[202x][0005] Implement cbuffer contexts by llvm-beanz · Pull Request #8935 · microsoft/DirectXShaderCompiler

Chris B (llvm-beanz) · 2026-09-21T03:20:43Z

This restricts the ability to nest namespaces and cbuffer/tbuffer declarations within cbuffers. This implements the language adopted by TC57 for the draft specification.

Fixes #8484

This restricts the ability to nest namespaces and cbuffer/tbuffer declarations within cbuffers. This implements the language adopted by TC57 for the draft specification. Fixes microsoft#8484 ../tools/clang/include/clang/Basic/DiagnosticSemaKinds.td ../tools/clang/test/SemaHLSL/hlsl/202x-cbuffer-contexts.hlsl

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The user-visible language change needs release-note coverage, and a source comment typo should be corrected.

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Fix typo: change resetricts to restricts · New
Add release note for HLSL language behavior change · New

What changed in this PR

Implements TC57 proposal 0005 by rejecting nested namespaces and buffer declarations in HLSL 202x buffers.

Changes:

Adds semantic validation and diagnostics.
Adds coverage for valid and invalid nesting.

File	Description
`SemaHLSL.cpp`	Validates buffer contents.
`DiagnosticSemaKinds.td`	Defines the new diagnostic.
`202x-cbuffer-contexts.hlsl`	Tests buffer-context restrictions.

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The user-visible language change needs an Upcoming Release note.

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Add release note for HLSL language behavior change

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Fix typo: change resetricts to restricts

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The denylist still accepts declaration kinds prohibited by the proposal.

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Add release note for HLSL language behavior change

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In code that hasn't changed since last review

Validate allowed declaration kinds instead of denying only two

tools/clang/lib/Sema/SemaHLSL.cpp:15394

This denylist does not enforce the proposal's allowed declaration set described above it. ParseCTBuffer parses arbitrary external declarations, so declarations such as typedef int T;, enum E { V };, namespace aliases, using declarations, and static_assert remain accepted in an HLSL 202x buffer because none is an HLSLBufferDecl or NamespaceDecl. Please validate against the proposal's allowed categories (including any permitted template wrappers) rather than only these two forbidden kinds, and add coverage for the other rejected declaration forms. The diagnostic path will also need to handle disallowed declarations that are not NamedDecl.

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The implementation does not enforce the documented declaration allowlist.

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Enforce the full allowlist of permitted declaration kinds · New

Resolved since last review (1)

Add release note for HLSL language behavior change

+    if (getLangOpts().HLSLVersion >= hlsl::LangStd::v202x &&
+        (isa<HLSLBufferDecl>(Field) || isa<NamespaceDecl>(Field))) {


../tools/clang/include/clang/Basic/DiagnosticCommonKinds.td ../tools/clang/include/clang/Basic/DiagnosticGroups.td ../tools/clang/test/DXC/dumpPSV_LinAlgAccumulate.hlsl ../tools/clang/test/DXC/dumpPSV_LinAlgConstructions.hlsl ../tools/clang/test/DXC/dumpPSV_LinAlgMatrixMultiply.hlsl ../tools/clang/test/SemaHLSL/removed-keywords-2026-warnings.hlsl ../tools/clang/test/SemaHLSL/removed-keywords-202x.hlsl

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Enforce the full allowlist of permitted declaration kinds

Copilot AI balanced review requested due to automatic review settings September 21, 2026 03:20

github-project-automation Bot added this to HLSL Roadmap Sep 21, 2026

github-project-automation Bot moved this to New in HLSL Roadmap Sep 21, 2026

Copilot started reviewing on behalf of Chris B (llvm-beanz) September 21, 2026 03:21 View session

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Comment thread tools/clang/lib/Sema/SemaHLSL.cpp Outdated

Comment thread tools/clang/lib/Sema/SemaHLSL.cpp

Fix typo in HLSL 202x proposal comment

e9a25e9

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Finn Plummer (inbelic) approved these changes Sep 21, 2026

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Chris B (llvm-beanz) mentioned this pull request Sep 22, 2026

[202x] Fix nesting cbuffers in namespaces #8943

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Update release notes

19e9faa

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Comment thread tools/clang/lib/Sema/SemaHLSL.cpp

Comment on lines +15393 to +15394

if (getLangOpts().HLSLVersion >= hlsl::LangStd::v202x &&

(isa<HLSLBufferDecl>(Field) || isa<NamespaceDecl>(Field))) {

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[202x][0005] Implement cbuffer contexts - #8935

[202x][0005] Implement cbuffer contexts#8935
Chris B (llvm-beanz) wants to merge 4 commits into
microsoft:mainfrom
llvm-beanz:0005-cbuffer-contexts

Chris B (llvm-beanz) commented Sep 21, 2026 •

edited

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		if (getLangOpts().HLSLVersion >= hlsl::LangStd::v202x &&
		(isa<HLSLBufferDecl>(Field) \|\| isa<NamespaceDecl>(Field))) {

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Chris B (llvm-beanz) commented Sep 21, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Chris B (llvm-beanz) commented Sep 21, 2026 •

edited

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