diff options
| author | Fangrui Song <maskray@google.com> | 2019-10-24 15:48:32 -0700 |
|---|---|---|
| committer | Fangrui Song <maskray@google.com> | 2019-11-05 08:56:15 -0800 |
| commit | 5ad0103d8a04cb066dfae4fc20b0dfcd9413f4d4 (patch) | |
| tree | 65dcbcfccb35bf5353a1bfac0b665bbf7421e1e4 /llvm/tools/llvm-objcopy/CommonOpts.td | |
| parent | ade55d07871040d0e75b94e3d3a1eaecbd704d36 (diff) | |
| download | bcm5719-llvm-5ad0103d8a04cb066dfae4fc20b0dfcd9413f4d4.tar.gz bcm5719-llvm-5ad0103d8a04cb066dfae4fc20b0dfcd9413f4d4.zip | |
[llvm-objcopy][ELF] Implement --only-keep-debug
--only-keep-debug produces a debug file as the output that only
preserves contents of sections useful for debugging purposes (the
binutils implementation preserves SHT_NOTE and non-SHF_ALLOC sections),
by changing their section types to SHT_NOBITS and rewritting file
offsets.
See https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
The intended use case is:
```
llvm-objcopy --only-keep-debug a a.dbg
llvm-objcopy --strip-debug a b
llvm-objcopy --add-gnu-debuglink=a.dbg b
```
The current layout algorithm is incapable of deleting contents and
shrinking segments, so it is not suitable for implementing the
functionality.
This patch adds a new algorithm which assigns sh_offset to sections
first, then modifies p_offset/p_filesz of program headers. It bears a
resemblance to lld/ELF/Writer.cpp.
Reviewed By: jhenderson, jakehehrlich
Differential Revision: https://reviews.llvm.org/D67137
Diffstat (limited to 'llvm/tools/llvm-objcopy/CommonOpts.td')
| -rw-r--r-- | llvm/tools/llvm-objcopy/CommonOpts.td | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/llvm/tools/llvm-objcopy/CommonOpts.td b/llvm/tools/llvm-objcopy/CommonOpts.td index ea3616589f5..6481d1d1df0 100644 --- a/llvm/tools/llvm-objcopy/CommonOpts.td +++ b/llvm/tools/llvm-objcopy/CommonOpts.td @@ -86,8 +86,9 @@ def keep_file_symbols : Flag<["--"], "keep-file-symbols">, def only_keep_debug : Flag<["--"], "only-keep-debug">, - HelpText<"Clear sections that would not be stripped by --strip-debug. " - "Currently only implemented for COFF.">; + HelpText< + "Produce a debug file as the output that only preserves contents of " + "sections useful for debugging purposes">; def discard_locals : Flag<["--"], "discard-locals">, HelpText<"Remove compiler-generated local symbols, (e.g. " |
