The current default is provided in various Makefile.inc in some top-level
directories and covers a good portion of the tree, but doesn't cover parts
of the build a little deeper (e.g. libcasper).
Provide a default in src.sys.mk and set WARNS to it in bsd.sys.mk if that
variable is defined. This lets us relatively cleanly provide a default WARNS
no matter where you're building in the src tree without breaking things
outside of the tree.
Crunchgen has been updated as a bootstrap tool to work on this change
because it needs r365605 at a minimum to succeed. The cleanup necessary to
successfully walk over this change on WITHOUT_CLEAN builds has been added.
There is a supplemental project to this to list all of the warnings that are
encountered when the environment has WARNS=6 NO_WERROR=yes:
https://warns.kevans.dev -- this project will hopefully eventually go away
in favor of CI doing a much better job than it.
Reviewed by: emaste, brooks, ngie (all earlier version)
Reviewed by: emaste, arichardson (depend-cleanup.sh change)
Differential Revision: https://reviews.freebsd.org/D26455
Linking the full version of clang 11 results in errors similar to:
lld: error: /usr/src/contrib/llvm-project/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:736:(.text._ZN5clang4ento22CreateAnalysisConsumerERNS_16CompilerInstanceE+0xE0): relocation R_MIPS_CALL16 out of range: 48920 is not in [-32768, 32767]; references operator new(unsigned long)
Add -mxgot to the compilation flags for llvm libraries to work around
this error. This may be too big of a hammer, but it can always be
refined later.
MFC after: 6 weeks
required by both the static analyzer (MK_CLANG_FULL) and clang-format
(MK_CLANG_FORMAT). We could also invent yet another SRCS variant, but
that seems a bit overkill.
10.0.1 final (aka llvmorg-10.0.1-0-gef32c611aa2).
There were no changes since rc2, except in the upstream regression
tests, which we do not ship.
Relnotes: yes
MFC after: immediately (no material changes except tag)
llvmorg-10.0.1-rc2-0-g77d76b71d7d.
Also add a few more llvm utilities under WITH_CLANG_EXTRAS:
* llvm-dwp, a utility for merging DWARF 5 Split DWARF .dwo files into
.dwp (DWARF package files)
* llvm-size, a size(1) replacement
* llvm-strings, a strings(1) replacement
MFC after: 3 weeks
clang-format is enabled conditional on either WITH_CLANG_EXTRAS or
WITH_CLANG_FORMAT. Some sources in libclang are build conditional on
either rule, and obviously the clang-format binary itself depends on the
rule.
clang-format could still use a manual page.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D25427
For head/, this will remain eternally default-on to maintain the status quo.
For stable/ branches, it should be flipped to default-off to maintain the
status quo.
There's value in being able to flip it one way or the other easily on head
or stable branches, whether you want to gain some performance back on head/
(for machines there's little chance you'll actually hit an assertion) or
potentially diagnose a problem with the version of llvm on an older branch.
Currently, stable branches get the CFLAGS+= -ndebug line uncommented; going
forward, they will instead have the default of LLVM_ASSERTIONS flipped.
Reviewed by: dim, emaste, re (gjb)
MFC after: 1 week
MFC note: flip the default of LLVM_ASSERTIONS
Differential Revision: https://reviews.freebsd.org/D24264
Building lldb's lua/python bindings requires swig, but we do not want to
include it in the FreeBSD base system (as a build tool) because it has
non-trivial dependencies. As a workaround, add a make rule to generate
LLDBWrapLua.cpp, and we will commit the generated file.
Requires the swig30 package.
Reviewed by: brooks
Discussed with: dim
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24265
Clang from 9.0.0 onwards already has the necessary relocation range
extenders, so this workaround is no longer needed (it produces longer
and slower code). Tested on real hardware, and in cross-compile
environment.
Submitted by: mmel
versions, use "git describe --tags --long" output, which is more
descriptive. E.g., "90c78073f73eac58f4f8b4772a896dc8aac023bc" becomes
"llvmorg-10.0.0-rc2-0-g90c78073f73".
clang binary, with:
ld: error: undefined symbol: llvm::EnableABIBreakingChecks
>>> referenced by PlistDiagnostics.cpp
>>> PlistDiagnostics.o:(.sdata+0x0) in archive /usr/obj/usr/src/riscv.riscv64/lib/clang/libclang/libclang.a
[... many more like this ...]
When bootstrapping on powerpc64 ELFv1, it is necessary to use binutils
ld.bfd from ports for the bootstrap, as this is the only modern linker for
ELFv1 host tools.
As binutils ld.bfd is rather strict in its handling of undefined symbols,
it is necessary to pull in Support/Atomic.cpp to avoid an undefined symbol.
Reviewed by: dim, emaste
Sponsored by: Tag1 Consulting, Inc.
Differential Revision: https://reviews.freebsd.org/D23072
This uses the new layout of the upstream repository, which was recently
migrated to GitHub, and converted into a "monorepo". That is, most of
the earlier separate sub-projects with their own branches and tags were
consolidated into one top-level directory, and are now branched and
tagged together.
Updating the vendor area to match this layout is next.
case. Otherwise, linking of clang and other llvm based executables
would complain about missing symbols.
Reported by: rstone
MFC after: 1 month
X-MFC-With: r353358
8.0.1 final release r366581. The only functional change is a fix for a
mismerge of upstream r360816, which properly restores the r2 register
when unwinding on PowerPC64 (See https://reviews.freebsd.org/D20337).
Relnotes: yes
PR: 236062
MFC after: 3 days
X-MFC-With: r349004
libunwind and openmp to the upstream release_80 branch r364487
(effectively, 8.0.1 rc3). The 8.0.1 release will most likely
have no further changes.
MFC after: 1 week
X-MFC-With: r349004
libunwind and openmp to the upstream release_80 branch r363030
(effectively, 8.0.1 rc2). The 8.0.1 release should follow this within a
week or so.
MFC after: 2 weeks
To facilitate experimentation with LTO we require an ar that supports
LLVM IR, and to a lesser degree also an nm. As a first step always
install llvm-ar and llvm-nm.
Sponsored by: The FreeBSD Foundation
ASAN reports become a lot more useful with llvm-symbolizer in $PATH, and the
build is not much more time-consuming. The added benefit is that the
resulting reports will actually include symbol information; without, thread
trace information includes a bunch of addresses that immediately resolve to
an inline function in
^/contrib/compiler-rt/lib/sanitizer_common/sanitizer_common.h and take a
little more effort to examine.
Reviewed by: emaste
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20484
CXXSTD was added as the C++ analogue to CSTD.
CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.
This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.
As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.
Notes:
This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.
Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:
Before this commit:
```
CXXFLAGS+= -std=c++14
```
After this commit:
```
CXXSTD= c++14
```
Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
MFC with: r345203, r345704, r345705
Relnotes: yes
Tested with: make tinderbox
Differential Revision: https://reviews.freebsd.org/D19732
When a review is closed via Phabricator it updates the patch attached to the
review. I downloaded the raw patch from Phabricator, applied it, and repeated
my mistake from r345704 by accident mixing content from D19732 and D19738.
For my own personal sanity, I will try not to mix reviews like this in the
future.
MFC after: 1 month
MFC with: r345706
Approved by: emaste (mentor, implicit)
CXXSTD was added as the C++ analogue to CSTD.
CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.
This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.
As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.
Notes:
This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.
Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:
Before this commit:
```
CXXFLAGS+= -std=c++14
```
After this commit:
```
CXXSTD= c++14
```
Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
MFC with: r345203, r345704, r345705
Relnotes: yes
Tested with: make tinderbox
Differential Revision: https://reviews.freebsd.org/D19732
I accidentally committed code from two reviews. I will reintroduce the code to
bsd.progs.mk as part of a separate commit from r345704.
Approved by: emaste (mentor, implicit)
MFC after: 2 months
MFC with: r345704
CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.
This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.
As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.
Notes:
This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.
Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:
Before this commit:
```
CXXFLAGS+= -std=c++14
```
After this commit:
```
CXXSTD= c++14
```
Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D19732
[ELF] Support --{,no-}allow-shlib-undefined
Summary:
In ld.bfd/gold, --no-allow-shlib-undefined is the default when
linking an executable. This patch implements a check to error on
undefined symbols in a shared object, if all of its DT_NEEDED entries
are seen.
Our approach resembles the one used in gold, achieves a good balance
to be useful but not too smart (ld.bfd traces all DSOs and emulates
the behavior of a dynamic linker to catch more cases).
The error is issued based on the symbol table, different from
undefined reference errors issued for relocations. It is most
effective when there are DSOs that were not linked with -z defs (e.g.
when static sanitizers runtime is used).
gold has a comment that some system libraries on GNU/Linux may have
spurious undefined references and thus system libraries should be
excluded (https://sourceware.org/bugzilla/show_bug.cgi?id=6811). The
story may have changed now but we make --allow-shlib-undefined the
default for now. Its interaction with -shared can be discussed in the
future.
Reviewers: ruiu, grimar, pcc, espindola
Reviewed By: ruiu
Subscribers: joerg, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D57385
Pull in r352943 from upstream lld trunk (by Fangrui Song):
[ELF] Default to --no-allow-shlib-undefined for executables
Summary:
This follows the ld.bfd/gold behavior.
The error check is useful as it captures a common type of ld.so
undefined symbol errors as link-time errors:
// a.cc => a.so (not linked with -z defs)
void f(); // f is undefined
void g() { f(); }
// b.cc => executable with a DT_NEEDED entry on a.so
void g();
int main() { g(); }
// ld.so errors when g() is executed (lazy binding) or when the program is started (-z now)
// symbol lookup error: ... undefined symbol: f
Reviewers: ruiu, grimar, pcc, espindola
Reviewed By: ruiu
Subscribers: llvm-commits, emaste, arichardson
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57569
Together, these add support for --no-allow-shlib-undefined, and make it
the default for executables, so they will fail to link if any symbols
from needed shared libraries are undefined.
Reported by: jbeich
PR: 236062, 236141
MFC after: 1 month
X-MFC-With: r344779
clang and various other executables will fail to link with undefined
symbols.
Reported by: O. Hartmann <ohartmann@walstatt.org>
MFC after: 1 month
X-MFC-With: r344779
The armv6 build failed in CI due to missing symbols (from these two
source files) in the bootstrap Clang.
This affected only armv6 because other Clang-using archs are using LLD
as the bootstrap linker, and thus include SRCS_MIW via LLD_BOOTSTRAP.
Reported by: CI, via lwhsu
Sponsored by: The FreeBSD Foundation
Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries).
With this change PIE objects have a .pieo extension and INTERNALLIB
libraries libXXX_pie.a.
MK_PIE is disabled for some kerberos5 tools, Clang, and Subversion, as
they explicitly reference .a libraries in their Makefiles. These can
be addressed on an individual basis later. MK_PIE is also disabled for
rtld-elf because it is already position-independent using bespoke
Makefile rules.
Currently only dynamically linked binaries will be built as PIE.
Discussed with: dim
Reviewed by: kib
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18423
[X86] Add FPSW as a Def on some FP instructions that were missing it.
Pull in r353141 from upstream llvm trunk (by Craig Topper):
[X86] Connect the default fpsr and dirflag clobbers in inline
assembly to the registers we have defined for them.
Summary:
We don't currently map these constraints to physical register numbers
so they don't make it to the MachineIR representation of inline
assembly.
This could have problems for proper dependency tracking in the
machine schedulers though I don't have a test case that shows that.
Reviewers: rnk
Reviewed By: rnk
Subscribers: eraman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57641
Pull in r353489 from upstream llvm trunk (by Craig Topper):
[X86] Add FPCW as a register and start using it as an implicit use on
floating point instructions.
Summary:
FPCW contains the rounding mode control which we manipulate to
implement fp to integer conversion by changing the roudning mode,
storing the value to the stack, and then changing the rounding mode
back. Because we didn't model FPCW and its dependency chain, other
instructions could be scheduled into the middle of the sequence.
This patch introduces the register and adds it as an implciit def of
FLDCW and implicit use of the FP binary arithmetic instructions and
store instructions. There are more instructions that need to be
updated, but this is a good start. I believe this fixes at least the
reduced test case from PR40529.
Reviewers: RKSimon, spatel, rnk, efriedma, andrew.w.kaylor
Subscribers: dim, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57735
These should fix a problem in clang 7.0 where it would sometimes emit
long double floating point instructions in a slightly wrong order,
leading to failures in our libm tests. In particular, the cbrt_test
test case 'cbrtl_powl' and the trig_test test case 'reduction'.
Also bump __FreeBSD_cc_version, to be able to detect this in our test
suite.
Reported by: lwhsu
PR: 234040
Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=40206
MFC after: 1 week
7.0.1 release r349250. There were no functional changes since the 7.0.1
rc3 import.
PR: 230240, 230355
Relnotes: yes
MFC after: 2 months
X-MFC-With: r341825
It is required by llvm-profdata, now built by default under the
LLVM_COV knob. The additional complexity that would come from avoiding
building it if CLANG_EXTRAS and LLVM_COV are both disabled is not worth
the small savings in build time.
Sponsored by: The FreeBSD Foundation
from 12.0-ALPHA10 to 13.0-CURRENT. This edit was a mistake,
and should have been applied to stable/12 upon branching, not
head.
Reported by: jbeich, dim
Sponsored by: The FreeBSD Foundation
ELF spec says that for SHT_REL and SHT_RELA sh_link should reference the
associated string table and sh_info should reference the "section to
which the relocation applies." ELF Tool Chain's elfcopy / strip use
this (in part) to control whether or not the relocation entry is copied
to the output.
LLVM PR 37538 https://bugs.llvm.org/show_bug.cgi?id=37538
Approved by: re (kib)
Obtained from: llvm r344226 (backported for 6.0)
Previously Clang required ifunc resolution functions to take no
arguments, presumably because GCC documented ifunc resolvers as taking
no arguments. However, GCC accepts resolvers accepting arguments, and
our rtld passes CPU ID information (cpuid, hwcap, etc.) to ifunc
resolvers. Just remove the check from the in-tree compiler for our in-
tree compiler; a different (per-OS) approach may be required upstream.
Reported by: mjg
Approved by: re (rgrimes)
MFC after: 1 week
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
BPF (eBPF) is an independent instruction set architecture which is
introduced in Linux a few years ago. Originally, eBPF execute
environment was only inside Linux kernel. However, recent years there
are some user space implementation (https://github.com/iovisor/ubpf,
https://doc.dpdk.org/guides/prog_guide/bpf_lib.html) and kernel space
implementation for FreeBSD is going on
(https://github.com/YutaroHayakawa/generic-ebpf).
The BPF target support can be enabled using WITH_LLVM_TARGET_BPF, as it
is not built by default.
Submitted by: Yutaro Hayakawa <yhayakawa3720@gmail.com>
Reviewed by: dim, bdrewery
Differential Revision: https://reviews.freebsd.org/D16033
All supported FreeBSD build host versions have backtrace.h, so we can
just eliminate that test. For futimes() we can test the compiler's
built-in __FreeBSD__ major version rather than relying on including
osreldate.h. This should reduce the frequency with which Clang gets
rebuilt when building world.
Reviewed by: dim
Sponsored by: The FreeBSD Foundation
This effectively reverts r335449 and changes the previous MK_LLD_IS_LD
to a MK_LLD_BOOTSTRAP check. If !TOOLS_PREFIX then these sources are
always built for llvm-objdump, lld, and llvm-cov. When TOOLS_PREFIX
is set then they are only needed if lld is being bootstrapped.
Reported by: dim
Pointyhat to: bdrewery
Sponsored by: Dell EMC
This makes it possible, through src.conf(5) settings, to select which
LLVM targets you want to build during buildworld. The current list is:
* (WITH|WITHOUT)_LLVM_TARGET_AARCH64
* (WITH|WITHOUT)_LLVM_TARGET_ARM
* (WITH|WITHOUT)_LLVM_TARGET_MIPS
* (WITH|WITHOUT)_LLVM_TARGET_POWERPC
* (WITH|WITHOUT)_LLVM_TARGET_SPARC
* (WITH|WITHOUT)_LLVM_TARGET_X86
To not influence anything right now, all of these are on by default, in
situations where clang is enabled.
Selectively turning a few targets off manually should work. Turning on
only one target should work too, even if that target does not correspond
to the build architecture. (In that case, LLVM_NATIVE_ARCH will not be
defined, and you can only use the resulting clang executable for
cross-compiling.)
I performed a few measurements on one of the FreeBSD.org reference
machines, building clang from scratch, with all targets enabled, and
with only the x86 target enabled. The latter was ~12% faster in real
time (on a 32-core box), and ~14% faster in user time. For a full
buildworld the difference will probably be less pronounced, though.
Reviewed by: bdrewery
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11077
lld always needs these DWARF sources, as well as other default and extra
tools. XDL seems to be the best fit list.
Remove MK_LLD_IS_LD check from SRCS_MIW which is now reduced to just a
few files for llvm-objdump.
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D15915
MK_LLD is for the installed lld while MK_LLD_BOOTSTRAP is for the build
tool. For WITH_SYSTEM_LINKER it is necesarry to separate the logic of
these two. When building libllvm TOOLS_PREFIX will be defined and
MK_LLD_BOOTSTRAP should be checked instead.
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D15837
A non-alloc note section should not have a PT_NOTE program header.
Found while linking ghc (Haskell compiler) with lld on FreeBSD. Haskell
emits a .debug-ghc-link-info note section (as the name suggests, it
contains link info) as a SHT_NOTE section without SHF_ALLOC set.
For this case ld.bfd does not emit a PT_NOTE segment for
.debug-ghc-link-info. lld previously emitted a PT_NOTE with p_vaddr = 0
and FreeBSD's rtld segfaulted when trying to parse a note at address 0.
LLVM PR: https://llvm.org/pr37361
LLVM review: https://reviews.llvm.org/D46623
PR: 226872
Reviewed by: dim
Sponsored by: The FreeBSD Foundation
EFLAGS copy that lives out of a basic block!" errors on i386.
Pull in r325446 from upstream clang trunk (by me):
[X86] Add 'sahf' CPU feature to frontend
Summary:
Make clang accept `-msahf` (and `-mno-sahf`) flags to activate the
`+sahf` feature for the backend, for bug 36028 (Incorrect use of
pushf/popf enables/disables interrupts on amd64 kernels). This was
originally submitted in bug 36037 by Jonathan Looney
<jonlooney@gmail.com>.
As described there, GCC also uses `-msahf` for this feature, and the
backend already recognizes the `+sahf` feature. All that is needed is
to teach clang to pass this on to the backend.
The mapping of feature support onto CPUs may not be complete; rather,
it was chosen to match LLVM's idea of which CPUs support this feature
(see lib/Target/X86/X86.td).
I also updated the affected test case (CodeGen/attr-target-x86.c) to
match the emitted output.
Reviewers: craig.topper, coby, efriedma, rsmith
Reviewed By: craig.topper
Subscribers: emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D43394
Pull in r328944 from upstream llvm trunk (by Chandler Carruth):
[x86] Expose more of the condition conversion routines in the public
API for X86's instruction information. I've now got a second patch
under review that needs these same APIs. This bit is nicely
orthogonal and obvious, so landing it. NFC.
Pull in r329414 from upstream llvm trunk (by Craig Topper):
[X86] Merge itineraries for CLC, CMC, and STC.
These are very simple flag setting instructions that appear to only
be a single uop. They're unlikely to need this separation.
Pull in r329657 from upstream llvm trunk (by Chandler Carruth):
[x86] Introduce a pass to begin more systematically fixing PR36028
and similar issues.
The key idea is to lower COPY nodes populating EFLAGS by scanning the
uses of EFLAGS and introducing dedicated code to preserve the
necessary state in a GPR. In the vast majority of cases, these uses
are cmovCC and jCC instructions. For such cases, we can very easily
save and restore the necessary information by simply inserting a
setCC into a GPR where the original flags are live, and then testing
that GPR directly to feed the cmov or conditional branch.
However, things are a bit more tricky if arithmetic is using the
flags. This patch handles the vast majority of cases that seem to
come up in practice: adc, adcx, adox, rcl, and rcr; all without
taking advantage of partially preserved EFLAGS as LLVM doesn't
currently model that at all.
There are a large number of operations that techinaclly observe
EFLAGS currently but shouldn't in this case -- they typically are
using DF. Currently, they will not be handled by this approach.
However, I have never seen this issue come up in practice. It is
already pretty rare to have these patterns come up in practical code
with LLVM. I had to resort to writing MIR tests to cover most of the
logic in this pass already. I suspect even with its current amount
of coverage of arithmetic users of EFLAGS it will be a significant
improvement over the current use of pushf/popf. It will also produce
substantially faster code in most of the common patterns.
This patch also removes all of the old lowering for EFLAGS copies,
and the hack that forced us to use a frame pointer when EFLAGS copies
were found anywhere in a function so that the dynamic stack
adjustment wasn't a problem. None of this is needed as we now lower
all of these copies directly in MI and without require stack
adjustments.
Lots of thanks to Reid who came up with several aspects of this
approach, and Craig who helped me work out a couple of things
tripping me up while working on this.
Differential Revision: https://reviews.llvm.org/D45146
Pull in r329673 from upstream llvm trunk (by Chandler Carruth):
[x86] Model the direction flag (DF) separately from the rest of
EFLAGS.
This cleans up a number of operations that only claimed te use EFLAGS
due to using DF. But no instructions which we think of us setting
EFLAGS actually modify DF (other than things like popf) and so this
needlessly creates uses of EFLAGS that aren't really there.
In fact, DF is so restrictive it is pretty easy to model. Only STD,
CLD, and the whole-flags writes (WRFLAGS and POPF) need to model
this.
I've also somewhat cleaned up some of the flag management instruction
definitions to be in the correct .td file.
Adding this extra register also uncovered a failure to use the
correct datatype to hold X86 registers, and I've corrected that as
necessary here.
Differential Revision: https://reviews.llvm.org/D45154
Pull in r330264 from upstream llvm trunk (by Chandler Carruth):
[x86] Fix PR37100 by teaching the EFLAGS copy lowering to rewrite
uses across basic blocks in the limited cases where it is very
straight forward to do so.
This will also be useful for other places where we do some limited
EFLAGS propagation across CFG edges and need to handle copy rewrites
afterward. I think this is rapidly approaching the maximum we can and
should be doing here. Everything else begins to require either heroic
analysis to prove how to do PHI insertion manually, or somehow
managing arbitrary PHI-ing of EFLAGS with general PHI insertion.
Neither of these seem at all promising so if those cases come up,
we'll almost certainly need to rewrite the parts of LLVM that produce
those patterns.
We do now require dominator trees in order to reliably diagnose
patterns that would require PHI nodes. This is a bit unfortunate but
it seems better than the completely mysterious crash we would get
otherwise.
Differential Revision: https://reviews.llvm.org/D45673
Together, these should ensure clang does not use pushf/popf sequences to
save and restore flags, avoiding problems with unrelated flags (such as
the interrupt flag) being restored unexpectedly.
Requested by: jtl
PR: 225330
MFC after: 1 week
This will faciliate a WITH_SYSTEM_LINKER option.
Reviewed by: dim
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D15110
[X86] Add 'sahf' CPU feature to frontend
Summary:
Make clang accept `-msahf` (and `-mno-sahf`) flags to activate the
`+sahf` feature for the backend, for bug 36028 (Incorrect use of
pushf/popf enables/disables interrupts on amd64 kernels). This was
originally submitted in bug 36037 by Jonathan Looney
<jonlooney@gmail.com>.
As described there, GCC also uses `-msahf` for this feature, and the
backend already recognizes the `+sahf` feature. All that is needed is
to teach clang to pass this on to the backend.
The mapping of feature support onto CPUs may not be complete; rather,
it was chosen to match LLVM's idea of which CPUs support this feature
(see lib/Target/X86/X86.td).
I also updated the affected test case (CodeGen/attr-target-x86.c) to
match the emitted output.
Reviewers: craig.topper, coby, efriedma, rsmith
Reviewed By: craig.topper
Subscribers: emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D43394
Pull in r328944 from upstream llvm trunk (by Chandler Carruth):
[x86] Expose more of the condition conversion routines in the public
API for X86's instruction information. I've now got a second patch
under review that needs these same APIs. This bit is nicely
orthogonal and obvious, so landing it. NFC.
Pull in r329414 from upstream llvm trunk (by Craig Topper):
[X86] Merge itineraries for CLC, CMC, and STC.
These are very simple flag setting instructions that appear to only
be a single uop. They're unlikely to need this separation.
Pull in r329657 from upstream llvm trunk (by Chandler Carruth):
[x86] Introduce a pass to begin more systematically fixing PR36028
and similar issues.
The key idea is to lower COPY nodes populating EFLAGS by scanning the
uses of EFLAGS and introducing dedicated code to preserve the
necessary state in a GPR. In the vast majority of cases, these uses
are cmovCC and jCC instructions. For such cases, we can very easily
save and restore the necessary information by simply inserting a
setCC into a GPR where the original flags are live, and then testing
that GPR directly to feed the cmov or conditional branch.
However, things are a bit more tricky if arithmetic is using the
flags. This patch handles the vast majority of cases that seem to
come up in practice: adc, adcx, adox, rcl, and rcr; all without
taking advantage of partially preserved EFLAGS as LLVM doesn't
currently model that at all.
There are a large number of operations that techinaclly observe
EFLAGS currently but shouldn't in this case -- they typically are
using DF. Currently, they will not be handled by this approach.
However, I have never seen this issue come up in practice. It is
already pretty rare to have these patterns come up in practical code
with LLVM. I had to resort to writing MIR tests to cover most of the
logic in this pass already. I suspect even with its current amount
of coverage of arithmetic users of EFLAGS it will be a significant
improvement over the current use of pushf/popf. It will also produce
substantially faster code in most of the common patterns.
This patch also removes all of the old lowering for EFLAGS copies,
and the hack that forced us to use a frame pointer when EFLAGS copies
were found anywhere in a function so that the dynamic stack
adjustment wasn't a problem. None of this is needed as we now lower
all of these copies directly in MI and without require stack
adjustments.
Lots of thanks to Reid who came up with several aspects of this
approach, and Craig who helped me work out a couple of things
tripping me up while working on this.
Differential Revision: https://reviews.llvm.org/D45146
Pull in r329673 from upstream llvm trunk (by Chandler Carruth):
[x86] Model the direction flag (DF) separately from the rest of
EFLAGS.
This cleans up a number of operations that only claimed te use EFLAGS
due to using DF. But no instructions which we think of us setting
EFLAGS actually modify DF (other than things like popf) and so this
needlessly creates uses of EFLAGS that aren't really there.
In fact, DF is so restrictive it is pretty easy to model. Only STD,
CLD, and the whole-flags writes (WRFLAGS and POPF) need to model
this.
I've also somewhat cleaned up some of the flag management instruction
definitions to be in the correct .td file.
Adding this extra register also uncovered a failure to use the
correct datatype to hold X86 registers, and I've corrected that as
necessary here.
Differential Revision: https://reviews.llvm.org/D45154
Together, these should ensure clang does not use pushf/popf sequences to
save and restore flags, avoiding problems with unrelated flags (such as
the interrupt flag) being restored unexpectedly.
Requested by: jtl
PR: 225330
MFC after: 1 week
