Restore -O3 default when we build with clang

[jeremy]

When we set the -Wno-error=shorten-64-to-32 cflags, Ruby says "oh, someone set cflags, I won't set any" and we lose its default -O3. That kills 1.9.3 and 2.0.0 perf.

Since clang can only build 1.9/2.0, we can safely assume that if we're adding the -Wno-error flag, we should also provide -O3 (-O2 is default for 1.8).

We set -O3 first since later -O options take precedence, so you can override with RUBY_CFLAGS="-Os" ...

[sstephenson]

😁

[mroth]

This is great! Could we please get a more recent v release version tag of the repository that contains it?

[rubemz]

+1

[sferik]

Tagged: https://github.com/sstephenson/ruby-build/tree/v20130501

[mroth]

@sferik excellent, thanks!

[SamSaffron]

I just grabbed source and did a 2.0.0-p0 install, ran my test suite and it half a minute slower than it is on a manual install of 2.0.0-p0

[jeremy]

@SamSaffron did you diagnose why?

[SamSaffron]

not yet ... need to read through the logs, which means I need to reinstall

[jeremy]

@SamSaffron you can check RbConfig::CONFIG['CC'] for your compiler and RbConfig::CONFIG['CFLAGS'] for -O3

[SamSaffron]

I am seeing:

config.status: creating Makefile
config.status: creating ruby-2.0.pc
CC = gcc
LD = ld
LDSHARED = gcc -shared
CFLAGS =
XCFLAGS = -include ruby/config.h -include ruby/missing.h -D_FORTIFY_SOURCE=2 -fstack-protector -fno-strict-overflow -fvisibility=hidden -DRUBY_EXPORT -fPIE
CPPFLAGS = -I'/home/sam/.rbenv/versions/2.0.0-p0/include' -I. -I.ext/include/x86_64-linux -I./include -I.
DLDFLAGS = -fstack-protector -pie
SOLIBS =

something that is probably not that good.

where do I look up RbConfig::CONFIG['CFLAGS'] ?

[jeremy]

That's Ruby code 😁

On Sunday, May 5, 2013, Sam wrote:

I am seeing:

config.status: creating Makefile
config.status: creating ruby-2.0.pc
CC = gcc
LD = ld
LDSHARED = gcc -shared
CFLAGS =
XCFLAGS = -include ruby/config.h -include ruby/missing.h
-D_FORTIFY_SOURCE=2 -fstack-protector -fno-strict-overflow
-fvisibility=hidden -DRUBY_EXPORT -fPIE
CPPFLAGS = -I'/home/sam/.rbenv/versions/2.0.0-p0/include' -I.
-I.ext/include/x86_64-linux -I./include -I.
DLDFLAGS = -fstack-protector -pie

SOLIBS =

something that is probably not that good.

where do I look up RbConfig::CONFIG['CFLAGS'] ?

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[SamSaffron]

Yeah my manual install has:

irb(main):002:0> RbConfig::CONFIG['CFLAGS']
=> " -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Werror=pointer-arith -Werror=write-strings -Werror=declaration-after-statement -Werror=implicit-function-declaration"
irb(main):003:0>

Brand new ruby-build install

irb(main):004:0> RbConfig::CONFIG['CFLAGS']
=> " "

---

maybe related to me running autoconf prior to configuring local when I did it manually ?