Loading trivial tesc shader crashes nv ogl driver

seanbax · August 12, 2020, 2:09pm

gist.github.com

https://gist.github.com/seanbaxter/43f0bb087692e42f4f884fb371c8a786

Terminal

$ glslc --target-env=opengl --target-spv=spv1.5 -o vert.spv vert.vert
$ glslc --target-env=opengl --target-spv=spv1.5 -o tesc.spv tesc.tesc
$ spirv-link vert.spv tesc.spv -o program.spv
$ clang++-9 segfault.cxx -lGL -lgl3w -lsfml-system -lsfml-window -lsfml-graphics -o segfault
$ ./segfault  
Loaded spv: 1908 bytes
spv loaded

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff1dc7a54 in ?? () from /usr/lib/x86_64-linux-gnu/libnvidia-glcore.so.450.57

program.spvasm

; SPIR-V
; Version: 1.5
; Generator: Khronos; 17
; Bound: 57
; Schema: 0
               OpCapability Shader
               OpCapability Tessellation
          %1 = OpExtInstImport "GLSL.std.450"
               OpMemoryModel Logical GLSL450
               OpEntryPoint Vertex %main "main" %_ %gl_VertexID %gl_InstanceID

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segfault.cxx

#include <gl3w/GL/gl3w.h>
#include <SFML/Graphics.hpp>

void debug_callback(GLenum source, GLenum type, GLuint id, GLenum severity,
  GLsizei length, const GLchar* message, const void* user_param) {
  printf("GOT DEBUG CALLBACK: %s\n", message);
  exit(1);
}

std::vector<char> load_file(const char* name) {

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I whittled a crash case down to two totally trivial shaders. When in the same spv module, the nv driver crashes in glSpecializeShader.

Anyone clue me in on what I’m doing wrong? Hard to believe something this simple is an actual driver bug. I’ve mucked around with the shader a great deal, and the presence of the second degree OpAccessChain to tesc’s gl_out is what crashes it. I.e., gl_out[gl_InvocationID].Position causes the crash, but gl_out[gl_InvocationID] does not.