…210)"
This reverts commit 9a14b1d254a43dc0d4445c3ffa3d393bca007ba3.
Revert "RuntimeLibcalls: Return StringRef for libcall names (#153209)"
This reverts commit cb1228fbd535b8f9fe78505a15292b0ba23b17de.
Revert "TableGen: Emit statically generated hash table for runtime
libcalls (#150192)"
This reverts commit 769a9058c8d04fc920994f6a5bbb03c8a4fbcd05.
Reverted three changes because of a CMake error while building llvm-nm
as reported in the following PR:
https://github.com/llvm/llvm-project/pull/150192#issuecomment-3192223073
Using LLVMContext to emit the error from `TargetRegistry::lookupTarget`
that was silently ignored and not propagated. This allows user to better
identify the kind of error occured.
rdar://157542119
With the current aliases metadata we lose information about which groups
of aliases survive symbol resolution. This causes various problems such
as #150075 where symbol resolution breaks the link between alias groups.
In this redesign of the aliases metadata, we stop representing the
individual aliases in !aliases. Instead, the individual aliases are
represented in !cfi.functions in the same way as functions, and the
alias groups (i.e. groups of symbols with the same address) are stored
in !aliases. At symbol resolution time, we filter out all non-prevailing
members of !aliases; the resulting set is used by LowerTypeTests to
recreate the aliases.
With this change it is now possible for a jump table entry to refer
to an alias in one of the ThinLTO object files (e.g. if a function is
non-prevailing but its alias is prevailing), so instead of deleting them,
rename them with the ".cfi" suffix.
Fixes#150070.
Fixes#150075.
Reviewers: teresajohnson, vitalybuka
Reviewed By: vitalybuka
Pull Request: https://github.com/llvm/llvm-project/pull/150690
Work towards separating the ABI existence of libcalls vs. the
lowering selection. Set libcall selection through enums, rather
than through raw string names.
This flag was used to let us incrementally introduce debug records
into LLVM, however everything is now using records. It serves no
purpose now, so delete it.
Currently, GlobalObject has an "alignment" property... but it's
basically nonsense: alignment doesn't mean the same thing for variables
and functions, and it's completely meaningless for ifuncs.
This "removes" (actually marking protected) the methods from
GlobalObject, adds the relevant methods to Function and GlobalVariable,
and adjusts the code appropriately.
This should make future alignment-related cleanups easier.
Start removing debug intrinsics support -- starting with the flag that
controls production of their replacement, debug records. This patch
removes the command-line-flag and with it the ability to switch back to
intrinsics. The module / function / block level "IsNewDbgInfoFormat"
flags get hardcoded to true, I'll to incrementally remove things that
depend on those flags.
## Purpose
This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/LTO` library. These
annotations currently have no meaningful impact on the LLVM build;
however, they are a prerequisite to support an LLVM Windows DLL (shared
library) build.
## Background
This effort is tracked in #109483. Additional context is provided in
[this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).
The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.
The following manual adjustments were also applied after running IDS on
Linux:
- Add `LLVM_ABI` to a small number of symbols that require export but
are not declared in headers
## Validation
Local builds and tests to validate cross-platform compatibility. This
included llvm, clang, and lldb on the following configurations:
- Windows with MSVC
- Windows with Clang
- Linux with GCC
- Linux with Clang
- Darwin with Clang
This annotates the `Twine` passed to the constructors of the various
DiagnosticInfo subclasses with `[[clang::lifetimebound]]`, which causes
us to warn when we would try to print the twine after it had already
been destructed.
We also update `DiagnosticInfoUnsupported` to hold a `const Twine &`
like all of the other DiagnosticInfo classes, since this warning allows
us to clean up all of the places where it was being used incorrectly.
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
This patch adds initial support for Integrated Distributed ThinLTO
(DTLTO) in LLVM, which manages distribution internally during the
traditional link step. This enables compatibility with any build
system that supports in-process ThinLTO. In contrast, existing
approaches to distributed ThinLTO, which split the thin-link
(--thinlto-index-only), backend compilation, and final link into
separate steps, require build system support, e.g. Bazel.
This patch implements the core DTLTO mechanism, which enables
delegation of ThinLTO backend jobs to an external process (the
distributor). The distributor can then manage job distribution through
systems like Incredibuild. A generic JSON interface is used to
communicate with the distributor, allowing for the creation of new
distributors (and thus integration with different distribution
systems) without modifying LLVM.
Please see llvm/docs/dtlto.rst for more details.
RFC: https://discourse.llvm.org/t/rfc-integrated-distributed-thinlto/69641
Design Review: https://github.com/llvm/llvm-project/pull/126654
Usage errors in `LTOBackend.cpp` were previously, misleadingly, reported
as internal crashes.
This PR updates `LTOBackend.cpp` to use `reportFatalUsageError` for
reporting usage-related issues.
LLVM Issue: https://github.com/llvm/llvm-project/issues/140953
Internal Tracker: TOOLCHAIN-17744
try_emplace can default-construct values, so we do not need to do so
on our own. Plus, try_emplace(Key) is much shorter than
insert(std::make_pair(Key, Value()).
The `CacheStream::commit()` function (defined in Caching.cpp) deletes
the underlying raw stream. Some output streamers may hold a pointer
to it, which then will outlive the stream object.
In particular, MCAsmStreamer keeps the pointer to the raw stream
though a separate `formatted_raw_stream` object, which buffers data and
there is no path to explicitly flush this data. Before this change,
the buffered data was flushed during the MCAsmStreamer destructor.
After #136121, this happened after the `commit()` function is called.
Therefore, it caused a crash because the `formatted_raw_stream` object
tries to write the buffered data into a deleted raw stream. Even if
we don't delete the stream to avoid the crash, it would be too late
as the output stream cannot accept data after commit().
Fixes: #138194.
This implements the result of the discussion at:
https://discourse.llvm.org/t/rfc-report-fatal-error-and-the-default-value-of-gencrashdialog/73587
There are two different use cases for report_fatal_error, so replace it
with two functions reportFatalInternalError() and
reportFatalUsageError(). The former indicates a bug in LLVM and
generates a crash dialog. The latter does not. The names have been
suggested by rnk and people seemed to like them.
This replaces a lot of the usages that passed an explicit value for
GenCrashDiag. I did not bulk replace remaining report_fatal_error usage
-- they probably require case by case review for which function to use.
See https://discourse.llvm.org/t/rfc-keep-globalvalue-guids-stable/84801
for context.
This is a non-functional change which just changes the interface of
GlobalValue, in preparation for future functional changes. This part
touches a fair few users, so is split out for ease of review. Future
changes to the GlobalValue implementation can then be focused purely on
that class.
This does the following:
* Rename GlobalValue::getGUID(StringRef) to
getGUIDAssumingExternalLinkage. This is simply making explicit at the
callsite what is currently implicit.
* Where possible, migrate users to directly calling getGUID on a
GlobalValue instance.
* Otherwise, where possible, have them call the newly renamed
getGUIDAssumingExternalLinkage, to make the assumption explicit.
There are a few cases where neither of the above are possible, as the
caller saves and reconstructs the necessary information to compute the
GUID themselves. We want to migrate these callers eventually, but for
this first step we leave them be.
…Stream.
CachedFileStream has previously performed the commit step in its
destructor, but this means its only recourse for error handling is
report_fatal_error. Modify this to add an explicit commit() method, and
call this in the appropriate places with appropriate error handling for
the location.
Currently the destructor of CacheStream gives an assert failure in Debug
builds if commit() was not called. This will help track down any
remaining uses of the API that assume the old destructior behaviour. In
Release builds we fall back to the previous behaviour and call
report_fatal_error if the commit fails.
This is version 2 of this PR, superseding reverted PR
https://github.com/llvm/llvm-project/pull/115331 . I have incorporated a
change to the testcase to make it more reliable on Windows, as well as
two follow-up changes
(df79000896
and
b0baa1d8bd)
that were also reverted when 115331 was reverted.
---------
Co-authored-by: Augie Fackler <augie@google.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>
On one hand, we intend to force import all functions when the option is
enabled.
On the other hand, we currently drop definitions of some functions and
convert
them to declarations, which contradicts this intent.
With this PR, functions will no longer be converted to declarations when
`force-import-all` is enabled.
We can use *Set::insert_range to collapse:
for (auto Elem : Range)
Set.insert(E);
down to:
Set.insert_range(Range);
In some cases, we can further fold that into the set declaration.
DenseSet, SmallPtrSet, SmallSet, SetVector, and StringSet recently
gained C++23-style insert_range. This patch uses insert_range with
iterator ranges. For each case, I've verified that foos is defined as
make_range(foo_begin(), foo_end()) or in a similar manner.
Before this patch, whole program devirtualization is suppressed on a
class if any superclass is visible to regular object files, by recording
the class GUID in `VisibleToRegularObjSymbols`.
This patch suppresses whole program devirtualization on a class if the
LTO unit doesn't have the prevailing definition of this class (e.g., the
prevailing definition is in a shared library)
Implementation summaries:
1. In llvm/lib/LTO/LTO.cpp, `IsVisibleToRegularObj` is updated to look
at the global resolution's `IsPrevailing` bit for ThinLTO and
regularLTO.
2. In llvm/tools/llvm-lto2/llvm-lto2.cpp,
- three command line options are added so `llvm-lto2` can override
`Conf.HasWholeProgramVisibility`, `Conf.ValidateAllVtablesHaveTypeInfos`
and `Conf.AllVtablesHaveTypeInfos`.
The test case is reduced from a small C++ program (main.cc, lib.cc/h
pasted below in [1]). To reproduce the program failure without this
patch, compile lib.cc into a shared library, and provide it to a ThinLTO
build of main.cc (commands are pasted in [2]).
[1]
* lib.h
```
#include <cstdio>
class Derived {
public:
void dispatch();
virtual void print();
virtual void sum();
};
void Derived::dispatch() {
static_cast<Derived*>(this)->print();
static_cast<Derived*>(this)->sum();
}
void Derived::sum() {
printf("Derived::sum\n");
}
__attribute__((noinline)) void* create(int i);
__attribute__((noinline)) void* getPtr(int i);
```
* lib.cc
```
#include "lib.h"
#include <cstdio>
#include <iostream>
class Derived2 : public Derived {
public:
void print() override {
printf("DerivedSharedLib\n");
}
void sum() override {
printf("DerivedSharedLib::sum\n");
}
};
void Derived::print() {
printf("Derived\n");
}
__attribute__((noinline)) void* create(int i) {
if (i & 1)
return new Derived2();
return new Derived();
}
```
* main.cc
```
cat main.cc
#include "lib.h"
class DerivedN : public Derived {
public:
};
__attribute__((noinline)) void* getPtr(int x) {
return new DerivedN();
}
int main() {
Derived*b = static_cast<Derived*>(create(201));
b->dispatch();
delete b;
Derived* a = static_cast<Derived*>(getPtr(202));
a->dispatch();
delete a;
return 0;
}
```
[2]
```
# compile lib.o in a shared library.
$ ./bin/clang++ -O2 -fPIC -c lib.cc -o lib.o
$ ./bin/clang++ -shared -o libdata.so lib.o
# Provide the shared library in `-ldata`
$ ./bin/clang++ -v -g -ldata --save-temps -fno-discard-value-names -Wl,-mllvm,-print-before=wholeprogramdevirt -Wl,-mllvm,-wholeprogramdevirt-check=trap -Rpass=wholeprogramdevirt -Wl,--lto-whole-program-visibility -Wl,--lto-validate-all-vtables-have-type-infos -mllvm -disable-icp=true -Wl,-mllvm,-disable-icp=false -flto=thin -fwhole-program-vtables -fno-split-lto-unit -fuse-ld=lld main.cc -L . -o main >/tmp/wholeprogramdevirt.ir 2>&1
# Run the program hits a segmentation fault with `-Wl,-mllvm,-wholeprogramdevirt-check=trap`
$ LD_LIBRARY_PATH=. ./main
DerivedSharedLib
Trace/breakpoint trap (core dumped)
```
…Stream.
CachedFileStream has previously performed the commit step in its
destructor, but this means its only recourse for error handling is
report_fatal_error. Modify this to add an explicit commit() method, and
call this in the appropriate places with appropriate error handling for
the location.
Currently the destructor of CacheStream gives an assert failure in Debug
builds if commit() was not called. This will help track down any
remaining uses of the API that assume the old destructior behaviour. In
Release builds we fall back to the previous behaviour and call
report_fatal_error if the commit fails.
…argetMachine
RISC-V's data layout is determined by the ABI, not just the target
triple. However, the TargetMachine is created using the data layout from
the target triple, which is not always correct. This patch uses the
target ABI from the module and passes it to the TargetMachine, ensuring
that the data layout is set correctly according to the ABI.
The same problem will happen with other targets like MIPS, but
unfortunately, MIPS didn't emit the target-abi into the module flags, so
this patch only fixes the issue for RISC-V.
NOTE: MIPS with -mabi=n32 can trigger the same issue.
Another possible solution is add new parameter to the TargetMachine
constructor, but that would require changes in all the targets.
The module currently stores the target triple as a string. This means
that any code that wants to actually use the triple first has to
instantiate a Triple, which is somewhat expensive. The change in #121652
caused a moderate compile-time regression due to this. While it would be
easy enough to work around, I think that architecturally, it makes more
sense to store the parsed Triple in the module, so that it can always be
directly queried.
For this change, I've opted not to add any magic conversions between
std::string and Triple for backwards-compatibilty purses, and instead
write out needed Triple()s or str()s explicitly. This is because I think
a decent number of them should be changed to work on Triple as well, to
avoid unnecessary conversions back and forth.
The only interesting part in this patch is that the default triple is
Triple("") instead of Triple() to preserve existing behavior. The former
defaults to using the ELF object format instead of unknown object
format. We should fix that as well.
Follow up to PR118508, to avoid unnecessary compile time for an empty
combind regular LTO module if all modules end up being ThinLTO only.
This required minor changes to a few tests to ensure they weren't empty.
On AIX, for undefined functions, only the dotnamed symbols (the address
of the function) are generated after linking (i.e., no named function
symbol is generated).
Currently, all alias symbols are added as defined data symbols when
parsing symbols in LTOModule (the Link Time Optimization library used by
linker to optimization code at link time). On AIX, if the function alias
is used in the native object, and only its dotnamed symbol is generated,
the linker will have problem to match the dotnamed symbol from the
native object and the defined symbol marked as data from the bitcode at
LTO linktime.
This patch is to add function alias as function instead of data.
This feature is enabled by `-codegen-data-thinlto-two-rounds`, which
effectively runs the `-codegen-data-generate` and `-codegen-data-use` in
two rounds to enable global outlining with ThinLTO.
1. The first round: Run both optimization + codegen with a scratch
output.
Before running codegen, we serialize the optimized bitcode modules to a
temporary path.
2. From the scratch object files, we merge them into the codegen data.
3. The second round: Read the optimized bitcode modules and start the
codegen only this time.
Using the codegen data, the machine outliner effectively performs the
global outlining.
Depends on #90934, #110461 and #110463.
This is a patch for
https://discourse.llvm.org/t/rfc-enhanced-machine-outliner-part-2-thinlto-nolto/78753.
This is a prep for https://github.com/llvm/llvm-project/pull/90933.
- Change `ThinBackend` from a function to a type.
- Store the parallelism level in the type, which will be used when creating two-codegen round backends that inherit this value.
- `ThinBackendProc` is hoisted to `LTO.h` from `LTO.cpp` to provide its body for `ThinBackend`. However, `emitFiles()` is still implemented separately in `LTO.cpp`, distinct from its parent class.
We've noticed that for large builds executing thin-link can take on the
order of 10s of minutes. We are only using a single thread to write the
sharded indices and import files for each input bitcode file. While we
need to ensure the index file produced lists modules in a deterministic
order, that doesn't prevent us from executing the rest of the work in
parallel.
In this change we use a thread pool to execute as much of the backend's
work as possible in parallel. In local testing on a machine with 80
cores, this change makes a thin-link for ~100,000 input files run in ~2
minutes. Without this change it takes upwards of 10 minutes.
---------
Co-authored-by: Nuri Amari <nuriamari@fb.com>
This is a prep for https://github.com/llvm/llvm-project/pull/90933.
- Change `FileCache` from a function to a type.
- Store the cache directory in the type, which will be used when creating additional caches for two-codegen round runs that inherit this value.
Fix the use-after-free bug and re-apply
https://github.com/llvm/llvm-project/pull/106193
* Without the fix, the string referenced by `objSym.Name` could be
destroyed even if string saver keeps a copy of the referenced string.
This caused use-after-free.
* The fix ([latest
commit](9776ed44cf))
updates `objSym.Name` to reference (via `StringRef`) the string saver's
copy.
Test:
1. For `lld/test/ELF/lto/asmundef.ll`, its test failure is reproducible
with `-DLLVM_USE_SANITIZER=Address` and gone with the fix.
3. Run all tests by following
https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild#try-local-changes.
* Without the fix, `ELF/lto/asmundef.ll` aborted the multi-stage test at
`@@@BUILD_STEP stage2/asan_ubsan check@@@`, defined
[here](https://github.com/llvm/llvm-zorg/blob/main/zorg/buildbot/builders/sanitizers/buildbot_fast.sh#L30)
* With the fix, the [multi-stage
test](https://github.com/llvm/llvm-zorg/blob/main/zorg/buildbot/builders/sanitizers/buildbot_fast.sh)
pass stage2 {asan, ubsan, masan}. This is also the test used by
https://lab.llvm.org/buildbot/#/builders/169
**Original commit message**
`StringMap<T>` creates a [copy of the
string](d4c519e7b2/llvm/include/llvm/ADT/StringMapEntry.h (L55-L58))
for entry insertions and intentionally keep copies [since the
implementation optimizes string memory
usage](d4c519e7b2/llvm/include/llvm/ADT/StringMap.h (L124)).
On the other hand, linker keeps copies of symbol names [1] in
`lld:🧝:parseFiles` [2] before invoking `compileBitcodeFiles` [3].
This change proposes to optimize away string copies inside
[LTO::GlobalResolutions](24e791b416/llvm/include/llvm/LTO/LTO.h (L409)),
which will make LTO indexing more memory efficient for ELF. There are
similar opportunities for other (COFF, wasm, MachO) formats.
The optimization takes place for lld (ELF) only. For the rest of use
cases (gold plugin, `llvm-lto2`, etc), LTO owns a string saver to keep
copies and use global resolution key for de-duplication.
Together with @kazutakahirata's work to make `ComputeCrossModuleImport`
more memory efficient, we see a ~20% peak memory usage reduction in a
binary where peak memory usage needs to go down. Thanks to the
optimization in
329ba523cc,
the max (as opposed to the sum) of `ComputeCrossModuleImport` or
`GlobalResolution` shows up in peak memory usage.
* Regarding correctness, the set of
[resolved](80c47ad3ae/llvm/lib/LTO/LTO.cpp (L739))
[per-module
symbols](80c47ad3ae/llvm/include/llvm/LTO/LTO.h (L188-L191))
is a subset of
[llvm::lto::InputFile::Symbols](80c47ad3ae/llvm/include/llvm/LTO/LTO.h (L120)).
And bitcode symbol parsing saves symbol name when iterating
`obj->symbols` in `BitcodeFile::parse` already. This change updates
`BitcodeFile::parseLazy` to keep copies of per-module undefined symbols.
* Presumably the undefined symbols in a LTO unit (copied in this patch
in linker unique saver) is a small set compared with the set of symbols
in global-resolution (copied before this patch), making this a
worthwhile trade-off. Benchmarking this change alone shows measurable
memory savings across various benchmarks.
[1] ELF
1cea5c2138/lld/ELF/InputFiles.cpp (L1748)
[2]
ef7b18a53c/lld/ELF/Driver.cpp (L2863)
[3]
ef7b18a53c/lld/ELF/Driver.cpp (L2995)
