Commit Graph

12045 Commits

Author SHA1 Message Date
Haojian Wu 241dcb386e Revert [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This reverts r361792 (git commit cfca5095df), the
revision causes link errors internally, will share more details with the
author.

llvm-svn: 361806
2019-05-28 11:21:59 +00:00
Fangrui Song 173a68f1fb [ELF] Replace two addSymbol() call sites with Symbol::resolve(). NFC
If we have a handle of the symbol, insert() called by addSymbol() is
redundant. Just call resolve().

llvm-svn: 361802
2019-05-28 10:12:06 +00:00
Fangrui Song cfca5095df [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded
This is implemented by creating Undefined (instead of Defined) for such
local STT_SECTION symbols. It allows us to catch errors when there are
relocations to such discarded sections (e.g. in PR41693, ld.bfd and gold
error but we don't). Updated comdat-discarded-error.s checks we emit
friendly error message.

For relocatable-eh-frame.s, ld.lld -r a.o a.o will now error
"STT_SECTION symbol should be defined" because the section .eh_frame
refers to is now an Undefined instead of a Defined.
So I have to change `error()` to `warn()` to retain the output.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61583

llvm-svn: 361792
2019-05-28 06:34:52 +00:00
Rui Ueyama d8f8abbd4a Use SymbolTable::insert() to implement --trace.
Differential Revision: https://reviews.llvm.org/D62381

llvm-svn: 361791
2019-05-28 06:33:06 +00:00
Rui Ueyama 92069605bf Merge ELFFileBase::{initSymtab,parseHeader} as ELFFileBase:init. NFC.
This patch simplifies ELFFile instance initialization by merging
two similar functions into a single function and call it from the
ctor.

llvm-svn: 361789
2019-05-28 05:17:21 +00:00
Rui Ueyama 76737f4d19 Remove elf::createSharedFile and move its code to SharedFile's ctor. NFC.
llvm-svn: 361747
2019-05-27 07:26:13 +00:00
Sam Clegg 59f959ff33 [WebAssembly] Relax signature checking for undefined functions that are not called directly
When function signatures don't match and the undefined function is not
called directly (i.e. only has its address taken) we don't issue a
warning or create a runtime thunk for the undefined function.

Instead in this case we simply use the defined version of the function.
This is possible since checking signatures of dynamic calls happens
at runtime so any invalid usage will still result in a runtime error.

This is needed to allow C++ programs to link without generating
warnings.  Its not uncommon in C++ for vtables to be populated by
function address whee the signature of the function is not known in the
compilation unit.  In this case clang declares the method as void(void)
and relies on the vtable caller casting the data back to the correct
signature.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=40412

Differential Revision: https://reviews.llvm.org/D62153

llvm-svn: 361678
2019-05-24 22:45:08 +00:00
Reid Kleckner a431dd7ae7 [COFF] De-virtualize Chunk and SectionChunk
Shaves another pointer off of SectionChunk, reducing the size from 96 to
88 bytes, down from 144 before I started working on this. Combined with
D62356, this reduced peak memory usage when linking chrome_child.dll
from 713MB to 675MB, or 5%.

Create NonSectionChunk to provide virtual dispatch to the rest of the
chunk types.

Reviewers: ruiu, aganea

Differential Revision: https://reviews.llvm.org/D62362

llvm-svn: 361667
2019-05-24 20:25:40 +00:00
Reid Kleckner 56bee1a90a [COFF] Replace OutputSection* with uint16_t index in Chunk
Shaves another 8 bytes off of SectionChunk, the most commonly allocated
type in LLD.

These indices are only valid after we've assigned chunks to output
sections and removed empty sections, so do that in a new pass.

Reviewers: ruiu, aganea

Differential Revision: https://reviews.llvm.org/D62356

llvm-svn: 361657
2019-05-24 18:25:49 +00:00
Sam Clegg a5ca34e6b3 [WebAssebmly] Add support for --wrap
The code for implementing this features is taken almost verbatim
from the ELF backend.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=41681

Differential Revision: https://reviews.llvm.org/D62380

llvm-svn: 361639
2019-05-24 14:14:25 +00:00
Sam Clegg 7991b68284 [lld] Trace all references with lld --trace-symbol
Previously undefined symbol references were only traced if they were
seen before that definition.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41878

Differential Revision: https://reviews.llvm.org/D61929

llvm-svn: 361636
2019-05-24 13:29:17 +00:00
Sam Clegg 35be7ff80c [WebAssembly] Add support for -emit-relocs
This can be useful for post-link tools and for testing.  Sometimes
it can be useful to produces a regular executable but with relocations
preserved.

Differential Revision: https://reviews.llvm.org/D62378

llvm-svn: 361635
2019-05-24 13:28:27 +00:00
Rui Ueyama 74de6203ef [LLD][COFF] Implement /filealign parameter
Patch by Stefan Schmidt.

This adds the /filealign parameter to lld, which allows to specify the
section alignment in the output file (as it does on Microsoft's
link.exe).

This is required to be able to load dynamically linked libraries on the
original Xbox, where the debugger monitor expects the section alignment
in the file to be the same as in memory.

llvm-svn: 361634
2019-05-24 12:42:36 +00:00
Simon Atanasyan 8362cbe13b [llvm-readobj] Implement GNU-style output for dynamic table
GNU readelf tool prints slightly different dynamic table "header" and
surrounds dynamic tag names by brackets. This patch implements the same
formatting for GNU-style output of the `llvm-readobj`.

LLVM
```
DynamicSection [ (13 entries)
  Tag        Type                 Name/Value
  0x00000006 SYMTAB               0x168
  ...
]
```

GNU
```
Dynamic section at offset 0x1d0 contains 13 entries:
  Tag        Type                 Name/Value
  0x00000006 (SYMTAB)             0x168
  ...
```

Differential Revision: https://reviews.llvm.org/D62256

llvm-svn: 361633
2019-05-24 12:22:53 +00:00
Fangrui Song 7d4a67852d [ELF] Fix a doc typo. NFC
llvm-svn: 361617
2019-05-24 09:53:25 +00:00
Fangrui Song 7f1ff68a16 [ELF] Deleted unused forward declarations. NFC
llvm-svn: 361614
2019-05-24 09:25:47 +00:00
Reid Kleckner 11c141eb68 [COFF] Remove finalizeContents virtual method from Chunk, NFC
This only needs to be done for MergeChunks, so just do that in a
separate pass in the Writer.

This is one small step towards eliminating the vtable in Chunk.

llvm-svn: 361573
2019-05-24 00:02:00 +00:00
Peter Collingbourne ca6a8ae0bf ELF: Remove a comparison against In.EhFrame. NFCI.
This won't work once we have multiple .eh_frame sections.

Differential Revision: https://reviews.llvm.org/D62280

llvm-svn: 361556
2019-05-23 21:30:30 +00:00
Reid Kleckner 14f4ff6e89 [COFF] Move KeepUnique bit from Chunk to SectionChunk, NFC
The KeepUnique bit is used during ICF, which only operates on
SectionChunks, so only SectionChunks need it. This frees up a byte in
Chunk, which I plan to use in a follow-up change.

llvm-svn: 361549
2019-05-23 20:26:41 +00:00
Nico Weber 9b2830b46e lld-link, clang: Treat non-existent input files as possible spellos for option flags
OptTable treats arguments starting with / that aren't a known option
as filenames. This means lld-link's and clang-cl's typo correction for
unknown flags didn't do spell checking for misspelled options that start
with /.

I first tried changing OptTable, but that got pretty messy, see PR41787
comments 2 and 3.

Instead, let lld-link's and clang's (including clang-cl's) "file not
found" diagnostic check if a non-existent file looks like it could be a
mis-spelled option, and if so add a "did you mean" suggestion to the
"file not found" diagnostic.

While here, make formatting of a few diagnostics a bit more
self-consistent.

Fixes PR41787.

Differential Revision: https://reviews.llvm.org/D62276

llvm-svn: 361518
2019-05-23 17:58:33 +00:00
Rui Ueyama f5d9d23905 Simplify InputFile::fetch().
We don't have to return a value from the function. Instead, we can
directly call parseFile from the functions.

llvm-svn: 361478
2019-05-23 10:15:12 +00:00
Rui Ueyama 821a1ac050 Remove LazyObjFile::AddedToLink.
Instead we can just clear a MemoryBuffer so that we cannot get the
same buffer more than once.

llvm-svn: 361477
2019-05-23 10:08:56 +00:00
Sam Clegg 4bce63a0e7 Reland: [WebAssembly] Add __start_/_stop_ symbols for data sections
This is a reland of rL361235.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41565

Differential Revision: https://reviews.llvm.org/D61876

llvm-svn: 361476
2019-05-23 10:06:03 +00:00
Rui Ueyama 7f7d2b2e62 Move code for symbol resolution from SymbolTable.cpp to Symbols.cpp.
My recent commits separated symbol resolution from the symbol table,
so the functions to resolve symbols are now in a somewhat wrong file.
This patch moves it to Symbols.cpp.

The functions are now member functions of the symbol.

This is code move change. I modified function names so that they are
appropriate as member functions, though. No functionality change
intended.

Differential Revision: https://reviews.llvm.org/D62290

llvm-svn: 361474
2019-05-23 09:58:08 +00:00
Rui Ueyama 4254840313 Speed up --start-lib and --end-lib.
--{start,end}-lib give files grouped by the options the archive file
semantics. That is, each object file between them acts as if it were
in an archive file whose sole member is the file.

Therefore, files between --{start,end}-lib are linked to the final
output only if they are needed to resolve some undefined symbols.

Previously, the feature was implemented this way:

 1. We read a symbol table and insert defined symbols to the symbol
    table as lazy symbols.

 2. If an undefind symbol is resolved to a lazy symbol, that lazy
    symbol instantiate ObjFile class for that symbol, which re-insert
    all defined symbols to the symbol table.

So, if an ObjFile is instantiated, defined symbols are inserted to the
symbol table twice. Since inserting long symbol names is not cheap,
there's a room to optimize here.

This patch optimzies it. Now, LazyObjFile remembers symbol handles and
passed them over to a new ObjFile instance, so that the ObjFile
doesn't insert the same strings.

Here is a quick benchmark to link clang. "Original" is the original
lld with unmodified command line options. For "Case 1" and "Case 2", I
extracted all files from archive files and replace .a's in a command
line with .o's wrapped with --{start,end}-lib. I used the original lld
for Case 1" and use this patch for Case 2.

  Original: 5.892
    Case 1: 6.001 (+1.8%)
    Case 2: 5.701 (-3.2%)

So, interestingly, --{start,end}-lib are now faster than the regular
linking scheme with archive files. That's perhaps not too surprising,
though, because for regular archive files, we look up the symbol table
with the same string twice.

Differential Revision: https://reviews.llvm.org/D62188

llvm-svn: 361473
2019-05-23 09:53:30 +00:00
George Rimar 77b4f0abb8 [LLD][ELF] - Improve diagnostic about unrecognized relocations.
This is a minor improvement inspired by https://bugs.llvm.org/show_bug.cgi?id=38303.

A person reported that he observed message complaining about unsupported R_ARM_V4BX:
error: can't create dynamic relocation R_ARM_V4BX against local symbol in readonly segment; recompile object files with -fPIC

But with -z notext he only saw a relocation number, what is not convenient:
error: ../../gfx/cairo/libpixman/src/pixman-arm-neon-asm-bilinear.o:(.text+0x4F0): unrecognized reloc 40

Also, in the error messages we use relocation but not reloc.

With this patch we start to print one of the following messages:
error: file.o: unrecognized relocation Unknown(999)
error: file.o: unrecognized relocation R_X_KNOWN_BY_LLVM_BUT_UNSUPPORTED_BY_LLD_NAME

There is no way to write a test for that I believe.

Differential revision: https://reviews.llvm.org/D62237

llvm-svn: 361472
2019-05-23 09:50:18 +00:00
Sam Clegg b9889bbacb [WebAssembly] Seal imports section before counting imports
Summary:
Before we can assign entries in the function of global index space
we need to know the total number of function and global imports
respectively.

To avoid programmer error this change seals that imports section before
assigned function and global index space.  Any attempt to add an import
after the section is sealed will assert.

The lack this such as check caused  https://reviews.llvm.org/D61876
to be reverted.  I'm also trying to craft a test case the this
failure.

Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62240

llvm-svn: 361470
2019-05-23 09:41:03 +00:00
Rui Ueyama 0baaf45be7 Move SymbolTable::addCombinedLTOObject() to LinkerDriver.
Also renames it LinkerDriver::compileBitcodeFiles.

The function doesn't logically belong to SymbolTable. We added this
function to the symbol table because symbol table used to be a
container of input files. This is no longer the case.

Differential Revision: https://reviews.llvm.org/D62291

llvm-svn: 361469
2019-05-23 09:26:27 +00:00
Reid Kleckner ee4e0a2942 Re-land r361206 "[COFF] Store alignment in log2 form, NFC"
The previous patch lost the call to PowerOf2Ceil, which causes LLD to
crash when handling common symbols with a non-power-of-2 size. I tweaked
the existing common.test to make the bsspad16 common symbol be 15 bytes
to add coverage for this case.

llvm-svn: 361426
2019-05-22 20:21:52 +00:00
Simon Atanasyan 74b791b4f7 [mips] Use GNU-style output to make tests smaller. NFC
llvm-svn: 361394
2019-05-22 15:03:52 +00:00
Simon Atanasyan 84f929d00c [mips] Replace multiple `-check-prefix` by single `-check-prefixes`. NFC
llvm-svn: 361393
2019-05-22 15:03:42 +00:00
Rui Ueyama ecf6eb515f Copy symbol length when we replace a symbol.
Symbol's NameSize is computed lazily. Currently, when we replace a symbol,
a cached length value can be discarded. This patch propagates that value.

Differential Revision: https://reviews.llvm.org/D62234

llvm-svn: 361364
2019-05-22 09:19:30 +00:00
Fangrui Song b72b091389 [ELF] Improve error message for relocations to symbols defined in discarded sections
Rather than report "undefined symbol: ", give more informative message
about the object file that defines the discarded section.

In particular, PR41133, if the section is a discarded COMDAT, print the
section group signature and the object file with the prevailing
definition. This is useful to track down some ODR issues.

We need to
* add `uint32_t DiscardedSecIdx` to Undefined for this feature.
* make ComdatGroups public and change its type to DenseMap<CachedHashStringRef, const InputFile *>

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D59649

llvm-svn: 361359
2019-05-22 09:06:42 +00:00
Rui Ueyama 33e74d9f62 Simplify the logic to instantiate Symbols. Should be NFC.
llvm-svn: 361350
2019-05-22 04:56:25 +00:00
Fangrui Song b372259ace [docs] Fix troff macro (.F1 -> .Fl) in ld.lld.1
llvm-svn: 361345
2019-05-22 02:15:25 +00:00
Richard Smith 32591ca4e2 Fix test to put its outputs into the temp directory.
llvm-svn: 361297
2019-05-21 19:41:19 +00:00
Sam Clegg c0a4f45bcb Revert "[WebAssembly] Add __start_/_stop_ symbols for data sections"
This reverts commit 7804dbddcc.

This change broke a bunch of tests of the WebAssembly waterfall.
Will hopefully reland with increased test coverage.

llvm-svn: 361273
2019-05-21 17:16:33 +00:00
Fangrui Song 5ea0d06e81 [ELF] Deleted unused ComdatGroups member variable left by D61854
llvm-svn: 361266
2019-05-21 14:40:38 +00:00
Rui Ueyama d3f27f2bf4 Fix test failure.
I forgot to submit a last-minute change to the last patch.

llvm-svn: 361249
2019-05-21 12:01:16 +00:00
Rui Ueyama 35150bb534 [WebAssembly] Add --reproduce.
--reproduce is a convenient option for debugging. If you invoke lld
with `--reproduce=repro.tar`, it creates `repro.tar` with all input
files and the command line options given to the linker, so that it is
very easy to run lld with the exact same inputs.

ELF and Windows lld have this option.

This patch add that option to lld/wasm.

Differential Revision: https://reviews.llvm.org/D62170

llvm-svn: 361244
2019-05-21 11:52:14 +00:00
Sam Clegg 7804dbddcc [WebAssembly] Add __start_/_stop_ symbols for data sections
Fixes https://bugs.llvm.org/show_bug.cgi?id=41565

Differential Revision: https://reviews.llvm.org/D61876

llvm-svn: 361236
2019-05-21 10:07:30 +00:00
Sam Clegg 8fcf012693 [WebAssembly] Refactor synthetic sections and relocation processing. NFC.
Major refactor to better match the structure of the ELF linker.

- Split out relocation processing into scanRelocations
- Split out synthetic sections into their own classes.

Differential Revision: https://reviews.llvm.org/D61811

llvm-svn: 361233
2019-05-21 09:13:09 +00:00
Fangrui Song ecf4c9e13c [ELF] Don't advance position in a memory region when assigning to the Dot
For memory5.test, ld.bfd appears to ignore `. += 0x2000;`, so the test was testing
a wrong behavior. After deleting the code added in rLLD336335, we match ld.bfd and thus fix PR41357.

PR37836 (memory4.test) seems to have been fixed by another change.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62177

llvm-svn: 361228
2019-05-21 08:21:44 +00:00
Fangrui Song 547e3e930c [ELF] Error on relocations to local undefined symbols
For a reference to a local symbol, ld.bfd and gold error if the symbol
is defined in a discarded section but accept it if the symbol is
undefined. This inconsistent behavior seems unnecessary for us (it
probably makes sense for them as they differentiate local/global
symbols, the error would mean more code).

Catch such errors. Symbol index 0 may be used by marker relocations,
e.g. R_*_NONE R_ARM_V4BX. Don't error on them.

The difference from D61563 (which caused msan failure) is we don't call
Sym.computeBinding() on local symbols - VersionId is uninitialized.

llvm-svn: 361213
2019-05-21 02:38:11 +00:00
Nico Weber 67510fac36 Revert r361206 "[COFF] Store alignment in log2 form, NFC"
Makes the linker crash when linking nasm.exe.

llvm-svn: 361212
2019-05-21 02:06:59 +00:00
Reid Kleckner 1a5cc629de [COFF] Store alignment in log2 form, NFC
Summary:
Valid section or chunk alignments are powers of 2 in the range [1,
8192]. These can be stored more canonically in log2 form to free up some
bits in Chunk. Combined with D61696, SectionChunk gets 8 bytes smaller.

Reviewers: ruiu, aganea

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61698

llvm-svn: 361206
2019-05-20 22:57:52 +00:00
Tiancong Wang a5d8d01d6f [ELF][Driver] Fix precedence of symbol ordering file and CGProfile
This patch is a fix for https://bugs.llvm.org/show_bug.cgi?id=41804.
We try to solve the precedence of user-specified symbol ordering file and C3 ordering provided as call graph. It deals with two case:
(1) When both --symbol-ordering-file=<file> and --call-graph-order-file=<file> are present, whichever flag comes later will take precedence.
(2) When only --symbol-ordering-file=<file> is present, it takes precedence over implicit call graph (CGProfile) generated by CGProfilePass enabled in new pass manager.

llvm-svn: 361190
2019-05-20 19:13:34 +00:00
Tiancong Wang af4219adf5 Test commit, add an empty line.
llvm-svn: 361186
2019-05-20 18:46:25 +00:00
Fangrui Song 055906e1e5 [ELF] -z combreloc: sort dynamic relocations by (!is_relative,symbol_index,r_offset)
We currently sort dynamic relocations by (!is_relative,symbol_index).
Add r_offset as the third key. This makes `readelf -r` debugging easier
(relocations to the same symbol are ordered by r_offset).

Refactor the test combreloc.s (renamed from combrelocs.s) to check
R_X86_64_RELATIVE, and delete --expand-relocs.

The difference from the reverted D61477 is that we keep !is_relative as
the first key. In local dynamic TLS model, DTPMOD (e.g.
R_ARM_TLS_DTPMOD32 R_X86_64_DTPMOD and R_PPC{,64}_DTPMOD) may use 0 as
the symbol index.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D62141

llvm-svn: 361164
2019-05-20 15:25:01 +00:00
Dmitri Gribenko 0429fddc9d Revert "[ELF] Error on relocations to local undefined symbols"
This reverts commit r361144.  It causes a use-of-uninitialized-value in
maybeReportUndefined at llvm/tools/lld/ELF/Relocations.cpp:682, as
detected by MemorySanitizer when local-undefined-symbol.s test is run.

llvm-svn: 361162
2019-05-20 15:04:08 +00:00