[MacPorts] #50953: gambit-c @4.7.6 Change compiler and add desirable ./configure option
MacPorts
noreply at macports.org
Thu Mar 24 01:18:16 PDT 2016
#50953: gambit-c @4.7.6 Change compiler and add desirable ./configure option
--------------------------+--------------------------------
Reporter: macports@… | Owner: macports-tickets@…
Type: enhancement | Status: new
Priority: Normal | Milestone:
Component: ports | Version: 2.3.4
Resolution: | Keywords: haspatch
Port: gambit-c |
--------------------------+--------------------------------
Changes (by ryandesign@…):
* cc: macports@… (removed)
* keywords: => haspatch
Old description:
> =Executive Summary:=
>
> The Gambit-C package should be compiled using recent versions of the
> “macports-gcc” compiler package. Note that I am deliberately
> distinguishing between the Apple version of GCC (“gcc-4.0”, “apple-
> gcc-4.0”, etc.) and the purer MacPorts version. Additionally, the
> “--enable-single-host” option should be specified to the “./configure”
> script when gambit is built.
>
> =Justification:=
>
> The Gambit-C package is a high-performance interpreter and compiler for
> the Scheme (LISP-family) programming language. The gambit compiler works
> by first translating Scheme source code into C code, which is then
> compiled using the system’s C compiler. Because Scheme programs can have
> a very nonlinear flow of control, including advanced features such as
> first class continuations, the C code produced by the gambit compiler is
> complicated and not intended for human consumption - it is an
> intermediate form generated by one compiler for another compiler,
> principally consisting of a single, exceedingly large, C function (a
> “trampoline” function).
>
> Note that the gambit compiler itself is mostly written in Scheme, so the
> choice of C compiler affects the building of the gambit package by the
> Macports buildbot, not just the usage of the gambit package by the end
> user.
>
> The complex nature of the intermediate C code generated by gambit tests
> the limits of even modern C compilers. My recommendation that the purest
> version of GCC (“macports-gcc”) be used to compile gambit is not based on
> compiler favouritism; past versions of all of the common compilers, GCC,
> LLVM, clang, and the Apple versions of these compilers, have had troubles
> compiling gambit C code in the past. But the original author of gambit
> “highly recommends” using GCC [see 1]. And currently it seems that
> recent versions [4] of the GCC compiler perform the best, and the
> difference between GCC and the other compilers is significant (30 times
> faster to compiler the gambit scheme compiler than even the Apple GCC
> compiler!) [3].
>
> Lastly, I would argue that the “--enable-single-host” option should be
> specified to “./configure” when gambit is built because this option
> dramatically improves the efficiency of the compiled code, and because
> this option is highly recommended by the original author of the gambit
> package [2]. Note that adding “--enable-single-host” increases the time
> needed to compile gambit, and this has caused problems for the macports
> buildbot in the past, when the pure macports gcc compiler was not used
> [for example, see https://trac.macports.org/ticket/46013]. The
> improvement in compile-time when using the macports-gcc package should
> more than offset the increased build time incurred by highly desirable
> “--enable-single-host” option.
>
> - William
>
>
> Notes:
>
> From: http://gambitscheme.org/wiki/index.php/Configure_script_options
>
> [1] “It is also highly recommended to use the GCC compiler to build the
> system as the source code can take advantage of some GCC extensions.
> Notably the use of GCC's computed gotos reduces the execution time by
> roughly 35%.”
>
> [2] “It is highly recommended to use the --enable-single-host option to
> improve the execution speed and compactness of the executables … [for
> example] the speed of the Gambit-C interpreter improves by a factor of 2
> as a result.”
>
>
> [3] From: https://webmail.iro.umontreal.ca/pipermail/gambit-
> list/2015-January/007698.html
>
> “As can be seen, the Apple C compilers build Gambit in roughly 30
> minutes, which is about 30x slower than when using GNU gcc 4.9.2 . The
> execution time is also better for GNU gcc, about 2.3x faster. So on OS X
> it is clearly advantageous to install GNU gcc when using Gambit.”
>
>
> [4] From:
> https://github.com/Homebrew/homebrew/commit/beb68f8a63243587ea736fd61e7cea2af4fdf9ab#Library/Formula
> /gambit-scheme.rb
>
> “don't try to build with GCC 4.2 or 4.3 … requires absurd amounts of RAM”
New description:
= Executive Summary: =
The Gambit-C package should be compiled using recent versions of the
“macports-gcc” compiler package. Note that I am deliberately
distinguishing between the Apple version of GCC (“gcc-4.0”, “apple-
gcc-4.0”, etc.) and the purer MacPorts version. Additionally, the
“--enable-single-host” option should be specified to the “./configure”
script when gambit is built.
= Justification: =
The Gambit-C package is a high-performance interpreter and compiler for
the Scheme (LISP-family) programming language. The gambit compiler works
by first translating Scheme source code into C code, which is then
compiled using the system’s C compiler. Because Scheme programs can have
a very nonlinear flow of control, including advanced features such as
first class continuations, the C code produced by the gambit compiler is
complicated and not intended for human consumption - it is an intermediate
form generated by one compiler for another compiler, principally
consisting of a single, exceedingly large, C function (a “trampoline”
function).
Note that the gambit compiler itself is mostly written in Scheme, so the
choice of C compiler affects the building of the gambit package by the
Macports buildbot, not just the usage of the gambit package by the end
user.
The complex nature of the intermediate C code generated by gambit tests
the limits of even modern C compilers. My recommendation that the purest
version of GCC (“macports-gcc”) be used to compile gambit is not based on
compiler favouritism; past versions of all of the common compilers, GCC,
LLVM, clang, and the Apple versions of these compilers, have had troubles
compiling gambit C code in the past. But the original author of gambit
“highly recommends” using GCC [see 1]. And currently it seems that recent
versions ![4] of the GCC compiler perform the best, and the difference
between GCC and the other compilers is significant (30 times faster to
compiler the gambit scheme compiler than even the Apple GCC compiler!)
![3].
Lastly, I would argue that the “--enable-single-host” option should be
specified to “./configure” when gambit is built because this option
dramatically improves the efficiency of the compiled code, and because
this option is highly recommended by the original author of the gambit
package ![2]. Note that adding “--enable-single-host” increases the time
needed to compile gambit, and this has caused problems for the macports
buildbot in the past, when the pure macports gcc compiler was not used
[for example, see #46013]. The improvement in compile-time when using the
macports-gcc package should more than offset the increased build time
incurred by highly desirable “--enable-single-host” option.
{{{-}}} William
Notes:
From: http://gambitscheme.org/wiki/index.php/Configure_script_options
![1] “It is also highly recommended to use the GCC compiler to build the
system as the source code can take advantage of some GCC extensions.
Notably the use of GCC's computed gotos reduces the execution time by
roughly 35%.”
![2] “It is highly recommended to use the --enable-single-host option to
improve the execution speed and compactness of the executables … [for
example] the speed of the Gambit-C interpreter improves by a factor of 2
as a result.”
![3] From: https://webmail.iro.umontreal.ca/pipermail/gambit-
list/2015-January/007698.html
“As can be seen, the Apple C compilers build Gambit in roughly 30 minutes,
which is about 30x slower than when using GNU gcc 4.9.2 . The execution
time is also better for GNU gcc, about 2.3x faster. So on OS X it is
clearly advantageous to install GNU gcc when using Gambit.”
![4] From:
https://github.com/Homebrew/homebrew/commit/beb68f8a63243587ea736fd61e7cea2af4fdf9ab#Library/Formula
/gambit-scheme.rb
“don't try to build with GCC 4.2 or 4.3 … requires absurd amounts of RAM”
--
Comment:
The compiler value `macports-gcc` means "the version of FSF gcc selected
by the user by running `sudo port select gcc`". No port should specify
this compiler value, because it would result in the port building
differently depending on which compiler the user has selected (see
ReproducibleBuilds), and causing the port to fail to build on the buildbot
and for any users who have not selected any gcc. In my opinion, MacPorts
should not offer `macports-gcc` as a possible value for
`configure.compiler`.
Ports that need to use FSF gcc should offer variants so the user can
choose which version of FSF gcc to use, with one (usually the most recent
stable version, which at the present time is gcc5) being the default. The
compilers 1.0 portgroup should be used to offer these variants.
Using FSF gcc is problematic on OS X because software built with it will
use FSF gcc's libgcc_s. On non OS X systems this is not a problem because
the OS and everything else is already using that libgcc_s. On OS X, the OS
and software compiled using clang, llvm-gcc or Apple gcc use Apple's copy
of libgcc_s, a.k.a. libSystem, which might not be 100% compatible with FSF
gcc's. I don't know what effect these issues might have on gambit-c or
other software that might be built using gambit-c but it is the usual
reason why we do not use FSF gcc, even if upstream developers state that
it is preferred, because upstream developers often do not understand this
nuanced situation as it applies to OS X.
Additional complications arise if any C++ code is used; see
wiki:FAQ#libcpp. (I don't know if gambit-c uses any C++.)
--
Ticket URL: <https://trac.macports.org/ticket/50953#comment:1>
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