microsoft / microsoft/DirectXShaderCompiler

Multiple subscript into descriptor heaps are allowed.

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bug incorrect-code
Dominant language
C++
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Description

Description

Accessing the heaps through multiple subscript expressions is accepted, but seems like this is wrong:

// RUN: %dxc -T cs_6_6 %s | FileCheck %s

[numthreads(1, 1, 1)]
void main() {
  RWStructuredBuffer<uint> a = SamplerDescriptorHeap[0][1][2];
  a[0] = 10;
}
  %1 = call %dx.types.Handle @dx.op.createHandleFromHeap(i32 218, i32 2, i1 true, i1 false)  ; CreateHandleFromHeap(index,samplerHeap,nonUniformIndex)

Environment

  • DXC version: HEAD (128e6ce2be8f09539c97cf28d6066d9a6b32b15c)
  • Host Operating System: Linux

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the inline HLSL reproducer with %dxc and FileCheck to confirm how repeated descriptor-heap subscripts are accepted. Trace the compiler handling for descriptor-heap subscripting, then add a regression check covering the intended rejection or diagnostic for multiple subscripts.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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