <{ [1 x <{ <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }>, target("dx.Padding", 12) }>], <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }> }>, target("dx.Padding", 12), <{ [1 x <{ %S, target("dx.Padding", 8) }>], %S }> }>
-// CHECK-DXIL: @CBArrays.cb = global target("dx.CBuffer", [[CBLayout]])
+// CHECK-DXIL: @CBArrays.cb = internal global target("dx.CBuffer", [[CBLayout]])
// CHECK-DXIL: @c1 = external hidden addrspace(2) global <{ [1 x <{ float, target("dx.Padding", 12) }>], float }>, align 4
// CHECK-DXIL: @c2 = external hidden addrspace(2) global [2 x <4 x i32>], align 4
// CHECK-DXIL: @c3 = external hidden addrspace(2) global <{ [1 x <{ <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }>, target("dx.Padding", 12) }>], <{ [1 x <{ i32, target("dx.Padding", 12) }>], i32 }> }>, align 4
// CHECK-DXIL: @c4 = external hidden addrspace(2) global <{ [1 x <{ %S, target("dx.Padding", 8) }>], %S }>, align 1
// CHECK-SPIR: [[CBLayout:%.*]] = type <{ <{ [1 x <{ float, target("spirv.Padding", 12) }>], float }>, target("spirv.Padding", 12), [2 x <4 x i32>], <{ [1 x <{ <{ [1 x <{ i32, target("spirv.Padding", 12) }>], i32 }>, target("spirv.Padding", 12) }>], <{ [1 x <{ i32, target("spirv.Padding", 12) }>], i32 }> }>, target("spirv.Padding", 12), <{ [1 x <{ %S, target("spirv.Padding", 8) }>], %S }> }>
-// CHECK-SPIR: @CBArrays.cb = global target("spirv.VulkanBuffer", %__cblayout_CBArrays, 2, 0) poison
+// CHECK-SPIR: @CBArrays.cb = internal global target("spirv.VulkanBuffer", %__cblayout_CBArrays, 2, 0) poison
// CHECK-SPIR: @c1 = external hidden addrspace(12) global <{ [1 x <{ float, target("spirv.Padding", 12) }>], float }>, align 4
// CHECK-SPIR: @c2 = external hidden addrspace(12) global [2 x <4 x i32>], align 4
// CHECK-SPIR: @c3 = external hidden addrspace(12) global <{ [1 x <{ <{ [1 x <{ i32, target("spirv.Padding", 12) }>], i32 }>, target("spirv.Padding", 12) }>], <{ [1 x <{ i32, target("spirv.Padding", 12) }>], i32 }> }>, align 4
diff --git a/clang/test/CodeGenHLSL/cbuffer-matrix-layout-keyword.hlsl b/clang/test/CodeGenHLSL/cbuffer-matrix-layout-keyword.hlsl
index 66f64b2bbe967..8027df5d8c27b 100644
--- a/clang/test/CodeGenHLSL/cbuffer-matrix-layout-keyword.hlsl
+++ b/clang/test/CodeGenHLSL/cbuffer-matrix-layout-keyword.hlsl
@@ -9,9 +9,9 @@
// { [2 x { <2 x float>, pad(8) }], <2 x float> }
// CHECK: %__cblayout_CB_CM = type <{ <{ [2 x <{ <2 x float>, target("dx.Padding", 8) }>], <2 x float> }> }>
-// CHECK: @CB_RM.cb = global target("dx.CBuffer", %__cblayout_CB_RM)
+// CHECK: @CB_RM.cb = internal global target("dx.CBuffer", %__cblayout_CB_RM)
// CHECK: @rm = external hidden addrspace(2) global <{ [1 x <{ <3 x float>, target("dx.Padding", 4) }>], <3 x float> }>, align 4
-// CHECK: @CB_CM.cb = global target("dx.CBuffer", %__cblayout_CB_CM)
+// CHECK: @CB_CM.cb = internal global target("dx.CBuffer", %__cblayout_CB_CM)
// CHECK: @cm = external hidden addrspace(2) global <{ [2 x <{ <2 x float>, target("dx.Padding", 8) }>], <2 x float> }>, align 4
cbuffer CB_RM {
diff --git a/clang/test/CodeGenHLSL/resources/cbuffer-empty-struct-array.hlsl b/clang/test/CodeGenHLSL/resources/cbuffer-empty-struct-array.hlsl
index 72939cab07ac5..2184f8fe7cda6 100644
--- a/clang/test/CodeGenHLSL/resources/cbuffer-empty-struct-array.hlsl
+++ b/clang/test/CodeGenHLSL/resources/cbuffer-empty-struct-array.hlsl
@@ -42,19 +42,19 @@ int4x4 n;
void main() {
}
-// CHECK-NOT: @CB.cb = global target("dx.CBuffer", %__cblayout_CB)
+// CHECK-NOT: @CB.cb = internal global target("dx.CBuffer", %__cblayout_CB)
// CHECK-NOT: @a = external hidden addrspace(2) global
// CHECK-NOT: @b = external hidden addrspace(2) global
// CHECK-NOT: @c = external hidden addrspace(2) global
-// CHECK-NOT: @"$Globals.cb" = global target("dx.CBuffer",
+// CHECK-NOT: @"$Globals.cb" = internal global target("dx.CBuffer",
-// CHECK2: @CB.cb = global target("dx.CBuffer", %__cblayout_CB)
+// CHECK2: @CB.cb = internal global target("dx.CBuffer", %__cblayout_CB)
// CHECK-NOT: @a = external hidden addrspace(2) global
// CHECK-NOT: @c = external hidden addrspace(2) global
// CHECK2: @i = external hidden addrspace(2) global i32
// CHECK2: @v = external hidden addrspace(2) global <2 x float>, align 4
// CHECK2: @m = external hidden addrspace(2) global [4 x <4 x i32>], align 4
-// CHECK2: @"$Globals.cb" = global target("dx.CBuffer",
+// CHECK2: @"$Globals.cb" = internal global target("dx.CBuffer",
// CHECK-NOT: @b = external hidden addrspace(2) global
// CHECK2: @j = external hidden addrspace(2) global i32
// CHECK2: @w = external hidden addrspace(2) global <2 x float>, align 4
diff --git a/clang/test/CodeGenHLSL/resources/cbuffer.hlsl b/clang/test/CodeGenHLSL/resources/cbuffer.hlsl
index ef9c63a9c8a41..39e0f468a1b69 100644
--- a/clang/test/CodeGenHLSL/resources/cbuffer.hlsl
+++ b/clang/test/CodeGenHLSL/resources/cbuffer.hlsl
@@ -130,7 +130,7 @@ cbuffer CBScalars : register(b1, space5) {
int64_t a8;
}
-// CHECK: @CBScalars.cb = global target("dx.CBuffer", %__cblayout_CBScalars)
+// CHECK: @CBScalars.cb = internal global target("dx.CBuffer", %__cblayout_CBScalars)
// CHECK: @a1 = external hidden addrspace(2) global float, align 4
// CHECK: @a2 = external hidden addrspace(2) global double, align 8
// CHECK: @a3 = external hidden addrspace(2) global half, align 2
@@ -152,7 +152,7 @@ cbuffer CBVectors {
// FIXME: add a bool vectors after llvm-project/llvm#91639 is added
}
-// CHECK: @CBVectors.cb = global target("dx.CBuffer", %__cblayout_CBVectors)
+// CHECK: @CBVectors.cb = internal global target("dx.CBuffer", %__cblayout_CBVectors)
// CHECK: @b1 = external hidden addrspace(2) global <3 x float>, align 4
// CHECK: @b2 = external hidden addrspace(2) global <3 x double>, align 8
// CHECK: @b3 = external hidden addrspace(2) global <2 x half>, align 2
@@ -173,7 +173,7 @@ cbuffer CBArrays : register(b2) {
bool c8[4];
}
-// CHECK: @CBArrays.cb = global target("dx.CBuffer", %__cblayout_CBArrays)
+// CHECK: @CBArrays.cb = internal global target("dx.CBuffer", %__cblayout_CBArrays)
// CHECK: @c1 = external hidden addrspace(2) global <{ [2 x <{ float, target("dx.Padding", 12) }>], float }>, align 4
// CHECK: @c2 = external hidden addrspace(2) global <{ [1 x <{ <3 x double>, target("dx.Padding", 8) }>], <3 x double> }>, align 8
// CHECK: @c3 = external hidden addrspace(2) global <{ [1 x <{ <{ [1 x <{ half, target("dx.Padding", 14) }>], half }>, target("dx.Padding", 14) }>], <{ [1 x <{ half, target("dx.Padding", 14) }>], half }> }>, align 2
@@ -193,7 +193,7 @@ cbuffer CBTypedefArray : register(space2) {
T2 t2[2];
}
-// CHECK: @CBTypedefArray.cb = global target("dx.CBuffer", %__cblayout_CBTypedefArray)
+// CHECK: @CBTypedefArray.cb = internal global target("dx.CBuffer", %__cblayout_CBTypedefArray)
// CHECK: @t1 = external hidden addrspace(2) global [2 x [2 x <4 x i32>]], align 4
// CHECK: @t2 = external hidden addrspace(2) global [2 x [2 x <4 x i32>]], align 4
// CHECK: @CBTypedefArray.str = private unnamed_addr constant [15 x i8] c"CBTypedefArray\00", align 1
@@ -217,7 +217,7 @@ struct D {
Empty es;
};
-// CHECK: @CBStructs.cb = global target("dx.CBuffer", %__cblayout_CBStructs)
+// CHECK: @CBStructs.cb = internal global target("dx.CBuffer", %__cblayout_CBStructs)
// CHECK: @a = external hidden addrspace(2) global %A, align 1
// CHECK: @b = external hidden addrspace(2) global %B, align 1
// CHECK: @c = external hidden addrspace(2) global %C, align 1
@@ -257,7 +257,7 @@ cbuffer CBClasses {
K ka[10];
};
-// CHECK: @CBClasses.cb = global target("dx.CBuffer", %__cblayout_CBClasses)
+// CHECK: @CBClasses.cb = internal global target("dx.CBuffer", %__cblayout_CBClasses)
// CHECK: @k = external hidden addrspace(2) global %K, align 1
// CHECK: @l = external hidden addrspace(2) global %L, align 1
// CHECK: @m = external hidden addrspace(2) global %M, align 1
@@ -268,7 +268,7 @@ struct Test {
float a, b;
};
-// CHECK: @CBMix.cb = global target("dx.CBuffer", %__cblayout_CBMix)
+// CHECK: @CBMix.cb = internal global target("dx.CBuffer", %__cblayout_CBMix)
// CHECK: @test = external hidden addrspace(2) global <{ [1 x <{ %Test, target("dx.Padding", 8) }>], %Test }>, align 1
// CHECK: @f1 = external hidden addrspace(2) global float, align 4
// CHECK: @f2 = external hidden addrspace(2) global <{ [2 x <{ <{ [1 x <{ <2 x float>, target("dx.Padding", 8) }>], <2 x float> }>, target("dx.Padding", 8) }>], <{ [1 x <{ <2 x float>, target("dx.Padding", 8) }>], <2 x float> }> }>, align 4
@@ -294,7 +294,7 @@ cbuffer CBMix {
uint16_t f9;
};
-// CHECK: @CB_A.cb = global target("dx.CBuffer", %__cblayout_CB_A)
+// CHECK: @CB_A.cb = internal global target("dx.CBuffer", %__cblayout_CB_A)
cbuffer CB_A {
double B0[2];
@@ -308,7 +308,7 @@ cbuffer CB_A {
half3 B8;
}
-// CHECK: @CB_B.cb = global target("dx.CBuffer", %__cblayout_CB_B)
+// CHECK: @CB_B.cb = internal global target("dx.CBuffer", %__cblayout_CB_B)
cbuffer CB_B {
double3 B9[3];
half3 B10;
@@ -343,7 +343,7 @@ struct G {
half C3;
};
-// CHECK: @CB_C.cb = global target("dx.CBuffer", %__cblayout_CB_C)
+// CHECK: @CB_C.cb = internal global target("dx.CBuffer", %__cblayout_CB_C)
cbuffer CB_C {
int D0;
F D1;
@@ -352,6 +352,10 @@ cbuffer CB_C {
double D4;
}
+// CHECK: @llvm.compiler.used = appending global [10 x ptr] [ptr @CBScalars.cb, ptr @CBVectors.cb,
+// CHECK-SAME: ptr @CBArrays.cb, ptr @CBTypedefArray.cb, ptr @CBStructs.cb, ptr @CBClasses.cb,
+// CHECK-SAME: ptr @CBMix.cb, ptr @CB_A.cb, ptr @CB_B.cb, ptr @CB_C.cb], section "llvm.metadata"
+
// CHECK: define internal void @_init_buffer_CBScalars.cb()
// CHECK-NEXT: entry:
// CHECK-NEXT: %CBScalars.cb_h = call target("dx.CBuffer", %__cblayout_CBScalars)
diff --git a/clang/test/CodeGenHLSL/resources/cbuffer_and_namespaces.hlsl b/clang/test/CodeGenHLSL/resources/cbuffer_and_namespaces.hlsl
index 1fe0a68261c94..3f51b8d8dcb06 100644
--- a/clang/test/CodeGenHLSL/resources/cbuffer_and_namespaces.hlsl
+++ b/clang/test/CodeGenHLSL/resources/cbuffer_and_namespaces.hlsl
@@ -7,13 +7,13 @@
// CHECK: %"n0::n2::__cblayout_C" = type <{ float, target("dx.Padding", 12), %"n0::Foo" }>
// CHECK: %"n0::Foo" = type <{ float }>
-// CHECK: @A.cb = global target("dx.CBuffer", %"n0::n1::__cblayout_A")
+// CHECK: @A.cb = internal global target("dx.CBuffer", %"n0::n1::__cblayout_A")
// CHECK: @_ZN2n02n11aE = external hidden addrspace(2) global float, align 4
-// CHECK: @B.cb = global target("dx.CBuffer", %"n0::__cblayout_B")
+// CHECK: @B.cb = internal global target("dx.CBuffer", %"n0::__cblayout_B")
// CHECK: @_ZN2n01aE = external hidden addrspace(2) global float, align 4
-// CHECK: @C.cb = global target("dx.CBuffer", %"n0::n2::__cblayout_C")
+// CHECK: @C.cb = internal global target("dx.CBuffer", %"n0::n2::__cblayout_C")
// CHECK: @_ZN2n02n21aE = external hidden addrspace(2) global float, align 4
// CHECK: external hidden addrspace(2) global %"n0::Foo", align 1
diff --git a/clang/test/CodeGenHLSL/resources/cbuffer_with_packoffset.hlsl b/clang/test/CodeGenHLSL/resources/cbuffer_with_packoffset.hlsl
index 818786c591189..ad8d619e9ac3b 100644
--- a/clang/test/CodeGenHLSL/resources/cbuffer_with_packoffset.hlsl
+++ b/clang/test/CodeGenHLSL/resources/cbuffer_with_packoffset.hlsl
@@ -16,7 +16,7 @@
// CHECK-SAME: float
// CHECK-SAME: }>
-// CHECK-DAG: @CB.cb = global target("dx.CBuffer", %__cblayout_CB)
+// CHECK-DAG: @CB.cb = internal global target("dx.CBuffer", %__cblayout_CB)
// CHECK-DAG: @a = external hidden addrspace(2) global float, align 4
// CHECK-DAG: @b = external hidden addrspace(2) global double, align 8
// CHECK-DAG: @c = external hidden addrspace(2) global <2 x i32>, align 4
@@ -28,7 +28,7 @@ cbuffer CB : register(b1, space3) {
int2 c : packoffset(c5.z);
}
-// CHECK-DAG: @CB.cb.1 = global target("dx.CBuffer", %__cblayout_CB_1)
+// CHECK-DAG: @CB.cb.1 = internal global target("dx.CBuffer", %__cblayout_CB_1)
// CHECK-DAG: @x = external hidden addrspace(2) global float, align 4
// CHECK-DAG: @y = external hidden addrspace(2) global <2 x float>, align 4
diff --git a/clang/test/CodeGenHLSL/resources/cbuffer_with_static_global_and_function.hlsl b/clang/test/CodeGenHLSL/resources/cbuffer_with_static_global_and_function.hlsl
index b8c7babb8d634..3d2739f01c1ba 100644
--- a/clang/test/CodeGenHLSL/resources/cbuffer_with_static_global_and_function.hlsl
+++ b/clang/test/CodeGenHLSL/resources/cbuffer_with_static_global_and_function.hlsl
@@ -2,7 +2,7 @@
// CHECK: %__cblayout_A = type <{ float }>
-// CHECK: @A.cb = global target("dx.CBuffer", %__cblayout_A)
+// CHECK: @A.cb = internal global target("dx.CBuffer", %__cblayout_A)
// CHECK: @a = external hidden addrspace(2) global float, align 4
// CHECK-DAG: @_ZL1b = internal global float 3.000000e+00, align 4
// CHECK-NOT: @B.cb
diff --git a/clang/test/CodeGenHLSL/resources/default_cbuffer.hlsl b/clang/test/CodeGenHLSL/resources/default_cbuffer.hlsl
index 5333dad962195..6abc337ca869d 100644
--- a/clang/test/CodeGenHLSL/resources/default_cbuffer.hlsl
+++ b/clang/test/CodeGenHLSL/resources/default_cbuffer.hlsl
@@ -4,12 +4,12 @@
// CHECK: %"__cblayout_$Globals" = type <{ float, float, target("{{.*}}.Padding", 8), %__cblayout_S }>
// CHECK: %__cblayout_S = type <{ float }>
-// DXIL-DAG: @"$Globals.cb" = global target("dx.CBuffer", %"__cblayout_$Globals")
+// DXIL-DAG: @"$Globals.cb" = internal global target("dx.CBuffer", %"__cblayout_$Globals")
// DXIL-DAG: @a = external hidden addrspace(2) global float
// DXIL-DAG: @g = external hidden addrspace(2) global float
// DXIL-DAG: @h = external hidden addrspace(2) global %__cblayout_S, align 4
-// SPIRV-DAG: @"$Globals.cb" = global target("spirv.VulkanBuffer", %"__cblayout_$Globals", 2, 0)
+// SPIRV-DAG: @"$Globals.cb" = internal global target("spirv.VulkanBuffer", %"__cblayout_$Globals", 2, 0)
// SPIRV-DAG: @a = external hidden addrspace(12) global float
// SPIRV-DAG: @g = external hidden addrspace(12) global float
// SPIRV-DAG: @h = external hidden addrspace(12) global %__cblayout_S, align 8
diff --git a/clang/test/CodeGenHLSL/resources/default_cbuffer_with_layout.hlsl b/clang/test/CodeGenHLSL/resources/default_cbuffer_with_layout.hlsl
index f3d85e57983b2..8bc2b8ee59fda 100644
--- a/clang/test/CodeGenHLSL/resources/default_cbuffer_with_layout.hlsl
+++ b/clang/test/CodeGenHLSL/resources/default_cbuffer_with_layout.hlsl
@@ -17,7 +17,7 @@
// CHECK: %S = type <{ <2 x float> }>
-// CHECK-DAG: @"$Globals.cb" = global target("dx.CBuffer", %"__cblayout_$Globals")
+// CHECK-DAG: @"$Globals.cb" = internal global target("dx.CBuffer", %"__cblayout_$Globals")
// CHECK-DAG: @a = external hidden addrspace(2) global i32, align 4
// CHECK-DAG: @b = external hidden addrspace(2) global float, align 4
// CHECK-DAG: @c = external hidden addrspace(2) global <{ [3 x <{ double, target("dx.Padding", 8) }>], double }>, align 8
diff --git a/llvm/include/llvm/Frontend/HLSL/CBuffer.h b/llvm/include/llvm/Frontend/HLSL/CBuffer.h
index f4e232ffe1745..e39b3f5c824f0 100644
--- a/llvm/include/llvm/Frontend/HLSL/CBuffer.h
+++ b/llvm/include/llvm/Frontend/HLSL/CBuffer.h
@@ -53,6 +53,7 @@ class CBufferMetadata {
iterator begin() { return Mappings.begin(); }
iterator end() { return Mappings.end(); }
+ void removeCBufferGlobalsFromUseList(Module &M);
void eraseFromModule();
};
diff --git a/llvm/lib/Frontend/HLSL/CBuffer.cpp b/llvm/lib/Frontend/HLSL/CBuffer.cpp
index 33d9b1a1b3102..b5377f666ee4f 100644
--- a/llvm/lib/Frontend/HLSL/CBuffer.cpp
+++ b/llvm/lib/Frontend/HLSL/CBuffer.cpp
@@ -11,6 +11,7 @@
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
using namespace llvm::hlsl;
@@ -71,6 +72,22 @@ CBufferMetadata::get(Module &M, llvm::function_ref<bool(Type *)> IsPadding) {
return Result;
}
+void CBufferMetadata::removeCBufferGlobalsFromUseList(Module &M) {
+
+ SmallPtrSet<GlobalVariable *, 8> CBGlobals;
+ for (const hlsl::CBufferMapping &Mapping : Mappings)
+ CBGlobals.insert(Mapping.Handle);
+
+ llvm::removeFromUsedLists(M, [&](Constant *C) -> bool {
+ if (auto *GV = dyn_cast<GlobalVariable>(C))
+ return CBGlobals.contains(GV);
+ return false;
+ });
+
+ for (GlobalVariable *HandleGV : CBGlobals)
+ HandleGV->removeDeadConstantUsers();
+}
+
void CBufferMetadata::eraseFromModule() {
// Remove the cbs named metadata
MD->eraseFromParent();
diff --git a/llvm/lib/Target/DirectX/DXILCBufferAccess.cpp b/llvm/lib/Target/DirectX/DXILCBufferAccess.cpp
index 56245321a522a..cb4d8039a84c0 100644
--- a/llvm/lib/Target/DirectX/DXILCBufferAccess.cpp
+++ b/llvm/lib/Target/DirectX/DXILCBufferAccess.cpp
@@ -59,6 +59,7 @@ static bool replaceCBufferAccesses(Module &M) {
for (const hlsl::CBufferMember &Member : Mapping.Members)
replaceUsersOfGlobal(Member.GV, Mapping.Handle, Member.Offset);
+ CBufMD->removeCBufferGlobalsFromUseList(M);
CBufMD->eraseFromModule();
return true;
}
diff --git a/llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp b/llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp
index 227d8716d974a..2918834bd0a11 100644
--- a/llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp
@@ -101,6 +101,8 @@ static bool replaceCBufferAccesses(Module &M) {
}
}
+ CBufMD->removeCBufferGlobalsFromUseList(M);
+
// Now that all uses are replaced, clean up the globals and metadata.
for (const hlsl::CBufferMapping &Mapping : *CBufMD) {
for (const auto &Member : Mapping.Members) {
diff --git a/llvm/test/CodeGen/DirectX/cbuffer_global_elim.ll b/llvm/test/CodeGen/DirectX/cbuffer_global_elim.ll
new file mode 100644
index 0000000000000..64d0bd4e04fa3
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/cbuffer_global_elim.ll
@@ -0,0 +1,38 @@
+; RUN: opt -S -passes='dxil-cbuffer-access' %s -o - | FileCheck %s --check-prefixes=CHECK
+; RUN: llc %s -o - | FileCheck %s --check-prefixes=CHECK-LOWERED
+; RUN: llc %s -O3 -o - | FileCheck %s --check-prefixes=CHECK-LOWERED
+
+target triple = "dxil-unknown-shadermodel6.6-compute"
+
+%__cblayout_CB = type <{ i32 }>
+ at CB.cb = internal global target("dx.CBuffer", %__cblayout_CB) poison
+ at i = external hidden local_unnamed_addr addrspace(2) global i32, align 4
+
+ at llvm.compiler.used = appending global [1 x ptr] [ptr @CB.cb], section "llvm.metadata"
+
+; Check that DXILCBufferAccessPass removes the cbuffer global from @llvm.compiler.used
+;
+; CHECK: @CB.cb = internal global target("dx.CBuffer", %__cblayout_CB) poison
+; CHECK-NOT: @i
+; CHECK-NOT: @llvm.compiler.used
+
+; Check that the cbuffer global is removed during lowering to DXIL
+;
+; CHECK-LOWERED-NOT: %__cblayout_CB = type <{ i32 }>
+; CHECK-LOWERED-NOT: @CB.cb = internal global target("dx.CBuffer", %__cblayout_CB) poison
+
+define void @main() {
+entry:
+ %cb_handle = tail call target("dx.CBuffer", %__cblayout_CB) @llvm.dx.resource.handlefromimplicitbinding.tdx.CBuffer_s___cblayout_CBst(i32 0, i32 0, i32 1, i32 0, ptr nonnull null)
+ store target("dx.CBuffer", %__cblayout_CB) %cb_handle, ptr @CB.cb, align 4
+ %1 = load i32, ptr addrspace(2) @i, align 4
+ ret void
+}
+
+; CHECK-NOT: !hlsl.cbs
+
+!hlsl.cbs = !{!0}
+
+!0 = !{ptr @CB.cb, ptr addrspace(2) @i}
+!1 = !{i32 1, i32 8}
+
diff --git a/llvm/test/CodeGen/SPIRV/cbuffer_global_elim.ll b/llvm/test/CodeGen/SPIRV/cbuffer_global_elim.ll
new file mode 100644
index 0000000000000..faac15fa24bf9
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/cbuffer_global_elim.ll
@@ -0,0 +1,36 @@
+; RUN: opt -S -passes='spirv-cbuffer-access' %s -o - | FileCheck %s
+; RUN: llc %s -o - | FileCheck %s
+; RUN: llc %s -O3 -o - | FileCheck %s
+
+target triple = "spirv-unknown-vulkan1.3-compute"
+
+%__cblayout_CB = type <{ i32 }>
+ at CB.cb = internal global target("spirv.VulkanBuffer", %__cblayout_CB, 2, 0) poison
+ at i = external hidden local_unnamed_addr addrspace(2) global i32, align 4
+
+ at llvm.compiler.used = appending global [1 x ptr] [ptr @CB.cb], section "llvm.metadata"
+
+; Check that SPRIVCBufferAccessPass removes the cbuffer global from @llvm.compiler.used
+; and from the module.
+;
+; CHECK-NOT: @CB.cb = internal global target("spirv.VulkanBuffer", %__cblayout_CB, 2, 0) poison
+; CHECK-NOT: @i
+; CHECK-NOT: @llvm.compiler.used
+
+; Check that the cbuffer global is removed during lowering to DXIL
+;
+define void @main() {
+entry:
+ %cb_handle = tail call target("spirv.VulkanBuffer", %__cblayout_CB, 2, 0) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_s___cblayout_CBs_2_0t(i32 0, i32 0, i32 1, i32 0, ptr nonnull null)
+ store target("spirv.VulkanBuffer", %__cblayout_CB, 2, 0) %cb_handle, ptr @CB.cb, align 4
+ %1 = load i32, ptr addrspace(2) @i, align 4
+ ret void
+}
+
+; CHECK-NOT: !hlsl.cbs
+
+!hlsl.cbs = !{!0}
+
+!0 = !{ptr @CB.cb, ptr addrspace(2) @i}
+!1 = !{i32 1, i32 8}
+
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