This patch adds the ability to identify instructions that are "move elimination
candidates". It also allows scheduling models to describe processor register
files that allow move elimination.
A move elimination candidate is an instruction that can be eliminated at
register renaming stage.
Each subtarget can specify which instructions are move elimination candidates
with the help of tablegen class "IsOptimizableRegisterMove" (see
llvm/Target/TargetInstrPredicate.td).
For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated.
The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this:
```
def : IsOptimizableRegisterMove<[
InstructionEquivalenceClass<[
// GPR variants.
MOV32rr, MOV64rr,
// MMX variants.
MMX_MOVQ64rr,
// SSE variants.
MOVAPSrr, MOVUPSrr,
MOVAPDrr, MOVUPDrr,
MOVDQArr, MOVDQUrr,
// AVX variants.
VMOVAPSrr, VMOVUPSrr,
VMOVAPDrr, VMOVUPDrr,
VMOVDQArr, VMOVDQUrr
], CheckNot<CheckSameRegOperand<0, 1>> >
]>;
```
Definitions of IsOptimizableRegisterMove from processor models of a same
Target are processed by the SubtargetEmitter to auto-generate a target-specific
override for each of the following predicate methods:
```
bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI)
const;
bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned
CPUID) const;
```
By default, those methods return false (i.e. conservatively assume that there
are no move elimination candidates).
Tablegen class RegisterFile has been extended with the following information:
- The set of register classes that allow move elimination.
- Maxium number of moves that can be eliminated every cycle.
- Whether move elimination is restricted to moves from registers that are
known to be zero.
This patch is structured in three part:
A first part (which is mostly boilerplate) adds the new
'isOptimizableRegisterMove' target hooks, and extends existing register file
descriptors in MC by introducing new fields to describe properties related to
move elimination.
A second part, uses the new tablegen constructs to describe move elimination in
the BtVer2 scheduling model.
A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove'
hook to mark instructions that are candidates for move elimination. It also
teaches class RegisterFile how to describe constraints on move elimination at
PRF granularity.
llvm-mca tests for btver2 show differences before/after this patch.
Differential Revision: https://reviews.llvm.org/D53134
llvm-svn: 344334
Summary:
This change adds support for the GNU --target flag, which sets both --input-target and --output-target.
GNU objcopy doesn't do any checking for whether both --target and --{input,output}-target are used, and so it allows both, e.g. "--target A --output-target B" is equivalent to "--input-target A --output-target B" since the later command line flag would override earlier ones. This may be error prone, so I chose to implement it as an error if both are used. I'm not sure if anyone is actually using both.
Reviewers: jakehehrlich, jhenderson, alexshap
Reviewed By: jakehehrlich, alexshap
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53029
llvm-svn: 344321
In this diff we move out CopyConfig from llvm-oobjcopy.cpp into a separate header CopyConfig.h
to enable us (in the future) reuse this class in the other implementations of objcopy (for coff, mach-o).
Additionally this enables us to unload the complexity from llvm-objcopy.cpp a little bit.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D53006
llvm-svn: 344307
error() in llvm-nm intentionally does not return so that the callee can move on to future files/slices. When printing the archive map, this is not currently handled (the caller assumes that error() returns), so processing continues despite there being an error.
Also, change one return to a break, so that symbols can be printed even if the archive map is corrupt.
llvm-svn: 344268
libtool requires this text to be present, in order to conclude that
the tool supports response files. Also add an explicit test of using
response files with llvm-nm.
Differential Revision: https://reviews.llvm.org/D53064
llvm-svn: 344222
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
Add a library that parses optimization remarks (currently YAML, so based
on the YAMLParser).
The goal is to be able to provide tools a remark parser that is not
completely dependent on YAML, in case we decide to change the format
later.
It exposes a C API which takes a handler that is called with the remark
structure.
It adds a libLLVMOptRemark.a static library, and it's used in-tree by
the llvm-opt-report tool (from which the parser has been mostly moved
out).
Differential Revision: https://reviews.llvm.org/D52776
Fixed the tests by removing the usage of C++11 strings, which seems not
to be supported by gcc 4.8.4 if they're used as a macro argument.
llvm-svn: 344171
Add a library that parses optimization remarks (currently YAML, so based
on the YAMLParser).
The goal is to be able to provide tools a remark parser that is not
completely dependent on YAML, in case we decide to change the format
later.
It exposes a C API which takes a handler that is called with the remark
structure.
It adds a libLLVMOptRemark.a static library, and it's used in-tree by
the llvm-opt-report tool (from which the parser has been mostly moved
out).
Differential Revision: https://reviews.llvm.org/D52776
llvm-svn: 344162
Summary: Simplify code by having LLVMState hold the RegisterAliasingTrackerCache.
Reviewers: courbet
Subscribers: tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D53078
llvm-svn: 344143
When fillMachineFunction generates a return on targets without a return opcode
(such as AArch64) it should pass an empty set of registers as the return
registers, not 0 which means register number zero.
Differential Revision: https://reviews.llvm.org/D53074
llvm-svn: 344139
sancov subtracts one from the address to get the previous instruction,
which makes sense on x86_64, but not on other platforms.
This change ensures that the offset is correct for different platforms.
The logic for computing the offset is copied from sanitizer_common.
Differential Revision: https://reviews.llvm.org/D53039
llvm-svn: 344103
Summary:
Before, "[options] <inputs>" is unconditionally appended to the `Name` parameter. It is more flexible to change its semantic to `Usage` and let user customize the usage line.
% llvm-objcopy
...
USAGE: llvm-objcopy <input> [ <output> ] [options] <inputs>
With this patch:
% llvm-objcopy
...
USAGE: llvm-objcopy input [output]
Reviewers: rupprecht, alexshap, jhenderson
Reviewed By: rupprecht
Subscribers: jakehehrlich, mehdi_amini, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D51009
llvm-svn: 344097
We changed an ArrayRef<uint8_t> to an ArrayRef<uint32_t>, but
it needs to be an ArrayRef<support::ulittle32_t>.
We also change ArrayRef<> to FixedStreamArray<>. Technically
an ArrayRef<> will work, but it can cause a copy in the underlying
implementation if the memory is not contiguous, and there's no
reason not to use a FixedStreamArray<>.
Thanks to nemanjai@ and thakis@ for helping me track this down
and confirm the fix.
llvm-svn: 344063
Summary:
This moves checking logic into the accessors and makes the structure smaller.
It will also help when/if Operand are generated from the TD files.
Subscribers: tschuett, courbet, llvm-commits
Differential Revision: https://reviews.llvm.org/D52982
llvm-svn: 344028
The Globals table is a hash table keyed on symbol name, so
it's possible to lookup symbols by name in O(1) time. Add
a function to the globals stream to do this, and add an option
to llvm-pdbutil to exercise this, then use it to write some
tests to verify correctness.
llvm-svn: 343951
Summary:
The POSIX spec says:
```
If the −t option is used with the −v option, the standard output format shall be:
"%s %u/%u %u %s %d %d:%d %d %s\n", <member mode>, <user ID>,
<group ID>, <number of bytes in member>,
<abbreviated month>, <day-of-month>, <hour>,
<minute>, <year>, <file>
where:
...
<abbreviated month>
Equivalent to the format of the %b conversion specification format in date.
<day-of-month>
Equivalent to the format of the %e conversion specification format in date.
<hour> Equivalent to the format of the %H conversion specification format in date.
<minute> Equivalent to the format of the %M conversion specification format in date.
<year> Equivalent to the format of the %Y conversion specification format in date.
```
This actually used to be the format printed by llvm-ar. It was apparently accidentally changed (see r207385 followed by comments in r207387). This makes it conform to GNU ar for easier replacement.
Reviewers: MaskRay
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52940
llvm-svn: 343901
This matches the output of binutils' nm and ensures that any scripts
or tools that use nm and expect empty output in case there no symbols
don't break.
Differential Revision: https://reviews.llvm.org/D52943
llvm-svn: 343887
DWARF v5 introduces DW_AT_call_all_calls, a subprogram attribute which
indicates that all calls (both regular and tail) within the subprogram
have call site entries. The information within these call site entries
can be used by a debugger to populate backtraces with synthetic tail
call frames.
Tail calling frames go missing in backtraces because the frame of the
caller is reused by the callee. Call site entries allow a debugger to
reconstruct a sequence of (tail) calls which led from one function to
another. This improves backtrace quality. There are limitations: tail
recursion isn't handled, variables within synthetic frames may not
survive to be inspected, etc. This approach is not novel, see:
https://gcc.gnu.org/wiki/summit2010?action=AttachFile&do=get&target=jelinek.pdf
This patch adds an IR-level flag (DIFlagAllCallsDescribed) which lowers
to DW_AT_call_all_calls. It adds the minimal amount of DWARF generation
support needed to emit standards-compliant call site entries. For easier
deployment, when the debugger tuning is LLDB, the DWARF requirement is
adjusted to v4.
Testing: Apart from check-{llvm, clang}, I built a stage2 RelWithDebInfo
clang binary. Its dSYM passed verification and grew by 1.4% compared to
the baseline. 151,879 call site entries were added.
rdar://42001377
Differential Revision: https://reviews.llvm.org/D49887
llvm-svn: 343883
Flag 'AllowZeroMoveEliminationOnly' should have been a property of the PRF, and
not set at register granularity.
This change also restricts move elimination to writes that update a full
physical register. We assume that there is a strong correlation between
logical registers that allow move elimination, and how those same registers are
allocated to physical registers by the register renamer.
This is still a no functional change, because this experimental code path is
disabled for now. This is done in preparation for another patch that will add
the ability to describe how move elimination works in scheduling models.
llvm-svn: 343787
This should help with catching inconsistent definitions of instructions with
zero opcodes, which also declare to consume scheduler/pipeline resources.
llvm-svn: 343766
Summary:
GNU nm (and other nm implementations, such as "go tool nm") prints an explicit "no symbols" message when an object file has no symbols. Currently llvm-nm just doesn't print anything. Adding an explicit "no symbols" message will allow llvm-nm to be used in place of nm: some scripts and build processes use `nm <file> | grep "no symbols"` as a test to see if a file has no symbols. It will also be more familiar to anyone used to nm.
That said, the format implemented here is slightly different, in that it doesn't print the tool name in the message (which IMHO is not useful to include).
Demo:
```
$ for nm in nm bin/llvm-nm ; do echo "nm implementation: $nm"; $nm /tmp/foo{1,2}.o; echo; done
nm implementation: nm
/tmp/foo1.o:
nm: /tmp/foo1.o: no symbols
/tmp/foo2.o:
0000000000000000 T foo2
nm implementation: bin/llvm-nm
/tmp/foo1.o:
no symbols
/tmp/foo2.o:
0000000000000000 T foo2
```
Reviewers: MaskRay
Reviewed By: MaskRay
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52810
llvm-svn: 343742
MCContext does not destroy MCSymbols on shutdown. So, rather than putting
SmallVectors (which may heap-allocate) inside MCSymbolWasm, use unowned pointer
to a WasmSignature instead. The signatures are now owned by the AsmPrinter.
Also uses WasmSignature instead of param and result vectors in TargetStreamer,
and leaves some TODOs for further simplification.
Differential Revision: https://reviews.llvm.org/D52580
llvm-svn: 343733
This patch teaches class RegisterFile how to analyze register writes from
instructions that are move elimination candidates.
In particular, it teaches it how to check if a move can be effectively eliminated
by the underlying PRF, and (if necessary) how to perform move elimination.
The long term goal is to allow processor models to describe instructions that
are valid move elimination candidates.
The idea is to let register file definitions in tablegen declare if/when moves
can be eliminated.
This patch is a non functional change.
The logic that performs move elimination is currently disabled. A future patch
will add support for move elimination in the processor models, and enable this
new code path.
llvm-svn: 343691
deserializeMCOperand - ensure that we at least match the first character of the sscanf pattern before calling
This reduces llvm-exegesis uops analysis of the instructions supported from btver2 from 5m13s to 2m1s on debug builds.
llvm-svn: 343690
Two cases in a ThinLTO test were passing for the wrong reasons, since
rL340374. The tests were supposed to be testing that files were being
pruned due to the cache size, but they were in fact being pruned because
they were older than the default expiration period of 1 week.
This change fixes the tests by explicitly setting the expiration time to
the maximum value. This required the option to be exposed in llvm-lto.
By assigning all files in the cache a similar time, it is possible to see
that the newest files are still being kept, and that we aren't passing
for the wrong reason again. In the event that the entry expiration were
to expire for them, then the test would start failing, because these
files would be removed too.
Reviewed by: rnk, inglorion
Differential Revision: https://reviews.llvm.org/D51992
llvm-svn: 343687
Andrea Di Biagio