Commit Graph

147 Commits

Author SHA1 Message Date
David Green 3e0bf1c7a9 [CodeGen] Move instruction predicate verification to emitInstruction
D25618 added a method to verify the instruction predicates for an
emitted instruction, through verifyInstructionPredicates added into
<Target>MCCodeEmitter::encodeInstruction. This is a very useful idea,
but the implementation inside MCCodeEmitter made it only fire for object
files, not assembly which most of the llvm test suite uses.

This patch moves the code into the <Target>_MC::verifyInstructionPredicates
method, inside the InstrInfo.  The allows it to be called from other
places, such as in this patch where it is called from the
<Target>AsmPrinter::emitInstruction methods which should trigger for
both assembly and object files. It can also be called from other places
such as verifyInstruction, but that is not done here (it tends to catch
errors earlier, but in reality just shows all the mir tests that have
incorrect feature predicates). The interface was also simplified
slightly, moving computeAvailableFeatures into the function so that it
does not need to be called externally.

The ARM, AMDGPU (but not R600), AVR, Mips and X86 backends all currently
show errors in the test-suite, so have been disabled with FIXME
comments.

Recommitted with some fixes for the leftover MCII variables in release
builds.

Differential Revision: https://reviews.llvm.org/D129506
2022-07-14 09:33:28 +01:00
David Green 95252133e1 Revert "Move instruction predicate verification to emitInstruction"
This reverts commit e2fb8c0f4b as it does
not build for Release builds, and some buildbots are giving more warning
than I saw locally. Reverting to fix those issues.
2022-07-13 13:28:11 +01:00
David Green e2fb8c0f4b Move instruction predicate verification to emitInstruction
D25618 added a method to verify the instruction predicates for an
emitted instruction, through verifyInstructionPredicates added into
<Target>MCCodeEmitter::encodeInstruction. This is a very useful idea,
but the implementation inside MCCodeEmitter made it only fire for object
files, not assembly which most of the llvm test suite uses.

This patch moves the code into the <Target>_MC::verifyInstructionPredicates
method, inside the InstrInfo.  The allows it to be called from other
places, such as in this patch where it is called from the
<Target>AsmPrinter::emitInstruction methods which should trigger for
both assembly and object files. It can also be called from other places
such as verifyInstruction, but that is not done here (it tends to catch
errors earlier, but in reality just shows all the mir tests that have
incorrect feature predicates). The interface was also simplified
slightly, moving computeAvailableFeatures into the function so that it
does not need to be called externally.

The ARM, AMDGPU (but not R600), AVR, Mips and X86 backends all currently
show errors in the test-suite, so have been disabled with FIXME
comments.

Differential Revision: https://reviews.llvm.org/D129506
2022-07-13 12:53:32 +01:00
Craig Topper 6cfe41dcc8 [X86] Rename more target feature related things consistency. NFC
-Rename Mode*Bit to Is*Bit to match X86Subtarget.
-Rename FeatureLAHFSAHF to FeatureLAFHSAFH64 to match X86Subtarget.
-Use consistent capitalization

Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D121975
2022-03-17 22:27:17 -07:00
Amir Ayupov 1d3719820f [X86] Preserve redundant Address-Size override prefix
Print and emit redundant Address-Size override prefix if it's set on the
instruction.

Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D120592
2022-03-16 08:30:29 -07:00
Martin Storsjö 70cb8daed4 [X86] [CodeView] Add codeview mappings for registers ST0-ST7
These can end up needed after https://reviews.llvm.org/D116821.

Suggested by Alexandre Ganea.

Differential Revision: https://reviews.llvm.org/D118072
2022-01-25 10:09:06 +02:00
Kazu Hirata bf039a8620 [Target] Use range-based for loops (NFC) 2022-01-23 22:53:15 -08:00
Ben Langmuir a2639dcbe6 [ORC] Add a utility for adding missing "self" relocations to a Symbol
If a tool wants to introduce new indirections via stubs at link-time in
ORC, it can cause fidelity issues around the address of the function if
some references to the function do not have relocations. This is known
to happen inside the body of the function itself on x86_64 for example,
where a PC-relative address is formed, but without a relocation.

```
_foo:
  leaq -7(%rip), %rax ## form pointer to '_foo' without relocation

_bar:
  leaq (%rip), %rax ##  uses X86_64_RELOC_SIGNED to '_foo'
```

The consequence of introducing a stub for such a function at link time
is that if it forms a pointer to itself without relocation, it will not
have the same value as a pointer from outside the function. If the
function pointer is used as a key, this can cause problems.

This utility provides best-effort support for adding such missing
relocations using MCDisassembler and MCInstrAnalysis to identify the
problematic instructions. Currently it is only implemented for x86_64.

Note: the related issue with call/jump instructions is not handled
here, only forming function pointers.

rdar://83514317

Differential revision: https://reviews.llvm.org/D113038
2021-11-04 15:01:05 -07:00
Reid Kleckner 89b57061f7 Move TargetRegistry.(h|cpp) from Support to MC
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454
2021-10-08 14:51:48 -07:00
Igor Kudrin 2c14798ead [ARM][llvm-objdump] Annotate PC-relative memory operands of VLDR instructions
This extends D105979 and adds support for VLDR instructions.

Differential Revision: https://reviews.llvm.org/D105980
2021-08-05 14:11:11 +07:00
Martin Storsjö 42f74e8249 [llvm] Rename StringRef _lower() method calls to _insensitive()
This is a mechanical change. This actually also renames the
similarly named methods in the SmallString class, however these
methods don't seem to be used outside of the llvm subproject, so
this doesn't break building of the rest of the monorepo.
2021-06-25 00:22:01 +03:00
Craig Topper c7a0b2684f [X86][MC][Target] Initial backend support a tune CPU to support -mtune
This patch implements initial backend support for a -mtune CPU controlled by a "tune-cpu" function attribute. If the attribute is not present X86 will use the resolved CPU from target-cpu attribute or command line.

This patch adds MC layer support a tune CPU. Each CPU now has two sets of features stored in their GenSubtargetInfo.inc tables . These features lists are passed separately to the Processor and ProcessorModel classes in tablegen. The tune list defaults to an empty list to avoid changes to non-X86. This annoyingly increases the size of static tables on all target as we now store 24 more bytes per CPU. I haven't quantified the overall impact, but I can if we're concerned.

One new test is added to X86 to show a few tuning features with mismatched tune-cpu and target-cpu/target-feature attributes to demonstrate independent control. Another new test is added to demonstrate that the scheduler model follows the tune CPU.

I have not added a -mtune to llc/opt or MC layer command line yet. With no attributes we'll just use the -mcpu for both. MC layer tools will always follow the normal CPU for tuning.

Differential Revision: https://reviews.llvm.org/D85165
2020-08-14 15:31:50 -07:00
Craig Topper 945ed22f33 [X86] Move the implicit enabling of sse2 for 64-bit mode from X86Subtarget::initSubtargetFeatures to X86_MC::ParseX86Triple.
ParseX86Triple already checks for 64-bit mode and produces a
static string. We can just add +sse2 to the end of that static
string. This avoids a potential reallocation when appending it
to the std::string at runtime.

This is a slight change to the behavior of tools that only use
MC layer which weren't implicitly enabling sse2 before, but will
now. I don't think we check for sse2 explicitly in any MC layer
components so this shouldn't matter in practice. And if it did
matter the new behavior is more correct.
2020-07-24 11:14:20 -07:00
Craig Topper deeb2fdbf4 [X86] Remove a couple temporary std::string for CPU names that I don't need to exist.
The input to these functions is a StringRef. We then convert it
to a std::string. Then maybe replace with "generic". I think we
can just overwrite the incoming StringRef with "generic" if needed
and then pass it along without creating any std::string.
2020-07-22 15:55:04 -07:00
Fangrui Song 773f8dbd1d [MC] Fix double negation of DW_CFA_def_cfa
Negations are incorrectly added in numerous places and the code just happens to work.
Also fix a missed DW_CFA_def_cfa_offset negation in c693b9c321d5a40d012340619674cf790c9ac86c:
ARMAsmBackendDarwin::generateCompactUnwindEncoding
2020-05-22 21:02:53 -07:00
Fangrui Song 7e49dc6184 [MC] Change MCCFIInstruction::createDefCfa to cfiDefCfa which does not negate Offset
The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the unneeded negation and fix all call sites.
2020-05-22 15:47:26 -07:00
Fangrui Song 52eb2f65a7 [MC] Move MCInstrAnalysis::evaluateBranch to X86MCInstrAnalysis::evaluateBranch
The generic implementation is actually specific to x86. It assumes the
offset is relative to the end of the instruction and the immediate is
not scaled (which is false on most RISC).
2020-04-29 23:23:52 -07:00
Simon Pilgrim 5cc84d095e X86MCTargetDesc.cpp - remove MSVC intrin.h include. NFC.
This was needed when the file called cpuid but that was removed at rL233170.
2020-04-26 14:50:52 +01:00
Eric Astor ee2c0f76d7 [ms] [llvm-ml] Add a draft MASM parser
Summary:
Many directives are unavailable, and support for others may be limited.

This first draft has preliminary support for:
    - conditional directives (including errors),
    - data allocation (unsigned types up to 8 bytes, and ALIGN),
    - equates/variables (numeric and text),
    - and procedure directives (without parameters),
as well as COMMENT, ECHO, INCLUDE, INCLUDELIB, PUBLIC, and EXTERN. Text variables (aka text macros) are expanded in-place wherever the identifier occurs.

We deliberately ignore all ml.exe processor directives.

Prominent features not yet supported:
    - structs
    - macros (both procedures and functions)
    - procedures (with specified parameters)
    - substitution & expansion operators

Conditional directives are complicated by the fact that "ifdef rax" is a valid way to check if a file is being assembled for a 64-bit x86 processor; we add support for "ifdef <register>" in general, which requires adding a tryParseRegister method to all MCTargetAsmParsers. (Some targets require backtracking in the non-register case.)

Reviewers: rnk, thakis

Reviewed By: thakis

Subscribers: kerbowa, merge_guards_bot, wuzish, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, mgorny, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Jim, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72680
2020-02-16 12:30:46 -05:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Tom Stellard 0dbcb36394 CMake: Make most target symbols hidden by default
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.

A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.

This patch reduces the number of public symbols in libLLVM.so by about
25%.  This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so

One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.

Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278

Reviewers: chandlerc, beanz, mgorny, rnk, hans

Reviewed By: rnk, hans

Subscribers: merge_guards_bot, luismarques, smeenai, ldionne, lenary, s.egerton, pzheng, sameer.abuasal, MaskRay, wuzish, echristo, Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D54439
2020-01-14 19:46:52 -08:00
Simon Pilgrim f722071a9e X86_MC::createX86MCSubtargetInfo - X86_MC::ParseX86Triple never returns an empty string. NFCI.
PVS Studio was complaining that the expression '!ArchFS.empty()' is always true.
2019-11-02 18:46:53 +00:00
Mirko Brkusanin 4b63ca1379 [Mips] Use appropriate private label prefix based on Mips ABI
MipsMCAsmInfo was using '$' prefix for Mips32 and '.L' for Mips64
regardless of -target-abi option. By passing MCTargetOptions to MCAsmInfo
we can find out Mips ABI and pick appropriate prefix.

Tags: #llvm, #clang, #lldb

Differential Revision: https://reviews.llvm.org/D66795
2019-10-23 12:24:35 +02:00
Andrea Di Biagio b1bdd97a26 [X86][Btver2] Fix latency and throughput of CMPXCHG instructions.
On Jaguar, CMPXCHG has a latency of 11cy, and a maximum throughput of 0.33 IPC.
Throughput is superiorly limited to 0.33 because of the implicit in/out
dependency on register EAX. In the case of repeated non-atomic CMPXCHG with the
same memory location, store-to-load forwarding occurs and values for sequent
loads are quickly forwarded from the store buffer.

Interestingly, the functionality in LLVM that computes the reciprocal throughput
doesn't seem to know about RMW instructions. That functionality only looks at
the "consumed resource cycles" for the throughput computation. It should be
fixed/improved by a future patch. In particular, for RMW instructions, that
logic should also take into account for the write latency of in/out register
operands.

An atomic CMPXCHG has a latency of ~17cy. Throughput is also limited to
~17cy/inst due to cache locking, which prevents other memory uOPs to start
executing before the "lock releasing" store uOP.

CMPXCHG8rr and CMPXCHG8rm are treated specially because they decode to one less
macro opcode. Their latency tend to be the same as the other RR/RM variants. RR
variants are relatively fast 3cy (but still microcoded - 5 macro opcodes).

CMPXCHG8B is 11cy and unfortunately doesn't seem to benefit from store-to-load
forwarding. That means, throughput is clearly limited by the in/out dependency
on GPR registers. The uOP composition is sadly unknown (due to the lack of PMCs
for the Integer pipes). I have reused the same mix of consumed resource from the
other CMPXCHG instructions for CMPXCHG8B too.
LOCK CMPXCHG8B is instead 18cycles.

CMPXCHG16B is 32cycles. Up to 38cycles when the LOCK prefix is specified. Due to
the in/out dependencies, throughput is limited to 1 instruction every 32 (or 38)
cycles dependeing on whether the LOCK prefix is specified or not.
I wouldn't be surprised if the microcode for CMPXCHG16B is similar to 2x
microcode from CMPXCHG8B. So, I have speculatively set the JALU01 consumption to
2x the resource cycles used for CMPXCHG8B.

The two new hasLockPrefix() functions are used by the btver2 scheduling model
check if a MCInst/MachineInst has a LOCK prefix. Calls to hasLockPrefix() have
been encoded in predicates of variant scheduling classes that describe lat/thr
of CMPXCHG.

Differential Revision: https://reviews.llvm.org/D66424

llvm-svn: 369365
2019-08-20 10:23:55 +00:00
Craig Topper a17d1d2250 [X86] Use Register/MCRegister in more places in X86
This was a quick pass through some obvious places. I haven't tried the clang-tidy check.

I also replaced the zeroes in getX86SubSuperRegister with X86::NoRegister which is the real sentinel name.

Differential Revision: https://reviews.llvm.org/D66363

llvm-svn: 369151
2019-08-16 20:50:23 +00:00
Seiya Nuta 21277e3ec2 [MC] Add MCInstrAnalysis::evaluateMemoryOperandAddress
Summary:
Add a new method which tries to compute the target address referenced by an operand.

This patch supports x86_64 RIP-relative addressing for now.

It is necessary to print referenced symbol names in llvm-objdump.

Reviewers: andreadb, MaskRay, grosbach, jgalenson, craig.topper

Reviewed By: MaskRay, craig.topper

Subscribers: bcain, rupprecht, jhenderson, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63847

llvm-svn: 366987
2019-07-25 06:57:09 +00:00
Tom Stellard 4b0b26199b Revert CMake: Make most target symbols hidden by default
This reverts r362990 (git commit 374571301d)

This was causing linker warnings on Darwin:

ld: warning: direct access in function 'llvm::initializeEvexToVexInstPassPass(llvm::PassRegistry&)'
from file '../../lib/libLLVMX86CodeGen.a(X86EvexToVex.cpp.o)' to global weak symbol
'void std::__1::__call_once_proxy<std::__1::tuple<void* (&)(llvm::PassRegistry&),
std::__1::reference_wrapper<llvm::PassRegistry>&&> >(void*)' from file '../../lib/libLLVMCore.a(Verifier.cpp.o)'
means the weak symbol cannot be overridden at runtime. This was likely caused by different translation
units being compiled with different visibility settings.

llvm-svn: 363028
2019-06-11 03:21:13 +00:00
Tom Stellard 374571301d CMake: Make most target symbols hidden by default
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.

A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.

This patch reduces the number of public symbols in libLLVM.so by about
25%.  This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so

One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.

Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278

Reviewers: chandlerc, beanz, mgorny, rnk, hans

Reviewed By: rnk, hans

Subscribers: Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D54439

llvm-svn: 362990
2019-06-10 22:12:56 +00:00
Richard Trieu 0116385452 [X86] Create a TargetInfo header. NFC
Move the declarations of getThe<Name>Target() functions into a new header in
TargetInfo and make users of these functions include this new header.
This fixes a layering problem.

llvm-svn: 360736
2019-05-15 01:17:58 +00:00
Richard Trieu b28b8b7724 [X86] Move InstPrinter files to MCTargetDesc. NFC
For some targets, there is a circular dependency between InstPrinter and
MCTargetDesc.  Merging them together will fix this.  For the other targets,
the merging is to maintain consistency so all targets will have the same
structure.

llvm-svn: 360484
2019-05-10 23:24:38 +00:00
Eric Christopher 6b06c6a5ef Add explicit dependencies on MCSection.h and MCDwarf.h to the .cpp
files rather than rely on transitive includes from MCStreamer.h.

llvm-svn: 358263
2019-04-12 07:40:01 +00:00
Luo, Yuanke a2b4d3fab6 [X86] Add MM register mapping from CodeView to MC register id
Differential Revision: https://reviews.llvm.org/D60437

Change-Id: I2183a6d825d0284b22705d423b88882992b236c5
llvm-svn: 358179
2019-04-11 15:01:03 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Evandro Menezes 9ef79c884a [TableGen] Refactor macro names (NFC)
Make the names for the macros for `TargetInstrInfo` uniform.

llvm-svn: 347706
2018-11-27 20:58:27 +00:00
Andrea Di Biagio 8b6c314be1 [TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions.
This patch adds the ability for processor models to describe dependency breaking
instructions.

Different processors may specify a different set of dependency-breaking
instructions.
That means, we cannot assume that all processors of the same target would use
the same rules to classify dependency breaking instructions.

The main goal of this patch is to provide the means to describe dependency
breaking instructions directly via tablegen, and have the following
TargetSubtargetInfo hooks redefined in overrides by tabegen'd
XXXGenSubtargetInfo classes (here, XXX is a Target name).

```
virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const {
  return false;
}

virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const {
  return isZeroIdiom(MI);
}
```

An instruction MI is a dependency-breaking instruction if a call to method
isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to
true. Similarly, an instruction MI is a special case of zero-idiom dependency
breaking instruction if a call to STI.isZeroIdiom(MI) returns true.
The extra APInt is used for those targets that may want to select which machine
operands have their dependency broken (see comments in code).
Note that by default, subtargets don't know about the existence of
dependency-breaking. In the absence of external information, those method calls
would always return false.

A new tablegen class named STIPredicate has been added by this patch to let
processor models classify instructions that have properties in common. The idea
is that, a MCInstrPredicate definition can be used to "generate" an instruction
equivalence class, with the idea that instructions of a same class all have a
property in common.

STIPredicate definitions are essentially a collection of instruction equivalence
classes.
Also, different processor models can specify a different variant of the same
STIPredicate with different rules (i.e. predicates) to classify instructions.
Tablegen backends (in this particular case, the SubtargetEmitter) will be able
to process STIPredicate definitions, and automatically generate functions in
XXXGenSubtargetInfo.

This patch introduces two special kind of STIPredicate classes named
IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a
definition for those in the BtVer2 scheduling model only.

This patch supersedes the one committed at r338372 (phabricator review: D49310).

The main advantages are:
 - We can describe subtarget predicates via tablegen using STIPredicates.
 - We can describe zero-idioms / dep-breaking instructions directly via
   tablegen in the scheduling models.

In future, the STIPredicates framework can be used for solving other problems.
Examples of future developments are:
 - Teach how to identify optimizable register-register moves
 - Teach how to identify slow LEA instructions (each subtarget defining its own
   concept of "slow" LEA).
 - Teach how to identify instructions that have undocumented false dependencies
   on the output registers on some processors only.

It is also (in my opinion) an elegant way to expose knowledge to both external
tools like llvm-mca, and codegen passes.
For example, machine schedulers in LLVM could reuse that information when
internally constructing the data dependency graph for a code region.

This new design feature is also an "opt-in" feature. Processor models don't have
to use the new STIPredicates. It has all been designed to be as unintrusive as
possible.

Differential Revision: https://reviews.llvm.org/D52174

llvm-svn: 342555
2018-09-19 15:57:45 +00:00
Joel Galenson c6f6c17c9b Add missing override keyword (NFC)
llvm-svn: 340615
2018-08-24 16:15:44 +00:00
Joel Galenson d36fb48a27 Find PLT entries for x86, x86_64, and AArch64.
This adds a new method to ELFObjectFileBase that returns the symbols and addresses of PLT entries.

This design was suggested by pcc and eugenis in https://reviews.llvm.org/D49383.

Differential Revision: https://reviews.llvm.org/D50203

llvm-svn: 340610
2018-08-24 15:21:56 +00:00
Zachary Turner bc94ae437f Add the extended XMM registers mappings for AVX-512.
After this we should have the entire AVX-512 register set
mapping in place.

llvm-svn: 340118
2018-08-18 03:54:16 +00:00
Reid Kleckner bd5d71229d [codeview] Use push_macro to avoid conflicts instead of a prefix
Summary:
This prefix was added in r333421, and it changed our dumper output to
say things like "CVRegEAX" instead of just "EAX". That's a functional
change that I'd rather avoid.

I tested GCC, Clang, and MSVC, and all of them support #pragma
push_macro. They don't issue warnings whem the macro is not defined
either.

I don't have a Mac so I can't test the real termios.h header, but I
looked at the termios.h sources online and looked for other conflicts.
I saw only the CR* macros, so those are the ones we work around.

Reviewers: zturner, JDevlieghere

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D50851

llvm-svn: 339907
2018-08-16 17:34:31 +00:00
Zachary Turner 2838b59121 Add support for AVX-512 CodeView registers.
When compiling with /arch:AVX512 and optimizations turned on,
we could crash while emitting debug info because we did not
have CodeView register constants for the AVX 512 register
set defined.  This patch defines them.

Differential Revision: https://reviews.llvm.org/D50819

llvm-svn: 339893
2018-08-16 16:17:55 +00:00
Andrea Di Biagio a1852b6194 [llvm-mca][BtVer2] Teach how to identify dependency-breaking idioms.
This patch teaches llvm-mca how to identify dependency breaking instructions on
btver2.

An example of dependency breaking instructions is the zero-idiom XOR (example:
`XOR %eax, %eax`), which always generates zero regardless of the actual value of
the input register operands.
Dependency breaking instructions don't have to wait on their input register
operands before executing. This is because the computation is not dependent on
the inputs.

Not all dependency breaking idioms are also zero-latency instructions. For
example, `CMPEQ %xmm1, %xmm1` is independent on
the value of XMM1, and it generates a vector of all-ones.
That instruction is not eliminated at register renaming stage, and its opcode is
issued to a pipeline for execution. So, the latency is not zero. 

This patch adds a new method named isDependencyBreaking() to the MCInstrAnalysis
interface. That method takes as input an instruction (i.e. MCInst) and a
MCSubtargetInfo.
The default implementation of isDependencyBreaking() conservatively returns
false for all instructions. Targets may override the default behavior for
specific CPUs, and return a value which better matches the subtarget behavior.

In future, we should teach to Tablegen how to automatically generate the body of
isDependencyBreaking from scheduling predicate definitions. This would allow us
to expose the knowledge about dependency breaking instructions to the machine
schedulers (and, potentially, other codegen passes).

Differential Revision: https://reviews.llvm.org/D49310

llvm-svn: 338372
2018-07-31 13:21:43 +00:00
Andrea Di Biagio b6022aa8d9 [X86][BtVer2] correctly model the latency/throughput of LEA instructions.
This patch fixes the latency/throughput of LEA instructions in the BtVer2
scheduling model.

On Jaguar, A 3-operands LEA has a latency of 2cy, and a reciprocal throughput of
1. That is because it uses one cycle of SAGU followed by 1cy of ALU1.  An LEA
with a "Scale" operand is also slow, and it has the same latency profile as the
3-operands LEA. An LEA16r has a latency of 3cy, and a throughput of 0.5 (i.e.
RThrouhgput of 2.0).

This patch adds a new TIIPredicate named IsThreeOperandsLEAFn to X86Schedule.td.
The tablegen backend (for instruction-info) expands that definition into this
(file X86GenInstrInfo.inc):
```
static bool isThreeOperandsLEA(const MachineInstr &MI) {
  return (
    (
      MI.getOpcode() == X86::LEA32r
      || MI.getOpcode() == X86::LEA64r
      || MI.getOpcode() == X86::LEA64_32r
      || MI.getOpcode() == X86::LEA16r
    )
    && MI.getOperand(1).isReg()
    && MI.getOperand(1).getReg() != 0
    && MI.getOperand(3).isReg()
    && MI.getOperand(3).getReg() != 0
    && (
      (
        MI.getOperand(4).isImm()
        && MI.getOperand(4).getImm() != 0
      )
      || (MI.getOperand(4).isGlobal())
    )
  );
}
```

A similar method is generated in the X86_MC namespace, and included into
X86MCTargetDesc.cpp (the declaration lives in X86MCTargetDesc.h).

Back to the BtVer2 scheduling model:
A new scheduling predicate named JSlowLEAPredicate now checks if either the
instruction is a three-operands LEA, or it is an LEA with a Scale value
different than 1.
A variant scheduling class uses that new predicate to correctly select the
appropriate latency profile.

Differential Revision: https://reviews.llvm.org/D49436

llvm-svn: 337469
2018-07-19 16:42:15 +00:00
Andrea Di Biagio 2145b13fc9 [llvm-mca][X86] Teach how to identify register writes that implicitly clear the upper portion of a super-register.
This patch teaches llvm-mca how to identify register writes that implicitly zero
the upper portion of a super-register.

On X86-64, a general purpose register is implemented in hardware as a 64-bit
register. Quoting the Intel 64 Software Developer's Manual: "an update to the
lower 32 bits of a 64 bit integer register is architecturally defined to zero
extend the upper 32 bits".  Also, a write to an XMM register performed by an AVX
instruction implicitly zeroes the upper 128 bits of the aliasing YMM register.

This patch adds a new method named clearsSuperRegisters to the MCInstrAnalysis
interface to help identify instructions that implicitly clear the upper portion
of a super-register.  The rest of the patch teaches llvm-mca how to use that new
method to obtain the information, and update the register dependencies
accordingly.

I compared the kernels from tests clear-super-register-1.s and
clear-super-register-2.s against the output from perf on btver2.  Previously
there was a large discrepancy between the estimated IPC and the measured IPC.
Now the differences are mostly in the noise.

Differential Revision: https://reviews.llvm.org/D48225

llvm-svn: 335113
2018-06-20 10:08:11 +00:00
Jonas Devlieghere 43dce3edbe [CodeView] Add prefix to CodeView registers.
Adds CVReg to CodeView register names to prevent a duplicate symbol with
CR3 defined in termios.h, as suggested by Zachary on the mailing list.

http://lists.llvm.org/pipermail/llvm-dev/2018-May/123372.html

Differential revision: https://reviews.llvm.org/D47478

rdar://39863705

llvm-svn: 333421
2018-05-29 14:35:34 +00:00
Reid Kleckner 9cdd4df81a [codeview] Implement FPO data assembler directives
Summary:
This adds a set of new directives that describe 32-bit x86 prologues.
The directives are limited and do not expose the full complexity of
codeview FPO data. They are merely a convenience for the compiler to
generate more readable assembly so we don't need to generate tons of
labels in CodeGen. If our prologue emission changes in the future, we
can change the set of available directives to suit our needs. These are
modelled after the .seh_ directives, which use a different format that
interacts with exception handling.

The directives are:
  .cv_fpo_proc _foo
  .cv_fpo_pushreg ebp/ebx/etc
  .cv_fpo_setframe ebp/esi/etc
  .cv_fpo_stackalloc 200
  .cv_fpo_endprologue
  .cv_fpo_endproc
  .cv_fpo_data _foo

I tried to follow the implementation of ARM EHABI CFI directives by
sinking most directives out of MCStreamer and into X86TargetStreamer.
This helps avoid polluting non-X86 code with WinCOFF specific logic.

I used cdb to confirm that this can show locals in parent CSRs in a few
cases, most importantly the one where we use ESI as a frame pointer,
i.e. the one in http://crbug.com/756153#c28

Once we have cdb integration in debuginfo-tests, we can add integration
tests there.

Reviewers: majnemer, hans

Subscribers: aemerson, mgorny, kristof.beyls, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D38776

llvm-svn: 315513
2017-10-11 21:24:33 +00:00
Hans Wennborg 660531085a CodeView: Provide a .def file with the register ids
The list of register ids was previously written out in a couple of dirrent
places. This puts it in a .def file and also adds a few more registers (e.g.
the x87 regs) which should lead to more readable dumps, but I didn't include
the whole list since that seems unnecessary.

X86_MC::initLLVMToSEHAndCVRegMapping is pretty ugly, but at least it's not
relying on magic constants anymore. The TODO of using tablegen still stands.

Differential revision: https://reviews.llvm.org/D38480

llvm-svn: 314821
2017-10-03 18:27:22 +00:00
Rafael Espindola 79e238afee Delete Default and JITDefault code models
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
2017-08-03 02:16:21 +00:00
Mehdi Amini f42454b94b Move the global variables representing each Target behind accessor function
This avoids "static initialization order fiasco"

Differential Revision: https://reviews.llvm.org/D25412

llvm-svn: 283702
2016-10-09 23:00:34 +00:00
Rafael Espindola d86e8bb0ed Delete MCCodeGenInfo.
MC doesn't really care about CodeGen stuff, so this was just
complicating target initialization.

llvm-svn: 274258
2016-06-30 18:25:11 +00:00
Reid Kleckner 5340b279ae [codeview] Add EFLAGS to the list of CodeView register numbers
llvm-svn: 273516
2016-06-22 23:50:19 +00:00