How can I overwrite the cflags/cxxflags (rtti and exceptions) in my module? (gn build system)

[Samuel Yang]

Hi, 

I have my own module and have a BUILD.gn , I have added the flags as below. However, there are still  -fno-rtti and -fno-exceptions after -frtti and -fexceptions in the compile log.  

How can I just enable rtti and exception in my module but disable rtti and exceptions the others in chromium(It already did)?  Great thanks.  

   cflags = [

    "-fexceptions",

    "-frtti",

    ]

   cflags_cc = [

    "-fexceptions",

    "-frtti",

    ]

 

 

[Thiago Farina]

In your BUILD.gn try doing:

configs -= [ "//build/config/gcc:no_exceptions" ]

--

Thiago Farina

[Thiago Farina]

For rtti:

  configs -= [ "//build/config/compiler:no_rtti" ] 

configs += [ "//build/config/compiler:rtti" ]

 

Example: https://cs.chromium.org/chromium/src/gpu/khronos_glcts_support/BUILD.gn?q=no_exceptions&sq=package:chromium&l=272&dr=C

--

Thiago Farina

[Samuel Yang]

Thank you. It works. 

在 2016年10月20日星期四 UTC+8下午7:08:13，Thiago Farina写道：

[Samuel Yang]

Is it possible that I only want to particular files enable rtti but not the whole module? 

在 2016年10月20日星期四 UTC+8下午7:08:13，Thiago Farina写道：

[Krzysztof Olczyk]

You may put them in the separate source_set-s.

-- 

Best regards,

Krzysztof Olczyk

Software Developer & Architect

TVSDK Core team

Opera TV

Pl. Teatralny 8, 50-051 Wroclaw, Poland

--
--
Chromium Developers mailing list: chromi...@chromium.org
View archives, change email options, or unsubscribe:
http://groups.google.com/a/chromium.org/group/chromium-dev
---
You received this message because you are subscribed to the Google Groups "Chromium-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chromium-dev+unsubscribe@chromium.org.

[unclerun...@gmail.com]

You can modify src/build/config/compiler/BUILD.gn by adding a declare_args :

declare_args(){

     ...

     use_rtti = false

     use_exceptions = false

     ...

}

set to false by default. 

In the same file, add a switch to config("no_rtti")  and config("no_exceptions"): 

config("no_rtti") {

if (!use_rtti) {

if (is_win) {

cflags_cc = [ "/GR-" ]

} else {

cflags_cc = [ "-fno-rtti" ]

cflags_objcc = cflags_cc

}

}

}

config("no_exceptions") {

if (!use_exceptions){

if (is_win) {

# Disables exceptions in the STL.

# libc++ uses the __has_feature macro to control whether to use exceptions,

# so defining this macro is unnecessary. Defining _HAS_EXCEPTIONS to 0 also

# breaks libc++ because it depends on MSVC headers that only provide certain

# declarations if _HAS_EXCEPTIONS is 1. Those MSVC headers do not use

# exceptions, despite being conditional on _HAS_EXCEPTIONS.

if (!use_custom_libcxx) {

defines = [ "_HAS_EXCEPTIONS=0" ]

}

} else {

cflags_cc = [ "-fno-exceptions" ]

cflags_objcc = cflags_cc

}

}

}

Then run gn gen with agrs:

gn gen out/default --args='use_rtti=true use_exceptions=true'

在 2016年10月20日星期四 UTC+8下午4:44:17，Samuel Yang写道：

[David Turner]

What you propose would turn on exceptions and RTTI for _all_ code compiled, which is not desirable, nor what the initial question was about.

An answer closer to being correct would be to remove the "no_rtti" and "no_exceptions"  configs the specific module, and replace them with "rtti" and "exceptions", e.g. something like:

source_set("foo_module") {

  sources = [ ... ]
  ...

  configs -= [ "//build/config/compiler:no_rtti" ]

  configs += [ "//build/config/compiler:rtti" ]

  configs -= [ "//build/config/compiler:no_exceptions" ]
  configs += [ "//build/config/compiler:exceptions" ]

}

--
--
Chromium Developers mailing list: chromi...@chromium.org
View archives, change email options, or unsubscribe:
http://groups.google.com/a/chromium.org/group/chromium-dev
---
You received this message because you are subscribed to the Google Groups "Chromium-dev" group.

To unsubscribe from this group and stop receiving emails from it, send an email to chromium-dev...@chromium.org.
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/494ebd19-0cb2-4087-af39-385d059a42af%40chromium.org.