Commit Graph

315 Commits

Author SHA1 Message Date
Fangrui Song 50225112b5 [lld-link] Fix -Wunused-but-set-variable in -DLLVM_ENABLE_ASSERTIONS=off build. NFC 2021-06-20 11:35:02 -07:00
Zequan Wu aa80955f63 [lld-link] Warn on exported deleting dtor
MSVC linker has this [[ https://docs.microsoft.com/en-us/cpp/error-messages/tool-errors/linker-tools-warning-lnk4102?view=msvc-160 | warning]], so lld-link should also warn on this.

Differential Revision: https://reviews.llvm.org/D100606
2021-04-20 14:06:31 -07:00
Pengfei Wang 184377da5c [LLD] Implement /guard:[no]ehcont
Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D99078
2021-04-14 15:06:49 +08:00
Andrew Paverd 0139c8af8d [CFGuard] Add address-taken IAT tables and delay-load support
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D87544
2020-11-17 18:24:45 -08:00
Hans Wennborg 418f18c6cd Revert "Reland [CFGuard] Add address-taken IAT tables and delay-load support"
This broke both Firefox and Chromium (PR47905) due to what seems like dllimport
function not being handled correctly.

> This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
> Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.
>
> Reviewed By: rnk
>
> Differential Revision: https://reviews.llvm.org/D87544

This reverts commit cfd8481da1.
2020-11-11 16:03:33 +01:00
Peter Penzin e59726220f [LLD] [COFF] Align all debug directories
Match MSVC linker output - align all debug directories on four bytes,
while removing debug directory alignment. This would have the same
effect on CETCOMPAT support as D89919.

Chromium bug: https://crbug.com/1136664

Differential Revision: https://reviews.llvm.org/D89921
2020-11-02 10:47:51 -08:00
Luqman Aden 6a73d6564a [LLD] Set alignment as part of Characteristics in TLS table.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46473

LLD wasn't previously specifying any specific alignment in the TLS table's Characteristics field so the loader would just assume the default value (16 bytes). This works most of the time except if you have thread locals that want specific higher alignments (e.g. 32 as in the bug) *even* if they specify an alignment on the thread local. This change updates LLD to take the max alignment from tls section.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D88637
2020-10-15 00:22:40 -07:00
Luqman Aden f87c98def8 Revert "[LLD] Set alignment as part of Characteristics in TLS table."
Revert individual wip commits and will instead follow up with a
single commit with all the changes. Makes cherry-picking easier
and will contain all the right tags.

This reverts commit 32a4ad3b6c.
This reverts commit 7fe13af676.
This reverts commit 51fbc1bef6.
This reverts commit f80950a8bb.
This reverts commit 0778cad9f3.
This reverts commit 8b70d527d7.
2020-10-15 00:21:36 -07:00
Luqman Aden 32a4ad3b6c [LLD] Set alignment as part of Characteristics in TLS table.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46473

LLD wasn't previously specifying any specific alignment in the TLS table's Characteristics field so the loader would just assume the default value (16 bytes). This works most of the time except if you have thread locals that want specific higher alignments (e.g. 32 as in the bug) *even* if they specify an alignment on the thread local. This change updates LLD to take the max alignment from tls section.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D88637
2020-10-14 19:41:03 -07:00
Luqman Aden 7fe13af676 Nit: Use early return to reduce indentation. 2020-10-14 19:34:32 -07:00
Luqman Aden 8b70d527d7 [LLD] Set alignment as part of Characteristics in TLS table.
Differential Revision: https://reviews.llvm.org/D88637
2020-10-14 19:34:31 -07:00
Andrew Paverd cfd8481da1 Reland [CFGuard] Add address-taken IAT tables and delay-load support
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D87544
2020-10-13 13:20:52 -07:00
Martin Storsjö 45c4c54003 [LLD] [COFF] Add a private option for setting the os version separately from subsystem version
The MinGW driver has separate options for OS and subsystem version.
Having this available in lld-link allows the MinGW driver to both match
GNU ld better and simplifies the code for merging two (potentially
mismatching) arguments into one.

Differential Revision: https://reviews.llvm.org/D88802
2020-10-05 23:08:01 +03:00
Arthur Eubanks 499260c03b Revert "[CFGuard] Add address-taken IAT tables and delay-load support"
This reverts commit ef4e971e5e.
2020-10-01 11:29:54 -07:00
Andrew Paverd ef4e971e5e [CFGuard] Add address-taken IAT tables and delay-load support
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D87544
2020-10-01 12:45:07 +01:00
Alexandre Ganea f2efb5742c [LLD][COFF] Cover usage of LLD-as-a-library in tests
In lit tests, we run each LLD invocation twice (LLD_IN_TEST=2), without shutting down the process in-between. This ensures a full cleanup is properly done between runs.
Only active for the COFF driver for now. Other drivers still use LLD_IN_TEST=1 which executes just one iteration with full cleanup, like before.
When the environment variable LLD_IN_TEST is unset, a shortcut is taken, only one iteration is executed, no cleanup for faster exit, like before.
A public API, lld::safeLldMain(), is also available when using LLD as a library.

Differential Revision: https://reviews.llvm.org/D70378
2020-09-24 15:07:50 -04:00
Bas Zalmstra 54f5a4ea4c [LLD][COFF] Reset outputSections for successive runs
The global variable outputSections in the COFF writer was not
cleared between runs which caused successive calls to lld::coff::link
to generate invalid binaries. These binaries when loaded would result
in "invalid win32 applications" and/or "bad image" errors.

Differential Revision: https://reviews.llvm.org/D86401
2020-08-22 23:08:43 +03:00
Zequan Wu 763671f387 [COFF] Port CallGraphSort to COFF from ELF 2020-07-30 15:21:44 -07:00
Martin Storsjö 745eb02496 [LLD] [MinGW] Implement the --no-seh flag
Previously this flag was just ignored. If set, set the
IMAGE_DLL_CHARACTERISTICS_NO_SEH bit, regardless of the normal safeSEH
machinery.

In mingw configurations, the safeSEH bit might not be set in e.g. object
files built from handwritten assembly, making it impossible to use the
normal safeseh flag. As mingw setups don't generally use SEH on 32 bit
x86 at all, it should be fine to set that flag bit though - hook up
the existing GNU ld flag for controlling that.

Differential Revision: https://reviews.llvm.org/D84701
2020-07-28 21:08:37 +03:00
Hans Wennborg e73d0b5719 [COFF] Error on unexpected .pdata size
Previously, lld would crash if the .pdata size was not an even multiple
of the expected .pdata entry size. This makes it error gracefully instead.

(We hit this in Chromium due to an assembler problem: https://crbug.com/1101577)

Differential revision: https://reviews.llvm.org/D83479
2020-07-13 13:38:39 +02:00
Martin Storsjö 7f0e6c31c2 [LLD] [COFF] Add options for disabling auto import and runtime pseudo relocs
Allow disabling either the full auto import feature, or just
forbidding the cases that require runtime fixups.

As long as all auto imported variables are referenced from separate
.refptr$<name> sections, we can alias them on top of the IAT entries
and don't actually need any runtime fixups via pseudo relocations.
LLVM generates references to variables in .refptr stubs, if it
isn't known that the variable for sure is defined in the same object
module. Runtime pseudo relocs are needed if the addresses of auto
imported variables are used in constant initializers though.

Fixing up runtime pseudo relocations requires the use of
VirtualProtect (which is disallowed in WinStore/UWP apps) or
VirtualProtectFromApp. To allow any risk of ambiguity, allow
rejecting cases that would require this at the linker stage.

This adds support for the --disable-runtime-pseudo-reloc and
--disable-auto-import options in the MinGW driver (matching GNU ld.bfd)
with corresponding lld private options in the COFF driver.

Differential Revision: https://reviews.llvm.org/D78923
2020-05-14 13:05:14 +03:00
Reid Kleckner 932f0276ea [Support] Move LLD's parallel algorithm wrappers to support
Essentially takes the lld/Common/Threads.h wrappers and moves them to
the llvm/Support/Paralle.h algorithm header.

The changes are:
- Remove policy parameter, since all clients use `par`.
- Rename the methods to `parallelSort` etc to match LLVM style, since
  they are no longer C++17 pstl compatible.
- Move algorithms from llvm::parallel:: to llvm::, since they have
  "parallel" in the name and are no longer overloads of the regular
  algorithms.
- Add range overloads
- Use the sequential algorithm directly when 1 thread is requested
  (skips task grouping)
- Fix the index type of parallelForEachN to size_t. Nobody in LLVM was
  using any other parameter, and it made overload resolution hard for
  for_each_n(par, 0, foo.size(), ...) because 0 is int, not size_t.

Remove Threads.h and update LLD for that.

This is a prerequisite for parallel public symbol processing in the PDB
library, which is in LLVM.

Reviewed By: MaskRay, aganea

Differential Revision: https://reviews.llvm.org/D79390
2020-05-05 15:21:05 -07:00
Sylvain Audi b91905a263 [lld-link] Support /map option, matching link.exe 's /map output format
Added support for /map and /map:[filepath].
The output was derived from Microsoft's Link.exe output when using that same option.
Note that /MAPINFO support was not added.

The previous implementation of MapFile.cpp/.h was meant for /lldmap, and was renamed to LLDMapFile.cpp/.h
MapFile.cpp/.h is now for /MAP
However, a small fix was added to lldmap, replacing a std::sort with std::stable_sort to enforce reproducibility.

Differential Revision: https://reviews.llvm.org/D70557
2020-03-24 09:48:00 -04:00
Vitaly Buka 8620bb9534 [lld] Fix "loop variable creates a copy" warning 2020-03-16 22:52:49 -07:00
Rui Ueyama a2923b2a1e Implement CET Shadow Stack (Intel Controlflow Enforcement Technology) support on Windows
Patch by Petr Penzin.

Windows support for CET is limited to shadow stack, which is enabled
by setting a PE bit in the linker.

Docs:

MSVC linker flag:
https://docs.microsoft.com/en-us/cpp/build/reference/cetcompat?view=vs-2019

IMAGE_DLLCHARACTERISTICS_EX_CET_COMPAT PE bit:
https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#extended-dll-characteristics

Differential Revision: https://reviews.llvm.org/D70606
2020-03-16 17:51:32 +09:00
Reid Kleckner 8a310f40d0 Remove namespace lld { namespace coff { from COFF LLD cpp files
Instead, use `using namespace lld(::coff)`, and fully qualify the names
of free functions where they are defined in cpp files.

This effectively reverts d79c3be618 to follow the new style guide added
in 236fcbc21a.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D74882
2020-02-25 17:30:53 -08:00
Rui Ueyama b11386f9be Make it possible to redirect not only errs() but also outs()
This change is for those who use lld as a library. Context:
https://reviews.llvm.org/D70287

This patch adds a new parmeter to lld::*::link() so that we can pass
an raw_ostream object representing stdout. Previously, lld::*::link()
took only an stderr object.

Justification for making stdoutOS and stderrOS mandatory: I wanted to
make link() functions to take stdout and stderr in that order.
However, if we change the function signature from

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stderrOS = llvm::errs());

to

  bool link(ArrayRef<const char *> args, bool canExitEarly,
            raw_ostream &stdoutOS = llvm::outs(),
            raw_ostream &stderrOS = llvm::errs());

, then the meaning of existing code that passes stderrOS silently
changes (stderrOS would be interpreted as stdoutOS). So, I chose to
make existing code not to compile, so that developers can fix their
code.

Differential Revision: https://reviews.llvm.org/D70292
2019-11-18 11:18:06 +09:00
Reid Kleckner f24c3352c9 [COFF] Don't include llvm/LTO/LTO.h in a header
LLVM's LTO header includes all of llvm/IR, which most of the COFF linker
doesn't need.
2019-11-14 13:47:18 -08:00
Rui Ueyama f95ed69641 Implement /driver, /driver:wdm and /driver:uponly
This patch implements /driver, /driver:wdm and /driver:uponly as
described in
https://docs.microsoft.com/en-us/cpp/build/reference/driver-windows-nt-kernel-mode-driver?view=vs-2019.

Differential Revision: https://reviews.llvm.org/D70162
2019-11-14 13:07:56 +09:00
Reid Kleckner deaf121b65 Warn when an output section name is longer than 8 characters
Recent versions of Microsoft's dumpbin tool cannot handle such PE files.
LLVM tools and GNU tools can, and use this to encode long section names
like ".debug_info", which is commonly used for DWARF. Don't do this in
mingw mode or when -debug:dwarf is passed, since the user probably wants
long section names for DWARF sections.

PR43754

Reviewers: ruiu, mstorsjo

Differential Revision: https://reviews.llvm.org/D69594
2019-11-01 12:59:13 -07:00
Fangrui Song d79c3be618 [COFF] Wrap definitions in namespace lld { namespace coff {. NFC
Similar to D67323, but for COFF. Many lld/COFF/ files already use
`namespace lld { namespace coff {`. Only a few need changing.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D68772

llvm-svn: 374314
2019-10-10 11:27:58 +00:00
Rui Ueyama c3c5e0fbbf [lld] Don't create hints-section if Hint/Name Table is empty
Fixes assert in addLinkerModuleCoffGroup() when using by-ordinal imports
only.

Patch by Stefan Schmidt.

Differential revision: https://reviews.llvm.org/D68352

llvm-svn: 374140
2019-10-09 06:48:24 +00:00
Bob Haarman 7dc5e7a0a4 reland "[lld-link] implement -start-lib and -end-lib"
Summary:
This is a re-land of r370487 with a fix for the use-after-free bug
that rev contained.

This implements -start-lib and -end-lib flags for lld-link, analogous
to the similarly named options in ld.lld. Object files after
-start-lib are included in the link only when needed to resolve
undefined symbols. The -end-lib flag goes back to the normal behavior
of always including object files in the link. This mimics the
semantics of static libraries, but without needing to actually create
the archive file.

Reviewers: ruiu, smeenai, MaskRay

Reviewed By: ruiu, MaskRay

Subscribers: akhuang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66848

llvm-svn: 370816
2019-09-03 20:32:16 +00:00
Vlad Tsyrklevich 802aab5de8 Revert "[lld-link] implement -start-lib and -end-lib"
This reverts commit r370487 as it is causing ASan/MSan failures on
sanitizer-x86_64-linux-fast

llvm-svn: 370550
2019-08-30 23:24:41 +00:00
Bob Haarman fd7569c8e3 [lld-link] implement -start-lib and -end-lib
Summary:
This implements -start-lib and -end-lib flags for lld-link, analogous
to the similarly named options in ld.lld. Object files after
-start-lib are included in the link only when needed to resolve
undefined symbols. The -end-lib flag goes back to the normal behavior
of always including object files in the link. This mimics the
semantics of static libraries, but without needing to actually create
the archive file.

Reviewers: ruiu, smeenai, MaskRay

Reviewed By: ruiu, MaskRay

Subscribers: akhuang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66848

llvm-svn: 370487
2019-08-30 16:50:10 +00:00
Martin Storsjo 08a5a0aa25 [COFF] Check errorCount before committing the output file
This avoids producing an output file if errors appeared late in the
linking process (e.g. while fixing relocations, or as in the test,
while checking for multiple resources). If an output file is produced,
build tools might not retry building it on rebuilds, even if a previous
build failed due to the error return code.

Differential Revision: https://reviews.llvm.org/D66491

llvm-svn: 369445
2019-08-20 21:08:14 +00:00
Martin Storsjo dadc6f2488 [COFF] Allow using custom .edata from input object files
This is used by Wine for manually crafting export tables.

If the input object contains .edata sections, GNU ld references them
in the export directory instead of synthesizing an export table using
either export directives or the normal auto export mechanism. (AFAIK,
historically, way way back, GNU ld didn't support synthesizing the
export table - one was supposed to generate it using dlltool and link
it in instead.)

If faced with --out-implib and --output-def, GNU ld still populates
those output files with the same export info as it would have generated
otherwise, disregarding the input .edata. As this isn't an intended
usage combination, I'm not adding checks for that in tests.

Differential Revision: https://reviews.llvm.org/D65903

llvm-svn: 369358
2019-08-20 09:53:06 +00:00
Rui Ueyama e6a33e1f11 Handle /align option.
Differential Revision: https://reviews.llvm.org/D65736

llvm-svn: 368145
2019-08-07 10:16:21 +00:00
Martin Storsjo a0cbe16ed5 [COFF] Omit automatically imported symbols from the symbol table
These symbols actually point to the symbol's IAT entry, which
obviously is different from the symbol itself (which is imported
from a different module and doesn't exist in the current one).

Omitting this symbol helps gdb inspect automatically imported
symbols, see https://sourceware.org/bugzilla/show_bug.cgi?id=24574
for discussion on the matter.

Surprisingly, those extra symbols don't seem to be an issue for
gdb when the sources have been built with clang, only with gcc.
The actual logic in gdb that this depends on still is unknown, but
omitting these symbols from the symbol table is the right thing to
do in any case.

Differential Revision: https://reviews.llvm.org/D65727

llvm-svn: 367836
2019-08-05 11:57:00 +00:00
Martin Storsjo 341a68ca2f [COFF] Unbreak sorting of mingw comdat .tls sections after SVN r363457
Code built for mingw with -fdata-sections will store each TLS variable
in a comdat section, named .tls$$<varname>. Normal TLS variables are
stored in sections named .tls$ with a trailing dollar, which are
sorted after a starter marker (in a later linked object file) in a
section named ".tls" (with no dollar suffix), before an ending marker
in a section named ".tls$ZZZ".

The mingw comdat section suffix stripping introduced in SVN r363457
broke sorting of such tls sections, ending up sorting the stripped
.tls$$<varname> sections (stripped to ".tls") before the start marker
in the section named ".tls".

We could add exceptions to the section name suffix stripping for
.tls (and .CRT, where suffixes always should be honored), but the
more conservative option is probably the reverse; to only apply the
stripping for the normal sections where sorting shouldn't have any
effect.

Differential Revision: https://reviews.llvm.org/D65018

llvm-svn: 366780
2019-07-23 06:38:04 +00:00
Reid Kleckner fe44a531e0 [COFF] Implement /safeseh:no and check @feat.00 flags by default
Summary:
Fixes PR41828. Before this, LLD always emitted SafeSEH chunks and
defined __safe_se_handler_table & size. Now, /safeseh:no leaves those
undefined.

Additionally, we were checking for the safeseh @feat.00 flag in two
places: once to emit errors, and once during safeseh table construction.
The error was set up to be off by default, but safeseh is supposed to be
on by default. I combined the two checks, so now LLD emits an error if
an input object lacks @feat.00 and safeseh is enabled. This caused the
majority of 32-bit LLD tests to fail, since many test input object files
lack @feat.00 symbols. I explicitly added -safeseh:no to those tests to
preserve behavior.

Finally, LLD no longer sets IMAGE_DLL_CHARACTERISTICS_NO_SEH if any
input file wasn't compiled for safeseh.

Reviewers: mstorsjo, ruiu, thakis

Reviewed By: ruiu, thakis

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63570

llvm-svn: 366238
2019-07-16 18:17:33 +00:00
Fangrui Song 2e2038b647 [COFF] Rename variale references in comments after VariableName -> variableName change
llvm-svn: 366193
2019-07-16 08:26:38 +00:00
Rui Ueyama 136d27ab4d [Coding style change][lld] Rename variables for non-ELF ports
This patch does the same thing as r365595 to other subdirectories,
which completes the naming style change for the entire lld directory.

With this, the naming style conversion is complete for lld.

Differential Revision: https://reviews.llvm.org/D64473

llvm-svn: 365730
2019-07-11 05:40:30 +00:00
Rui Ueyama 7e296adec7 Make functions and member variables distinguishable even after the name style change. NFC.
llvm-svn: 365605
2019-07-10 09:10:01 +00:00
Martin Storsjo 5cbff43178 [COFF] Fix .rsrc sections with differing permissions
GNU windres, and MS cvtres (unless the /readonly option is passed)
produce read-write .rsrc sections, when creating resource object files.
This caused the sections to not be added to the precreated RsrcSec,
and therefore not be added to the data directory.

Differential Revision: https://reviews.llvm.org/D63837

llvm-svn: 364660
2019-06-28 17:13:52 +00:00
Martin Storsjo 2de984cd30 [COFF] Strip section name suffix from mingw comdats
This is the second part of the fix for PR42217.

Differential Revision: https://reviews.llvm.org/D63352

llvm-svn: 363457
2019-06-14 21:02:09 +00:00
Nico Weber 80571d8ed2 Wrap comment to 80 columns
llvm-svn: 363017
2019-06-11 01:14:23 +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
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