On Dec 25, 2019, Alexandre Oliva <ol...@adacore.com> wrote:
> 3. do not take the executable name into account when it shares the
> basename with an input file; combine executable basename with input name
> otherwise. this makes gcc -o foo[.exe] -g -gsplit-dwarf foo.c output
> foo.dwo rather than foo-foo.dwo, which is nice, but then dwo files
> compiled for use with foo won't all match foo-*.dwo; it seems more
> desirable that they all do
> 4. same as above, but only when there is only one input file, so that
> after adding bar.c to the command above, you'd get foo-foo.dwo and
> foo-bar.dwo
> Me, I'm leaning towards 5.
And yet I ended up implementing 4 after some more thinking, because the
point was to reduce gratuitous and unnecessary changes.
Here's my first cut at documenting all of the various complex
interactions between -o, -dumpbase, -dumpbase-ext, -dumpdir, and
save-temps=*
Is this too cryptic, to the point of requiring lots of examples to make
it understandable, or is this usable enough?
@@ -1561,6 +1563,89 @@ assembler file in @file{@var{source}.s}, a precompiled
header file in
@file{@var{source}.@var{suffix}.gch}, and all preprocessed C source on
standard output.
+
+@item -dumpbase @var{dumpbase}
+@opindex dumpbase
+This option sets the base name for auxiliary and dump output files. It
+does not affect the name of the main output file, implied or specified
+with @option{-o}. It may affect intermediate outputs, however:
+
+@smallexample
+gcc -save-temps -S foo.c&
+@end smallexample
+
+saves the (no longer) temporary preprocessed file in @file{foo.i}, and
+then compiles to the (implied) output file @file{foo.s}, whereas:
+
+@smallexample
+gcc -save-temps -dumpbase save-foo -c foo.c&
+@end smallexample
+
+preprocesses to in @file{save-foo.i}, compiles to @file{save-foo.s} (now
+an intermediate, thus auxiliary output), and then assembles to the
+(implied) output file @file{foo.o}.
+
+If absent, dump and aux files their names from the input file, or from
+the (non-linker) output file, if one is explicitly specified: dump
+output files (e.g. those requested by -fdump-* options) with the input
+name suffix, and aux output files (those requested by other non-dump
+options, e.g. @code{-save-temps}, @code{-gsplit-dwarf},
+@code{-fcallgraph-info}) without it.
+
+Similar suffix differentiation of dump and aux outputs can be attained
+for explicitly-given @option{-dumpbase basename.suf} by also specifying
+@option{-dumpbase-ext .suf}.
+
+If @var{dumpbase} is explicitly specified with any directory component,
+@option{-dumpdir} and other @var{dumppfx}-setting @option{-save-temps=*}
+options are ignored, and instead of appending to it, @var{dumpbase}
+fully overrides it.
+
+When @option{-dumpbase} is specified in a command that compiles multiple
+inputs, or that compiles and then links, it may be combined with
+@var{dumppfx}, as specified under @option{-dumpdir}, and each input file
+is then compiled using the combined @var{dumppfx}, and default values
+for @var{dumpbase} and @var{auxdropsuf} computed for each input file.
+
+
+@item -dumpbase-ext @var{auxdropsuf}
+@opindex dumpbase-ext
+When forming the name of an auxiliary (but not a dump) output file, drop
+trailing @var{auxdropsuf} from @var{dumpbase} before appending any
+suffixes. If not specified, this option defaults to the suffix of the
+input file, including the period.
+
+
+@item -dumpdir @var{dumppfx}
+@opindex dumpdir
+When forming the name of an auxiliary or dump output file, use
+@var{dumppfx} as a prefix. If it is to be used as a directory name, it
+must end with a directory separator.
+
+It defaults to the location of the output file; options
+@option{-save-temps=cwd} and @option{-save-temps=obj} override this
+default, just like an explicit @option{-dumpdir} option. In case
+multiple such options are given, the last one prevails.
+
+When compiling from multiple input files, if @option{-dumpbase} is
+specified, @var{dumpbase}, minus a @var{auxdropsuf} suffix, and a dash
+are appended to (or override, if containing any directory components) an
+explicit or defaulted @var{dumppfx}, so that each of the multiple
+compilations gets differently-named aux and dump outputs.
+
+When compiling and then linking from multiple input files, a defaulted
+or explicitly specified @var{dumppfx} also undergoes the @var{dumpbase}-
+transformation above. If neither @option{-dumpdir} nor
+@option{-dumpbase} are given, the linker output base name, minus the
+executable suffix, plus a dash is appended to the default @var{dumppfx}
+instead.
+
+When compiling and then linking from a single input file, the linker
+output base name will only be appended to the default @var{dumppfx} as
+above if it does not share the base name with the single input file
+name.
+
+
@item -v
@opindex v
Print (on standard error output) the commands executed to run the stages
--
Alexandre Oliva, freedom fighter he/him https://FSFLA.org/blogs/lxo
Free Software Evangelist Stallman was right, but he's left :(
GNU Toolchain Engineer FSMatrix: It was he who freed the first of us
FSF & FSFLA board member The Savior shall return (true);
