[Interest] Linking issues with Angle and Qt 5.12.x

[Federico Buti]

Hi all.

We are facing a quite strange behaviour with qnanopainter
<https://github.com/QUItCoding/qnanopainter>.
Building/running the library and the examples works smoothly on Qt 5.9.8
and no issue is found. I guess everything was fixed there, see for instance
here <https://github.com/QUItCoding/qnanopainter/issues/16#issue-235192684>.

Building the code on 5.12.x results in a similar linker issue as depicted
in the last link. In particular we have a series of undefined references as
shown below:

libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x12b):
undefined reference to `_imp__glDeleteTextures at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1b4):
undefined reference to `glDeleteShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d5):
undefined reference to `glDeleteBuffers at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1e5):
undefined reference to `glDeleteShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f5):
undefined reference to `glDeleteProgram at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x988):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x9a0):
undefined reference to `_imp__glPixelStorei at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x9fc):
undefined reference to `_imp__glTexSubImage2D at 36'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0xa43):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1361):
undefined reference to `_imp__glDeleteTextures at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1388):
undefined reference to `_imp__glGetError at 0'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1407):
undefined reference to `_imp__glGenTextures at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x143a):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1442):
undefined reference to `_imp__glPixelStorei at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x14ae):
undefined reference to `_imp__glTexImage2D at 36'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x14d7):
undefined reference to `_imp__glTexParameteri at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1638):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x16b9):
undefined reference to `glGenerateMipmap at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x16fa):
undefined reference to `_imp__glTexImage2D at 36'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x171a):
undefined reference to `_imp__glTexParameteri at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x17e0):
undefined reference to `glUniform4fv at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1828):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x185f):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x18bb):
undefined reference to `glGetProgramInfoLog at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x192e):
undefined reference to `glGetShaderInfoLog at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x19c9):
undefined reference to `glCreateProgram at 0'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x19d7):
undefined reference to `glCreateShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x19e8):
undefined reference to `glCreateShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1a19):
undefined reference to `glShaderSource at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1a44):
undefined reference to `glShaderSource at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1a4f):
undefined reference to `glCompileShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1a6a):
undefined reference to `glGetShaderiv at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1a94):
undefined reference to `glCompileShader at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1aaf):
undefined reference to `glGetShaderiv at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1adb):
undefined reference to `glAttachShader at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1aea):
undefined reference to `glAttachShader at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1b05):
undefined reference to `glBindAttribLocation at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1b20):
undefined reference to `glBindAttribLocation at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1b2b):
undefined reference to `glLinkProgram at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1b46):
undefined reference to `glGetProgramiv at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1bd9):
undefined reference to `glGetUniformLocation at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1bf1):
undefined reference to `glGetUniformLocation at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1c09):
undefined reference to `glGetUniformLocation at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1c22):
undefined reference to `glGenBuffers at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1c38):
undefined reference to `_imp__glFinish at 0'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d14):
undefined reference to `_imp__glStencilFunc at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d5f):
undefined reference to `glUseProgram at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d64):
undefined reference to `_imp__glEnable at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d86):
undefined reference to `_imp__glCullFace at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1d96):
undefined reference to `_imp__glFrontFace at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1da7):
undefined reference to `_imp__glDisable at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1dca):
undefined reference to `_imp__glColorMask at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1df7):
undefined reference to `_imp__glStencilMask at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1e0c):
undefined reference to `_imp__glStencilOp at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1e4c):
undefined reference to `_imp__glStencilFunc at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1e5b):
undefined reference to `glActiveTexture at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1e60):
undefined reference to `_imp__glBindTexture at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1edf):
undefined reference to `glBindBuffer at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f07):
undefined reference to `glBufferData at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f16):
undefined reference to `glEnableVertexAttribArray at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f25):
undefined reference to `glEnableVertexAttribArray at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f5c):
undefined reference to `glVertexAttribPointer at 24'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1f93):
undefined reference to `glVertexAttribPointer at 24'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1fa9):
undefined reference to `glUniform1i at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1fc6):
undefined reference to `glUniform4fv at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x1fce):
undefined reference to `_imp__glDrawArrays at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2085):
undefined reference to `glBlendFuncSeparate at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2141):
undefined reference to `glStencilOpSeparate at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2168):
undefined reference to `glStencilOpSeparate at 16'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x217f):
undefined reference to `_imp__glDrawArrays at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2289):
undefined reference to `glDisableVertexAttribArray at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2298):
undefined reference to `glDisableVertexAttribArray at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x22bd):
undefined reference to `glBindBuffer at 8'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x22cc):
undefined reference to `glUseProgram at 4'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2374):
undefined reference to `_imp__glDrawArrays at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x249e):
undefined reference to `_imp__glDrawArrays at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2532):
undefined reference to `_imp__glDrawArrays at 12'
libqnanopainter.a(qnanobackendgles2.cpp.o):qnanobackendgles2.cpp:(.text+0x2843):
undefined reference to `_imp__glDrawArrays at 12'

When we substituted the "liblibGLESv2.a" from Qt 5.12 with the one from 5.9
- just to do a wild test - compilation succeeded but then we had a runtime
failure which was totally expected.

The very same series of undefined references are also spotted while
cross-compiling with MXE and a patched Qt version to have dynamic selection
of the GL backend.

What is exactly happening here? How can we proceed? What's the best way to
use angle when cross-compiling Qt, e.g. with MXE?

Thanks in advance,
F.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20190525/ae77b863/attachment.html>