| From ae9c3e354440c4a0f105a9eabfb2f77be085ebc1 Mon Sep 17 00:00:00 2001 |
| From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
| Date: Thu, 18 Aug 2016 17:59:16 +0200 |
| Subject: [PATCH] libgcc/mkmap-symver: support skip_underscore |
| |
| 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> |
| --- |
| libgcc/mkmap-symver.awk | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| diff --git a/libgcc/mkmap-symver.awk b/libgcc/mkmap-symver.awk |
| index 266832a..30bb179 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) |
| + symname = substr(s[1], 2); |
| + else |
| + symname = s[1]; |
| + def[symname] = 1; |
| sawsymbol = 1; |
| next; |
| } |
| -- |
| 2.7.4 |
| |
