[llvm] r338173 - [llvm-objcopy] Make --strip-debug strip .zdebug* (zlib-gnu) sections
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 30 13:34:57 PDT 2018
GNU objcopy -g (STRIP_DEBUG) will strip .gdb_index
This is probably because sections marked as SEC_DEBUGGING will be
stripped. .debug .zdebug are modern while .line* .stab* should be very
uncommon, not sure about .gnu.linkonce.wi.* though.
binutils-gdb/bfd/elf.c:1053
/* The debugging sections appear to be recognized only by name,
not any sort of flag. Their SEC_ALLOC bits are cleared. */
if (name [0] == '.')
{
const char *p;
int n;
if (name[1] == 'd')
p = ".debug", n = 6;
else if (name[1] == 'g' && name[2] == 'n')
p = ".gnu.linkonce.wi.", n = 17;
else if (name[1] == 'g' && name[2] == 'd')
p = ".gdb_index", n = 11; /* yes we really do mean 11. */
else if (name[1] == 'l')
p = ".line", n = 5;
else if (name[1] == 's')
p = ".stab", n = 5;
else if (name[1] == 'z')
p = ".zdebug", n = 7;
else
p = NULL, n = 0;
if (p != NULL && strncmp (name, p, n) == 0)
flags |= SEC_DEBUGGING;
}
On 2018-07-30, David Blaikie wrote:
>Might want to check what binutils objcopy does with .gdb_index too - sort of
>debug info section without the ".debug_" prefix.
>
>On Fri, Jul 27, 2018 at 3:51 PM Fangrui Song via llvm-commits <
>llvm-commits at lists.llvm.org> wrote:
>
> Author: maskray
> Date: Fri Jul 27 15:51:36 2018
> New Revision: 338173
>
> URL: http://llvm.org/viewvc/llvm-project?rev=338173&view=rev
> Log:
> [llvm-objcopy] Make --strip-debug strip .zdebug* (zlib-gnu) sections
>
> This behavior matches GNU objcopy.
>
> Modified:
> llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp
>
> Modified: llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/
> llvm-objcopy.cpp?rev=338173&r1=338172&r2=338173&view=diff
> ===========================================================================
> ===
> --- llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp (original)
> +++ llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp Fri Jul 27 15:51:36 2018
> @@ -185,6 +185,10 @@ LLVM_ATTRIBUTE_NORETURN void reportError
> } // end namespace objcopy
> } // end namespace llvm
>
> +static bool IsDebugSection(const SectionBase &Sec) {
> + return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug");
> +}
> +
> static bool IsDWOSection(const SectionBase &Sec) {
> return Sec.Name.endswith(".dwo");
> }
> @@ -316,8 +320,7 @@ static void HandleArgs(const CopyConfig
> // Removes:
> if (!Config.ToRemove.empty()) {
> RemovePred = [&Config](const SectionBase &Sec) {
> - return std::find(std::begin(Config.ToRemove), std::end
> (Config.ToRemove),
> - Sec.Name) != std::end(Config.ToRemove);
> + return find(Config.ToRemove, Sec.Name) != Config.ToRemove.end();
> };
> }
>
> @@ -346,7 +349,7 @@ static void HandleArgs(const CopyConfig
> case SHT_STRTAB:
> return true;
> }
> - return Sec.Name.startswith(".debug");
> + return IsDebugSection(Sec);
> };
>
> if (Config.StripSections) {
> @@ -357,7 +360,7 @@ static void HandleArgs(const CopyConfig
>
> if (Config.StripDebug) {
> RemovePred = [RemovePred](const SectionBase &Sec) {
> - return RemovePred(Sec) || Sec.Name.startswith(".debug");
> + return RemovePred(Sec) || IsDebugSection(Sec);
> };
> }
>
> @@ -385,8 +388,7 @@ static void HandleArgs(const CopyConfig
> if (!Config.OnlyKeep.empty()) {
> RemovePred = [&Config, RemovePred, &Obj](const SectionBase &Sec) {
> // Explicitly keep these sections regardless of previous removes.
> - if (std::find(std::begin(Config.OnlyKeep), std::end
> (Config.OnlyKeep),
> - Sec.Name) != std::end(Config.OnlyKeep))
> + if (find(Config.OnlyKeep, Sec.Name) != Config.OnlyKeep.end())
> return false;
>
> // Allow all implicit removes.
> @@ -408,8 +410,7 @@ static void HandleArgs(const CopyConfig
> if (!Config.Keep.empty()) {
> RemovePred = [Config, RemovePred](const SectionBase &Sec) {
> // Explicitly keep these sections regardless of previous removes.
> - if (std::find(std::begin(Config.Keep), std::end(Config.Keep),
> Sec.Name) !=
> - std::end(Config.Keep))
> + if (find(Config.Keep, Sec.Name) != Config.Keep.end())
> return false;
> // Otherwise defer to RemovePred.
> return RemovePred(Sec);
>
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--
宋方睿
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