This is what ld64 does too, so we have parity here (though I think ld64
still removes dead code more effectively than we do...)
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D112485
The hack is irrelevant for two reasons:
* binutils 2.24 is quite old and cannot handle R_X86_64_REX_GOTPCRELX from 2016 onwards anyway
* `canMergeToProgbits` allows combining SHT_INIT_ARRAY/SHT_FINI_ARRAY into SHT_PROGBITS
For a function call (using the default `-fplt`), GCC `-mcmodel=large` generates an assembly modifier which
leads to an R_X86_64_PLTOFF64 relocation. In real world,
http://git.ageinghacker.net/jitter (used by GNU poke) uses `-mcmodel=large`.
R_X86_64_PLTOFF64's formula is (if preemptible) `L - GOT + A` or (if non-preemptible) `S - GOT + A`
where `GOT` is (confusingly) the address of `.got.plt`
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D112386
GNU ld doesn't support `--no-pic-executable`.
`-p` has been removed from likely the only use case (Linux kernel) for over 2.5 years: https://git.kernel.org/linus/091bb549f7722723b284f63ac665e2aedcf9dec9
`--no-add-needed` was the pre-binutils-2.23 spelling for `--no-copy-dt-needed-entries`.
The legacy alias is irrelevant in 2021.
While attempting to simplify it, I discovered a concerning discrepancy
between our handling of LC_LINKER_OPTION vs ld64's. In particular, ld64
does not appear to check for `-all_load` nor `-ObjC` when processing
those options. Thus, if/when we fix this behavior, no duplicate symbol
error will be expected regardless of the use-after-free. As such, I've
removed the test logic that tries to induce the duplicate symbol error.
We can just rely on ASAN to do the verification.
In order to make the test run on Windows, I've removed the symlink
logic. Both ld64 and LLD handle this un-symlinked framework just fine.
I also capitalized the framework name, since that's the typical
convention.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D112195
If segments are defined in a linker script, placing an orphan section
before the found closest-rank section can result in adding it in a
previous segment and changing flags of that segment. This happens if
the orphan section has a lower sort rank than the found section. To
avoid that, the patch forces orphan sections to be moved after the
found section if segments are explicitly defined.
Differential Revision: https://reviews.llvm.org/D111717
In Driver.cpp, addFramework used std::string instance to represent the path of a framework, which will be freed after the function returns. However, this string is stored in loadedArchive, which will be used later to compare with path of newly added frameworks. This caused https://bugs.llvm.org/show_bug.cgi?id=52133. A test is included in this commit to reproduce this bug.
Now resolveDylibPath returns a StringRef instance, and it uses StringSaver to save its data, then returns it to functions on the top. This ensures the resolved framework path is still valid after LC_LINKER_OPTION is parsed.
Reviewed By: int3, #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D111706
This change implements new DAG nodes TABLE_GET/TABLE_SET, and lowering
methods for load and stores of reference types from IR arrays. These
global LLVM IR arrays represent tables at the Wasm level.
Differential Revision: https://reviews.llvm.org/D111154
This change is derived from a test case we have locally but I could not
see an equivalent in LLD's testing.
Differential Revision: https://reviews.llvm.org/D111803
prepareSymbolRelocation() in Writer.cpp adds both symbols that need binding and
symbols relocated with a pointer relocation to the got.
Pointer relocations are emitted for non-movq GOTPCREL(%rip) loads. (movqs
become GOT_LOADs so that the linker knows they can be relaxed to leaqs, while
others, such as addq, become just GOT -- a pointer relocation -- since they
can't be relaxed in that way).
For example, this C file produces a private_extern GOT relocation when
compiled with -O2 with clang:
extern const char kString[];
const char* g(int a) { return kString + a; }
Linkers need to put pointer-relocated symbols into the GOT, but ld64 marks them
as LOCAL in the indirect symbol table. This matters, since `strip -x` looks at
the indirect symbol table when deciding what to strip.
The indirect symtab emitting code was assuming that only symbols that need
binding are in the GOT, but pointer relocations where there too. Hence, the
code needs to explicitly check if a symbol is a private extern.
Fixes https://crbug.com/1242638, which has some more information in comments 14
and 15. With this patch, the output of `nm -U` on Chromium Framework after
stripping now contains just two symbols when using lld, just like with ld64.
Differential Revision: https://reviews.llvm.org/D111852
This makes Wasm EH work with dynamic linking. So far we were only able
to handle destructors, which do not use any tags or LSDA info.
1. This uses `TargetExternalSymbol` for `GCC_except_tableN` symbols,
which points to the address of per-function LSDA info. It is more
convenient to use than `MCSymbol` because it can take additional
target flags.
2. When lowering `wasm_lsda` intrinsic, if PIC is enabled, make the
symbol relative to `__memory_base` and generate the `add` node. If
PIC is disabled, continue to use the absolute address.
3. Make tag symbols (`__cpp_exception` and `__c_longjmp`) undefined in
the backend, because it is hard to make it work with dynamic
linking's loading order. Instead, we make all tag symbols undefined
in the LLVM backend and import it from JS.
4. Add support for undefined tags to the linker.
Companion patches:
- https://github.com/WebAssembly/binaryen/pull/4223
- https://github.com/emscripten-core/emscripten/pull/15266
Reviewed By: sbc100
Differential Revision: https://reviews.llvm.org/D111388
I noticed that we had this case in our internal testsuite but couldn't find it in LLD's tests.
This adds that case.
Differential Revision: https://reviews.llvm.org/D110716
This field only exists if the directory exists on the machine running
the test. It likely exists for most Intel macOS users because of
homebrew, but doesn't exist on some of the CI machines. This
unfortunately makes this test a bit less strict.
Differential Revision: https://reviews.llvm.org/D111361
Some subprojects like compiler-rt define the `darwin` feature in their
lit config, but lld does not do that, so we need to use the global
system-darwin here instead. This test seems to have drifted from the
actual behavior so I also had to add `/usr/local/lib` here to make it
pass.
Differential Revision: https://reviews.llvm.org/D111268
This removes `WasmTagType`. `WasmTagType` contained an attribute and a
signature index:
```
struct WasmTagType {
uint8_t Attribute;
uint32_t SigIndex;
};
```
Currently the attribute field is not used and reserved for future use,
and always 0. And that this class contains `SigIndex` as its property is
a little weird in the place, because the tag type's signature index is
not an inherent property of a tag but rather a reference to another
section that changes after linking. This makes tag handling in the
linker also weird that tag-related methods are taking both `WasmTagType`
and `WasmSignature` even though `WasmTagType` contains a signature
index. This is because the signature index changes in linking so it
doesn't have any info at this point. This instead moves `SigIndex` to
`struct WasmTag` itself, as we did for `struct WasmFunction` in D111104.
In this CL, in lib/MC and lib/Object, this now treats tag types in the
same way as function types. Also in YAML, this removes `struct Tag`,
because now it only contains the tag index. Also tags set `SigIndex` in
`WasmImport` union, as functions do.
I think this makes things simpler and makes tag handling more in line
with function handling. These two shares similar properties in that both
of them have signatures, but they are kind of nominal so having the same
signature doesn't mean they are the same element.
Also a drive-by fix: the reserved 'attirubute' part's encoding changed
from uleb32 to uint8 a while ago. This was fixed in lib/MC and
lib/Object but not in YAML. This doesn't change object files because the
field's value is always 0 and its encoding is the same for the both
encoding.
This is effectively NFC; I didn't mark it as such just because it
changed YAML test results.
Reviewed By: sbc100, tlively
Differential Revision: https://reviews.llvm.org/D111086
PT_LOAD segments in the program header must be sorted by their virtual
addresses, so they should be defined in a similar order as the
associated sections.
Differential Revision: https://reviews.llvm.org/D111068
A number of the ICF tests were not updated to use --print-icf-sections
instead of --verbose and various '-NOT' checks were not updated to the
latest output format of --print-icf-sections. Because these are all
'negative' tests, these issues have gone unnoticed.
Differential Revision: https://reviews.llvm.org/D110353
Try to address Windows flakes from d87bdc272b
by adding "|| true" as suggested in D110276 so the whole test doesn't
fail when Windows thinks it can't remove the binary.
Instead, just make the later flag win, like usual.
Implement this by making -no_deduplicate an actual alias for --icf=none
at the Options.td level.
Differential Revision: https://reviews.llvm.org/D110672
In looking at the disk space used by a ninja check-all, I found that a
few of the largest files were copies of clang and lld made into temp
directories by a couple of tests. These tests were added in D53021 and
D74811. Clean up these copies after usage.
Differential Revision: https://reviews.llvm.org/D110276
The ARM backend was explicitly setting global binding on the personality
symbol. This was added without any comment in a7ec2dcefd, which
introduced EHABI support (back in 2011). None of the other backends do
anything equivalent, as far as I can tell.
This causes problems when attempting to wrap the personality symbol.
Wrapped symbols are marked as weak inside LTO to inhibit IPO (see
https://reviews.llvm.org/D33621). When we wrap the personality symbol,
it initially gets weak binding, and then the ARM backend attempts to
change the binding to global, which causes an error in MC because of
attempting to change the binding of a symbol from non-global to global
(the error was added in https://reviews.llvm.org/D90108).
Simply drop the ARM backend's explicit global binding setting to fix
this. This matches all the other backends, and a large internal
application successfully linked and ran with this change, so it
shouldn't cause any problems. Test via LLD, since wrapping is required
to exhibit the issue.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D110609
* Add a newline before `DYNAMIC RELOCATION RECORDS` (see D101796)
* Add the missing `OFFSET TYPE VALUE` line
* Align columns
Note: llvm-readobj/ELFDumper.cpp `loadDynamicTable` has sophisticated PT_DYNAMIC
code which is unavailable in llvm-objdump.
Reviewed By: jhenderson, Higuoxing
Differential Revision: https://reviews.llvm.org/D110595
(As I mentioned in https://reviews.llvm.org/D62609#1534158 ,
the condition for using bti c for executable can be loosened.)
In two cases the address of a PLT may escape:
* canonical PLT entry for a STT_FUNC
* non-preemptible STT_GNU_IFUNC which is converted to STT_FUNC
The first case can be detected with `needsPltAddr`.
The second case is not straightforward to detect because for the Relocations.cpp
created `directSym`, it's difficult to know whether the associated `sym` has
exercised the `!needsPlt(expr)` code path. Just use the conservative `isInIplt`
condition. A non-preemptible ifunc not referenced by non-GOT-generating
non-PLT-generating relocations will have an unneeded `bti c`, but the cost is acceptable.
The second case fixes a bug as well: a -shared link may have non-preemptible ifunc.
Before the patch we did not emit `bti c` and could be wrong if the PLT address escaped.
GNU ld doesn't handle the case: `relocation R_AARCH64_ADR_PREL_PG_HI21 against STT_GNU_IFUNC symbol 'ifunc2' isn't handled by elf64_aarch64_final_link_relocate` (https://sourceware.org/bugzilla/show_bug.cgi?id=28370)
For -shared, if BTI is enabled but PAC is disabled, the PLT entry size increases
from 16 to 24 because we have to select the PLT scheme early, but the cost is
acceptable.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D110217
Currenlty PseudoProbeInserter is a pass conditioned on a target switch. It works well with a single clang invocation. It doesn't work so well when the backend is called separately (i.e, through the linker or llc), where user has always to pass -pseudo-probe-for-profiling explictly. I'm making the pass a default pass that requires no command line arg to trigger, but will be actually run depending on whether the CU comes with `llvm.pseudo_probe_desc` metadata.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D110209
Restore the checking of addresses in ICF test which was testing the
behaviour of ICF with regards to different alignments of otherwise
identical sections. Also make the test more robust to layout changes.
Differential Revision: https://reviews.llvm.org/D110090
Similar to D69607 but for archive member extraction unrelated to GC. This patch adds --why-extract=.
Prior art:
GNU ld -M prints
```
Archive member included to satisfy reference by file (symbol)
a.a(a.o) main.o (a)
b.a(b.o) (b())
```
-M is mainly for input section/symbol assignment <-> output section mapping
(often huge output) and the information may appear ad-hoc.
Apple ld64
```
__Z1bv forced load of b.a(b.o)
_a forced load of a.a(a.o)
```
It doesn't say the reference file.
Arm's proprietary linker
```
Selecting member vsnprintf.o(c_wfu.l) to define vsnprintf.
...
Loading member vsnprintf.o from c_wfu.l.
definition: vsnprintf
reference : _printf_a
```
---
--why-extract= gives the user the full data (which is much shorter than GNU ld
-Map). It is easy to track a chain of references to one archive member with a
one-liner, e.g.
```
% ld.lld main.o a_b.a b_c.a c.a -o /dev/null --why-extract=- | tee stdout
reference extracted symbol
main.o a_b.a(a_b.o) a
a_b.a(a_b.o) b_c.a(b_c.o) b()
b_c.a(b_c.o) c.a(c.o) c()
% ruby -ane 'BEGIN{p={}}; p[$F[1]]=[$F[0],$F[2]] if $.>1; END{x="c.a(c.o)"; while y=p[x]; puts "#{y[0]} extracts #{x} to resolve #{y[1]}"; x=y[0] end}' stdout
b_c.a(b_c.o) extracts c.a(c.o) to resolve c()
a_b.a(a_b.o) extracts b_c.a(b_c.o) to resolve b()
main.o extracts a_b.a(a_b.o) to resolve a
```
Archive member extraction happens before --gc-sections, so this may not be a live path
under --gc-sections, but I think it is a good approximation in practice.
* Specifying a file avoids output interleaving with --verbose.
* Required `=` prevents accidental overwrite of an input if the user forgets `=`. (Most of compiler drivers' long options accept `=` but not ` `)
Differential Revision: https://reviews.llvm.org/D109572
Original commit description:
[LLD] Remove global state in lld/COFF
This patch removes globals from the lldCOFF library, by moving globals
into a context class (COFFLinkingContext) and passing it around wherever
it's needed.
See https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html for
context about removing globals from LLD.
I also haven't moved the `driver` or `config` variables yet.
Differential Revision: https://reviews.llvm.org/D109634
This reverts commit a2fd05ada9.
Original commits were b4fa71eed3
and e03c7e367a.
Sometimes people intentionally re-define a dylib personlity symbol as a local defined symbol as a workaround to a ld -r bug.
As a result, we could see "too many personalities" to encode. This patch tries to handle this case by ignoring the local symbols entirely.
Differential Revision: https://reviews.llvm.org/D107533
Add a test to ensure that MachO files including
a LC_CODE_SIGNATURE load command produced by lld
are signed correctly.
Reviewed By: #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D109840
This test checks that timers are working and printing as expected.
I also seem to have changed the order of the timers in my globals refactoring
patch, so I fixed it here.
Differential Revision: https://reviews.llvm.org/D109904
Rather than depending on the hex dump from obj2yaml. Now the test shows the
expected function body in a human readable format.
Differential Revision: https://reviews.llvm.org/D109730
This matters for example for the iPhoneSimulator14.0.sdk, which has
a System/Library/Frameworks/UIKit.framework/UIKit that has
LC_BUILD_VERSION with minos of 14.0, so linking against that file
will produce warnings like:
.../iPhoneSimulator14.0.sdk/System/Library/Frameworks/UIKit.framework/UIKit
has version 14.0.0, which is newer than target minimum of 12.0.0
when targeting x86_64-apple-ios12.0-simulator. That doens't happen when
linking against UIKit.tbd instead, obviously.
Linking with RC_TRACE_DYLIB_SEARCHING=1 shows that ld64 also searches
the tbd file first, and we already get that right for non-framework
dylibs.
Fixes crbug.com/1249456.
Differential Revision: https://reviews.llvm.org/D109768
We previously had a limitation that TLS variables could not
be exported (and therefore could also not be imported). This
change removed that limitation.
Differential Revision: https://reviews.llvm.org/D108877
For multithreaded modules (i.e. modules with a shared memory), lld injects a
synthetic Wasm start function that is automatically called during instantiation
to initialize memory from passive data segments. Even though the module will be
instantiated separately on each thread, memory initialization should happen only
once. Furthermore, memory initialization should be finished by the time each
thread finishes instantiation. Since multiple threads may be instantiating their
modules at the same time, the synthetic function must synchronize them.
The current synchronization tries to atomically increment a flag from 0 to 1 in
memory then enters one of two cases. First, if the increment was successful, the
current thread is responsible for initializing memory. It does so, increments
the flag to 2 to signify that memory has been initialized, then notifies all
threads waiting on the flag. Otherwise, the thread atomically waits on the flag
with an expected value of 1 until memory has been initialized. Either the
initializer thread finishes initializing memory (i.e. sets the flag to 2) first
and the waiter threads do not end up blocking, or the waiter threads succesfully
start waiting before memory is initialized so they will be woken by the
initializer thread once it has finished.
One complication with this scheme is that there are various contexts on the Web,
most notably on the main browser thread, that cannot successfully execute a
wait. Executing a wait in these contexts causes a trap, and in this case would
cause instantiation to fail. The embedder must therefore ensure that these
contexts win the race and become responsible for initializing memory, since that
is the only code path that does not execute a wait.
Unfortunately, since only one thread can win the race and initialize memory,
this scheme makes it impossible to have multiple threads in contexts that cannot
wait. For example, it is not currently possible to instantiate the module on
both the main browser thread as well as in an AudioWorklet. To loosen this
restriction, this commit inserts an extra check so that the wait will not be
executed at all when memory has already been initialized, i.e. when the flag
value is 2. After this change, the module can be instantiated on threads in
non-waiting contexts as long as the embedder can guarantee either that the
thread will win the race and initialize memory (as before) or that memory has
already been initialized when instantiation begins. Threads in contexts that can
wait can continue racing to initialize memory.
Fixes (or at least improves) PR51702.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D109722
In the case that TLS is used in the single-threaded program, and
therefore effectively lowered away, we still optionally create a
`__tls_base` symbols, but the code for setting it was assuming it was
always created.
Differential Revision: https://reviews.llvm.org/D109518
Failing to do so results in `std::bad_function_call` being
thrown when a pass tries to emit a diagnostic.
I've copied the relevant test over from LLD-ELF's test suite.
Reviewed By: #lld-macho, thevinster
Differential Revision: https://reviews.llvm.org/D109274
We end up calling resolveBranchVA(), which asserts for Undefineds.
As fix, just return early in Writer::run() if there are any diagnostics
after processing relocations (which is where undefined symbol errors are
emitted). This matches what the ELF port does.
Differential Revision: https://reviews.llvm.org/D109079
Fixes PR51578 in practice.
Currently there's only enough room for a single thunk, which for real-life code
isn't enough. The error case only happens when there are many branch statements
very close to each other (0 or 1 instructions apart), with the function at the
finalization barrier small.
There's a FIXME on what to do if we hit this case, but that suggestion sounds
complicated to me (see end of PR51578 comment 5 for why).
Instead, just leave more room for thunks. Chromium's unit_tests links fine with
room for 3 thunks. Leave room for 100, which should fix this for most cases in
practice.
There's little cost for leaving lots of room: This slop value only determines
when we finalize sections, and we insert thunks for forward jumps into
unfinalized sections. So leaving room means we'll need a few more thunks, but
the thunk jump range is 128 MiB while a single thunk is just 12 bytes.
For Chromium's unit_tests:
With a slop of 3: thunk calls = 355418, thunks = 10903
With a slop of 100: thunk calls = 355426, thunks = 10904
Chances are 100 is enough for all use cases we'll hit in practice, but even
bumping it to 1000 would probably be fine.
Differential Revision: https://reviews.llvm.org/D108930
The assert is harmless and thinks worked fine in builds with asserts enabled,
but it's still nice to fix the assert.
Differential Revision: https://reviews.llvm.org/D108853
This is what ld64 does. Deviating in behavior here can result
in some subtle duplicate symbol errors, as detailed in the objc.s test.
Differential Revision: https://reviews.llvm.org/D108781
The previous logic was duplicated between symbol-initiated
archive loads versus flag-initiated loads (i.e. `-force_load` and
`-ObjC`). This resulted in code duplication as well as redundant work --
we would create Archive instances twice whenever we had one of those
flags; once in `getArchiveMembers` and again when we constructed the
ArchiveFile.
This was motivated by an upcoming diff where we load archive members
containing ObjC-related symbols before loading those containing
ObjC-related sections, as well as before performing symbol resolution.
Without this refactor, it would be difficult to do that while avoiding
loading the same archive member twice.
Differential Revision: https://reviews.llvm.org/D108780
If multiple /manifestdependency: flags are passed, they are
naively deduped, but after that each of them should have an
effect, instead of just the last one.
Also, /manifestdependency: flags are allowed in .drectve sections
(from `#pragma comment(linker, ...`). To make the interaction between
/manifestdependency: flags enabling manifest by default but
/manifest:no overriding this work, add an explict ManifestKind::Default
state to represent no explicit /manifest flag being passed.
To make /manifestdependency: flags from input file .drectve sections
work with /manifest:embed, delay embedded manifest emission until
after input files have been read.
Differential Revision: https://reviews.llvm.org/D108628
This CL is small, but the description can be a little long because I'm
trying to sum up the status quo for Emscripten/Wasm EH/SjLj options.
First, this CL adds an option for Wasm SjLj (`-wasm-enable-sjlj`), which
handles SjLj using Wasm EH. The implementation for this will be added as
a followup CL, but this adds the option first to do error checking.
This also adds an option for Wasm EH (`-wasm-enable-eh`), which has been
already implemented. Before we used `-exception-model=wasm` as the same
meaning as enabling Wasm EH, but after we add Wasm SjLj, it will be
possible to use Wasm EH instructions for Wasm SjLj while not enabling
EH, so going forward, to use Wasm EH, `opt` and `llc` will need this
option. This only affects `opt` and `llc` command lines and does not
affect Emscripten user interface.
Now we have two modes of EH (Emscripten/Wasm) and also two modes of SjLj
(also Emscripten/Wasm). The options corresponding to each of are:
- Emscripten EH: `-enable-emscripten-cxx-exceptions`
- Emscripten SjLj: `-enable-emscripten-sjlj`
- Wasm EH: `-wasm-enable-eh -exception-model=wasm`
`-mattr=+exception-handling`
- Wasm SjLj: `-wasm-enable-sjlj -exception-model=wasm`
`-mattr=+exception-handling`
The reason Wasm EH/SjLj's options are a little complicated are
`-exception-model` and `-mattr` are common LLVM options ane not under
our control. (`-mattr` can be omitted if it is embedded within the
bitcode file.)
And we have the following rules of the option composition:
- Emscripten EH and Wasm EH cannot be turned on at the same itme
- Emscripten SjLj and Wasm SjLj cannot be turned on at the same time
- Wasm SjLj should be used with Wasm EH
Which means we now allow these combinations:
- Emscripten EH + Emscripten SjLj: the current default in `emcc`
- Wasm EH + Emscripten SjLj:
This is allowed, but only as an interim step in which we are testing
Wasm EH but not yet have a working implementation of Wasm SjLj. This
will error out (D107687) in compile time if `setjmp` is called in a
function in which Wasm exception is used.
- Wasm EH + Wasm SjLj:
This will be the default mode later when using Wasm EH. Currently Wasm
SjLj implementation doesn't exist, so it doesn't work.
- Emscripten EH + Wasm SjLj will not work.
This CL moves these error checking routines to
`WebAssemblyPassConfig::addIRPasses`. Not sure if this is an ideal place
to do this, but I couldn't find elsewhere. Currently some checking is
done within LowerEmscriptenEHSjLj, but these checks only run if
LowerEmscriptenEHSjLj runs so it may not run when Wasm EH is used. This
moves that to `addIRPasses` and adds some more checks.
Currently LowerEmscriptenEHSjLj pass is responsible for Emscripten EH
and Emscripten SjLj. Wasm EH transformations are done in multiple
places, including WasmEHPrepare, LateEHPrepare, and CFGStackify. But in
the followup CL, LowerEmscriptenEHSjLj pass will be also responsible for
a part of Wasm SjLj transformation, because WasmSjLj will also be using
several Emscripten library functions, and we will be sharing more than
half of the transformation to do that between Emscripten SjLj and Wasm
SjLj.
Currently we have `-enable-emscripten-cxx-exceptions` and
`-enable-emscripten-sjlj` but these only work for `llc`, because for
`llc` we feed these options to the pass but when we run the pass using
`opt` the pass will be created with no options and the default options
will be used, which turns both Emscripten EH and Emscripten SjLj on.
Now we have one more SjLj option to care for, LowerEmscriptenEHSjLj pass
needs a finer way to control these options. This CL removes those
default parameters and make LowerEmscriptenEHSjLj pass read directly
from command line options specified. So if we only run
`opt -wasm-lower-em-ehsjlj`, currently both Emscripten EH and Emscripten
SjLj will run, but with this CL, none will run unless we additionally
pass `-enable-emscripten-cxx-exceptions` or `-enable-emscripten-sjlj`,
or both. This does not affect users; this only affects our `opt` tests
because `emcc` will not call either `opt` or `llc`. As a result of this,
our existing Emscripten EH/SjLj tests gained one or both of those
options in their `RUN` lines.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D107685
In the case of weakly defined symbols in shared libraries we now
generate both an import and an export. The dynamic linker can then
choose how a winner from among all the shared libraries that define a
given symbol.
Previously any direct usage of a weakly defined symbol would use the
DSO-local definition (For example, even through there would be single
address for a weakly defined function, each DSO could end up directly
calling its local version).
Fixes: https://github.com/emscripten-core/emscripten/issues/13773
Differential Revision: https://reviews.llvm.org/D108413
In PIC mode we import function address via `GOT.mem` imports but for
direct function calls we still import the first class function.
However, if the function is never directly called we can avoid the first
class import completely.
Differential Revision: https://reviews.llvm.org/D108345
The convention is not to check the prefix before `error: `.
This gives flexibility if we need to rename ld64.lld to something else,
(e.g. a while ago we used ld64.lld.darwinnew).
There was an instance of a third-party archive containing multiple
_llvm symbols from different files that clashed with each other
producing duplicate symbols. Symbols under the LLVM segment
don't seem to be producing any meaningful value, so just ignore them.
Reviewed By: #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D108016
In e72403f96d, we added the flag
"--no-dynamicbase" for disabling the dynamicbase flag which we set
by default. At the time, ld.bfd didn't have any corresponding
option (as ld.bfd defaulted to not setting the flag). Almost at
the same time, corresponding options were added to ld.bfd for
disabling it (while it was being enabled by default), with a
different name, "--disable-dynamicbase".
Thus add the "--disable-dynamicbase" option. Make this default
one advertised in the help listing, but keep the "--no-dynamicbase"
form as an alias. Also improve checking for the last option set
if there are multiple ones on the same command line.
Also add corresponding disable options for a lot of other flags
that we set by default, also added in ld.bfd in the same commit:
https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=514b4e191d5f46de8e142fe216e677a35fa9c4bb
Differential Revision: https://reviews.llvm.org/D107930
When enable CSPGO for ThinLTO, there are profile cfg mismatch warnings that will cause lld-link errors (with /WX)
due to source changes (e.g. `#if` code runs for profile generation but not for profile use)
To disable it we have to use an internal "/mllvm:-no-pgo-warn-mismatch" option.
In contrast clang uses option ”-Wno-backend-plugin“ to avoid such warnings and gcc has an explicit "-Wno-coverage-mismatch" option.
Add "lto-pgo-warn-mismatch" option to lld COFF/ELF to help turn on/off the profile mismatch warnings explicitly when build with ThinLTO and CSPGO.
Differential Revision: https://reviews.llvm.org/D104431
When enable CSPGO for ThinLTO, there are profile cfg mismatch warnings that will cause lld-link errors (with /WX).
To disable it we have to use an internal "/mllvm:-no-pgo-warn-mismatch" option.
In contrast clang uses option ”-Wno-backend-plugin“ to avoid such warnings and gcc has an explicit "-Wno-coverage-mismatch" option.
Add this "lto-pgo-warn-mismatch" option to lld to help turn on/off the profile mismatch warnings explicitly when build with ThinLTO and CSPGO.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D104431
Now that we have https://reviews.llvm.org/D105539 we can
use objdump -d to actually check for instruction sequences
rather than binary blobs.
This is just an example of how to do that we should followup
with a wider ranging conversion of existing tests.
Differential Revision: https://reviews.llvm.org/D106897
Clang diagnostics refer to identifier names in quotes.
This patch makes inline remarks conform to the convention.
New behavior:
```
% clang -O2 -Rpass=inline -Rpass-missed=inline -S a.c
a.c:4:25: remark: 'foo' inlined into 'bar' with (cost=-30, threshold=337) at callsite bar:0:25; [-Rpass=inline]
int bar(int a) { return foo(a); }
^
```
Reviewed By: hoy
Differential Revision: https://reviews.llvm.org/D107791
This adds thin archives to the map file test.
I noticed that we had this test-case in our downstream
testsuite but it wasn't in the upstream testing.
Differential revision: https://reviews.llvm.org/D107555
This patch enables compressed input sections on big-endian targets by
checking the target endianness and selecting an appropriate `Chdr`
structure.
Fixes PR51369
Differential Revision: https://reviews.llvm.org/D107635
See: http://45.33.8.238/macm1/15677/step_10.txt
This is a test that has `REQUIRES: x86` which means it never ran
before; I don't have a MachO environment but based on the FileCheck
output it looks like it should be sufficient to remove one CHECK line.
Copy relocation on a non-default version symbol is unsupported and can crash at
runtime. Fortunately there is a one-line fix which works for most cases:
ensure `getSymbolsAt` unconditionally returns `ss`.
If two non-default version symbols are defined at the same place and both
are copy relocated, our implementation will copy relocated them into different
addresses. The pointer inequality is very unlikely an issue. In GNU ld, copy
relocating version aliases seems to create more pointer inequality problems than
us.
(
In glibc, sys_errlist@GLIBC_2.2.5 sys_errlist@GLIBC_2.3 sys_errlist@GLIBC_2.4
are defined at the same place, but it is unlikely they are all copy relocated in
one executable. Even if so, the variables are read-only and pointer inequality
should not be a problem.
)
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107535
Currently version script patterns are ignored for .symver produced
non-default version (single @) symbols. This makes such symbols
not localizable by `local:`, e.g.
```
.symver foo3_v1,foo3@v1
.globl foo_v1
foo3_v1:
ld.lld --version-script=a.ver -shared a.o
```
This patch adds the support:
* Move `config->versionDefinitions[VER_NDX_LOCAL].patterns` to `config->versionDefinitions[versionId].localPatterns`
* Rename `config->versionDefinitions[versionId].patterns` to `config->versionDefinitions[versionId].nonLocalPatterns`
* Allow `findAllByVersion` to find non-default version symbols when `includeNonDefault` is true. (Note: `symtab` keys do not have `@@`)
* Make each pattern check both the unversioned `pat.name` and the versioned `${pat.name}@${v.name}`
* `localPatterns` can localize `${pat.name}@${v.name}`. `nonLocalPatterns` can prevent localization by assigning `verdefIndex` (before `parseSymbolVersion`).
---
If a user notices new `undefined symbol` errors with a version script containing
`local: *;`, the issue is likely due to a missing `global:` pattern.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107234
Due to an assembler design flaw (IMO), `.symver foo,foo@v1` produces two symbols `foo` and `foo@v1` if `foo` is defined.
* `v1 {};` produces both `foo` and `foo@v1`, but GNU ld only produces `foo@v1`
* `v1 { foo; };` produces both `foo@@v1` and `foo@v1`, but GNU ld only produces `foo@v1`
* `v2 { foo; };` produces both `foo@@v2` and `foo@v1`, matching GNU ld. (Tested by symver.s)
This patch implements the GNU ld behavior by reusing the symbol redirection mechanism
in D92259. The new test symver-non-default.s checks the first two cases.
Without the patch, the second case will produce `foo@v1` and `foo@@v1` which
looks weird and makes foo unnecessarily default versioned.
Note: `.symver foo,foo@v1,remove` exists but the unfortunate `foo` will not go
away anytime soon.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107235
Currently version script patterns are ignored for .symver produced
non-default version (single @) symbols. This makes such symbols
not localizable by `local:`, e.g.
```
.symver foo3_v1,foo3@v1
.globl foo_v1
foo3_v1:
ld.lld --version-script=a.ver -shared a.o
# In a.out, foo3@v1 is incorrectly exported.
```
This patch adds the support:
* Move `config->versionDefinitions[VER_NDX_LOCAL].patterns` to `config->versionDefinitions[versionId].localPatterns`
* Rename `config->versionDefinitions[versionId].patterns` to `config->versionDefinitions[versionId].nonLocalPatterns`
* Allow `findAllByVersion` to find non-default version symbols when `includeNonDefault` is true. (Note: `symtab` keys do not have `@@`)
* Make each pattern check both the unversioned `pat.name` and the versioned `${pat.name}@${v.name}`
* `localPatterns` can localize `${pat.name}@${v.name}`. `nonLocalPatterns` can prevent localization by assigning `verdefIndex` (before `parseSymbolVersion`).
---
If a user notices new `undefined symbol` errors with a version script containing
`local: *;`, the issue is likely due to a missing `global:` pattern.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107234
GNU ld doesn't support multiple SHF_TLS SHT_NOBITS output sections (it restores
the address after an SHF_TLS SHT_NOBITS section, so consecutive SHF_TLS
SHT_NOBITS sections will have conflicting address ranges).
That said, `threadBssOffset` implements limited support for consecutive SHF_TLS
SHT_NOBITS sections. (SHF_TLS SHT_PROGBITS following a SHF_TLS SHT_NOBITS can still be
incorrect.)
`.` in an output section description of an SHF_TLS SHT_NOBITS section is
incorrect. (https://lists.llvm.org/pipermail/llvm-dev/2021-July/151974.html)
This patch saves the end address of the previous tbss section in
`ctx->tbssAddr`, changes `dot` in the beginning of `assignOffset` so
that `.` evaluation will be correct.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107208
This is available in GNU ld 2.35 and can be seen as a shortcut for multiple
--export-dynamic-symbol, or a --dynamic-list variant without the symbolic intention.
In the long term, this option probably should be preferred over --dynamic-list.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107317
This does the same fix as D107237 but for a couple more options,
converting all remaining cases of such options to accept both
forms, for consistency. This fixes building e.g. openldap, which
uses --image-base=<value>.
Differential Revision: https://reviews.llvm.org/D107253
This option is a subset of -Bsymbolic-functions. It applies to STB_GLOBAL
STT_FUNC definitions.
The address of a vague linkage function (STB_WEAK STT_FUNC, e.g. an inline
function, a template instantiation) seen by a -Bsymbolic-functions linked
shared object may be different from the address seen from outside the shared
object. Such cases are uncommon. (ELF/Mach-O programs may use
`-fvisibility-inlines-hidden` to break such pointer equality. On Windows,
correct dllexport and dllimport are needed to make pointer equality work.
Windows link.exe enables /OPT:ICF by default so different inline functions may
have the same address.)
```
// a.cc -> a.o -> a.so (-Bsymbolic-functions)
inline void f() {}
void *g() { return (void *)&f; }
// b.cc -> b.o -> exe
// The address is different!
inline void f() {}
```
-Bsymbolic-non-weak-functions is a safer (C++ conforming) subset of
-Bsymbolic-functions, which can make such programs work.
Implementations usually emit a vague linkage definition in a COMDAT group. We
could detect the group (with more code) but I feel that we should just check
STB_WEAK for simplicity. A weak definition will thus serve as an escape hatch
for rare cases when users want interposition on definitions.
GNU ld feature request: https://sourceware.org/bugzilla/show_bug.cgi?id=27871
Longer write-up: https://maskray.me/blog/2021-05-16-elf-interposition-and-bsymbolic
If Linux distributions migrate to protected non-vague-linkage external linkage
functions by default, the linker option can still be handy because it allows
rapid experiment without recompilation. Protected function addresses currently
have deep issues in GNU ld.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D102570
Jez Ng