Joseph Myers: > On Wed, 2 Nov 2016, Ximin Luo wrote: > >> This patch series adds a new environment variable SOURCE_PREFIX_MAP. When >> this >> is set, GCC will treat this as an implicit "-fdebug-prefix-map=$value" >> command-line argument. This makes the final binary output reproducible, and > > Only one argument? Sometimes you may want multiple -fdebug-prefix-map > options (for both source and build directories, for example). Perhaps the > value should be split on spaces to provide multiple such mappings? >
We wanted to keep this environment variable simple, and allowing this would make it more costly for other projects to adopt. Whichever separator character we choose, we would have to either (a) disallow it within the oldprefix/newprefix strings like what PATH does or (b) think of an escaping scheme. Neither choice is great - with (a) since we want to map *arbitrary* paths the restriction is less acceptable here than in PATH, and with (b) it adds complexity to the spec, for uncommon use-cases. In the case of an out-of-tree build, it is still possible with the current proposal. Instead of: SOURCE_PREFIX_MAP="srcprefix=srcname:buildprefix=buildname" One could arrange the tree like: commonprefix/srcname commonprefix/buildname then set SOURCE_PREFIX_MAP="commonprefix=." or SOURCE_PREFIX_MAP="commonprefix/=". X -- GPG: ed25519/56034877E1F87C35 GPG: rsa4096/1318EFAC5FBBDBCE https://github.com/infinity0/pubkeys.git
