The Generic_GCC::GCCInstallationDetector class picks the GCC installation directory with the largest version number. Since the location of the libstdc++ include directories is tied to the GCC version, this can break C++ compilation if the libstdc++ headers for this particular GCC version are not available. Linux distributions tend to package the libstdc++ headers separately from GCC. This frequently leads to situations in which a newer version of GCC gets installed as a dependency of another package without installing the corresponding libstdc++ package. Clang then fails to compile C++ code because it cannot find the libstdc++ headers. Since libstdc++ headers are in fact installed on the system, the GCC installation continues to work, the user may not be aware of the details of the GCC detection, and the compiler does not recognize the situation and emit a warning, this behavior can be hard to understand - as witnessed by many related bug reports over the years.
The goal of this work is to change the GCC detection to prefer GCC installations that contain libstdc++ include directories over those which do not. This should happen regardless of the input language since picking different GCC installations for a build that mixes C and C++ might lead to incompatibilities.
Any change to the GCC installation detection will probably have a negative impact on some users. For instance, for a C user who relies on using the GCC installation with the largest version number, it might become necessary to use the --gcc-install-dir option to ensure that this GCC version is selected.
This seems like an acceptable trade-off given that the situation for users who do not have any special demands on the particular GCC installation directory would be improved significantly.
This patch does not yet change the automatic GCC installation directory choice. Instead, it does introduce a warning that informs the user about the future change if the chosen GCC installation directory differs from the one that would be chosen if the libstdc++ headers are taken into account.
See also this related Discourse discussion: https://discourse.llvm.org/t/rfc-take-libstdc-into-account-during-gcc-detection/86992.
This patch reapplies #145056. The test in the original PR did not specify a target in the clang RUN line and used a wrong way of piping to FileCheck.
The Generic_GCC::GCCInstallationDetector class picks the GCC
installation directory with the largest version number. Since the
location of the libstdc++ include directories is tied to the GCC
version, this can break C++ compilation if the libstdc++ headers for
this particular GCC version are not available. Linux distributions tend
to package the libstdc++ headers separately from GCC. This frequently
leads to situations in which a newer version of GCC gets installed as a
dependency of another package without installing the corresponding
libstdc++ package. Clang then fails to compile C++ code because it
cannot find the libstdc++ headers. Since libstdc++ headers are in fact
installed on the system, the GCC installation continues to work, the
user may not be aware of the details of the GCC detection, and the
compiler does not recognize the situation and emit a warning, this
behavior can be hard to understand - as witnessed by many related bug
reports over the years.
The goal of this work is to change the GCC detection to prefer GCC
installations that contain libstdc++ include directories over those
which do not. This should happen regardless of the input language since
picking different GCC installations for a build that mixes C and C++
might lead to incompatibilities.
Any change to the GCC installation detection will probably have a
negative impact on some users. For instance, for a C user who relies on
using the GCC installation with the largest version number, it might
become necessary to use the --gcc-install-dir option to ensure that this
GCC version is selected.
This seems like an acceptable trade-off given that the situation for
users who do not have any special demands on the particular GCC
installation directory would be improved significantly.
This patch does not yet change the automatic GCC installation directory
choice. Instead, it does introduce a warning that informs the user about
the future change if the chosen GCC installation directory differs from
the one that would be chosen if the libstdc++ headers are taken into
account.
See also this related Discourse discussion:
https://discourse.llvm.org/t/rfc-take-libstdc-into-account-during-gcc-detection/86992.
Implement the -mfix-cortex-a53-843419 and -mno-fix-cortex-a53-843419 options,
which have been introduced to GCC to allow the user to control the workaround
for the erratum. If the option is enabled (which is the default, unchanged by
this patch), Clang passes --fix-cortex-a53-843419 to the linker when it cannot
ensure that the target is not a Cortex A53, otherwise it doesn't.
See https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#index-mfix-cortex-a53-843419
for information on the GCC options.
This patch moves the CommonArgs utilities into a location visible by the
Frontend Drivers, so that the Frontend Drivers may share option parsing
code with the Compiler Driver. This is useful when the Frontend Drivers
would like to verify that their incoming options are well-formed and
also not reinvent the option parsing wheel.
We already see code in the Clang/Flang Drivers that is parsing and
verifying its incoming options. E.g. OPT_ffp_contract. This option is
parsed in the Compiler Driver, Clang Driver, and Flang Driver, all with
slightly different parsing code. It would be nice if the Frontend
Drivers were not required to duplicate this Compiler Driver code. That
way there is no/low maintenance burden on keeping all these parsing
functions in sync.
Along those lines, the Frontend Drivers will now have a useful mechanism
to verify their incoming options are well-formed. Currently, the
Frontend Drivers trust that the Compiler Driver is not passing back junk
in some cases. The Language Drivers may even accept junk with no error
at all. E.g.:
`clang -cc1 -mprefer-vector-width=junk test.c'
With this patch, we'll now be able to tighten up incomming options to
the Frontend drivers in a lightweight way.
---------
Co-authored-by: Cameron McInally <cmcinally@nvidia.com>
Co-authored-by: Shafik Yaghmour <shafik.yaghmour@intel.com>
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.
Add a new Cygwin toolchain that just goes through the motions to
initialize the Generic_GCC base properly. This allows removing some old,
almost certainly wrong hard-coded paths from Lex/InitHeaderSearch.cpp.
MSYS2 (GCC triple (arch)-pc-msys) is a fork of Cygwin (GCC triple
(arch)-pc-cygwin), and this driver can be used for either.
Add a simple test for this driver.
This PR is to improve the driver code to build `flang-rt` path by
re-using the logic and code of `compiler-rt`.
1. Moved `addFortranRuntimeLibraryPath` and `addFortranRuntimeLibs` to
`ToolChain.h` and made them virtual so that they can be overridden if
customization is needed. The current implementation of those two
procedures is moved to `ToolChain.cpp` as the base implementation to
default to.
2. Both AIX and PPCLinux now override `addFortranRuntimeLibs`.
The overriding function of `addFortranRuntimeLibs` for both AIX and
PPCLinux calls `getCompilerRTArgString` => `getCompilerRT` =>
`buildCompilerRTBasename` to get the path to `flang-rt`. This code
handles `LLVM_ENABLE_PER_TARGET_RUNTIME_DIR` setting. As shown in
`PPCLinux.cpp`, `FT_static` is the default. If not found, it will search
and build for `FT_shared`. To differentiate `flang-rt` from `clang-rt`,
a boolean flag `IsFortran` is passed to the chain of functions in order
to reach `buildCompilerRTBasename`.
The i6400 and i6500 are high performance multi-core microprocessors from
MIPS that provide best in class power efficiency for use in
system-on-chip (SoC) applications. i6400 and i6500 implements Release 6
of the MIPS64 Instruction Set Architecture with full hardware
multithreading and hardware virtualization support.
Summary:
Offloading tends to have a bound architecture that directly correponds
to the `-mcpu` argument for that embedded job. This is currently handled
by the GPU offloading toolchains, but is ignored by the CPU ones. This
is problematic for languages like SYCL or OpenMP which permit
'offloading' to non-GPU targets. This patch handles this by putting
generic handling in the GCC toolchain for those languages.
I would've made this fully generic but it regressed some HIP sanitizer
tests because their use-case is really weird. This also only goes for
the languages that inherit from 'generic_gcc`. I could've made it in the
base class, but I felt like it wasn't necessary as we only support
offloading based off of this toolchain. In the future if we need it we
can move it around.
---------
Co-authored-by: Nick Sarnie <nick.sarnie@intel.com>
This commit completed four tasks:
- Add `-mrelax/-mno-relax` options support for LoongArch in clang
driver.
- Print error for `-gsplit-dwarf` with LoongArch linker relaxation
(`-mrelax`).
- Pass `-X` to linker to discard a plethora of `.L` symbols due to
linker relaxation.
- Forward `--no-relax` option to linker.
Introduces the SYCL based toolchain and initial toolchain construction
when using the '-fsycl' option. This option will enable SYCL based
offloading, creating a SPIR-V based IR file packaged into the compiled
host object.
This includes early support for creating the host/device object using
the new offloading model. The device object is created using the
spir64-unknown-unknown target triple.
New/Updated Options:
-fsycl Enables SYCL offloading for host and device
-fsycl-device-only
Enables device only compilation for SYCL
-fsycl-host-only
Enables host only compilation for SYCL
RFC Reference:
https://discourse.llvm.org/t/rfc-sycl-driver-enhancements/74092
This is a reland of: https://github.com/llvm/llvm-project/pull/107493
The name getSanitizerArgs seems to mislead callers that this is a cheap
function, but it extracts the SanitizerArgs each time it is called.
So we try to reuse it a bit more.
Introduces the SYCL based toolchain and initial toolchain construction
when using the '-fsycl' option. This option will enable SYCL based
offloading, creating a SPIR-V based IR file packaged into the compiled
host object.
This includes early support for creating the host/device object using
the new offloading model. The device object is created using the
spir64-unknown-unknown target triple.
New/Updated Options:
-fsycl Enables SYCL offloading for host and device
-fsycl-device-only
Enables device only compilation for SYCL
-fsycl-host-only
Enables host only compilation for SYCL
RFC Reference:
https://discourse.llvm.org/t/rfc-sycl-driver-enhancements/74092
Gentoo is planning to introduce a `*t64` suffix for triples that will be
used by 32-bit platforms that use 64-bit `time_t`. Add support for
parsing and accepting these triples, and while at it make clang
automatically enable the necessary glibc feature macros when this suffix
is used.
An open question is whether we can backport this to LLVM 19.x. After
all, adding new triplets to Triple sounds like an ABI change — though I
suppose we can minimize the risk of breaking something if we move new
enum values to the very end.
This adds support for:
* `muslabin32` (MIPS N32)
* `muslabi64` (MIPS N64)
* `muslf32` (LoongArch ILP32F/LP64F)
* `muslsf` (LoongArch ILP32S/LP64S)
As we start adding glibc/musl cross-compilation support for these
targets in Zig, it would make our life easier if LLVM recognized these
triples. I'm hoping this'll be uncontroversial since the same has
already been done for `musleabi`, `musleabihf`, and `muslx32`.
I intentionally left out a musl equivalent of `gnuf64` (LoongArch
ILP32D/LP64D); my understanding is that Loongson ultimately settled on
simply `gnu` for this much more common case, so there doesn't *seem* to
be a particularly compelling reason to add a `muslf64` that's basically
deprecated on arrival.
Note: I don't have commit access.
Sometimes a collection of multilibs has a gap in it, where a set of
driver command-line options can't work with any of the available
libraries.
For example, the Arm MVE extension requires special startup code (you
need to initialize FPSCR.LTPSIZE), and also benefits greatly from
-mfloat-abi=hard. So a multilib provider might build a library for
systems without MVE, and another for MVE with -mfloat-abi=hard,
anticipating that that's what most MVE users would want. But then if a
user compiles for MVE _without_ -mfloat-abi=hard, thhey can't use either
of those libraries – one has an ABI mismatch, and the other will fail to
set up LTPSIZE.
In that situation, it's useful to include a multilib.yaml entry for the
unworkable intermediate situation, and have it map to a fatal error
message rather than a set of actual libraries. Then the user gets a
build failure with a sensible explanation, instead of selecting an
unworkable library and silently generating bad output. The new
regression test demonstrates this case.
This patch introduces extra syntax into multilib.yaml, so that a record
in the `Variants` list can omit the `Dir` key, and in its place, provide
a `FatalError` key. Then, if that variant is selected, the error message
is emitted as a clang diagnostic, and multilib selection fails.
In order to emit the error message in `MultilibSet::select`, I had to
pass a `Driver &` to that function, which involved plumbing one through
to every call site, and in the unit tests, constructing one specially.
`clang` currently fails to find a GCC installation on Linux/sparc64 with
`-m32`. `strace` reveals that `clang` tries to access
`/usr/lib/gcc/sparcv9-linux-gnu` (which doesn't exist) instead of
`/usr/lib/gcc/sparc64-linux-gnu`.
It turns out that 20d497c26fc95c80a1bacb38820d92e5f52bec58 was overeager
in removing some of the necessary directories.
Fixed by reverting the Linux/sparc* part of the patch.
Tested on `sparc64-unknown-linux-gnu`.
Recommit 435ea21c897f94b5a3777a9f152e4c5bb4a371a3.
As the comment added by a07727199db0525e9d2df41e466a2a1611b3c8e1
suggests, these `*Triples` lists should shrink over time.
https://reviews.llvm.org/D158183 allows *-unknown-linux-gnu to detect
*-linux-gnu. If we additionally allow x86_64-unknown-linux-gnu
-m32/-mx32 to detect x86_64-linux-gnu, we can mostly remove these
*-linux-gnu elements.
Retain x86_64-linux-gnu for now to work around #93609.
(In addition, Debian /usr/bin/clang --version uses x86_64-pc-linux-gnu).
Retain i586-linux-gnu for now to work around #93502.
As the comment added by a07727199db0525e9d2df41e466a2a1611b3c8e1
suggests, these `*Triples` lists should shrink over time.
https://reviews.llvm.org/D158183 allows *-unknown-linux-gnu to detect
*-linux-gnu. If we additionally allow x86_64-unknown-linux-gnu
-m32/-mx32 to detect x86_64-linux-gnu, we can mostly remove these
*-linux-gnu elements.
This introduces a new file, RISCVISAUtils.cpp and moves the rest of
RISCVISAInfo to the TargetParser library.
This will allow us to generate part of RISCVISAInfo.cpp using tablegen.
Summary:
We want to pass these GPU libraries by default if a certain offloading
toolchain is loaded for OpenMP. Previously I parsed this from the
arguments because it's only available in the compilation. This doesn't
really work for `native` and it's extra effort, so this patch just
passes in the `Compilation` as an extr argument and uses that. Tests
should be unaffected.
In the case of -mno-relax option. Otherwise, we cannot prevent
relaxation if we split compilation and linking using Clang driver.
One can consider the following use case:
clang [...] -c -o myobject.o (just compile)
clang [...] myobject.o -o myobject.elf -mno-relax (linking)
In this case, myobject.elf will be relaxed, the -mno-relax will be
silently ignored.
Fix the bug where merge-fdata unconditionally outputs boltedcollection
line, regardless of whether input files have it set.
Test Plan:
Added bolt/test/X86/merge-fdata-nobat-mode.test which fails without this
fix.
-fandroid-pad-segment is an Android-specific opt-in option that
links in crt_pad_segment.o (beside other crt*.o relocatable files).
crt_pad_segment.o contains a note section, which will be included in the
linker-created PT_NOTE segment. This PT_NOTE tell Bionic that: when
create a map for a PT_LOAD segment, extend the end to cover the gap so
that we will have fewer kernel 'struct vm_area_struct' objects when
page_size < MAXPAGESIZE.
See also https://sourceware.org/bugzilla/show_bug.cgi?id=31076
Link: https://r.android.com/2902180
This adds Hurd toolchain support to Clang's driver in addition to
handling
translating the triple from GCC toolchain-compatible form (x86_64-gnu)
to
the actual triple registered in LLVM (x86_64-pc-hurd-gnu).
If using multiarch directories with musl, the multiarch directory still
uses *-linux-gnu triples - which may or may not be intentional, while it
is somewhat consistent at least.
However, for musl armhf targets, make sure that this also picks
arm-linux-gnueabihf, rather than arm-linux-gnueabi.
When --gcc-triple is used, the driver will search for the 'best' gcc
installation that has the given triple. This is useful for distributions
that want clang to use a specific gcc triple, but do not want to pin to
a specific version as would be required by using --gcc-install-dir.
Having clang linked to a specific gcc version can cause clang to stop
working when the version of gcc installed on the system gets updated.
Extend the multi-lib re-use selection mechanism for RISC-V.
This funciton will try to re-use multi-lib if they are compatible.
Definition of compatible:
- ABI must be the same.
- multi-lib is a subset of current arch, e.g. multi-lib=march=rv32im
is a subset of march=rv32imc.
- march that contains atomic extension can't reuse multi-lib that
doesn't has atomic, vice versa. e.g. multi-lib=march=rv32im and
march=rv32ima are not compatible, because software and hardware
atomic operation can't work together correctly.
Extend the multi-lib re-use selection mechanism for RISC-V.
This funciton will try to re-use multi-lib if they are compatible.
Definition of compatible:
- ABI must be the same.
- multi-lib is a subset of current arch, e.g. multi-lib=march=rv32im
is a subset of march=rv32imc.
- march that contains atomic extension can't reuse multi-lib that
doesn't has atomic, vice versa. e.g. multi-lib=march=rv32im and
march=rv32ima are not compatible, because software and hardware
atomic operation can't work together correctly.
