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llvm-mirror/tools/llvm-objcopy/CommonOpts.td
Fangrui Song dd2cb2d821 [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
2019-11-05 08:56:15 -08:00

126 lines
4.8 KiB
TableGen

include "llvm/Option/OptParser.td"
multiclass Eq<string name, string help> {
def NAME : Separate<["--"], name>;
def NAME #_eq : Joined<["--"], name #"=">,
Alias<!cast<Separate>(NAME)>,
HelpText<help>;
}
def help : Flag<["--"], "help">;
def h : Flag<["-"], "h">, Alias<help>;
def allow_broken_links
: Flag<["--"], "allow-broken-links">,
HelpText<"Allow the tool to remove sections even if it would leave "
"invalid section references. The appropriate sh_link fields "
"will be set to zero.">;
def enable_deterministic_archives
: Flag<["--"], "enable-deterministic-archives">,
HelpText<"Enable deterministic mode when operating on archives (use "
"zero for UIDs, GIDs, and timestamps).">;
def D : Flag<["-"], "D">,
Alias<enable_deterministic_archives>,
HelpText<"Alias for --enable-deterministic-archives">;
def disable_deterministic_archives
: Flag<["--"], "disable-deterministic-archives">,
HelpText<"Disable deterministic mode when operating on archives (use "
"real values for UIDs, GIDs, and timestamps).">;
def U : Flag<["-"], "U">,
Alias<disable_deterministic_archives>,
HelpText<"Alias for --disable-deterministic-archives">;
def preserve_dates : Flag<["--"], "preserve-dates">,
HelpText<"Preserve access and modification timestamps">;
def p : Flag<["-"], "p">,
Alias<preserve_dates>,
HelpText<"Alias for --preserve-dates">;
def strip_all : Flag<["--"], "strip-all">,
HelpText<"Remove non-allocated sections outside segments. "
".gnu.warning* and .ARM.attribute sections are not "
"removed">;
def strip_all_gnu
: Flag<["--"], "strip-all-gnu">,
HelpText<"Compatible with GNU's --strip-all">;
def strip_debug : Flag<["--"], "strip-debug">,
HelpText<"Remove all debug sections">;
def g : Flag<["-"], "g">,
Alias<strip_debug>,
HelpText<"Alias for --strip-debug">;
def strip_unneeded : Flag<["--"], "strip-unneeded">,
HelpText<"Remove all symbols not needed by relocations">;
defm remove_section : Eq<"remove-section", "Remove <section>">,
MetaVarName<"section">;
def R : JoinedOrSeparate<["-"], "R">,
Alias<remove_section>,
HelpText<"Alias for --remove-section">;
def strip_sections
: Flag<["--"], "strip-sections">,
HelpText<"Remove all section headers and all sections not in segments">;
defm strip_symbol : Eq<"strip-symbol", "Strip <symbol>">,
MetaVarName<"symbol">;
def N : JoinedOrSeparate<["-"], "N">,
Alias<strip_symbol>,
HelpText<"Alias for --strip-symbol">;
defm keep_section : Eq<"keep-section", "Keep <section>">,
MetaVarName<"section">;
defm keep_symbol : Eq<"keep-symbol", "Do not remove symbol <symbol>">,
MetaVarName<"symbol">;
def K : JoinedOrSeparate<["-"], "K">,
Alias<keep_symbol>,
HelpText<"Alias for --keep-symbol">;
def keep_file_symbols : Flag<["--"], "keep-file-symbols">,
HelpText<"Do not remove file symbols">;
def only_keep_debug
: Flag<["--"], "only-keep-debug">,
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. "
"symbols starting with .L)">;
def X : Flag<["-"], "X">,
Alias<discard_locals>,
HelpText<"Alias for --discard-locals">;
def discard_all
: Flag<["--"], "discard-all">,
HelpText<"Remove all local symbols except file and section symbols">;
def x : Flag<["-"], "x">,
Alias<discard_all>,
HelpText<"Alias for --discard-all">;
def regex
: Flag<["--"], "regex">,
HelpText<"Permit regular expressions in name comparison">;
def version : Flag<["--"], "version">,
HelpText<"Print the version and exit.">;
def V : Flag<["-"], "V">,
Alias<version>,
HelpText<"Alias for --version">;
def wildcard
: Flag<["--"], "wildcard">,
HelpText<"Allow wildcard syntax for symbol-related flags. Incompatible "
"with --regex. Allows using '*' to match any number of "
"characters, '?' to match any single character, '\' to escape "
"special characters, and '[]' to define character classes. "
"Wildcards beginning with '!' will prevent a match, for example "
"\"-N '*' -N '!x'\" will strip all symbols except for \"x\".">;
def w : Flag<["-"], "w">, Alias<wildcard>, HelpText<"Alias for --wildcard">;