This allows later passes (in particular InstCombine) to optimize more
cases.
One that's important to us is `memcmp(p, q, constant) < 0` and memcmp(p, q, constant) > 0.
llvm-svn: 364412
Use -fsave-optimization-record=<format> to specify a different format
than the default, which is YAML.
For now, only YAML is supported.
llvm-svn: 363573
* Add a common function to setup opt-remarks
* Rename common options to the same names
* Add error types to distinguish between file errors and regex errors
llvm-svn: 363415
* Add a common function to setup opt-remarks
* Rename common options to the same names
* Add error types to distinguish between file errors and regex errors
llvm-svn: 363328
This was using its own, outdated list of possible captures. This was
at minimum not catching cmpxchg and addrspacecast captures.
One change is now any volatile access is treated as capturing. The
test coverage for this pass is quite inadequate, but this required
removing volatile in the lifetime capture test.
Also fixes some infrastructure issues to allow running just the IR
pass.
Fixes bug 42238.
llvm-svn: 363169
Patch which introduces a target-independent framework for generating
hardware loops at the IR level. Most of the code has been taken from
PowerPC CTRLoops and PowerPC has been ported over to use this generic
pass. The target dependent parts have been moved into
TargetTransformInfo, via isHardwareLoopProfitable, with
HardwareLoopInfo introduced to transfer information from the backend.
Three generic intrinsics have been introduced:
- void @llvm.set_loop_iterations
Takes as a single operand, the number of iterations to be executed.
- i1 @llvm.loop_decrement(anyint)
Takes the maximum number of elements processed in an iteration of
the loop body and subtracts this from the total count. Returns
false when the loop should exit.
- anyint @llvm.loop_decrement_reg(anyint, anyint)
Takes the number of elements remaining to be processed as well as
the maximum numbe of elements processed in an iteration of the loop
body. Returns the updated number of elements remaining.
llvm-svn: 362774
Separate the remark serialization to YAML from the LLVM Diagnostics.
This adds a new serialization abstraction: remarks::Serializer. It's
completely independent from lib/IR and it provides an easy way to
replace YAML by providing a new remarks::Serializer.
Differential Revision: https://reviews.llvm.org/D62632
llvm-svn: 362160
Summary:
For the most part this consists of replacing ${LLVM_TARGETS_TO_BUILD} with
some combination of AllTargets* so that they depend on specific components
of a target backend rather than all of it. The overall effect of this is
that, for example, tools like opt no longer falsely depend on the
disassembler, while tools like llvm-ar no longer depend on the code
generator.
There's a couple quirks to point out here:
* AllTargetsCodeGens is a bit more prevalent than expected. Tools like dsymutil
seem to need it which I was surprised by.
* llvm-xray linked to all the backends but doesn't seem to need any of them.
It builds and passes the tests so that seems to be correct.
* I left gold out as it's not built when binutils is not available so I'm
unable to test it
Reviewers: bogner, JDevlieghere
Reviewed By: bogner
Subscribers: mehdi_amini, mgorny, steven_wu, dexonsmith, rupprecht, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62331
llvm-svn: 361567
TypedDINodeRef<T> is a redundant wrapper of Metadata * that is actually a T *.
Accordingly, change DI{Node,Scope,Type}Ref uses to DI{Node,Scope,Type} * or their const variants.
This allows us to delete many resolve() calls that clutter the code.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D61369
llvm-svn: 360108
Summary:
When refactoring vectorization flags, vectorization was disabled by default in the new pass manager.
This patch re-enables is for both managers, and changes the assumptions opt makes, based on the new defaults.
Comments in opt.cpp should clarify the intended use of all flags to enable/disable vectorization.
Reviewers: chandlerc, jgorbe
Subscribers: jlebar, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61091
llvm-svn: 359167
Summary:
Trying to add the plumbing necessary to add tuning options to the new pass manager.
Testing with the flags for loop vectorize.
Reviewers: chandlerc
Subscribers: sanjoy, mehdi_amini, jlebar, steven_wu, dexonsmith, dang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59723
llvm-svn: 358763
Removes the code from opt and the pass manager builder.
The code was unused - even by the C library code that was supposed to set
it and had been removed previously.
llvm-svn: 358024
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
Original llvm-svn: 355964
llvm-svn: 355984
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
llvm-svn: 355964
This allows us to store more info about where we're emitting the remarks
without cluttering LLVMContext. This is needed for future support for
the remark section.
Differential Revision: https://reviews.llvm.org/D58996
Original llvm-svn: 355507
llvm-svn: 355514
This allows us to store more info about where we're emitting the remarks
without cluttering LLVMContext. This is needed for future support for
the remark section.
Differential Revision: https://reviews.llvm.org/D58996
llvm-svn: 355507
Partly addresses PR15026.
There are a few tests that passed in invalid architectures, which are fixed in: rL355349 and D58931
Reviewers: echristo, efriedma, rengolin, atrick
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D58933
llvm-svn: 355455
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Currently we have pgo options defined in PassManagerBuilder.cpp only for
instrument pgo, but not for sample pgo. We also have pgo options defined
in NewPMDriver.cpp in opt only for new pass manager and for all kinds of
pgo. They have some inconsistency.
To make the options more consistent and make tests writing easier, the
patch let old pass manager to share the same pgo options with new pass
manager in opt, and removes the options in PassManagerBuilder.cpp.
Differential Revision: https://reviews.llvm.org/D56749
llvm-svn: 351392
Summary:
Records in the module summary index whether the bitcode was compiled
with the option necessary to enable splitting the LTO unit
(e.g. -fsanitize=cfi, -fwhole-program-vtables, or -fsplit-lto-unit).
The information is passed down to the ModuleSummaryIndex builder via a
new module flag "EnableSplitLTOUnit", which is propagated onto a flag
on the summary index.
This is then used during the LTO link to check whether all linked
summaries were built with the same value of this flag. If not, an error
is issued when we detect a situation requiring whole program visibility
of the class hierarchy. This is the case when both of the following
conditions are met:
1) We are performing LowerTypeTests or Whole Program Devirtualization.
2) There are type tests or type checked loads in the code.
Note I have also changed the ThinLTOBitcodeWriter to also gate the
module splitting on the value of this flag.
Reviewers: pcc
Subscribers: ormris, mehdi_amini, Prazek, inglorion, eraman, steven_wu, dexonsmith, arphaman, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D53890
llvm-svn: 350948
This will hold flags specific to subprograms. In the future
we could potentially free up scarce bits in DIFlags by moving
subprogram-specific flags from there to the new flags word.
This patch does not change IR/bitcode formats, that will be
done in a follow-up.
Differential Revision: https://reviews.llvm.org/D54597
llvm-svn: 347239
This patch defines an interleaved-load-combine pass. The pass searches
for ShuffleVector instructions that represent interleaved loads. Matches are
converted such that they will be captured by the InterleavedAccessPass.
The pass extends LLVMs capabilities to use target specific instruction
selection of interleaved load patterns (e.g.: ld4 on Aarch64
architectures).
Differential Revision: https://reviews.llvm.org/D52653
llvm-svn: 347208
Summary:
It turns out that we need an OptimizerLast PassBuilder extension point
after all. I missed the relevance of this EP the first time. By legacy PM magic,
function passes added at this EP get added to the last _Function_ PM, which is a
feature we lost when dropping this EP for the new PM.
A key difference between this and the legacy PassManager's OptimizerLast
callback is that this extension point is not triggered at O0. Extensions
to the O0 pipeline should append their passes to the end of the overall
pipeline.
Differential Revision: https://reviews.llvm.org/D54374
llvm-svn: 346645
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.
TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.
Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246
llvm-svn: 344685
Summary:
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.
TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.
Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246
llvm-svn: 344519
This can be used to preserve profiling information across codebase
changes that have widespread impact on mangled names, but across which
most profiling data should still be usable. For example, when switching
from libstdc++ to libc++, or from the old libstdc++ ABI to the new ABI,
or even from a 32-bit to a 64-bit build.
The user can provide a remapping file specifying parts of mangled names
that should be treated as equivalent (eg, std::__1 should be treated as
equivalent to std::__cxx11), and profile data will be treated as
applying to a particular function if its name is equivalent to the name
of a function in the profile data under the provided equivalences. See
the documentation change for a description of how this is configured.
Remapping is supported for both sample-based profiling and instruction
profiling. We do not support remapping indirect branch target
information, but all other profile data should be remapped
appropriately.
Support is only added for the new pass manager. If someone wants to also
add support for this for the old pass manager, doing so should be
straightforward.
This is the LLVM side of Clang r344199.
Reviewers: davidxl, tejohnson, dlj, erik.pilkington
Subscribers: mehdi_amini, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D51249
llvm-svn: 344200
Implementing -print-before-all/-print-after-all/-filter-print-func support
through PassInstrumentation callbacks.
- PrintIR routines implement printing callbacks.
- StandardInstrumentations class provides a central place to manage all
the "standard" in-tree pass instrumentations. Currently it registers
PrintIR callbacks.
Reviewers: chandlerc, paquette, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D50923
llvm-svn: 342896
Add a -debugify-export option to opt. This exports per-pass `debugify`
loss statistics to a file in CSV format.
For some interesting numbers on debug value loss during an -O2 build
of the sqlite3 amalgamation, see the review thread.
Differential Revision: https://reviews.llvm.org/D49003
llvm-svn: 337787
This is a minor cleanup in preparation for a change to export DI
statistics from -check-debugify. To do that, it would be cleaner to have
a dedicated header for the debugify interface.
llvm-svn: 337786
Suppress the diagnostic for mis-sized dbg.values when a value operand is
narrower than the unsigned variable it describes. Assume that a debugger
would implicitly zero-extend these values.
llvm-svn: 336452
The checking logic should not treat artificial locations as being
somehow problematic. Producing these locations can be the desired
behavior of some passes.
See llvm.org/PR37961.
llvm-svn: 335897
It's not possible to get the fragment size of some dbg.values. Teach the
mis-sized dbg.value diagnostic to detect this scenario and bail out.
Tested with:
$ find test/Transforms -print -exec opt -debugify-each -instcombine {} \;
llvm-svn: 335695
Report an error in -check-debugify when the size of a dbg.value operand
doesn't match up with the size of the variable it describes.
Eventually this check should be moved into the IR verifier. For the
moment, it's useful to include the check in -check-debugify as a means
of catching regressions and finding existing bugs.
Here are some instances of bugs the new check finds in the -O2 pipeline
(all in InstCombine):
1) A float is used where a double is expected:
ERROR: dbg.value operand has size 32, but its variable has size 64:
call void @llvm.dbg.value(metadata float %expf, metadata !12, metadata
!DIExpression()), !dbg !15
2) An i8 is used where an i32 is expected:
ERROR: dbg.value operand has size 8, but its variable has size 32:
call void @llvm.dbg.value(metadata i8 %t4, metadata !14, metadata
!DIExpression()), !dbg !24
3) A <4 x i32> is used where something twice as large is expected
(perhaps a <4 x i64>, I haven't double-checked):
ERROR: dbg.value operand has size 128, but its variable has size 256:
call void @llvm.dbg.value(metadata <4 x i32> %4, metadata !40, metadata
!DIExpression()), !dbg !95
Differential Revision: https://reviews.llvm.org/D48408
llvm-svn: 335682
When checking the debug info in a module, don't treat a missing
dbg.value as an error. The dbg.value may simply have been DCE'd, in
which case the debugger has enough information to display the variable
as <optimized out>.
llvm-svn: 335647
Before this patch, debugify would insert debug value intrinsics before the
terminating instruction in a block. This had the advantage of being simple,
but was a bit too simple/unrealistic.
This patch teaches debugify to insert debug values immediately after their
operand defs. This enables better testing of the compiler.
For example, with this patch, `opt -debugify-each` is able to identify a
vectorizer DI-invariance bug fixed in llvm.org/PR32761. In this bug, the
vectorizer produced different output with/without debug info present.
Reverting Davide's bugfix locally, I see:
$ ~/scripts/opt-check-dbg-invar.sh ./bin/opt \
.../SLPVectorizer/AArch64/spillcost-di.ll -slp-vectorizer
Comparing: -slp-vectorizer .../SLPVectorizer/AArch64/spillcost-di.ll
Baseline: /var/folders/j8/t4w0bp8j6x1g6fpghkcb4sjm0000gp/T/tmp.iYYeL1kf
With DI : /var/folders/j8/t4w0bp8j6x1g6fpghkcb4sjm0000gp/T/tmp.sQtQSeet
9,11c9,11
< %5 = getelementptr inbounds %0, %0* %2, i64 %0, i32 1
< %6 = bitcast i64* %4 to <2 x i64>*
< %7 = load <2 x i64>, <2 x i64>* %6, align 8, !tbaa !0
---
> %5 = load i64, i64* %4, align 8, !tbaa !0
> %6 = getelementptr inbounds %0, %0* %2, i64 %0, i32 1
> %7 = load i64, i64* %6, align 8, !tbaa !5
12a13
> store i64 %5, i64* %8, align 8, !tbaa !0
14,15c15
< %10 = bitcast i64* %8 to <2 x i64>*
< store <2 x i64> %7, <2 x i64>* %10, align 8, !tbaa !0
---
> store i64 %7, i64* %9, align 8, !tbaa !5
:: Found a test case ^
Running this over the *.ll files in tree, I found four additional examples
which compile differently with/without DI present. I plan on filing bugs for
these.
llvm-svn: 334118
The -check-debugify pass should preserve all analyses. Otherwise, it may
invalidate an optional analysis and inadvertently alter codegen.
The test case is reduced from deopt-bundle.ll. The result of `opt -O1`
on this file would differ when -debugify-each was toggled. That happened
because CheckDebugify failed to preserve GlobalsAA.
Thanks to Davide Italiano for his help chasing this down!
llvm-svn: 333959
After r333856, opt -debugify would just stop emitting debug value
intrinsics after encountering a musttail call. This wasn't sufficient to
avoid verifier failures.
Debug value intrinicss for all instructions preceding a musttail call
must also be emitted before the musttail call.
llvm-svn: 333866
Applying synthetic debug info before the bitcode writer pass has no
testing-related purpose. This commit prevents that from happening.
It also adds tests which check that IR produced with/without
-debugify-each enabled is identical after stripping. This makes it
possible to check that individual passes (or full pipelines) are
invariant to debug info.
llvm-svn: 333861
The -strip-module-flags option strips llvm.module.flags metadata from a
module at the beginning of the opt pipeline.
This will be used to test whether the output of a pass is debug info
(DI) invariant.
E.g, after applying synthetic debug info to a test case, we'd like to
strip out all DI-related metadata and check that the final IR is
identical to a baseline file without any DI applied, to check that
optimizations aren't inhibited by debug info.
llvm-svn: 333860
Setting the "Debug Info Version" module flag makes it possible to pipe
synthetic debug info into llc, which is useful for testing backends.
llvm-svn: 333237
Currently debugify prints it's output to stdout,
with this patch all the output generated goes to stderr.
This change lets us use debugify without taking away
the ability to pipe the output to other llvm tools.
llvm-svn: 332642
This adds a -debugify-each mode to opt which, when enabled, wraps each
{Module,Function}Pass in a pipeline with logic to add, check, and strip
synthetic debug info for testing purposes.
This mode can be used to test complex pipelines for debug info bugs, or
to collect statistics about the number of debug values & locations lost
throughout various stages of a pipeline.
Patch by Son Tuan Vu!
Differential Revision: https://reviews.llvm.org/D46525
llvm-svn: 332312
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
See r331124 for how I made a list of files missing the include.
I then ran this Python script:
for f in open('filelist.txt'):
f = f.strip()
fl = open(f).readlines()
found = False
for i in xrange(len(fl)):
p = '#include "llvm/'
if not fl[i].startswith(p):
continue
if fl[i][len(p):] > 'Config':
fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
found = True
break
if not found:
print 'not found', f
else:
open(f, 'w').write(''.join(fl))
and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.
No intended behavior change.
llvm-svn: 331184
As demonstrated by the regression tests added in this patch, the
following cases are valid cases:
1. A Function with no DISubprogram attached, but various debug info
related to its instructions, coming, for instance, from an inlined
function, also defined somewhere else in the same module;
2. ... or coming exclusively from the functions inlined and eliminated
from the module entirely.
The ValueMap shared between CloneFunctionInto calls within CloneModule
needs to contain identity mappings for all of the DISubprogram's to
prevent them from being duplicated by MapMetadata / RemapInstruction
calls, this is achieved via DebugInfoFinder collecting all the
DISubprogram's. However, CloneFunctionInto was missing calls into
DebugInfoFinder for functions w/o DISubprogram's attached, but still
referring DISubprogram's from within (case 1). This patch fixes that.
The fix above, however, exposes another issue: if a module contains a
DISubprogram referenced only indirectly from other debug info
metadata, but not attached to any Function defined within the module
(case 2), cloning such a module causes a DICompileUnit duplication: it
will be moved in indirecty via a DISubprogram by DebugInfoFinder first
(because of the first bug fix described above), without being
self-mapped within the shared ValueMap, and then will be copied during
named metadata cloning. So this patch makes sure DebugInfoFinder
visits DICompileUnit's referenced from DISubprogram's as it goes w/o
re-processing llvm.dbg.cu list over and over again for every function
cloned, and makes sure that CloneFunctionInto self-maps
DICompileUnit's referenced from the entire function, not just its own
DISubprogram attached that may also be missing.
The most convenient way of tesing CloneModule I found is to rely on
CloneModule call from `opt -run-twice`, instead of writing tedious
unit tests. That feature has a couple of properties that makes it hard
to use for this purpose though:
1. CloneModule doesn't copy source filename, making `opt -run-twice`
report it as a difference.
2. `opt -run-twice` does the second run on the original module, not
its clone, making the result of cloning completely invisible in opt's
actual output with and without `-run-twice` both, which directly
contradicts `opt -run-twice`s own error message.
This patch fixes this as well.
Reviewed By: aprantl
Reviewers: loladiro, GorNishanov, espindola, echristo, dexonsmith
Subscribers: vsk, debug-info, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D45593
llvm-svn: 330069
We have a few functions that virtually all command wants to run on
process startup/shutdown. This patch adds InitLLVM class to do that
all at once, so that we don't need to copy-n-paste boilerplate code
to each llvm command's main() function.
Differential Revision: https://reviews.llvm.org/D45602
llvm-svn: 330046
These aren't the .def style files used in LLVM that require a macro
defined before their inclusion - they're just basic non-modular includes
to stamp out command line flag variables.
llvm-svn: 329840
Summary:
Add a new plugin API. This closes the gap between pass registration and out-of-tree passes for the new PassManager.
Unlike with the existing API, interaction with a plugin is always
initiated from the tools perspective. I.e., when a plugin is loaded, it
resolves and calls a well-known symbol `llvmGetPassPluginInfo` to obtain
details about the plugin. The fundamental motivation is to get rid of as
many global constructors as possible. The API exposed by the plugin
info is kept intentionally minimal.
Reviewers: chandlerc
Reviewed By: chandlerc
Subscribers: bollu, grosser, lksbhm, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D35258
llvm-svn: 329273
If a function doesn't have an exact definition, don't apply debugify
metadata as it triggers a DIVerifier failure.
The issue is that it's invalid to have DILocations inside a DISubprogram
which isn't a definition ("scope points into the type hierarchy!").
llvm-svn: 325036
Sometimes users do not specify data layout in LLVM assembly and let llc set the
data layout by target triple after loading the LLVM assembly.
Currently the parser checks alloca address space no matter whether the LLVM
assembly contains data layout definition, which causes false alarm since the
default data layout does not contain the correct alloca address space.
The parser also calls verifier to check debug info and updating invalid debug
info. Currently there is no way to let the verifier to check debug info only.
If the verifier finds non-debug-info issues the parser will fail.
For llc, the fix is to remove the check of alloca addr space in the parser and
disable updating debug info, and defer the updating of debug info and
verification to be after setting data layout of the IR by target.
For other llvm tools, since they do not override data layout by target but
instead can override data layout by a command line option, an argument for
overriding data layout is added to the parser. In cases where data layout
overriding is necessary for the parser, the data layout can be provided by
command line.
Differential Revision: https://reviews.llvm.org/D41832
llvm-svn: 323826
Combine expression patterns to form expressions with fewer, simple instructions.
This pass does not modify the CFG.
For example, this pass reduce width of expressions post-dominated by TruncInst
into smaller width when applicable.
It differs from instcombine pass in that it contains pattern optimization that
requires higher complexity than the O(1), thus, it should run fewer times than
instcombine pass.
Differential Revision: https://reviews.llvm.org/D38313
llvm-svn: 323321
Opt's "-enable-debugify" mode adds an instance of Debugify at the
beginning of the pass pipeline, and an instance of CheckDebugify at the
end.
You can enable this mode with lit using: -Dopt="opt -enable-debugify".
Note that running test suites in this mode will result in many failures
due to strict FileCheck commands, etc.
It can be more useful to look for assertion failures which arise only
when Debugify is enabled, e.g to prove that we have (or do not have)
test coverage for some code path with debug info present.
Differential Revision: https://reviews.llvm.org/D41793
llvm-svn: 323256
This applies to most pipelines except the LTO and ThinLTO backend
actions - it is for use at the beginning of the overall pipeline.
This extension point will be used to add the GCOV pass when enabled in
Clang.
llvm-svn: 323166
Summary:
First, we need to explain the core of the vulnerability. Note that this
is a very incomplete description, please see the Project Zero blog post
for details:
https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html
The basis for branch target injection is to direct speculative execution
of the processor to some "gadget" of executable code by poisoning the
prediction of indirect branches with the address of that gadget. The
gadget in turn contains an operation that provides a side channel for
reading data. Most commonly, this will look like a load of secret data
followed by a branch on the loaded value and then a load of some
predictable cache line. The attacker then uses timing of the processors
cache to determine which direction the branch took *in the speculative
execution*, and in turn what one bit of the loaded value was. Due to the
nature of these timing side channels and the branch predictor on Intel
processors, this allows an attacker to leak data only accessible to
a privileged domain (like the kernel) back into an unprivileged domain.
The goal is simple: avoid generating code which contains an indirect
branch that could have its prediction poisoned by an attacker. In many
cases, the compiler can simply use directed conditional branches and
a small search tree. LLVM already has support for lowering switches in
this way and the first step of this patch is to disable jump-table
lowering of switches and introduce a pass to rewrite explicit indirectbr
sequences into a switch over integers.
However, there is no fully general alternative to indirect calls. We
introduce a new construct we call a "retpoline" to implement indirect
calls in a non-speculatable way. It can be thought of loosely as
a trampoline for indirect calls which uses the RET instruction on x86.
Further, we arrange for a specific call->ret sequence which ensures the
processor predicts the return to go to a controlled, known location. The
retpoline then "smashes" the return address pushed onto the stack by the
call with the desired target of the original indirect call. The result
is a predicted return to the next instruction after a call (which can be
used to trap speculative execution within an infinite loop) and an
actual indirect branch to an arbitrary address.
On 64-bit x86 ABIs, this is especially easily done in the compiler by
using a guaranteed scratch register to pass the target into this device.
For 32-bit ABIs there isn't a guaranteed scratch register and so several
different retpoline variants are introduced to use a scratch register if
one is available in the calling convention and to otherwise use direct
stack push/pop sequences to pass the target address.
This "retpoline" mitigation is fully described in the following blog
post: https://support.google.com/faqs/answer/7625886
We also support a target feature that disables emission of the retpoline
thunk by the compiler to allow for custom thunks if users want them.
These are particularly useful in environments like kernels that
routinely do hot-patching on boot and want to hot-patch their thunk to
different code sequences. They can write this custom thunk and use
`-mretpoline-external-thunk` *in addition* to `-mretpoline`. In this
case, on x86-64 thu thunk names must be:
```
__llvm_external_retpoline_r11
```
or on 32-bit:
```
__llvm_external_retpoline_eax
__llvm_external_retpoline_ecx
__llvm_external_retpoline_edx
__llvm_external_retpoline_push
```
And the target of the retpoline is passed in the named register, or in
the case of the `push` suffix on the top of the stack via a `pushl`
instruction.
There is one other important source of indirect branches in x86 ELF
binaries: the PLT. These patches also include support for LLD to
generate PLT entries that perform a retpoline-style indirection.
The only other indirect branches remaining that we are aware of are from
precompiled runtimes (such as crt0.o and similar). The ones we have
found are not really attackable, and so we have not focused on them
here, but eventually these runtimes should also be replicated for
retpoline-ed configurations for completeness.
For kernels or other freestanding or fully static executables, the
compiler switch `-mretpoline` is sufficient to fully mitigate this
particular attack. For dynamic executables, you must compile *all*
libraries with `-mretpoline` and additionally link the dynamic
executable and all shared libraries with LLD and pass `-z retpolineplt`
(or use similar functionality from some other linker). We strongly
recommend also using `-z now` as non-lazy binding allows the
retpoline-mitigated PLT to be substantially smaller.
When manually apply similar transformations to `-mretpoline` to the
Linux kernel we observed very small performance hits to applications
running typical workloads, and relatively minor hits (approximately 2%)
even for extremely syscall-heavy applications. This is largely due to
the small number of indirect branches that occur in performance
sensitive paths of the kernel.
When using these patches on statically linked applications, especially
C++ applications, you should expect to see a much more dramatic
performance hit. For microbenchmarks that are switch, indirect-, or
virtual-call heavy we have seen overheads ranging from 10% to 50%.
However, real-world workloads exhibit substantially lower performance
impact. Notably, techniques such as PGO and ThinLTO dramatically reduce
the impact of hot indirect calls (by speculatively promoting them to
direct calls) and allow optimized search trees to be used to lower
switches. If you need to deploy these techniques in C++ applications, we
*strongly* recommend that you ensure all hot call targets are statically
linked (avoiding PLT indirection) and use both PGO and ThinLTO. Well
tuned servers using all of these techniques saw 5% - 10% overhead from
the use of retpoline.
We will add detailed documentation covering these components in
subsequent patches, but wanted to make the core functionality available
as soon as possible. Happy for more code review, but we'd really like to
get these patches landed and backported ASAP for obvious reasons. We're
planning to backport this to both 6.0 and 5.0 release streams and get
a 5.0 release with just this cherry picked ASAP for distros and vendors.
This patch is the work of a number of people over the past month: Eric, Reid,
Rui, and myself. I'm mailing it out as a single commit due to the time
sensitive nature of landing this and the need to backport it. Huge thanks to
everyone who helped out here, and everyone at Intel who helped out in
discussions about how to craft this. Also, credit goes to Paul Turner (at
Google, but not an LLVM contributor) for much of the underlying retpoline
design.
Reviewers: echristo, rnk, ruiu, craig.topper, DavidKreitzer
Subscribers: sanjoy, emaste, mcrosier, mgorny, mehdi_amini, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D41723
llvm-svn: 323155
The Debugify pass synthesizes debug info for IR. It's paired with a
CheckDebugify pass which determines how much of the original debug info
is preserved. These passes make it easier to create targeted tests for
debug info preservation.
Here is the Debugify algorithm:
NextLine = 1
for (Instruction &I : M)
attach DebugLoc(NextLine++) to I
NextVar = 1
for (Instruction &I : M)
if (canAttachDebugValue(I))
attach dbg.value(NextVar++) to I
The CheckDebugify pass expects contiguous ranges of DILocations and
DILocalVariables. If it fails to find all of the expected debug info, it
prints a specific error to stderr which can be FileChecked.
This was discussed on llvm-dev in the thread:
"Passes to add/validate synthetic debug info"
Differential Revision: https://reviews.llvm.org/D40512
llvm-svn: 320202
We currently use target_link_libraries without an explicit scope
specifier (INTERFACE, PRIVATE or PUBLIC) when linking executables.
Dependencies added in this way apply to both the target and its
dependencies, i.e. they become part of the executable's link interface
and are transitive.
Transitive dependencies generally don't make sense for executables,
since you wouldn't normally be linking against an executable. This also
causes issues for generating install export files when using
LLVM_DISTRIBUTION_COMPONENTS. For example, clang has a lot of LLVM
library dependencies, which are currently added as interface
dependencies. If clang is in the distribution components but the LLVM
libraries it depends on aren't (which is a perfectly legitimate use case
if the LLVM libraries are being built static and there are therefore no
run-time dependencies on them), CMake will complain about the LLVM
libraries not being in export set when attempting to generate the
install export file for clang. This is reasonable behavior on CMake's
part, and the right thing is for LLVM's build system to explicitly use
PRIVATE dependencies for executables.
Unfortunately, CMake doesn't allow you to mix and match the keyword and
non-keyword target_link_libraries signatures for a single target; i.e.,
if a single call to target_link_libraries for a particular target uses
one of the INTERFACE, PRIVATE, or PUBLIC keywords, all other calls must
also be updated to use those keywords. This means we must do this change
in a single shot. I also fully expect to have missed some instances; I
tested by enabling all the projects in the monorepo (except dragonegg),
and configuring both with and without shared libraries, on both Darwin
and Linux, but I'm planning to rely on the buildbots for other
configurations (since it should be pretty easy to fix those).
Even after this change, we still have a lot of target_link_libraries
calls that don't specify a scope keyword, mostly for shared libraries.
I'm thinking about addressing those in a follow-up, but that's a
separate change IMO.
Differential Revision: https://reviews.llvm.org/D40823
llvm-svn: 319840
Since this isn't a real header - it includes static functions and had
external linkage variables (though this change makes them static, since
that's what they should be) so can't be included more than once in a
program.
llvm-svn: 319082
Clang implements the -finstrument-functions flag inherited from GCC, which
inserts calls to __cyg_profile_func_{enter,exit} on function entry and exit.
This is useful for getting a trace of how the functions in a program are
executed. Normally, the calls remain even if a function is inlined into another
function, but it is useful to be able to turn this off for users who are
interested in a lower-level trace, i.e. one that reflects what functions are
called post-inlining. (We use this to generate link order files for Chromium.)
LLVM already has a pass for inserting similar instrumentation calls to
mcount(), which it does after inlining. This patch renames and extends that
pass to handle calls both to mcount and the cygprofile functions, before and/or
after inlining as controlled by function attributes.
Differential Revision: https://reviews.llvm.org/D39287
llvm-svn: 318195
Probably due to a change of how some pass initializes its dependencies,
the -write-bitcode pass (Bitcode/Writer/BitcodeWriterPass.cpp) is not
initialized in opt anymore and therefore not usable with
opt -write-bitcode
Explicitly call initializeWriteBitcodePassPass() to make it available
in opt again.
Differential Revision: https://reviews.llvm.org/D39223
llvm-svn: 316464
Reverting to investigate layering effects of MCJIT not linking
libCodeGen but using TargetMachine::getNameWithPrefix() breaking the
lldb bots.
This reverts commit r315633.
llvm-svn: 315637
Merge LLVMTargetMachine into TargetMachine.
- There is no in-tree target anymore that just implements TargetMachine
but not LLVMTargetMachine.
- It should still be possible to stub out all the various functions in
case a target does not want to use lib/CodeGen
- This simplifies the code and avoids methods ending up in the wrong
interface.
Differential Revision: https://reviews.llvm.org/D38489
llvm-svn: 315633
This came out of a recent discussion on llvm-dev
(https://reviews.llvm.org/D38042). Currently the Verifier will strip
the debug info metadata from a module if it finds the dbeug info to be
malformed. This feature is very valuable since it allows us to improve
the Verifier by making it stricter without breaking bcompatibility,
but arguable the Verifier pass should not be modifying the IR. This
patch moves the stripping of broken debug info into AutoUpgrade
(UpgradeDebugInfo to be precise), which is a much better location for
this since the stripping of malformed (i.e., produced by older, buggy
versions of Clang) is a (harsh) form of AutoUpgrade.
This change is mostly NFC in nature, the one big difference is the
behavior when LLVM module passes are introducing malformed debug
info. Prior to this patch, a NoAsserts build would have printed a
warning and stripped the debug info, after this patch the Verifier
will report a fatal error. I believe this behavior is actually more
desirable anyway.
Differential Revision: https://reviews.llvm.org/D38184
llvm-svn: 314699
Summary:
The New Pass Manager infrastructure was forgetting to keep around the optimization remark yaml file that the compiler might have been producing. This meant setting the option to '-' for stdout worked, but setting it to a filename didn't give file output (presumably it was deleted because compilation didn't explicitly keep it). This change just ensures that the file is kept if compilation succeeds.
So far I have updated one of the optimization remark output tests to add a version with the new pass manager. It is my intention for this patch to also include changes to all tests that use `-opt-remark-output=` but I wanted to get the code patch ready for review while I was making all those changes.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33951
Reviewers: anemet, chandlerc
Reviewed By: anemet, chandlerc
Subscribers: javed.absar, chandlerc, fhahn, llvm-commits
Differential Revision: https://reviews.llvm.org/D36906
llvm-svn: 311271
Summary: When polly is linked into the tools because of the LLVM_POLLY_LINK_INTO_TOOLS option being set, we need to register its passes with the PassBuilder. Because polly is linked in, we can directly call its callback registration method, which registers the appropriate callbacks with the new PM's PassBuilder. This essentially follows exactly the way it worked with the legacy PM.
Reviewers: grosser, chandlerc, bollu
Reviewed By: grosser
Subscribers: pollydev, llvm-commits
Differential Revision: https://reviews.llvm.org/D36273
llvm-svn: 310043
IMHO it is an antipattern to have a enum value that is Default.
At any given piece of code it is not clear if we have to handle
Default or if has already been mapped to a concrete value. In this
case in particular, only the target can do the mapping and it is nice
to make sure it is always done.
This deletes the two default enum values of CodeModel and uses an
explicit Optional<CodeModel> when it is possible that it is
unspecified.
llvm-svn: 309911
Summary: The new PM needs to invoke add-discriminator pass when building with -fdebug-info-for-profiling.
Reviewers: chandlerc, davidxl
Reviewed By: chandlerc
Subscribers: sanjoy, llvm-commits
Differential Revision: https://reviews.llvm.org/D35744
llvm-svn: 309121
Summary: This patch adds flags and tests to cover the PGOOpt handling logic in new PM.
Reviewers: chandlerc, davide
Reviewed By: chandlerc
Subscribers: sanjoy, llvm-commits
Differential Revision: https://reviews.llvm.org/D35807
llvm-svn: 309076
There were two errors in the parsing of opt's command line options for
extension point pipelines. The EP callbacks are not supposed to return a
value. To check the pipeline text for correctness, I now try to parse it
into a temporary PM object, and print a message on failure. This solves
the compile time error for the lambda return type, as well as correctly
handles unparsable pipelines now.
llvm-svn: 307649
Summary:
This patch adds a callback registration API to the PassBuilder,
enabling registering out-of-tree passes with it.
Through the Callback API, callers may register callbacks with the
various stages at which passes are added into pass managers, including
parsing of a pass pipeline as well as at extension points within the
default -O pipelines.
Registering utilities like `require<>` and `invalidate<>` needs to be
handled manually by the caller, but a helper is provided.
Additionally, adding passes at pipeline extension points is exposed
through the opt tool. This patch adds a `-passes-ep-X` commandline
option for every extension point X, which opt parses into pipelines
inserted into that extension point.
Reviewers: chandlerc
Reviewed By: chandlerc
Subscribers: lksbhm, grosser, davide, mehdi_amini, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D33464
llvm-svn: 307532
Summary:
Add an option to prevent diagnostics that do not meet a minimum hotness
threshold from being output. When generating optimization remarks for
large codebases with a ton of cold code paths, this option can be used
to limit the optimization remark output at a reasonable size. Discussion of
this change can be read here:
http://lists.llvm.org/pipermail/llvm-dev/2017-June/114377.html
Reviewers: anemet, davidxl, hfinkel
Reviewed By: anemet
Subscribers: qcolombet, javed.absar, fhahn, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D34867
llvm-svn: 306912
Summary:
To enable profile hotness information in diagnostics output, Clang takes
the option `-fdiagnostics-show-hotness` -- that's "diagnostics", with an
"s" at the end. Clang also defines `CodeGenOptions::DiagnosticsWithHotness`.
LLVM, on the other hand, defines
`LLVMContext::getDiagnosticHotnessRequested` -- that's "diagnostic", not
"diagnostics". It's a small difference, but it's confusing, typo-inducing, and
frustrating.
Add a new method with the spelling "diagnostics", and "deprecate" the
old spelling.
Reviewers: anemet, davidxl
Reviewed By: anemet
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D34864
llvm-svn: 306848
Summary: Also see D33429 for other ThinLTO + New PM related changes.
Reviewers: davide, chandlerc, tejohnson
Subscribers: mehdi_amini, Prazek, cfe-commits, inglorion, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D33525
llvm-svn: 304378
This provides a new way to access the TargetMachine through
TargetPassConfig, as a dependency.
The patterns replaced here are:
* Passes handling a null TargetMachine call
`getAnalysisIfAvailable<TargetPassConfig>`.
* Passes not handling a null TargetMachine
`addRequired<TargetPassConfig>` and call
`getAnalysis<TargetPassConfig>`.
* MachineFunctionPasses now use MF.getTarget().
* Remove all the TargetMachine constructors.
* Remove INITIALIZE_TM_PASS.
This fixes a crash when running `llc -start-before prologepilog`.
PEI needs StackProtector, which gets constructed without a TargetMachine
by the pass manager. The StackProtector pass doesn't handle the case
where there is no TargetMachine, so it segfaults.
Related to PR30324.
Differential Revision: https://reviews.llvm.org/D33222
llvm-svn: 303360
Currently, when masked load, store, gather or scatter intrinsics are used, we check in CodeGenPrepare pass if the subtarget support these intrinsics, if not we replace them with scalar code - this is a functional transformation not an optimization (not optional).
CodeGenPrepare pass does not run when the optimization level is set to CodeGenOpt::None (-O0).
Functional transformation should run with all optimization levels, so here I created a new pass which runs on all optimization levels and does no more than this transformation.
Differential Revision: https://reviews.llvm.org/D32487
llvm-svn: 303050
This pass uses a new target hook to decide whether or not to expand a particular
intrinsic to the shuffevector sequence.
Differential Revision: https://reviews.llvm.org/D32245
llvm-svn: 302631
This lets the pass focus on gathering the required analyzes, and the
utility class focus on the transformation.
Differential Revision: https://reviews.llvm.org/D31303
llvm-svn: 302609
DISubprogram currently has 10 pointer operands, several of which are
often nullptr. This patch reduces the amount of memory allocated by
DISubprogram by rearranging the operands such that containing type,
template params, and thrown types come last, and are only allocated
when they are non-null (or followed by non-null operands).
This patch also eliminates the entirely unused DisplayName operand.
This saves up to 4 pointer operands per DISubprogram. (I tried
measuring the effect on peak memory usage on an LTO link of an X86
llc, but the results were very noisy).
This reapplies r301498 with an attempted workaround for g++.
Differential Revision: https://reviews.llvm.org/D32560
llvm-svn: 301501
DISubprogram currently has 10 pointer operands, several of which are
often nullptr. This patch reduces the amount of memory allocated by
DISubprogram by rearranging the operands such that containing type,
template params, and thrown types come last, and are only allocated
when they are non-null (or followed by non-null operands).
This patch also eliminates the entirely unused DisplayName operand.
This saves up to 4 pointer operands per DISubprogram. (I tried
measuring the effect on peak memory usage on an LTO link of an X86
llc, but the results were very noisy).
llvm-svn: 301498
Summary:
The cumulative size of the bitcode files for a very large application
can be huge, particularly with -g. In a distributed build environment,
all of these files must be sent to the remote build node that performs
the thin link step, and this can exceed size limits.
The thin link actually only needs the summary along with a bitcode
symbol table. Until we have a proper bitcode symbol table, simply
stripping the debug metadata results in significant size reduction.
Add support for an option to additionally emit minimized bitcode
modules, just for use in the thin link step, which for now just strips
all debug metadata. I plan to add a cc1 option so this can be invoked
easily during the compile step.
However, care must be taken to ensure that these minimized thin link
bitcode files produce the same index as with the original bitcode files,
as these original bitcode files will be used in the backends.
Specifically:
1) The module hash used for caching is typically produced by hashing the
written bitcode, and we want to include the hash that would correspond
to the original bitcode file. This is because we want to ensure that
changes in the stripped portions affect caching. Added plumbing to emit
the same module hash in the minimized thin link bitcode file.
2) The module paths in the index are constructed from the module ID of
each thin linked bitcode, and typically is automatically generated from
the input file path. This is the path used for finding the modules to
import from, and obviously we need this to point to the original bitcode
files. Added gold-plugin support to take a suffix replacement during the
thin link that is used to override the identifier on the MemoryBufferRef
constructed from the loaded thin link bitcode file. The assumption is
that the build system can specify that the minimized bitcode file has a
name that is similar but uses a different suffix (e.g. out.thinlink.bc
instead of out.o).
Added various tests to ensure that we get identical index files out of
the thin link step.
Reviewers: mehdi_amini, pcc
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D31027
llvm-svn: 298638
Summary: Because SamplePGO passes will be invoked twice in ThinLTO build: once at compile phase, the other at backend. We want to make sure the IR at the 2nd phase matches the hot part in profile, thus we do not want to inline hot callsites in the first phase.
Reviewers: tejohnson, eraman
Reviewed By: tejohnson
Subscribers: mehdi_amini, llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D31201
llvm-svn: 298428
We had various variants of defining dump() functions in LLVM. Normalize
them (this should just consistently implement the things discussed in
http://lists.llvm.org/pipermail/cfe-dev/2014-January/034323.html
For reference:
- Public headers should just declare the dump() method but not use
LLVM_DUMP_METHOD or #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- The definition of a dump method should look like this:
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MyClass::dump() {
// print stuff to dbgs()...
}
#endif
llvm-svn: 293359
This change introduces adjustPassManager target callback giving a
target an opportunity to tweak PassManagerBuilder before pass
managers are populated.
This generalizes and replaces addEarlyAsPossiblePasses target
callback. In particular that can be used to add custom passes to
extension points other than EP_EarlyAsPossible.
Differential Revision: https://reviews.llvm.org/D28336
llvm-svn: 293189
the latter to the Transforms library.
While the loop PM uses an analysis to form the IR units, the current
plan is to have the PM itself establish and enforce both loop simplified
form and LCSSA. This would be a layering violation in the analysis
library.
Fundamentally, the idea behind the loop PM is to *transform* loops in
addition to running passes over them, so it really seemed like the most
natural place to sink this was into the transforms library.
We can't just move *everything* because we also have loop analyses that
rely on a subset of the invariants. So this patch splits the the loop
infrastructure into the analysis management that has to be part of the
analysis library, and the transform-aware pass manager.
This also required splitting the loop analyses' printer passes out to
the transforms library, which makes sense to me as running these will
transform the code into LCSSA in theory.
I haven't split the unittest though because testing one component
without the other seems nearly intractable.
Differential Revision: https://reviews.llvm.org/D28452
llvm-svn: 291662
This pass prepares a module containing type metadata for ThinLTO by splitting
it into regular and thin LTO parts if possible, and writing both parts to
a multi-module bitcode file. Modules that do not contain type metadata are
written unmodified as a single module.
All globals with type metadata are added to the regular LTO module, and
the rest are added to the thin LTO module.
Differential Revision: https://reviews.llvm.org/D27324
llvm-svn: 289899
Summary:
This makes it explicit that ownership is taken. Also replace all `new`
with make_unique<> at call sites.
Reviewers: anemet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26884
llvm-svn: 287449
AnalysisWrappers.cpp has the following include chain:
llvm/Analysis/CallGraph.h
llvm/IR/CallSite.h
llvm/IR/Attributes.h
llvm/IR/Attributes.gen
This means opt needs to depend on intrinsics_gen.
llvm-svn: 287433
This restores the rest of r286297 (part was restored in r286475).
Specifically, it restores the part requiring adding a dependency from
the Analysis to Object library (downstream use changed to correctly
model split BitReader vs BitWriter libraries).
Original description of this part of patch follows:
Module level asm may also contain defs of values. We need to prevent
export of any refs to local values defined in module level asm (e.g. a
ref in normal IR), since that also requires renaming/promotion of the
local. To do that, the summary index builder looks at all values in the
module level asm string that are not marked Weak or Global, which is
exactly the set of locals that are defined. A summary is created for
each of these local defs and flagged as NoRename.
This required adding handling to the BitcodeWriter to look at GV
declarations to see if they have a summary (rather than skipping them
all).
Finally, added an assert to IRObjectFile::CollectAsmUndefinedRefs to
ensure that an MCAsmParser is available, otherwise the module asm parse
would silently fail. Initialized the asm parser in the opt tool for use
in testing this fix.
Fixes PR30610.
llvm-svn: 286844
Summary:
This patch uses the same approach added for inline asm in r285513 to
similarly prevent promotion/renaming of locals used or defined in module
level asm.
All static global values defined in normal IR and used in module level asm
should be included on either the llvm.used or llvm.compiler.used global.
The former were already being flagged as NoRename in the summary, and
I've simply added llvm.compiler.used values to this handling.
Module level asm may also contain defs of values. We need to prevent
export of any refs to local values defined in module level asm (e.g. a
ref in normal IR), since that also requires renaming/promotion of the
local. To do that, the summary index builder looks at all values in the
module level asm string that are not marked Weak or Global, which is
exactly the set of locals that are defined. A summary is created for
each of these local defs and flagged as NoRename.
This required adding handling to the BitcodeWriter to look at GV
declarations to see if they have a summary (rather than skipping them
all).
Finally, added an assert to IRObjectFile::CollectAsmUndefinedRefs to
ensure that an MCAsmParser is available, otherwise the module asm parse
would silently fail. Initialized the asm parser in the opt tool for use
in testing this fix.
Fixes PR30610.
Reviewers: mehdi_amini
Subscribers: johanengelen, krasin, llvm-commits
Differential Revision: https://reviews.llvm.org/D26146
llvm-svn: 286297
(Re-committed after moving the template specialization under the yaml
namespace. GCC was complaining about this.)
This allows various presentation of this data using an external tool.
This was first recommended here[1].
As an example, consider this module:
1 int foo();
2 int bar();
3
4 int baz() {
5 return foo() + bar();
6 }
The inliner generates these missed-optimization remarks today (the
hotness information is pulled from PGO):
remark: /tmp/s.c:5:10: foo will not be inlined into baz (hotness: 30)
remark: /tmp/s.c:5:18: bar will not be inlined into baz (hotness: 30)
Now with -pass-remarks-output=<yaml-file>, we generate this YAML file:
--- !Missed
Pass: inline
Name: NotInlined
DebugLoc: { File: /tmp/s.c, Line: 5, Column: 10 }
Function: baz
Hotness: 30
Args:
- Callee: foo
- String: will not be inlined into
- Caller: baz
...
--- !Missed
Pass: inline
Name: NotInlined
DebugLoc: { File: /tmp/s.c, Line: 5, Column: 18 }
Function: baz
Hotness: 30
Args:
- Callee: bar
- String: will not be inlined into
- Caller: baz
...
This is a summary of the high-level decisions:
* There is a new streaming interface to emit optimization remarks.
E.g. for the inliner remark above:
ORE.emit(DiagnosticInfoOptimizationRemarkMissed(
DEBUG_TYPE, "NotInlined", &I)
<< NV("Callee", Callee) << " will not be inlined into "
<< NV("Caller", CS.getCaller()) << setIsVerbose());
NV stands for named value and allows the YAML client to process a remark
using its name (NotInlined) and the named arguments (Callee and Caller)
without parsing the text of the message.
Subsequent patches will update ORE users to use the new streaming API.
* I am using YAML I/O for writing the YAML file. YAML I/O requires you
to specify reading and writing at once but reading is highly non-trivial
for some of the more complex LLVM types. Since it's not clear that we
(ever) want to use LLVM to parse this YAML file, the code supports and
asserts that we're writing only.
On the other hand, I did experiment that the class hierarchy starting at
DiagnosticInfoOptimizationBase can be mapped back from YAML generated
here (see D24479).
* The YAML stream is stored in the LLVM context.
* In the example, we can probably further specify the IR value used,
i.e. print "Function" rather than "Value".
* As before hotness is computed in the analysis pass instead of
DiganosticInfo. This avoids the layering problem since BFI is in
Analysis while DiagnosticInfo is in IR.
[1] https://reviews.llvm.org/D19678#419445
Differential Revision: https://reviews.llvm.org/D24587
llvm-svn: 282539
This allows various presentation of this data using an external tool.
This was first recommended here[1].
As an example, consider this module:
1 int foo();
2 int bar();
3
4 int baz() {
5 return foo() + bar();
6 }
The inliner generates these missed-optimization remarks today (the
hotness information is pulled from PGO):
remark: /tmp/s.c:5:10: foo will not be inlined into baz (hotness: 30)
remark: /tmp/s.c:5:18: bar will not be inlined into baz (hotness: 30)
Now with -pass-remarks-output=<yaml-file>, we generate this YAML file:
--- !Missed
Pass: inline
Name: NotInlined
DebugLoc: { File: /tmp/s.c, Line: 5, Column: 10 }
Function: baz
Hotness: 30
Args:
- Callee: foo
- String: will not be inlined into
- Caller: baz
...
--- !Missed
Pass: inline
Name: NotInlined
DebugLoc: { File: /tmp/s.c, Line: 5, Column: 18 }
Function: baz
Hotness: 30
Args:
- Callee: bar
- String: will not be inlined into
- Caller: baz
...
This is a summary of the high-level decisions:
* There is a new streaming interface to emit optimization remarks.
E.g. for the inliner remark above:
ORE.emit(DiagnosticInfoOptimizationRemarkMissed(
DEBUG_TYPE, "NotInlined", &I)
<< NV("Callee", Callee) << " will not be inlined into "
<< NV("Caller", CS.getCaller()) << setIsVerbose());
NV stands for named value and allows the YAML client to process a remark
using its name (NotInlined) and the named arguments (Callee and Caller)
without parsing the text of the message.
Subsequent patches will update ORE users to use the new streaming API.
* I am using YAML I/O for writing the YAML file. YAML I/O requires you
to specify reading and writing at once but reading is highly non-trivial
for some of the more complex LLVM types. Since it's not clear that we
(ever) want to use LLVM to parse this YAML file, the code supports and
asserts that we're writing only.
On the other hand, I did experiment that the class hierarchy starting at
DiagnosticInfoOptimizationBase can be mapped back from YAML generated
here (see D24479).
* The YAML stream is stored in the LLVM context.
* In the example, we can probably further specify the IR value used,
i.e. print "Function" rather than "Value".
* As before hotness is computed in the analysis pass instead of
DiganosticInfo. This avoids the layering problem since BFI is in
Analysis while DiagnosticInfo is in IR.
[1] https://reviews.llvm.org/D19678#419445
Differential Revision: https://reviews.llvm.org/D24587
llvm-svn: 282499
As discussed in https://reviews.llvm.org/D22666, our current mechanism to
support -pg profiling, where we insert calls to mcount(), or some similar
function, is fundamentally broken. We insert these calls in the frontend, which
means they get duplicated when inlining, and so the accumulated execution
counts for the inlined-into functions are wrong.
Because we don't want the presence of these functions to affect optimizaton,
they should be inserted in the backend. Here's a pass which would do just that.
The knowledge of the name of the counting function lives in the frontend, so
we're passing it here as a function attribute. Clang will be updated to use
this mechanism.
Differential Revision: https://reviews.llvm.org/D22825
llvm-svn: 280347
minimal and boring form than the old pass manager's version.
This pass does the very minimal amount of work necessary to inline
functions declared as always-inline. It doesn't support a wide array of
things that the legacy pass manager did support, but is alse ... about
20 lines of code. So it has that going for it. Notably things this
doesn't support:
- Array alloca merging
- To support the above, bottom-up inlining with careful history
tracking and call graph updates
- DCE of the functions that become dead after this inlining.
- Inlining through call instructions with the always_inline attribute.
Instead, it focuses on inlining functions with that attribute.
The first I've omitted because I'm hoping to just turn it off for the
primary pass manager. If that doesn't pan out, I can add it here but it
will be reasonably expensive to do so.
The second should really be handled by running global-dce after the
inliner. I don't want to re-implement the non-trivial logic necessary to
do comdat-correct DCE of functions. This means the -O0 pipeline will
have to be at least 'always-inline,global-dce', but that seems
reasonable to me. If others are seriously worried about this I'd like to
hear about it and understand why. Again, this is all solveable by
factoring that logic into a utility and calling it here, but I'd like to
wait to do that until there is a clear reason why the existing
pass-based factoring won't work.
The final point is a serious one. I can fairly easily add support for
this, but it seems both costly and a confusing construct for the use
case of the always inliner running at -O0. This attribute can of course
still impact the normal inliner easily (although I find that
a questionable re-use of the same attribute). I've started a discussion
to sort out what semantics we want here and based on that can figure out
if it makes sense ta have this complexity at O0 or not.
One other advantage of this design is that it should be quite a bit
faster due to checking for whether the function is a viable candidate
for inlining exactly once per function instead of doing it for each call
site.
Anyways, hopefully a reasonable starting point for this pass.
Differential Revision: https://reviews.llvm.org/D23299
llvm-svn: 278896
Summary:
Port the ModuleSummaryAnalysisWrapperPass to the new pass manager.
Use it in the ported BitcodeWriterPass (similar to how we use the
legacy ModuleSummaryAnalysisWrapperPass in the legacy WriteBitcodePass).
Also, pass the -module-summary opt flag through to the new pass
manager pipeline and through to the bitcode writer pass, and add
a test that uses it.
Reviewers: mehdi_amini
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23439
llvm-svn: 278508
Summary:
Having -O0 in opt allows testing that -O0 optimization
pipeline is built correctly.
Reviewers: majnemer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23208
llvm-svn: 277829
This adds boilerplate code for all coroutine passes,
the passes are no-ops for now.
Also, a small test has been added to verify that passes execute in
the expected order or not at all if coroutine support is disabled.
Patch by Gor Nishanov!
Differential Revision: https://reviews.llvm.org/D22847
llvm-svn: 277033
Summary:
This is the first set of changes implementing the RFC from
http://thread.gmane.org/gmane.comp.compilers.llvm.devel/98334
This is a cross-sectional patch; rather than implementing the hotness
attribute for all optimization remarks and all passes in a patch set, it
implements it for the 'missed-optimization' remark for Loop
Distribution. My goal is to shake out the design issues before scaling
it up to other types and passes.
Hotness is computed as an integer as the multiplication of the block
frequency with the function entry count. It's only printed in opt
currently since clang prints the diagnostic fields directly. E.g.:
remark: /tmp/t.c:3:3: loop not distributed: use -Rpass-analysis=loop-distribute for more info (hotness: 300)
A new API added is similar to emitOptimizationRemarkMissed. The
difference is that it additionally takes a code region that the
diagnostic corresponds to. From this, hotness is computed using BFI.
The new API is exposed via an analysis pass so that it can be made
dependent on LazyBFI. (Thanks to Hal for the analysis pass idea.)
This feature can all be enabled by setDiagnosticHotnessRequested in the
LLVM context. If this is off, LazyBFI is not calculated (D22141) so
there should be no overhead.
A new command-line option is added to turn this on in opt.
My plan is to switch all user of emitOptimizationRemark* to use this
module instead.
Reviewers: hfinkel
Subscribers: rcox2, mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D21771
llvm-svn: 275583
Previously, there was a discrepancy between the population of function
passes in FPasses, and their invocation. Function passes specified on
the command line, after an optimizaton level was simply discared. This
fix PR27509.
Patch by Jesper Antonsson.
Differential Review: http://reviews.llvm.org/D20725
llvm-svn: 272770
looking for it along $PATH. This allows installs of LLVM tools outside of
$PATH to find the symbolizer and produce pretty backtraces if they crash.
llvm-svn: 272232
Having an enum member named Default is quite confusing: Is it distinct
from the others?
This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.
llvm-svn: 269988
Summary:
This is a hook to allow TargetMachine to install passes at the
EP_EarlyAsPossible PassManagerBuilder extension point.
Reviewers: chandlerc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18614
llvm-svn: 267763
Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*. It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.
Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType. The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.
This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata. Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.
The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html
llvm-svn: 267296
This intrinsic takes two arguments, ``%ptr`` and ``%offset``. It loads
a 32-bit value from the address ``%ptr + %offset``, adds ``%ptr`` to that
value and returns it. The constant folder specifically recognizes the form of
this intrinsic and the constant initializers it may load from; if a loaded
constant initializer is known to have the form ``i32 trunc(x - %ptr)``,
the intrinsic call is folded to ``x``.
LLVM provides that the calculation of such a constant initializer will
not overflow at link time under the medium code model if ``x`` is an
``unnamed_addr`` function. However, it does not provide this guarantee for
a constant initializer folded into a function body. This intrinsic can be
used to avoid the possibility of overflows when loading from such a constant.
Differential Revision: http://reviews.llvm.org/D18367
llvm-svn: 267223