On Sun, 2002-08-18 at 05:46, Richard Braakman wrote:
> For that matter, there are also Heisenbugs to consider: some bugs only
> appear in the optimized version, not the un-optimized. Compiling the
> debugging version with different optimization flags would make tracking
> down these bugs needlessly difficult.
Right. I sort of guessed someone might raise this issue, but I wasn't
sure how often it would come up in practise.
I then propose the following patch.
--- debian-policy-3.5.6.1/policy.sgml 2002-03-14 13:17:48.000000000 -0500
+++ debian-policy-3.5.6.1.hacked/policy.sgml 2002-08-18 18:06:50.000000000
-0400
@@ -5357,34 +5357,63 @@
Debugging symbols are useful for error diagnosis,
investigation of core dumps (which may be submitted by users
in bug reports), or testing and developing the software.
- Therefore it is recommended to support building the package
- with debugging information through the following interface:
- If the environment variable <tt>DEB_BUILD_OPTIONS</tt>
- contains the string <tt>debug</tt>, compile the software
- with debugging information (usually this involves adding the
- <tt>-g</tt> flag to <tt>CFLAGS</tt>). This allows the
- generation of a build tree with debugging information. If
- the environment variable <tt>DEB_BUILD_OPTIONS</tt> contains
- the string <tt>nostrip</tt>, do not strip the files at
- installation time. This allows one to generate a package
- with debugging information included.<footnote>
- <p>
- Rationale: Using <tt>-g</tt> by default causes wasted
- CPU cycles since the information is stripped away
- anyway; this can have a significant impact on the
- efficiency of the autobuilders. Having a standard way
- to build a debugging variant also makes it easier to
- build debugging bins and libraries since it provides a
- documented way of getting this type of build; one does
- not have to manually edit <tt>debian/rules</tt> or
- <tt>Makefile</tt>s.
- </p>
- </footnote>
+ For this reason, it is recommended to support the
+ standardized environment variable <tt>DEB_BUILD_OPTIONS</tt>.
+ This variable can contain several flags to change how a
+ package is compiled.
+ </p>
+ <p>
+ <taglist>
+ <tag>debug</tag>
+ <item>
+ <p>
+ If this string is present in <tt>DEB_BUILD_OPTIONS</tt>,
+ then ensure that the package is compiled with whatever
+ additional information is necessary for debugging. For
+ programs written in the C language, this usually means
+ adding <tt>-g</tt> to the <tt>CFLAGS</tt> environment
+ variable.
+ </p>
+ </item>
+ <tag>noopt</tag>
+ <item>
+ <p>
+ The presence of this string means that the package
+ should be complied with the minumum possible amount of
+ optimization. For C programs, this usually implies
+ adding <tt>-O0</tt> to <tt>CFLAGS</tt>. Some programs
+ might fail to build or run at this level of
+ optimization; it may be necessary to use <tt>-O1</tt>.
+ </p>
+ </item>
+ <tag>nostrip</tag>
+ <item>
+ <p>
+ This string implies that the debugging symbols should
+ not be stripped from the binary during installation, so
+ that debugging information may be included in the
+ package.
+ </p>
+ </item>
+ </taglist>
+ </p>
+ <p>
+ Rationale: Using <tt>-g</tt> by default causes wasted
+ CPU cycles since the information is stripped away
+ anyway; this can have a significant impact on the
+ efficiency of the autobuilders. Having a standard way
+ to build a debugging variant also makes it easier to
+ build debugging bins and libraries since it provides a
+ documented way of getting this type of build; one does
+ not have to manually edit <tt>debian/rules</tt> or
+ <tt>Makefile</tt>s.
+ </p>
+ <p>
The following makefile snippet is an example of how one may
test for either condition; you will probably have to massage
this example in order to make it work for your package.
<example compact="compact">
-CFLAGS = -O2 -Wall
+CFLAGS = -Wall
INSTALL = install
INSTALL_FILE = $(INSTALL) -p -o root -g root -m 644
INSTALL_PROGRAM = $(INSTALL) -p -o root -g root -m 755
@@ -5394,12 +5423,16 @@
ifneq (,$(findstring debug,$(DEB_BUILD_OPTIONS)))
CFLAGS += -g
endif
+ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))
+CFLAGS += -O0
+else
+CFLAGS += -O2
+endif
ifeq (,$(findstring nostrip,$(DEB_BUILD_OPTIONS)))
INSTALL_PROGRAM += -s
endif
</example>
</p>
-
<p>
It is up to the package maintainer to decide what
compilation options are best for the package. Certain
