questions about --compilation_mode

[haodah...@gmail.com]

Hello everyone:

I see that bazel has three compilation modes: fastbuild, opt and dbg.
When I want to have a binary that contains debug information, I choose dbg, when I want to generate a binary for release, I choose opt, so when should fastbuild be used?

And more specifically, what options are they using to build my C++ projects.

And is there any options like RelWithDebInfo, with which I don't need to worry about performance issue and also have debug information written in binaries for testing.

Thanks in advance.

[Thiago Farina]

On Wednesday, August 3, 2016, <haodah...@gmail.com> wrote:

Hello everyone:

I see that bazel has three compilation modes: fastbuild, opt and dbg.
When I want to have a binary that contains debug information, I choose dbg, when I want to generate a binary for release, I choose opt, so when should fastbuild be used?

fastbuild is the default.

 

And more specifically, what options are they using to build my C++ projects.

I think they are in https://github.com/bazelbuild/bazel/blob/master/tools/cpp/CROSSTOOL

And you can probably see what it is doing by passing -s flag (--subcommands) to build command.

--

Thiago Farina

[Brian Silverman]

On Wed, Aug 3, 2016 at 9:37 AM, Thiago Farina <tfa...@chromium.org> wrote:

On Wednesday, August 3, 2016, <haodah...@gmail.com> wrote:

Hello everyone:

I see that bazel has three compilation modes: fastbuild, opt and dbg.
When I want to have a binary that contains debug information, I choose dbg, when I want to generate a binary for release, I choose opt, so when should fastbuild be used?

fastbuild is the default.

 

As far as why it exists, it's intended to build quickly. When the slowest part of your compile-test iteration is compiling (which it often is for C++), making the compiler faster by not dealing with debug information etc is helpful.

[haodah...@gmail.com]

在 2016年8月4日星期四 UTC+8上午12:37:39，Thiago Farina写道：

Yeah, I can see. So there is no things like RelWithDebInfo?
Currently, my solution is: bazel build *** -c dbg --copt=-O3