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Fix uninitialized use of TIntermediate::resource (#2424)

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TIntermediate was constructed without initializing any of the `resources` fields,
and `TProgram::linkStage()` was not calling `TIntermediate::setLimits()`
after constructing new `TIntermediate`s for non-first stages.

Fields of `resources` were then read in `TIntermediate::finalCheck()`
triggering undefined behavior.

This CL makes three changes:
(1) `TIntermediate::setLimits()` is now called for non-first stages by
    copying the `firstIntermediate`'s limits. This ensures that the
    `resources` fields is initialized, fixing the bug.
(2) `TIntermediate::resources` is now wrapped in a `MustBeAssigned<>`
    helper struct, asserting in non-release builds that this field is
    always initialized before reading.
(3) `TIntermediate::resources` is now zero-initialized, so that if
    the `TIntermediate::resources` field is not set in a release build
    (and so the `assert()` will be disabled) behavior is still
    deterministic.

Fixes #2423
This commit is contained in:
Ben Clayton 2020-10-19 22:21:12 +01:00 • committed by GitHub
parent f4f1d8a352
commit 5b99b448b3
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 23 additions and 4 deletions
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4
glslang/MachineIndependent/linkValidate.cpp
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@ -736,10 +736,10 @@ void TIntermediate::finalCheck(TInfoSink& infoSink, bool keepUncalled)
// "The resulting stride (implicit or explicit), when divided by 4, must be less than or equal to the
// implementation-dependent constant gl_MaxTransformFeedbackInterleavedComponents."
if (xfbBuffers[b].stride > (unsigned int)(4 * resources.maxTransformFeedbackInterleavedComponents)) {
if (xfbBuffers[b].stride > (unsigned int)(4 * resources->maxTransformFeedbackInterleavedComponents)) {
error(infoSink, "xfb_stride is too large:");
infoSink.info.prefix(EPrefixError);
infoSink.info << " xfb_buffer " << (unsigned int)b << ", components (1/4 stride) needed are " << xfbBuffers[b].stride/4 << ", gl_MaxTransformFeedbackInterleavedComponents is " << resources.maxTransformFeedbackInterleavedComponents << "\n";
infoSink.info << " xfb_buffer " << (unsigned int)b << ", components (1/4 stride) needed are " << xfbBuffers[b].stride/4 << ", gl_MaxTransformFeedbackInterleavedComponents is " << resources->maxTransformFeedbackInterleavedComponents << "\n";
}
}