[202x][0004] Disallow ignored initializers by llvm-beanz · Pull Request #8985 · microsoft/DirectXShaderCompiler

Chris B (llvm-beanz) · 2026-09-30T00:24:39Z

This PR does two things: first it refactors the existing warning on ignored global initializers to move the general case (implicit cbuffer & groupshared) into Sema from the DXIL & SPIRV codegen layers. This generalization fixes issues where the warning wasn't firing, and expands it to all cbuffer members.

Second, this PR turns that warning into an error in HLSL 202x+.

Resolves #8483

This PR does two things: first it refactors the existing warning on ignored global initializers to move the general case (implicit cbuffer) into Sema from the DXIL & SPIRV codegen layers. This generalization fixes issues where the warning wasn't firing, and expands it to all cbuffer members. Second, this PR turns that warning into an error in HLSL 202x+. Resolves microsoft#8483

Copilot

Copilot review overview

🔵 Needs a closer look

Moving diagnostics across semantic analysis and both backends leaves a DXIL groupshared-initializer warning gap that needs correction and human validation.

Review effort: Balanced
Findings: 1

Open (1)

Restore DXIL warning for ignored groupshared initializers · New

What changed in this PR

This PR moves ignored buffer-initializer diagnostics into HLSL semantic analysis and makes initializers on shader constants an error in HLSL 202x, addressing #8483.

Changes:

Adds version-dependent diagnostics for explicit buffers and implicit $Globals, with a suppressible warning in older versions.
Removes overlapping DXIL and SPIR-V warnings and updates regression tests.
Documents the HLSL 202x change in the release notes.

File	Description
`tools/clang/test/SemaHLSL/vector-syntax.hlsl`	Expects global-initializer warnings.
`tools/clang/test/SemaHLSL/vector-syntax-exact-precision.hlsl`	Expects warnings with exact precision.
`tools/clang/test/SemaHLSL/varmods-syntax.hlsl`	Updates modifier diagnostic expectations.
`tools/clang/test/SemaHLSL/v2021-static-assert-not-keyword.hlsl`	Keeps the test global outside `$Globals`.
`tools/clang/test/SemaHLSL/typemods-syntax.hlsl`	Expects explicit-buffer warnings.
`tools/clang/test/SemaHLSL/subobjects-syntax.hlsl`	Expects warnings for two globals.
`tools/clang/test/SemaHLSL/removed-keywords-202x.hlsl`	Keeps keyword-test globals outside `$Globals`.
`tools/clang/test/SemaHLSL/rayquery-omm-diag-TU-export-sm65.hlsl`	Expects the new global warning.
`tools/clang/test/SemaHLSL/hlsl/buffer-initializers-pre202x.hlsl`	Tests warnings before 202x.
`tools/clang/test/SemaHLSL/hlsl/buffer-initializers-nowarn.hlsl`	Tests warning suppression.
`tools/clang/test/SemaHLSL/hlsl/buffer-initializers-202x.hlsl`	Tests 202x errors.
`tools/clang/test/HLSLFileCheckLit/hlsl/auto/auto-no-reference.hlsl`	Keeps the test global outside `$Globals`.
`tools/clang/test/HLSL/rewriter/varmods-syntax_noerr.hlsl`	Updates rewriter-test warnings.
`tools/clang/test/HLSL/rewriter/typemods-syntax_noerr.hlsl`	Updates buffer-member warnings.
`tools/clang/test/HLSL/rewriter/cpp-errors_noerr.hlsl`	Expects global-initializer warnings.
`tools/clang/test/HLSL/cpp-errors.hlsl`	Expects global-initializer warnings.
`tools/clang/test/HLSL/cpp-errors-hv2015.hlsl`	Suppresses unrelated warnings.
`tools/clang/test/CodeGenSPIRV/var.init.warning.ignored.hlsl`	Suppresses the new warning in a codegen test.
`tools/clang/test/CodeGenSPIRV/var.init.tbuffer.hlsl`	Verifies tbuffer diagnostics.
`tools/clang/test/CodeGenSPIRV/var.init.cbuffer.hlsl`	Verifies cbuffer diagnostics.
`tools/clang/test/CodeGenSPIRV/var.globals.error.hlsl`	Updates expected diagnostics.
`tools/clang/test/CodeGenSPIRV/implicit.global.ubo.hlsl`	Checks compilation under both language modes.
`tools/clang/test/CodeGenSPIRV/groupshared.init.warning.hlsl`	Updates the SPIR-V groupshared warning.
`tools/clang/lib/SPIRV/SpirvEmitter.cpp`	Removes buffer warnings; retains a groupshared warning.
`tools/clang/lib/SPIRV/DeclResultIdMapper.cpp`	Removes the `$Globals` warning.
`tools/clang/lib/Sema/SemaDecl.cpp`	Diagnoses buffer initializers by language version.
`tools/clang/lib/CodeGen/CodeGenModule.cpp`	Removes DXIL global-initializer warnings.
`tools/clang/include/clang/Basic/DiagnosticSemaKinds.td`	Defines the warning and error messages.
`tools/clang/include/clang/Basic/DiagnosticGroups.td`	Adds a warning-suppression group.
`docs/ReleaseNotes.md`	Records the HLSL 202x change.

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Copilot

Copilot review overview

🔵 Needs a closer look

The cross-backend diagnostic change warrants final human validation despite focused test coverage.

Review effort: Balanced
Findings: 1

Open (1)

Restore DXIL warning for ignored groupshared initializers

Copilot

Copilot review overview

🔵 Needs a closer look

The diagnostic move changes compiler behavior across semantic analysis and two backends, so final human validation is warranted.

Review effort: Balanced
Findings: None

Resolved since last review (1)

Restore DXIL warning for ignored groupshared initializers

Copilot

Copilot review overview

🟡 Changes recommended

A rewriter verification test still has unaccounted-for groupshared warnings and will fail.

Review effort: Balanced
Findings: 1 · 1

Open (2)

Suppress unexpected groupshared initializer warnings in rewriter test · New
Document new initializer warnings for earlier HLSL versions · New

Helena Kotas (hekota)

LGTM!

../tools/clang/test/CodeGenSPIRV/var.init.cbuffer.hlsl

Copilot

Copilot review overview

🟢 Approval recommended

The centralized diagnostics match the intended versioned behavior and are covered across DXIL, SPIR-V, warning suppression, and buffer variants.

Review effort: Balanced
Findings: None

Resolved since last review (2)

Suppress unexpected groupshared initializer warnings in rewriter test
Document new initializer warnings for earlier HLSL versions

Sarah Spall (spall) · 2026-10-06T16:52:12Z

-
-// CHECK: warning: Initializer of external global will be ignored
-// CHECK-NEXT: groupshared uint testing = 0;
+}


../tools/clang/test/CodeGenSPIRV/groupshared.init.warning.hlsl

Copilot

Copilot review overview

🔵 Needs a closer look

The diagnostic migration misses mixed aggregates and removes the warning for ignored SPIR-V resource initializers.

Review effort: Balanced
Findings: None

Previously missed (2)

In code that hasn't changed since last review

Retain warnings for ignored external resource initializers

tools/clang/lib/SPIRV/SpirvEmitter.cpp:2191

Removing this warning also silences ignored external resource initializers, which the new Sema checks exclude. For example, when Texture2D a; Texture2D b = a; is emitted for SPIR-V, createExternVar(b) still creates an independent resource rather than evaluating the initializer, but now gives no warning. Retain the backend warning for resource and resource-only aggregate initializers, while leaving the buffer and groupshared diagnostics to Sema. Add a codegen diagnostic regression for this case.

Handle mixed resource and numeric globals in initializer diagnostics

tools/clang/lib/Sema/SemaDecl.cpp:87

This numeric-only predicate excludes global structs containing both resource and numeric fields. DXIL still places their numeric fields in $Globals, as covered by tools/clang/test/HLSLFileCheck/hlsl/resource_binding/resource_in_cbuffer2.hlsl, and CodeGenModule.cpp still discards their initializers. An initialized mixed aggregate therefore misses both the warning in older language modes and the required HLSL 202x error now that the backend warning is removed. Classify mixed aggregates according to their constant-buffer storage, and add regression coverage for both language modes.

Copilot AI balanced review requested due to automatic review settings September 30, 2026 00:24

github-project-automation Bot added this to HLSL Roadmap Sep 30, 2026

github-project-automation Bot moved this to New in HLSL Roadmap Sep 30, 2026

Copilot started reviewing on behalf of Chris B (llvm-beanz) September 30, 2026 00:25 View session

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

clang-format

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respond to feedback

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Missed updating these tests

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Comment thread tools/clang/test/HLSL/rewriter/varmods-syntax_noerr.hlsl

Comment thread docs/ReleaseNotes.md

Helena Kotas (hekota) approved these changes Sep 30, 2026

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Comment thread tools/clang/test/CodeGenSPIRV/var.init.cbuffer.hlsl Outdated

missing newline

3e4b2ad

../tools/clang/test/CodeGenSPIRV/var.init.cbuffer.hlsl

Copilot AI balanced review requested due to automatic review settings October 1, 2026 02:43

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Chris B (llvm-beanz) changed the title ~~[202x][0004] Disallow initializers on cbuffer members~~ [202x][0004] Disallow initializers ignored initializers Oct 6, 2026

Chris B (llvm-beanz) changed the title ~~[202x][0004] Disallow initializers ignored initializers~~ [202x][0004] Disallow ignored initializers Oct 6, 2026

Sarah Spall (spall) approved these changes Oct 6, 2026

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Missing newline

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../tools/clang/test/CodeGenSPIRV/groupshared.init.warning.hlsl

Copilot AI balanced review requested due to automatic review settings October 6, 2026 19:33

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Chris B (llvm-beanz) enabled auto-merge (squash) October 6, 2026 20:42

Chris B (llvm-beanz) merged commit dba1207 into microsoft:main Oct 6, 2026
12 checks passed

Chris B (llvm-beanz) deleted the cbuffer-initializers branch October 6, 2026 21:19

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[202x][0004] Disallow ignored initializers - #8985

[202x][0004] Disallow ignored initializers#8985
Chris B (llvm-beanz) merged 6 commits into
microsoft:mainfrom
llvm-beanz:cbuffer-initializers

Chris B (llvm-beanz) commented Sep 30, 2026 •

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Chris B (llvm-beanz) commented Sep 30, 2026 •

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