| Message ID | 20161126094237.GE18881@waldemar-brodkorb.de |
|---|---|
| State | New |
| Headers | show |
On 11/26/2016 02:42 AM, Waldemar Brodkorb wrote: > Hi, > > Some platforms, such as Blackfin, have a special prefix for assembly > symbols as opposed to C symbols. For this reason, a function named > "foo()" in C will in fact be visible as a symbol called "_foo" in the > ELF binary. > > The current linker version script logic in libgcc doesn't take into > account this situation properly. The Blackfin specific > libgcc/config/bfin/libgcc-glibc.ver has an additional "_" in front of > every symbol so that it matches the output of "nm" (which gets parsed to > produce the final linker version script). But due to this additional > "_", ld no longer matches with the symbols since "ld" does the matching > with the original symbol name, not the one prefixed with "_". > > Due to this, none of the symbols in libgcc/config/bfin/libgcc-glibc.ver > are actually matched with symbols in libgcc. This causes all libgcc > symbols to be left as "LOCAL", which causes lots of "undefined > reference" whenever some C or C++ code that calls a function of libgcc > is compiled. > > To address this, this commit introduces a "skip_underscore" variable to > the mkmap-symver script. It tells mkmap-symver to ignore the leading > underscore from the "nm" output. > > Note that this new argument is different from the existing > "leading_underscore" argument, which *adds* an additional underscore to > the generated linker version script. > > Having this functionality paves the way to using the generic linker > version information for Blackfin, instead of using a custom one. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > Tested-by: Waldemar Brodkorb <wbx@openadk.org> > > 2016-11-26 Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > > PR gcc/74748 > * libgcc/mkmap-symver.awk: add support for skip_underscore THanks. Installed. jeff
diff --git a/libgcc/mkmap-symver.awk b/libgcc/mkmap-symver.awk index 266832a..0a57d31 100644 --- a/libgcc/mkmap-symver.awk +++ b/libgcc/mkmap-symver.awk @@ -47,7 +47,11 @@ state == "nm" && ($1 == "U" || $2 == "U") { state == "nm" && NF == 3 { split ($3, s, "@") - def[s[1]] = 1; + if (skip_underscore && substr(s[1], 1, 1) == "_") + symname = substr(s[1], 2); + else + symname = s[1]; + def[symname] = 1; sawsymbol = 1; next; }