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Fix struct_padding required size to include trailing padding #4613

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Merged
shaoboyan091 merged 4 commits into from
Mar 17, 2026
Merged

Fix struct_padding required size to include trailing padding #4613

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7c75438
Fix struct_padding required size to include trailing padding
shaoboyan091 Mar 16, 2026
368eb05
Fix trailing bytes but ensure setImmediates doesn't count it
shaoboyan091 Mar 17, 2026
47aec92
Be more accurate for overprovision cases
shaoboyan091 Mar 17, 2026
09c2a97
Merge branch 'main' into immediate-cts-change
shaoboyan091 Mar 17, 2026
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30 changes: 21 additions & 9 deletions src/webgpu/api/validation/encoding/programmable/pipeline_immediate.spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,8 @@ g.test('required_slots_set')
const { encoderType, scenario, usage, stage } = t.params;

let code = '';
let kRequiredSize = 0;
let layoutImmediateSize = 0;
let trailingPaddingBytes = 0;

const use_vertex = stage === 'vertex' || stage === 'both';
const use_fragment = stage === 'fragment' || stage === 'both';
Expand All @@ -117,17 +118,18 @@ g.test('required_slots_set')

switch (scenario) {
case 'scalar':
kRequiredSize = 4;
layoutImmediateSize = 4;
declarations = 'var<immediate> data: u32;';
helpers = 'fn use_data() { _ = data; }';
break;
case 'vector':
kRequiredSize = 16;
layoutImmediateSize = 16;
declarations = 'var<immediate> data: vec4<u32>;';
helpers = 'fn use_data() { _ = data; }';
break;
case 'struct_padding':
kRequiredSize = 40;
layoutImmediateSize = 64;
trailingPaddingBytes = 24;
declarations = `
struct A { v: vec3<u32> }
struct B { v: vec2<u32> }
Expand All @@ -141,7 +143,7 @@ g.test('required_slots_set')
callFragment = 'use_b();';
break;
case 'mixed_types':
kRequiredSize = 32;
layoutImmediateSize = 32;
declarations = `
struct Mixed { v: u32, f: vec4<u32> }
var<immediate> data: Mixed;`;
Expand All @@ -153,7 +155,7 @@ g.test('required_slots_set')
callFragment = 'use_f();';
break;
case 'dynamic_indexing':
kRequiredSize = 16;
layoutImmediateSize = 16;
declarations = 'var<immediate> data: array<u32, 4>;';
helpers = 'fn use_data(i: u32) { _ = data[i]; }';
computeArgs = '@builtin(local_invocation_index) i: u32';
Expand All @@ -165,7 +167,7 @@ g.test('required_slots_set')
callFragment = 'use_data(i);';
break;
case 'multiple_variables':
kRequiredSize = 32;
layoutImmediateSize = 32;
declarations = `
struct S1 { a: u32, x: u32 }
struct S2 { a: u32, y: vec4<u32> }
Expand Down Expand Up @@ -197,7 +199,14 @@ g.test('required_slots_set')
}
`;

const layoutSize = usage === 'overprovision' ? kRequiredSize + 4 : kRequiredSize;
const kRequiredSize = layoutImmediateSize - trailingPaddingBytes;
// When overprovisioning: if the struct already has trailing padding, the layout
// size is already larger than what the shader uses, so no extra bytes are needed.
// Only when there's no trailing padding do we need to increase the layout size.
const layoutSize =
usage === 'overprovision' && trailingPaddingBytes === 0
? layoutImmediateSize + 4
: layoutImmediateSize;
if (layoutSize > t.device.limits.maxImmediateSize!) {
t.skip('maxImmediateSize not large enough for overprovision test');
}
Expand All @@ -210,7 +219,10 @@ g.test('required_slots_set')
};

if (usage === 'overprovision') {
setImmediates(0, kRequiredSize + 4);
// When trailingPaddingBytes > 0, the layout already overprovisions beyond
// shader usage, so set the full layoutImmediateSize. When trailingPaddingBytes
// is 0, we added +4 to the layout, so set kRequiredSize + 4.
setImmediates(0, trailingPaddingBytes > 0 ? layoutImmediateSize : kRequiredSize + 4);
} else if (usage === 'full') {
setImmediates(0, kRequiredSize);
} else if (usage === 'partial') {
Expand Down
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