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[SPIRV] Error for zero-length arrays if not a shader #169732

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Merged
sarnex merged 2 commits into from
Dec 2, 2025
Merged

[SPIRV] Error for zero-length arrays if not a shader #169732

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7c4cc9e
[SPIRV] Error for zero-length arrays if not a shader
sarnex Nov 26, 2025
11f3d9d
address feedback
sarnex Dec 2, 2025
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13 changes: 9 additions & 4 deletions llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -883,10 +883,15 @@ SPIRVType *SPIRVGlobalRegistry::getOpTypeArray(uint32_t NumElems,
.addUse(NumElementsVReg);
});
} else {
assert(ST.isShader() && "Runtime arrays are not allowed in non-shader "
"SPIR-V modules.");
if (!ST.isShader())
return nullptr;
if (!ST.isShader()) {
Function &Fn = MIRBuilder.getMF().getFunction();
Fn.getContext().diagnose(DiagnosticInfoUnsupported(
Fn,
"Runtime arrays are not allowed in non-shader "
"SPIR-V modules",
MIRBuilder.getDebugLoc()));
return ElemType;
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@jmmartinez jmmartinez Nov 27, 2025

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Does diagnose(...) return and continues executing the backend code?

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@sarnex sarnex Dec 1, 2025 •
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Yes, but it properly errors out a bit after this. If we don't do this it still crashes with an error, with this there's just an error. If you know a better way to prevent a crash/assert but still throw an error let me know, I'd prefer that too.

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@maarquitos14 maarquitos14 Dec 2, 2025 •
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Would llvm::report_fatal_error be better then? Reporting the error and immediately aborting seems to me like what you're asking for.

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@jmmartinez jmmartinez Dec 2, 2025

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I'm ok if we use llvm::reportFatalUsageError here (llvm::report_fatal_error is deprecated).

We can revisit having proper diagnostics later.

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@sarnex sarnex Dec 2, 2025

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Thanks for the feedback, I reworked the error to use llvm::reportFatalUsageError in my latest commit

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@maarquitos14 maarquitos14 Nov 27, 2025

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I'm not sure this is what we want to do. The caller of this function is expecting an OpTypeArray, but we will be returning the ElemType in this case. Can you please explain why that is okay? And why is that better than returning nullptr, which signals that something went wrong?

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@sarnex sarnex Dec 1, 2025 •
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Replied to the same comment in Juan's review of this, thanks.

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@sarnex sarnex Dec 2, 2025

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I think this feedback should be addressed in my latest commit

}
ArrayType = createOpType(MIRBuilder, [&](MachineIRBuilder &MIRBuilder) {
return MIRBuilder.buildInstr(SPIRV::OpTypeRuntimeArray)
.addDef(createTypeVReg(MIRBuilder))
Expand Down
10 changes: 8 additions & 2 deletions llvm/test/CodeGen/SPIRV/zero-length-array.ll
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@@ -1,7 +1,9 @@
; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - | FileCheck %s
; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan-compute < %s | FileCheck %s
; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan-compute %s -o - -filetype=obj | spirv-val %}

; Nothing is generated, but compilation doesn't crash.
; RUN: not llc -verify-machineinstrs -O0 -mtriple=spirv64-unknown-unknown < %s 2>&1 | FileCheck -check-prefix=CHECK-ERR %s

; For compute, nothing is generated, but compilation doesn't crash.
; CHECK: OpName %[[#FOO:]] "foo"
; CHECK: OpName %[[#RTM:]] "reg2mem alloca point"
; CHECK: %[[#INT:]] = OpTypeInt 32 0
Expand All @@ -11,6 +13,10 @@
; CHECK-NEXT: OpReturn
; CHECK-NEXT: OpFunctionEnd


; For non-compute, error.
; CHECK-ERR: in function foo void (): Runtime arrays are not allowed in non-shader SPIR-V modules

define spir_func void @foo() {
entry:
%i = alloca [0 x i32], align 4
Expand Down