4 Commits

Author SHA1 Message Date
Derek Schuff
1b21067cf2 [WebAssembly][Objcopy] Write output section headers identically to inputs
Previously when objcopy generated section headers, it padded the LEB
that encodes the section size out to 5 bytes, matching the behavior of
clang. This is correct, but results in a binary that differs from the
input. This can sometimes have undesirable consequences (e.g. breaking
source maps).

This change makes the object reader remember the size of the LEB
encoding in the section header, so that llvm-objcopy can reproduce it
exactly. For sections not read from an object file (e.g. that
llvm-objcopy is adding itself), pad to 5 bytes.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D155535
2023-07-27 15:43:51 -07:00
Derek Schuff
2ae385e560 [WebAssembly] Add WASM_SEC_LAST_KNOWN to BinaryFormat section types list [NFC]
There are 3 places where we were using WASM_SEC_TAG as the "last" known
section type, which requires updating (or leaves a bug) when a new known
section type is added. Instead add a "last type" to the enum for this
purpose.

Differential Revision: https://reviews.llvm.org/D127164
2022-06-07 12:05:23 -07:00
Derek Schuff
c9dd1cc6f0 [Objcopy][Wasm] Allow selecting known sections by name
Currently, only custom sections can be selected by operations that use section
names, because only custom sections have explicit names (whereas known sections
have names defined by the spec and only use their indices in the binary format).
This CL makes objdopy use the spec-defined names for these sections, allowing
them to be used in operations such as dumping and removal.

This is a prerequisite for fixing
https://github.com/emscripten-core/emscripten/issues/13084

Differential Revision: https://reviews.llvm.org/D126509
2022-06-06 13:54:01 -07:00
Alexey Lapshin
25d7b4fb44 [objcopy][NFC] Rename files to avoid clashing of archive members.
libtool uses file names to name members of an static library.
Files, located in different directories and having matching name,
would have the same name inside an archive. This is not a problem
for ld, but may be a problem for ar. This patch renames files
from ObjCopy library to avoid names clashing.

See https://reviews.llvm.org/D88827#3335814

Differential Revision: https://reviews.llvm.org/D120345
2022-02-23 13:05:39 +03:00