Pth not supported

[Maeiky]

Include a precompiled header file not work in emscripten :

Generate Pch:
-std=c++11 -m32 -fno-exceptions -O2 -x c++-header xxx.h -o xxx.pch

Compile Obj:
-std=c++11 -m32 -fno-exceptions -O2 -c xxx.cpp -include-pch xxx.pch -o xxx.o

I have this error :
ERROR:root:xxx.pch: Input file has an unknown suffix, don't know what to do with it!

[kripken]

emcc supports precompiled headers with suffix gch, which I thought was the standard gcc suffix, but that might have been wrong?

[Maeiky]

Same error with gch,
gch is for GCC, but emscripten is based on Clang!?

http://clang.llvm.org/docs/UsersManual.html

generate a PCH file using Clang, one invokes Clang with the -x -header option. This mirrors the interface in GCC for generating PCH files:
$ gcc -x c-header test.h -o test.h.gch
$ clang -x c-header test.h -o test.h.pch

http://clang.llvm.org/docs/PCHInternals.html
http://clang.llvm.org/docs/PTHInternals.html

[kripken]

gch is still the default clang emits, if you run clang -x c-header test.h -c (i.e. if you don't tell it the output name).

Looking into this more carefully, the core issue is that we didn't recognize the -include-pch argument. Added support for that, and verified it works with both gch and pch.

[kripken]

The one thing I didn't do is anything with pth files - is that important as well?

[Maeiky]

Yes, for future versions of Clang> = 3.9. This will provide a more flexible precompilation of headers.
Thanks

[kripken]

Ok, reopening for pth.

[froydnj]

I don't know if PTH files are worth supporting. The official clang user's manual doesn't mention PTH files at all, preferring to focus on PCH files instead. (PTH files are mentioned in the in design documents, but nowhere else AFAICS.) The clang driver doesn't recognize -include-pth; that's a cc1 option, so you need to pass it down with -Xclang...but that confuses emcc's extraction of input files. WDYT, @kripken, should we just close this?

[kripken]

Sounds reasonable to close, yeah.

[pouyarb]

hello
built with qmake and mingw 13:
emcc -c -Xclang -include-pch -Xclang wasm\z_token_wasm.js.pch\c.pch -std=c11 -O2 -Wall -Wextra -s ALLOW_MEMORY_GROWTH=1 -Dzf_using_z_token_v4 -Dzf_e_core -Dzf_use_pana_keya -Dzf_using_z_token_v4 -Dzf_using_cipher_lib_v6 -Dzf_custom_hash_exists -Dzf_using_z_token_v4 -DZ_32 -DZ_LIN -D__UNIX__ -Dzf_use_epass -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -I..\z_tokensrc -I. -I....\include -IC:\boost\boost_1_80_0 -I/home/boost/boost_1_80_0/ -I. -I./../Source_other/lib/panakey -IC:\Qt\Qt5.15\5.15.2\wasm_32\include -IC:\Qt\Qt5.15\5.15.2\wasm_32\include\QtNetwork -IC:\Qt\Qt5.15\5.15.2\wasm_32\include\QtCore -I/.emscripten_ports/openssl/include -IC:\Qt\Qt5.15\5.15.2\wasm_32\mkspecs\wasm-emscripten -o wasm\global.obj ..\z_tokensrc\unimate\global.c

i have error:
shared:ERROR: wasm\z_token_wasm.js.pch\c.pch: Input file has an unknown suffix, don't know what to do with it!

[sbc100]

@pouyarb what version of emscripten are you using? The error message you getting looks like it was removed in #10560 (2020).. but the way the error is presented (with shared:ERROR at the start) make it look like this version goes back to before 2017. That error reporting for that message back in #5710 (2017).. so it looks like you are using 1.37.23 or older?

[pouyarb]

Im using version 1.39.7 due to qt requirements. I can not update emscripten

[sbc100]

In that case maybe you could petition the qt folks to update their emscripten requirements, since this issue has already been fixed on the emscripten side.

[pouyarb]

thank you for your help. could you tell me which commit have fixed this issue?

[sbc100]

#10560 looks like a likely candidate since it removes the error in question. For that you would need version 1.40.1 or above. But honestly I wouldn't recommend upgrading to anything other than the very latest release (3.1.42).