skia2/tests/sksl/inliner/InlinerAvoidsVariableNameOverlap.glsl


out vec4 sk_FragColor;
in vec2 x;
vec4 main() {
    vec2 _1_reusedName = x + vec2(1.0, 2.0);
    vec2 _2_reusedName = _1_reusedName + vec2(3.0, 4.0);

    return _2_reusedName.xyxy;

}
Demonstrate name reuse error in inliner. The following conditions lead to the error: - A pair of nested functions, both of which must be inlined. - Both inlined functions create a variable with the same name. - The outer function passes its variable to the inner function. - The initialization of the inner variable uses the value from the outer variable. - The inner function does not mutate the variable, use it as an out- parameter, or otherwise cause it to receive a temporary copy. When all these conditions are met, both variable declarations are inlined as-is without performing any name salting, because it's seemingly safe to do so. The name overlap issue is not considered in the safety checks. Inlined variable declarations are not subject to name salting but they should be; I suspect other adversarial examples could be crafted as well where unhandled name overlap leads to errors. Change-Id: Ia754bee8e45c8a5c7548436594bbf04abc7a8396 Bug: skia:10722 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/316945 Reviewed-by: Brian Osman <brianosman@google.com> Commit-Queue: Brian Osman <brianosman@google.com> Auto-Submit: John Stiles <johnstiles@google.com> 2020-09-14 22:23:54 +00:00
Support half4 return values from main() in the SPIR-V code generator. This creates a helper function, _entrypoint, which invokes main() and assigns its result into sk_FragColor. We also make sure to prevent sk_FragColor from being dead-stripped from the code during IR generation. At present this is useful for allowing our SkSL test shaders to compile. Change-Id: I2d7fab0e1959a77778ffdb18ca569e869bcaeece Reviewed-on: https://skia-review.googlesource.com/c/skia/+/358525 Commit-Queue: John Stiles <johnstiles@google.com> Reviewed-by: Brian Osman <brianosman@google.com> 2021-01-27 00:58:22 +00:00			`out vec4 sk_FragColor;`
Align default values of GrShaderCaps with StandaloneShaderCaps. `fBuiltinFMASupport` is now true on both, and `fUsesPrecisionModifiers` is now false. Other mismatching flags exist, but they are non-trivial to synchronize as they are tied to extension strings. This will help our skslc-based unit tests generate the same results as our C++ unit tests did, but should not affect real-world results as these defaults will all be overwritten in a non-testing scenario. In practice, the `fUsesPrecisionModifiers` change is responsible for all of the diffs below. The other flags did not change the results of any of the currently-ported tests. Change-Id: Ieb056d852b027fa87c56fd89f971a77a10a8a124 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/317204 Commit-Queue: John Stiles <johnstiles@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Auto-Submit: John Stiles <johnstiles@google.com> 2020-09-15 20:09:11 +00:00			`in vec2 x;`
			`vec4 main() {`
Avoid generating unused variables in the Inliner. These variables were later being eliminated by the dead-code-elimination pass, so you can't see them directly in the final output, but removing them affects the name mangling off all future symbols, so it causes an enormous ripple effect in the diff. And of course, it's a waste of time and memory to synthesize IRNodes just to destroy them later. If we disable control-flow analysis, we lose the dead-code-elimination pass entirely; this change is also beneficial for emitting better code when optimizations are turned off. Change-Id: I882b3be4f3fd99b77d99b6abe128f26bb9252c89 Bug: skia:11319 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/375776 Commit-Queue: John Stiles <johnstiles@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Reviewed-by: Ethan Nicholas <ethannicholas@google.com> 2021-02-25 16:17:02 +00:00			`vec2 _1_reusedName = x + vec2(1.0, 2.0);`
			`vec2 _2_reusedName = _1_reusedName + vec2(3.0, 4.0);`
Avoid creating unnecessary scopes during inlining. The additional scopes were harmless, but didn't really add any value. Originally they were used to tightly scope inlined variables, but we now mangle inlined variable names. Change-Id: I7b35e737598036c0b6d3d9f71cbcd4a53d609ce9 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/344757 Auto-Submit: John Stiles <johnstiles@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Commit-Queue: John Stiles <johnstiles@google.com> 2020-12-15 20:21:03 +00:00
Avoid generating unused variables in the Inliner. These variables were later being eliminated by the dead-code-elimination pass, so you can't see them directly in the final output, but removing them affects the name mangling off all future symbols, so it causes an enormous ripple effect in the diff. And of course, it's a waste of time and memory to synthesize IRNodes just to destroy them later. If we disable control-flow analysis, we lose the dead-code-elimination pass entirely; this change is also beneficial for emitting better code when optimizations are turned off. Change-Id: I882b3be4f3fd99b77d99b6abe128f26bb9252c89 Bug: skia:11319 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/375776 Commit-Queue: John Stiles <johnstiles@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Reviewed-by: Ethan Nicholas <ethannicholas@google.com> 2021-02-25 16:17:02 +00:00			`return _2_reusedName.xyxy;`
Demonstrate name reuse error in inliner. The following conditions lead to the error: - A pair of nested functions, both of which must be inlined. - Both inlined functions create a variable with the same name. - The outer function passes its variable to the inner function. - The initialization of the inner variable uses the value from the outer variable. - The inner function does not mutate the variable, use it as an out- parameter, or otherwise cause it to receive a temporary copy. When all these conditions are met, both variable declarations are inlined as-is without performing any name salting, because it's seemingly safe to do so. The name overlap issue is not considered in the safety checks. Inlined variable declarations are not subject to name salting but they should be; I suspect other adversarial examples could be crafted as well where unhandled name overlap leads to errors. Change-Id: Ia754bee8e45c8a5c7548436594bbf04abc7a8396 Bug: skia:10722 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/316945 Reviewed-by: Brian Osman <brianosman@google.com> Commit-Queue: Brian Osman <brianosman@google.com> Auto-Submit: John Stiles <johnstiles@google.com> 2020-09-14 22:23:54 +00:00
			`}`