Under --icf=all we now only apply KeepUnique to non-executable
address-significant sections. This has the effect of making --icf=all
mean unsafe ICF for executable sections and safe ICF for non-executable
sections.
With this change the meaning of the KeepUnique bit changes to
"does the current ICF mode (together with the --keep-unique and
--ignore-data-address-equality flags) require this section to be
kept unique".
Differential Revision: https://reviews.llvm.org/D49626
llvm-svn: 337640
The only restriction is that we cannot merge more than one KeepUnique
section together. This matches gold's behaviour and reduces code size
when using --icf=safe.
Differential Revision: https://reviews.llvm.org/D49622
llvm-svn: 337638
lld currently prepends the absolute path to itself to every diagnostic it
emits. This path can be longer than the diagnostic, and makes the actual error
message hard to read.
There isn't a good reason for printing this path: if you want to know which lld
you're running, pass -v to clang – chances are that if you're unsure of this,
you're not only unsure when it errors out. Some people want an indication that
the diagnostic is from the linker though, so instead print just the basename of
the linker's path.
Before:
```
$ out/bin/clang -target x86_64-unknown-linux -x c++ /dev/null -fuse-ld=lld
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crt1.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crti.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtbegin.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc_s
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc_s
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtend.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtn.o: No such file or directory
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```
After:
```
$ out/bin/clang -target x86_64-unknown-linux -x c++ /dev/null -fuse-ld=lld
ld.lld: error: cannot open crt1.o: No such file or directory
ld.lld: error: cannot open crti.o: No such file or directory
ld.lld: error: cannot open crtbegin.o: No such file or directory
ld.lld: error: unable to find library -lgcc
ld.lld: error: unable to find library -lgcc_s
ld.lld: error: unable to find library -lc
ld.lld: error: unable to find library -lgcc
ld.lld: error: unable to find library -lgcc_s
ld.lld: error: cannot open crtend.o: No such file or directory
ld.lld: error: cannot open crtn.o: No such file or directory
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```
https://reviews.llvm.org/D49189
llvm-svn: 337634
If a binary is stripped, which can remove discardable sections (except
for the .reloc section, which also is marked as discardable as it isn't
loaded at runtime, only read by the loader), the .reloc section should
be first of them, in order not to create gaps in the image.
Previously, binaries with relocations were broken if they were stripped
by GNU binutils strip. Trying to execute such binaries produces an error
about "xx is not a valid win32 application".
This fixes GNU binutils bug 23348.
Prior to SVN r329370 (which didn't intend to have functional changes),
the code for moving discardable sections to the end didn't clearly
express how other discardable sections should be ordered compared to
.reloc, but the change retained the exact same end result as before.
After SVN r329370, the code (and comments) more clearly indicate that
it tries to make the .reloc section the absolutely last one; this patch
changes that.
This matches how GNU binutils ld sorts .reloc compared to dwarf debug
info sections.
Differential Revision: https://reviews.llvm.org/D49351
Signed-off-by: Martin Storsjö <martin@martin.st>
llvm-svn: 337598
For dwarf debug info, an executable normally either contains the debug
info, or it is stripped out. To reduce the storage needed (slightly)
for the debug info kept separately from the released, stripped binaries,
one can choose to only copy the debug data from the original executable
(essentially the reverse of the strip operation), producing a file with
only debug info.
When copying the debug data from an executable with GNU objcopy,
the build id and debug directory need to reside in a separate section,
as this will be kept while the rest of the .rdata section is removed.
Differential Revision: https://reviews.llvm.org/D49352
llvm-svn: 337526
This patch changes relative path for source files in obj files to
absolute path in PDB when linking with added flag.
I will make obj file generated by clang-cl independent from build
directory for chromium build. But I don't want to confuse visual studio
debugger or require additional configuration. To attain this goal, I
added flag to convert relative source file path in obj to absolute path
when emitting PDB.
By removing absolute path from obj files, we can share build cache
between chromium developers even when they are doing debug build.
That will make build time faster.
More context:
https://bugs.chromium.org/p/chromium/issues/detail?id=712796https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/5HXSVX-7fPc
llvm-svn: 337439
Dwarf debug info contains some data that contains absolute addresses.
Since these sections are discardable and aren't loaded at runtime,
there's no point in adding base relocations for them.
This makes sure that after stripping out dwarf debug info, there are no
base relocations that point to nonexistent sections.
Differential Revision: https://reviews.llvm.org/D49350
llvm-svn: 337438
Currently, getFdePC() returns uint64_t. Its because the following
encodings might use 8 bytes: DW_EH_PE_absptr and DW_EH_PE_udata8.
But caller assigns returned value to uint32_t field:
https://github.com/llvm-mirror/lld/blob/master/ELF/SyntheticSections.cpp#L508
Value is used for building .eh_frame_hdr section.
We use DW_EH_PE_sdata4 encoding for building it at this moment:
https://github.com/llvm-mirror/lld/blob/master/ELF/SyntheticSections.cpp#L2545
And that means that an overflow issue might happen if
DW_EH_PE_absptr/DW_EH_PE_udata8 address encodings are present
in .eh_frame. In that case, before this patch, we silently would
truncate the address and produced broken .eh_frame_hdr section.
It would be not hard to support real 64-bit values for
DW_EH_PE_absptr/DW_EH_PE_udata8 encodings, but it is
unclear if it is usefull and if we should do it.
Since nobody faced/reported it, int this patch I only implement
a check to stop producing broken output silently for now.
llvm-svn: 337382
This is a part of ttps://bugs.llvm.org//show_bug.cgi?id=38119
We produce broken ELF header now when the number of output sections is >= SHN_LORESERVE (0xff00).
ELF spec says (http://www.sco.com/developers/gabi/2003-12-17/ch4.eheader.html):
e_shnum:
If the number of sections is greater than or equal to SHN_LORESERVE (0xff00), this member has the value zero
and the actual number of section header table entries is contained in the sh_size field of the section header at index 0.
(Otherwise, the sh_size member of the initial entry contains 0.)
e_shstrndx
If the section name string table section index is greater than or equal to SHN_LORESERVE (0xff00), this member has the
value SHN_XINDEX (0xffff) and the actual index of the section name string table section is contained in the sh_link field of
the section header at index 0. (Otherwise, the sh_link member of the initial entry contains 0.)
We did not set these fields correctly earlier. The patch fixes the issue.
Differential revision: https://reviews.llvm.org/D49371
llvm-svn: 337363
Code was dead because at the moment of BssSection creation
it can never have a parent. Also, code simply does not
make sence as alignment adjastment happens when
BssSection is added to its parent later.
llvm-svn: 337276
There are following symbols currently available:
DefinedKind, SharedKind, UndefinedKind, LazyArchiveKind, LazyObjectKind.
Our code calls getSize() only for first two and there
seems to be no reason to return 0 for the rest.
llvm-svn: 337265
We did not try to support this intentionally but have
an error handling and reporting logic that can take care
of that and hence needs a test.
llvm-svn: 337250
Summary:
This removes the %T/dwo directory before calling ld.lld in ELF/lto/thinlto-debug-fission.ll so that
files aren't left over from previous runs.
Reviewers: espindola, pcc
Reviewed By: pcc
Subscribers: inglorion, emaste, arichardson, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D49390
llvm-svn: 337210
Summary:
This adds support to option -plugin-opt=dwo_dir=${DIR}. This option is used to specify the directory to store the .dwo files when LTO and debug fission is used
at the same time.
Reviewers: ruiu, espindola, pcc
Reviewed By: pcc
Subscribers: eraman, dexonsmith, mehdi_amini, emaste, arichardson, steven_wu, llvm-commits
Differential Revision: https://reviews.llvm.org/D47904
llvm-svn: 337195
Peter Collingbourne