Submitted for mcgrathr.
On AArch64, Fuchsia fully supports both SafeStack and ShadowCallStack ABIs.
The latter is now preferred and will be the default. It's possible to
enable both simultaneously, but ShadowCallStack is believed to have most
of the practical benefit of SafeStack with less cost.
Differential Revision: https://reviews.llvm.org/D66712
Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.
Reviewers: thakis, rnk, theraven, pcc
Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65761
Summary:
- As variadic parameters have the lowest rank in overload resolution,
without real usage of `va_arg`, they are commonly used as the
catch-all fallbacks in SFINAE. As the front-end still reports errors
on calls to `va_arg`, the declaration of functions with variadic
arguments should be allowed in general.
Reviewers: jlebar, tra, yaxunl
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69389
Summary:
A necessary step to let build system caching work for its output.
Reviewers: tejohnson, steven_wu
Reviewed by: tejohnson
Subscribers: mehdi_amini, inglorion, dexonsmith, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69406
This adds support for reserving GPRs such that the compiler will not
choose a register for register allocation. The implementation follows
the same design as for AArch64; each reserved register becomes a target
feature and used for getting the reserved registers for a given
MachineFunction. The backend checks that it does not need to write to
any reserved register; if it does a relevant error is generated.
Differential Revision: https://reviews.llvm.org/D67185
Add this option to allow device side class type global variables
with non-trivial ctor/dtor. device side init/fini functions will
be emitted, which will be executed by HIP runtime when
the fat binary is loaded/unloaded.
This feature is to facilitate implementation of device side
sanitizer which requires global vars with non-trival ctors.
By default this option is disabled.
Differential Revision: https://reviews.llvm.org/D69268
Works on this dependency chain:
ArrayRef.h ->
Hashing.h -> --CUT--
Host.h ->
StringMap.h / StringRef.h
ArrayRef is very popular, but Host.h is rarely needed. Move the
IsBigEndianHost constant to SwapByteOrder.h. Clients of that header are
more likely to need it.
llvm-svn: 375316
When the %m filename pattern is used, the filename is unique to each
image, so the cached value is wrong.
It struck me that the full filename isn't something that's recomputed
often, so perhaps it doesn't need to be cached at all. David Li pointed
out we can go further and just hide lprofCurFilename. This may regress
workflows that depend on using the set-filename API to change filenames
across all loaded DSOs, but this is expected to be very rare.
rdar://55137071
Differential Revision: https://reviews.llvm.org/D69137
llvm-svn: 375301
This is clang part of the patch. It adds -flto-unit flag for thin LTO
builds on Mac and PS4
Differential revision: https://reviews.llvm.org/D68950
llvm-svn: 375224
Summary:
The sign extension proposal was motivated by a desire to not have
separate sign-extending atomic operations, so it is meant to be
enabled when threads are used.
Reviewers: aheejin, dschuff
Subscribers: sbc100, jgravelle-google, sunfish, jfb, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69075
llvm-svn: 375199
Remove dead virtual functions from vtables with
replaceNonMetadataUsesWith, so that CGProfile metadata gets cleaned up
correctly.
Original commit message:
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 375094
Since `-mfloat-abi=soft` is taken to mean turning off all uses of the
FP registers, it should turn off the MVE vector instructions as well
as NEON and scalar FP. But it wasn't doing so.
So the options `-march=armv8.1-m.main+mve.fp+fp.dp -mfloat-abi=soft`
would cause the underlying LLVM to //not// support MVE (because it
knows the real target feature relationships and turned off MVE when
the `fpregs` feature was removed), but the clang layer still thought
it //was// supported, and would misleadingly define the feature macro
`__ARM_FEATURE_MVE`.
The ARM driver code already has a long list of feature names to turn
off when `-mfloat-abi=soft` is selected. The fix is to add the missing
entries `mve` and `mve.fp` to that list.
Reviewers: dmgreen
Subscribers: kristof.beyls, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69025
llvm-svn: 375001
The final list of OpenMP offload targets becomes known only at the link time and since offload registration code depends on the targets list it makes sense to delay offload registration code generation to the link time instead of adding it to the host part of every fat object. This patch moves offload registration code generation from clang to the offload wrapper tool.
This is the last part of the OpenMP linker script elimination patch https://reviews.llvm.org/D64943
Differential Revision: https://reviews.llvm.org/D68746
llvm-svn: 374937
Summary:
When files often get touched during builds, the mtime based validation
leads to different problems in implicit modules builds, even when the
content doesn't actually change:
- Modules only: module invalidation due to out of date files. Usually causing rebuild traffic.
- Modules + PCH: build failures because clang cannot rebuild a module if it comes from building a PCH.
- PCH: build failures because clang cannot rebuild a PCH in case one of the input headers has different mtime.
This patch proposes hashing the content of input files (headers and
module maps), which is performed during serialization time. When looking
at input files for validation, clang only computes the hash in case
there's a mtime mismatch.
I've tested a couple of different hash algorithms availble in LLVM in
face of building modules+pch for `#import <Cocoa/Cocoa.h>`:
- `hash_code`: performace diff within the noise, total module cache increased by 0.07%.
- `SHA1`: 5% slowdown. Haven't done real size measurements, but it'd be BLOCK_ID+20 bytes per input file, instead of BLOCK_ID+8 bytes from `hash_code`.
- `MD5`: 3% slowdown. Like above, but BLOCK_ID+16 bytes per input file.
Given the numbers above, the patch uses `hash_code`. The patch also
improves invalidation error msgs to point out which type of problem the
user is facing: "mtime", "size" or "content".
rdar://problem/29320105
Reviewers: dexonsmith, arphaman, rsmith, aprantl
Subscribers: jkorous, cfe-commits, ributzka
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67249
> llvm-svn: 374841
llvm-svn: 374895
Summary:
When files often get touched during builds, the mtime based validation
leads to different problems in implicit modules builds, even when the
content doesn't actually change:
- Modules only: module invalidation due to out of date files. Usually causing rebuild traffic.
- Modules + PCH: build failures because clang cannot rebuild a module if it comes from building a PCH.
- PCH: build failures because clang cannot rebuild a PCH in case one of the input headers has different mtime.
This patch proposes hashing the content of input files (headers and
module maps), which is performed during serialization time. When looking
at input files for validation, clang only computes the hash in case
there's a mtime mismatch.
I've tested a couple of different hash algorithms availble in LLVM in
face of building modules+pch for `#import <Cocoa/Cocoa.h>`:
- `hash_code`: performace diff within the noise, total module cache increased by 0.07%.
- `SHA1`: 5% slowdown. Haven't done real size measurements, but it'd be BLOCK_ID+20 bytes per input file, instead of BLOCK_ID+8 bytes from `hash_code`.
- `MD5`: 3% slowdown. Like above, but BLOCK_ID+16 bytes per input file.
Given the numbers above, the patch uses `hash_code`. The patch also
improves invalidation error msgs to point out which type of problem the
user is facing: "mtime", "size" or "content".
rdar://problem/29320105
Reviewers: dexonsmith, arphaman, rsmith, aprantl
Subscribers: jkorous, cfe-commits, ributzka
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67249
llvm-svn: 374841
Summary:
Currently clang does not support -Wa,-W, which suppresses warning
messages in GNU assembler. Add this option for gcc compatibility.
https://bugs.llvm.org/show_bug.cgi?id=43651. Reland with differential
information.
Reviewers: bcain
Reviewed By: bcain
Subscribers: george.burgess.iv, gbiv, llozano, manojgupta, nickdesaulniers, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68884
llvm-svn: 374834
Currently clang does not support -Wa,-W, which suppresses warning
messages in GNU assembler. Add this option for gcc compatibility.
https://bugs.llvm.org/show_bug.cgi?id=43651
llvm-svn: 374822
The goal is to have 100% fidelity in clang-scan-deps behavior when
--analyze is present in compilation command.
At the same time I don't want to break clang-tidy which expects
__static_analyzer__ macro defined as built-in.
I introduce new cc1 options (-setup-static-analyzer) that controls
the macro definition and is conditionally set in driver.
Differential Revision: https://reviews.llvm.org/D68093
llvm-svn: 374815
Summary:
This patch restores the behaviour that -fpu overwrites the
architecture obtained from -march or -mcpu flags, not enforcing to
disable 'crypto' if march=armv7 and mfpu=neon-fp-armv8.
However, it does warn that 'crypto' is ignored when passing
mfpu=crypto-neon-fp-armv8.
Reviewers: peter.smith, labrinea
Reviewed By: peter.smith
Subscribers: nickdesaulniers, kristof.beyls, dmgreen, cfe-commits, krisb
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67608
llvm-svn: 374785
Summary:
1. enable LTO need to pass target feature and abi to LTO code generation
RISCV backend need the target feature to decide which extension used in
code generation.
2. move getTargetFeatures to CommonArgs.h and add ForLTOPlugin flag
3. add general tools::getTargetABI in CommonArgs.h because different target uses different
way to get the target ABI.
Patch by Kuan Hsu Chen (khchen)
Reviewers: lenary, lewis-revill, asb, MaskRay
Reviewed By: lenary
Subscribers: hiraditya, dschuff, aheejin, fedor.sergeev, mehdi_amini, inglorion, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, edward-jones, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, rkruppe, PkmX, jocewei, psnobl, benna, Jim, lenary, s.egerton, pzheng, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67409
llvm-svn: 374774
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 374539
I noticed that compiling on Windows with -fno-ms-compatibility had the
side effect of defining __GNUC__, along with __GNUG__, __GXX_RTTI__, and
a number of other macros for GCC compatibility. This is undesirable and
causes Chromium to do things like mix __attribute__ and __declspec,
which doesn't work. We should have a positive language option to enable
GCC compatibility features so that we can experiment with
-fno-ms-compatibility on Windows. This change adds -fgnuc-version= to be
that option.
My issue aside, users have, for a long time, reported that __GNUC__
doesn't match their expectations in one way or another. We have
encouraged users to migrate code away from this macro, but new code
continues to be written assuming a GCC-only environment. There's really
nothing we can do to stop that. By adding this flag, we can allow them
to choose their own adventure with __GNUC__.
This overlaps a bit with the "GNUMode" language option from -std=gnu*.
The gnu language mode tends to enable non-conforming behaviors that we'd
rather not enable by default, but the we want to set things like
__GXX_RTTI__ by default, so I've kept these separate.
Helps address PR42817
Reviewed By: hans, nickdesaulniers, MaskRay
Differential Revision: https://reviews.llvm.org/D68055
llvm-svn: 374449
This patch removes the remaining part of the OpenMP offload linker scripts which was used for inserting device binaries into the output linked binary. Device binaries are now inserted into the host binary with a help of the wrapper bit-code file which contains device binaries as data. Wrapper bit-code file is dynamically created by the clang driver with a help of new tool clang-offload-wrapper which takes device binaries as input and produces bit-code file with required contents. Wrapper bit-code is then compiled to an object and resulting object is appended to the host linking by the clang driver.
This is the second part of the patch for eliminating OpenMP linker script (please see https://reviews.llvm.org/D64943).
Differential Revision: https://reviews.llvm.org/D68166
llvm-svn: 374219
Currently clang does not save some of the intermediate file generated during device compilation for HIP when -save-temps is specified.
This patch fixes that.
Differential Revision: https://reviews.llvm.org/D68665
llvm-svn: 374198
Second Landing Attempt:
This patch enables end to end support for generating ELF interface stubs
directly from clang. Now the following:
clang -emit-interface-stubs -o libfoo.so a.cpp b.cpp c.cpp
will product an ELF binary with visible symbols populated. Visibility attributes
and -fvisibility can be used to control what gets populated.
* Adding ToolChain support for clang Driver IFS Merge Phase
* Implementing a default InterfaceStubs Merge clang Tool, used by ToolChain
* Adds support for the clang Driver to involve llvm-ifs on ifs files.
* Adds -emit-merged-ifs flag, to tell llvm-ifs to emit a merged ifs text file
instead of the final object format (normally ELF)
Differential Revision: https://reviews.llvm.org/D63978
llvm-svn: 374061
Sometimes it is useful to compile HIP device code to LLVM BC. It is not convenient to use clang -cc1 since
there are lots of options needed.
This patch allows clang driver to compile HIP device code to LLVM BC with -emit-llvm -c.
Differential Revision: https://reviews.llvm.org/D68284
llvm-svn: 373561
This patch enables end to end support for generating ELF interface stubs
directly from clang. Now the following:
clang -emit-interface-stubs -o libfoo.so a.cpp b.cpp c.cpp
will product an ELF binary with visible symbols populated. Visibility attributes
and -fvisibility can be used to control what gets populated.
* Adding ToolChain support for clang Driver IFS Merge Phase
* Implementing a default InterfaceStubs Merge clang Tool, used by ToolChain
* Adds support for the clang Driver to involve llvm-ifs on ifs files.
* Adds -emit-merged-ifs flag, to tell llvm-ifs to emit a merged ifs text file
instead of the final object format (normally ELF)
Differential Revision: https://reviews.llvm.org/D63978
llvm-svn: 373538
Summary:
To trigger the index-only Whole Program Devirt support added to LLVM, we
need to be able to specify -fno-split-lto-unit in conjunction with
-fwhole-program-vtables. Keep the default for -fwhole-program-vtables as
-fsplit-lto-unit, but don't error on that option combination.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, steven_wu, dexonsmith, arphaman, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68029
llvm-svn: 373370
Linker automatically provides __start_<section name> and __stop_<section name> symbols to satisfy unresolved references if <section name> is representable as a C identifier (see https://sourceware.org/binutils/docs/ld/Input-Section-Example.html for details). These symbols indicate the start address and end address of the output section respectively. Therefore, renaming OpenMP offload entries section name from ".omp.offloading_entries" to "omp_offloading_entries" to use this feature.
This is the first part of the patch for eliminating OpenMP linker script (please see https://reviews.llvm.org/D64943).
Differential Revision: https://reviews.llvm.org/D68070
llvm-svn: 373118
The only functional change here is that -coverage-notes-file is not
passed to -cc1 in some situations.
This code appears to be trying to put the gcno and gcda output next to
the final object file, but it's doing that in a really convoluted way
that needs to be re-examined. It looks for -c or -S in the original
command, and then looks at the -o argument if present in order to handle
the -fno-integrated-as case. However, this doesn't work if this is a
link command with multiple inputs. I looked into fixing this, but the
check-profile test suite has a lot of dependencies on this behavior, so
I left it all alone.
llvm-svn: 373004
Leonard Chan