Crash when function named in patchconstantfun does not exist

[petrsm]

Compiling the attached shader with latest released DXC compiler causes crash.

Steps to Reproduce:

godbolt repro: https://godbolt.org/z/c9MKcP5ae

Please download attached shader file and compile with following command line:

dxc.exe -Wno-misplaced-attributes -flegacy-resource-reservation -Zi -Qembed_debug -D NX_IS_DXC_COMPILER /D "NX_GPU_TARGET_SHADER_MODEL=NX_SHADER_MODEL6" -T lib_6_6 /O3 /D NX_GPU_TARGET shaders_r2_dx12.txt

Actual Behavior:
"Internal compiler error: access violation. Attempted to read from address 0x0000000000000028"

shaders_r2_dx12.txt

Environment

• DXC version : dxcompiler.dll: 1.9 - 1.8.2505.32 (b106a96); dxil.dll: 1.9(1.8.2505.32)
• Host Operating System : Windows 10 Pro, 22H2

[noahwhygodwhy]

simpler repro-ing case i think?

https://godbolt.org/z/c9MKcP5ae

(@petrsm if you give them 26000 lines of complicated shader you're unlikely to get a solution lmao)

[petrsm]

@noahwhygodwhy apparently you have no clue how bug like this is solved. You just let the compiler compile attached shader under debugger and look at the callstack when it crashes.

[llvm-beanz]

simpler repro-ing case i think?

https://godbolt.org/z/c9MKcP5ae

(@petrsm if you give them 26000 lines of complicated shader you're unlikely to get a solution lmao)

Thank you! This is extremely helpful.

[V-FEXrt]

@noahwhygodwhy apparently you have no clue how bug like this is solved. You just let the compiler compile attached shader under debugger and look at the callstack when it crashes.

Please keep communication kind and focused on the technical issues.

[qtow]

Seems like using the patchconstantfunc attribute with the name of a function that doesn't exist causes the crash. In @petrsm's original shader, that attribute on HS_DepthOnly_PNTris specifies a function named HSConst_DepthOnly_PNTris, while what I assume is the intended function is actually named HSConst_DepthOnly_PNtris (notice the lowercase "t" near the end). @noahwhygodwhy's smaller repro omits the latter function entirely, and so crashes for the same reason.