[llvm] [DirectX] Fix crash when naming buffers of arrays (PR #164553)

[Justin Bogner via llvm-commits]

https://github.com/bogner created https://github.com/llvm/llvm-project/pull/164553

DXILResource was falling over trying to name a resource type that contained an array, such as `StructuredBuffer<float[3][2]>`. Handle this by walking through array types to gather the dimensions.

>From 99f760cbf9de2e3d237decd34021f369044c587c Mon Sep 17 00:00:00 2001
From: Justin Bogner <mail at justinbogner.com>
Date: Tue, 9 Sep 2025 14:08:37 -0700
Subject: [PATCH] [DirectX] Fix crash when naming buffers of arrays

DXILResource was falling over trying to name a resource type that
contained an array, such as `StructuredBuffer<float[3][2]>`. Handle this
by walking through array types to gather the dimensions.
---
 llvm/lib/Analysis/DXILResource.cpp                     | 8 ++++++++
 llvm/test/CodeGen/DirectX/Metadata/resource-symbols.ll | 9 ++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Analysis/DXILResource.cpp b/llvm/lib/Analysis/DXILResource.cpp
index f9bf09262dd1f..6f19a68dcd194 100644
--- a/llvm/lib/Analysis/DXILResource.cpp
+++ b/llvm/lib/Analysis/DXILResource.cpp
@@ -255,6 +255,12 @@ static void formatTypeName(SmallString<64> &Dest, StringRef Name,
   if (!ContainedType)
     return;
 
+  SmallVector<uint64_t> ArrayDimensions;
+  while (ArrayType *AT = dyn_cast<ArrayType>(ContainedType)) {
+    ArrayDimensions.push_back(AT->getNumElements());
+    ContainedType = AT->getElementType();
+  }
+
   StringRef ElementName;
   ElementType ET = toDXILElementType(ContainedType, IsSigned);
   if (ET != ElementType::Invalid) {
@@ -271,6 +277,8 @@ static void formatTypeName(SmallString<64> &Dest, StringRef Name,
   DestStream << "<" << ElementName;
   if (const FixedVectorType *VTy = dyn_cast<FixedVectorType>(ContainedType))
     DestStream << VTy->getNumElements();
+  for (uint64_t Dim : ArrayDimensions)
+    DestStream << "[" << Dim << "]";
   DestStream << ">";
 }
 
diff --git a/llvm/test/CodeGen/DirectX/Metadata/resource-symbols.ll b/llvm/test/CodeGen/DirectX/Metadata/resource-symbols.ll
index 4f13f4789cd66..56798c8382d45 100644
--- a/llvm/test/CodeGen/DirectX/Metadata/resource-symbols.ll
+++ b/llvm/test/CodeGen/DirectX/Metadata/resource-symbols.ll
@@ -28,6 +28,11 @@ define void @test() {
       @llvm.dx.resource.handlefrombinding(i32 0, i32 10, i32 1, i32 0, ptr @SB.str)
   ; CHECK: %"StructuredBuffer<struct.S>" = type { %struct.S }
 
+  ; StructuredBuffer<float[3][2]>
+  %struct1 = call target("dx.RawBuffer", [3 x [2 x float]], 0, 0)
+      @llvm.dx.resource.handlefrombinding(i32 0, i32 12, i32 1, i32 0, ptr null)
+  ; CHECK: %"StructuredBuffer<float[3][2]>" = type { [3 x [2 x float]] }
+
   ; ByteAddressBuffer
   %byteaddr = call target("dx.RawBuffer", i8, 0, 0)
       @llvm.dx.resource.handlefrombinding(i32 0, i32 20, i32 1, i32 0, ptr null)
@@ -40,12 +45,14 @@ define void @test() {
 ; CHECK-NEXT: @[[T1:.*]] = external constant %"Buffer<int32_t>"
 ; CHECK-NEXT: @[[T2:.*]] = external constant %"Buffer<uint32_t3>"
 ; CHECK-NEXT: @[[S0:.*]] = external constant %"StructuredBuffer<struct.S>"
+; CHECK-NEXT: @[[S1:.*]] = external constant %"StructuredBuffer<float[3][2]>"
 ; CHECK-NEXT: @[[B0:.*]] = external constant %ByteAddressBuffer
 
 ; CHECK: !{i32 0, ptr @[[T0]], !"A"
 ; CHECK: !{i32 1, ptr @[[T1]], !""
 ; CHECK: !{i32 2, ptr @[[T2]], !""
 ; CHECK: !{i32 3, ptr @[[S0]], !"SB"
-; CHECK: !{i32 4, ptr @[[B0]], !""
+; CHECK: !{i32 4, ptr @[[S1]], !""
+; CHECK: !{i32 5, ptr @[[B0]], !""
 
 attributes #0 = { nocallback nofree nosync nounwind willreturn memory(none) }