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
This patch splits atomics out of the generic G_LOAD/G_STORE and into their own
G_ATOMIC_LOAD/G_ATOMIC_STORE. This is a pragmatic decision rather than a
necessary one. Atomic load/store has little in implementation in common with
non-atomic load/store. They tend to be handled very differently throughout the
backend. It also has the nice side-effect of slightly improving the common-case
performance at ISel since there's no longer a need for an atomicity check in the
matcher table.
All targets have been updated to remove the atomic load/store check from the
G_LOAD/G_STORE path. AArch64 has also been updated to mark
G_ATOMIC_LOAD/G_ATOMIC_STORE legal.
There is one issue with this patch though which also affects the extending loads
and truncating stores. The rules only match when an appropriate G_ANYEXT is
present in the MIR. For example,
(G_ATOMIC_STORE (G_TRUNC:s16 (G_ANYEXT:s32 (G_ATOMIC_LOAD:s16 X))))
will match but:
(G_ATOMIC_STORE (G_ATOMIC_LOAD:s16 X))
will not. This shouldn't be a problem at the moment, but as we get better at
eliminating extends/truncates we'll likely start failing to match in some
cases. The current plan is to fix this in a patch that changes the
representation of extending-load/truncating-store to allow the MMO to describe
a different type to the operation.
llvm-svn: 319691
The variable named `minor` was actually pointing to the patch part of
the version. While I was changing this I also made the check for Apple
clang more robust by checking both patch and minor rather than just
minor.
llvm-svn: 319656
This is causing a failure in the llvm-clang-x86_64-expensive-checks-win
buildbot, and I can't reproduce it locally, so reverting until I can work out
what is wrong.
llvm-svn: 319654
This adds a "invalid operands for instruction" diagnostic for
instructions where there is an instruction encoding with the correct
mnemonic and which is available for this target, but where multiple
operands do not match those which were provided. This makes it clear
that there is some combination of operands that is valid for the current
target, which the default diagnostic of "invalid instruction" does not.
Since this is a very general error, we only emit it if we don't have a
more specific error.
Differential revision: https://reviews.llvm.org/D36747
llvm-svn: 319649
Added some commonly used Arm triples to the script, with and without
the -eabi suffix.
Differential Revision: https://reviews.llvm.org/D40708
llvm-svn: 319545
The latest clang that ships with Xcode (clang 900 or 9.0.0) does not
support LSan. This fixes the lit configuration to reflect that.
Differential revision: https://reviews.llvm.org/D40672
llvm-svn: 319530
GIM_CheckNonAtomic has been replaced by GIM_CheckAtomicOrdering to allow it to support a wider
range of orderings. This has then been used to import patterns using nodes such
as atomic_cmp_swap, atomic_swap, and atomic_load_*.
llvm-svn: 319232
Add support for mips, particularly skipping the matching of .frame, .(f)mask
and LLVM's usage of the .set no(reorder|at|macro) directives.
Reviewers: spatel
Differential Revision: https://reviews.llvm.org/D40268
llvm-svn: 319001
RecordKeeper::getDef() is a hot place, it shows up in profiling
and it creates std::string instance for each search in RecordMap
though RecordKeeper::RecordMap can use StringRef as a key
instead to avoid that. Patch do that change.
Differential revision: https://reviews.llvm.org/D40170
llvm-svn: 318822
When searching for a resource unit, use the reference location instead of
the definition location in case of an error.
Differential revision: https://reviews.llvm.org/D40263
llvm-svn: 318803
- We can still emit this error if the actual instruction has two or more
operands missing compared to the expected one.
- We should only emit this error once per instruction.
Differential revision: https://reviews.llvm.org/D36746
llvm-svn: 318770
This is NFC, as the matcher would continue looping up to the maximum
number of operands with no effect, but this should improve performance a
bit, and makes the debug trace clearer.
Differential revision: https://reviews.llvm.org/D36744
llvm-svn: 318769
Summary:
The generated diagnostic by the AsmMatcher isn't always applicable to the AsmOperand.
This is because the code will only update the diagnostic if it is more specific than the previous diagnostic. However, when having validated operands and 'moved on' to a next operand (for some instruction/alias for which all previous operands are valid), if the diagnostic is InvalidOperand, than that should be set as the diagnostic, not the more specific message about a previous operand for some other instruction/alias candidate.
Reviewers: craig.topper, olista01, rengolin, stoklund
Reviewed By: olista01
Subscribers: javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D40011
llvm-svn: 318759
This is still breaking greendragon.
At this point I give up until someone can fix the greendragon
bots, and I will probably abandon this effort in favor of using
a private github repository.
llvm-svn: 318722
This was reverted due to the tests being run twice on some
build bots. Each run had a slightly different configuration
due to the way in which it was being invoked. This fixes
the problem (albeit in a somewhat hacky way). Hopefully in
the future we can get rid of the workflow of running
debuginfo-tests as part of clang, and then this hack can
go away.
llvm-svn: 318697
Summary:
This patch fixes an issue so that the right alias is printed when the instruction has tied operands. It checks the number of operands in the resulting instruction as opposed to the alias, and then skips over tied operands that should not be printed in the alias.
This allows to generate the preferred assembly syntax for the AArch64 'ins' instruction, which should always be displayed as 'mov' according to the ARM Architecture Reference Manual. Several unit tests have changed as a result, but only to reflect the preferred disassembly. Some other InstAlias patterns (movk/bic/orr) needed a slight adjustment to stop them becoming the default and breaking other unit tests.
Please note that the patch is mostly the same as https://reviews.llvm.org/D29219 which was reverted because of an issue found when running TableGen with the Address Sanitizer. That issue has been addressed in this iteration of the patch.
Reviewers: rengolin, stoklund, huntergr, SjoerdMeijer, rovka
Reviewed By: rengolin, SjoerdMeijer
Subscribers: fhahn, aemerson, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D40030
llvm-svn: 318650
Summary:
Currently, LIT configures the LLVM binary path before the Clang binary path. However this breaks testing out-of-tree Clang builds (where the LLVM binary path includes a copy of Clang).
This patch reverses the order of the paths when looking for Clang, putting the Clang binary directory first.
Reviewers: zturner, beanz, chapuni, modocache, EricWF
Reviewed By: EricWF
Subscribers: mgorny, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D40217
llvm-svn: 318607
ptypeN is functionally the same as typeN except that it informs the
SelectionDAG importer that an operand should be treated as a pointer even
if it was written as iN. This is important for patterns that use iN instead
of iPTR to represent pointers. E.g.:
(set GPR64:$dst, (load GPR64:$addr))
Previously, this was handled as a hardcoded special case for the appropriate
operands to G_LOAD and G_STORE.
llvm-svn: 318574
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).
llvm-svn: 318490
This is still broken because it causes certain tests to be
run twice with slightly different configurations, which is
wrong in some cases.
You can observe this by running:
ninja -nv check-all | grep debuginfo-tests
And seeing that it passes clang/test and clang/test/debuginfo-tests
to lit, which causes it to run debuginfo-tests twice. The fix is
going to involve either:
a) figuring out that we're running in this "deprecated" configuration,
and then deleting the clang/test/debuginfo-tests path, which should
cause it to behave identically to before, or:
b) make lit smart enough that it doesn't descend into a sub-suite if
that sub-suite already has a lit.cfg file.
llvm-svn: 318486
This was reverted due to some failures on specific darwin buildbots,
the issue being that the new lit configuration was not setting the
SDKROOT environment variable. We've tested a fix locally and confirmed
that it works, so this patch resubmits everything with the fix
applied.
llvm-svn: 318435
Summary:
This patch adds a LLVM_ENABLE_GISEL_COV which, like LLVM_ENABLE_DAGISEL_COV,
causes TableGen to instrument the generated table to collect rule coverage
information. However, LLVM_ENABLE_GISEL_COV goes a bit further than
LLVM_ENABLE_DAGISEL_COV. The information is written to files
(${CMAKE_BINARY_DIR}/gisel-coverage-* by default). These files can then be
concatenated into ${LLVM_GISEL_COV_PREFIX}-all after which TableGen will
read this information and use it to emit warnings about untested rules.
This technique could also be used by SelectionDAG and can be further
extended to detect hot rules and give them priority over colder rules.
Usage:
* Enable LLVM_ENABLE_GISEL_COV in CMake
* Build the compiler and run some tests
* cat gisel-coverage-[0-9]* > gisel-coverage-all
* Delete lib/Target/*/*GenGlobalISel.inc*
* Build the compiler
Known issues:
* ${LLVM_GISEL_COV_PREFIX}-all must be generated as a manual
step due to a lack of a portable 'cat' command. It should be the
concatenation of all ${LLVM_GISEL_COV_PREFIX}-[0-9]* files.
* There's no mechanism to discard coverage information when the ruleset
changes
Depends on D39742
Reviewers: ab, qcolombet, t.p.northover, aditya_nandakumar, rovka
Reviewed By: rovka
Subscribers: vsk, arsenm, nhaehnle, mgorny, kristof.beyls, javed.absar, igorb, llvm-commits
Differential Revision: https://reviews.llvm.org/D39747
llvm-svn: 318356
This is a tablegen backend to generate documentation for the opcodes that exist
for each target. For each opcode, it lists the assembly string, the names and
types of all operands, and the flags and predicates that apply to the opcode.
Differential revision: https://reviews.llvm.org/D31025
llvm-svn: 318155
This reverts the aforementioned patch and 2 subsequent follow-ups,
as some buildbots are still failing 2 tests because of it.
Investigation is ongoing into the cause of the failures.
llvm-svn: 318112
Similar to r315841, GlobalISel and SelectionDAG require different code for the
common atomic predicates due to differences in the representation.
Even without that, differences in the IR (SDNode vs MachineInstr) require
differences in the C++ predicate.
This patch moves the implementation of the common atomic predicates related to
ordering into tablegen so that it can handle these differences.
It's NFC for SelectionDAG since it emits equivalent code and it's NFC for
GlobalISel since the rules involving the relevant predicates are still
rejected by the importer.
llvm-svn: 318102
Similar to r315841, GlobalISel and SelectionDAG require different code for the
common atomic predicates due to differences in the representation.
Even without that, differences in the IR (SDNode vs MachineInstr) require
differences in the C++ predicate.
This patch moves the implementation of the common atomic predicates related to
memory type into tablegen so that it can handle these differences.
It's NFC for SelectionDAG since it emits equivalent code and it's NFC for
GlobalISel since the rules involving the relevant predicates are still
rejected by the importer.
llvm-svn: 318095
Some alias instructions are printed with an extra space after the tab
character. Fix this by skipping that space when the tab character is printed
so that the instructions are aligned with the rest of the code.
Patch by Milos Stojanovic.
Differential Revision: https://reviews.llvm.org/D35946
llvm-svn: 318059
Allow a pattern rewriter to be installed in CodeGenDAGPatterns and use it to
correct situations where SelectionDAG and GlobalISel disagree on
representation. For example, it would rewrite:
(sextload:i32 $ptr)<<unindexedload>><<sextload>><<sextloadi16>
to:
(sext:i32 (load:i16 $ptr)<<unindexedload>>)
I'd have preferred to replace the fragments and have the expansion happen
naturally as part of PatFrag expansion but the type inferencing system can't
cope with loads of types narrower than those mentioned in register classes.
This is because the SDTCisInt's on the sext constrain both the result and
operand to the 'legal' integer types (where legal is defined as 'a register
class can contain the type') which immediately rules the narrower types out.
Several targets (those with only one legal integer type) would then go on to
crash on the SDTCisOpSmallerThanOp<> when it removes all the possible types
for the result of the extend.
Also, improve isObviouslySafeToFold() slightly to automatically return true for
neighbouring instructions. There can't be any re-ordering problems if
re-ordering isn't happenning. We'll need to improve it further to handle
sign/zero-extending loads when the extend and load aren't immediate neighbours
though.
llvm-svn: 317971
Previously, debuginfo-tests was expected to be checked out into
clang/test and then the tests would automatically run as part of
check-clang. This is not a standard workflow for handling
external projects, and it brings with it some serious drawbacks
such as the inability to depend on things other than clang, which
we will need going forward.
The goal of this patch is to migrate towards a more standard
workflow. To ease the transition for build bot maintainers,
this patch tries not to break the existing workflow, but instead
simply deprecate it to give maintainers a chance to update
the build infrastructure.
Differential Revision: https://reviews.llvm.org/D39605
llvm-svn: 317925
This patch adds the ability to include the member function declarations
in the instruction selector class separately from the member bodies.
Defining GET_DAGISEL_DECL macro to any value will only include the member
declarations. To include bodies, define GET_DAGISEL_BODY macro to be the
selector class name. Example:
class FooDAGToDAGISel : public SelectionDAGISel {
// Pull in declarations only.
#define GET_DAGISEL_DECL
#include "FooISelDAGToDAG.inc"
};
// Include the function bodies (with names qualified with the provided
// class name).
#define GET_DAGISEL_BODY FooDAGToDAGISel
#include "FooISelDAGToDAG.inc"
When neither of the two macros are defined, the function bodies are emitted
inline (in the same way as before this patch).
Differential Revision: https://reviews.llvm.org/D39596
llvm-svn: 317903
This should be a trivial change, and I've started using it for generating all
tests at https://github.com/lowrisc/riscv-llvm (i.e. it's been tested in
action quite a lot). Note that the regex does not attempt to match
.cfi_startproc, as I want to ensure compatibility with functions that have the
nounwind attribute.
Differential Revision: https://reviews.llvm.org/D39789
llvm-svn: 317693
Summary:
This makes it very easy to test files that only differ in a constant
value somewhere in the test case.
Reviewers: jlebar, hfinkel, chandlerc, probinson
Reviewed By: probinson
Subscribers: probinson, llvm-commits
Differential Revision: https://reviews.llvm.org/D39629
llvm-svn: 317572
Patch [1/5] in a series to add assembler/disassembler support for AArch64 SVE
unpredicated ADD/SUB instructions.
Patch by Sander De Smalen.
Reviewed by: rengolin
Differential Revision: https://reviews.llvm.org/D39087
llvm-svn: 317564
Previously, this could end up replacing a vreg like %14 with
[[VREG1]]4, where VREG1 was the match for %1. That's obviously not
correct, though it hasn't actually come up in any tests I've converted
so far.
llvm-svn: 317509
The GlobalISel TableGen backend didn't check for predicates on the
source children. This caused it to generate code for ARM patterns such
as SMLABB or similar, but without properly checking for the sext_16_node
part of the operands. This in turn meant that we would select SMLABB
instead of MLA for simple sequences such as s32 + s32 * s32, which is
wrong (we want a MLA on the full operands, not just their bottom 16
bits).
This patch forces TableGen to skip patterns with predicates on the src
children, so it doesn't generate code for SMLABB and other similar ARM
instructions at all anymore. AArch64 and X86 are not affected.
Differential Revision: https://reviews.llvm.org/D39554
llvm-svn: 317313
This will enable us to prefer VALIGND/Q during shuffle lowering in order to get the extended register encoding space when BWI isn't available. But if we end up not using the extended registers we can switch VPALIGNR for the shorter VEX encoding.
Differential Revision: https://reviews.llvm.org/D39401
llvm-svn: 317122
The importer will now accept nested instructions in the result pattern such as
(ADDWrr $a, (SUBWrr $b, $c)). This is only valid when the nested instruction
def's a single vreg and the parent instruction consumes a single vreg where a
nested instruction is specified. The importer will automatically create a vreg
to connect the two using the type information from the pattern. This vreg will
be constrained to the register classes given in the instruction definitions*.
* REG_SEQUENCE is explicitly rejected because of this. The definition doesn't
constrain to a register class and it therefore needs special handling.
llvm-svn: 317117
The next commit will add support for multi-instruction emission so we need to
start allocating instruction ID's instead of hard-coding them to 0.
llvm-svn: 317057
I need a test that only runs in a reasonable amount of time on systems
that have sparse files. The broadest class of systems that support
sparse files are linux systems. So restricting my test to linux systems
should suffice. This change adds the system-linux feature to llvm-lit so
that it can be required.
Differential Revision: https://reviews.llvm.org/D39482
llvm-svn: 317055
Multi-instruction emission needs to ensure the the instructions are generated
a depth-first fashion. For example:
(ADDWrr (SUBWrr a, b), c)
needs to emit the SUBWrr before the ADDWrr. However, our walk over
TreePatternNode's is highly context sensitive which makes it difficult to append
BuildMIActions in the order we want. To fix this, we now keep track of the
insertion point as we add actions. This will allow multi-insn emission to insert
BuildMI's in the correct place.
The previous commit failed on the Ubuntu bots using GCC 4.8. These bots lack the
const_iterator forms of insert() and emplace() that were added in C++11. As a
result I've switched the const_iterators to iterators.
llvm-svn: 317049
The same bots fail but I believe I know what the issue is now. These bots are
missing the const_iterator versions of insert/emplace/etc. that were introduced
in C++11.
llvm-svn: 317042
Multi-instruction emission needs to ensure the the instructions are generated
a depth-first fashion. For example:
(ADDWrr (SUBWrr a, b), c)
needs to emit the SUBWrr before the ADDWrr. However, our walk over
TreePatternNode's is highly context sensitive which makes it difficult to append
BuildMIActions in the order we want. To fix this, we now keep track of the
insertion point as we add actions. This will allow multi-insn emission to insert
BuildMI's in the correct place.
The previous commit failed on the Ubuntu bots using GCC 4.8. These bots didn't
like a call to emplace(). I've replaced it with insert() to see if it's a quirk
of the C++11 support.
llvm-svn: 317040
Multi-instruction emission needs to ensure the the instructions are generated
a depth-first fashion. For example:
(ADDWrr (SUBWrr a, b), c)
needs to emit the SUBWrr before the ADDWrr. However, our walk over
TreePatternNode's is highly context sensitive which makes it difficult to append
BuildMIActions in the order we want. To fix this, we now keep track of the
insertion point as we add actions. This will allow multi-insn emission to insert
BuildMI's in the correct place.
llvm-svn: 317029
Multi-instruction emission will require that we have separate handling for
the defs between the implicitly created temporaries and the rule outputs.
The former require new temporary vregs while the latter should copy existing
operands. Factor out the implicit def/use renderers to minimize the code
duplication when we implement that.
llvm-svn: 317025
Prepare for multiple instruction emission by allowing BuildMIAction to
search for a suitable matcher that will support mutation.
This patch deliberately neglects to add matchers aside from the root to
preserve NFC. That said, it should be noted that until we support mutations
other than just the opcode the chances of finding a non-root instruction
for which canMutate() is true, is essentially zero. Furthermore in the
presence of multi-instruction emission the chances of finding any
instruction for which canMutate() is true is also zero. Nevertheless, we
can't continue to require that all BuildMIAction's consider the root of the match
to be recyclable due to the risk of recycling it twice in the same rule.
llvm-svn: 317022
Based on similar python tool - utils/shuffle-fuzz.py - this tool extends the ability of it's previous by optionally attaching select instruction to the generated shufflevector instructions.
This was mainly developed to perform exhaustive testing of the X86 AVX512 masked shuffle instructions. But yet it can be used for various other targets.
The general design of the implementation is much modular than the original shuffle_fuzz.py tool, which makes it easier for anyone to extend it further.
Differential Revision: https://reviews.llvm.org/D38031
Change-Id: I0efc2aaa091b61a8a9552311c21cc77916a97111
llvm-svn: 316989
gtest depends on this #define to determine whether it can
use various classes like std::tuple, or whether it has to fall
back to experimental classes in the std::tr1 namespace. The
check in the current version of gtest relies on the value of
the `__cplusplus` macro, but MSVC provides a non-conformant
value of this macro, making it effectively impossible to detect
C++11. In short, LLVM compiled with MSVC has been silently
using the tr1 versions of several classes since the beginning of
time.
This would normally be pretty benign, except that in the latest
preview of MSVC they have marked all of the tr1 classes
deprecated, so it spews thousands of warnings.
llvm-svn: 316798
When multi-instruction emission is supported, it will no longer be guaranteed
that every BuildMIAction has a corresponding matched instruction. BuildMIAction
should support not having one to cover the case where a rule produces more
instructions than it matched.
llvm-svn: 316463
Ideally, we should compare 32- and 64-bit versions to see if the
ret line is the only difference and then insert the regex only
in that case. But this is a quick hack to avoid a bunch of noise
as existing tests are updated.
llvm-svn: 316443
This patch enables the import of stores. Unfortunately, doing so by itself,
loses an optimization where storing 0 to memory makes use of WZR/XZR.
To mitigate this, this patch also introduces a new feature that allows register
operands to nominate a zero register. When this is done, GlobalISel will
substitute (G_CONSTANT 0) with the nominated register automatically. This
is currently configured to only apply to the stores.
Applying it to GPR32/GPR64 register classes in general will be done after
review see (https://reviews.llvm.org/D39150).
llvm-svn: 316360
Summary: test/CodeGen/PowerPC/pr33093.ll uses both powerpc64 (big-endian) and powerpc64le while the former was unsupported.
Subscribers: nemanjai
Differential Revision: https://reviews.llvm.org/D39164
llvm-svn: 316297
This is similar to how we generate the VEX tables.
More fixes are still needed for the instructions that use EVEX.b (broadcast and embedded rounding).
llvm-svn: 316294
This introduces a new operand type to encode the whether the index register should be XMM/YMM/ZMM. And new code to fixup the results created by readSIB.
This has the nice effect of removing a bunch of code that hard coded the name of every GATHER and SCATTER instruction to map the index type.
This fixes PR32807.
llvm-svn: 316273
This is a temporary hack to support adding checks for the "registers:"
block of mir functions. This is necessary to convert a number of tests
so that there's less churn when we change the MIR printer to put the
vreg classes on defs instead of in their own block.
llvm-svn: 316134
An empty livein block doesn't make much sense (why not just omit it?)
but they're legal and some tests have them, so its best to handle it.
llvm-svn: 316089
Matching prefixes isn't good enough, because it leads to things like
calling the first constant C3 just because there were two copies
before it. Tighten up the check to match more precisely, but also be
careful about ambiguity when dealing with target opcodes that end in a
number.
llvm-svn: 316088
This adds update_mir_test_checks, which updates the check lines in mir
tests. This can only update tests that start and end with .mir
currently (ie, -run-pass) but it should be sufficient for updating at
least some of the GlobalISel tests.
llvm-svn: 316057
The new scheme should match the normalization of embedded paths in
linkrepro tar files.
Differential Revision: https://reviews.llvm.org/D39023
llvm-svn: 316044
MSVC doesn't seem to like implicitly instantiating addPredicate and then
explicitly specializing it later. It causes an internal compiler error.
llvm-svn: 315930
Summary:
iPTR is a pointer of subtarget-specific size to any address space. Therefore
type checks on this size derive the SizeInBits from a subtarget hook.
At this point, we can import the simplests G_LOAD rules and select load
instructions using them. Further patches will support for the predicates to
enable additional loads as well as the stores.
The previous commit failed on MSVC due to a failure to convert an
initializer_list to a std::vector. Hopefully, MSVC will accept this version.
Depends on D37457
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: kristof.beyls, javed.absar, llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37458
llvm-svn: 315887
Summary:
iPTR is a pointer of subtarget-specific size to any address space. Therefore
type checks on this size derive the SizeInBits from a subtarget hook.
At this point, we can import the simplests G_LOAD rules and select load
instructions using them. Further patches will support for the predicates to
enable additional loads as well as the stores.
Depends on D37457
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: kristof.beyls, javed.absar, llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37458
llvm-svn: 315885
Summary:
This includes some context-sensitivity in the MVT to LLT conversion so that
pointer types are tested correctly.
FIXME: I'm not happy with the way this is done since everything is a
special-case. I've yet to find a reasonable way to implement it.
select-load.mir fails because <1 x s64> loads in tablegen get priority over s64
loads. This is fixed in the next patch and as such they should be committed
together, I've posted them separately to help with the review.
Depends on D37456
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Subscribers: kristof.beyls, javed.absar, llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37457
llvm-svn: 315884
Summary:
It's possible for a ComplexPattern to be used as an operator in a match
pattern. This is used by the load/store patterns in AArch64 to name the
suboperands returned by ComplexPattern predicate so that they can be broken
apart and referenced independently in the result pattern.
This patch adds support for this in order to enable the import of load/store
patterns.
Depends on D37445
Hopefully fixed the ambiguous constructor that a large number of bots reported.
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: aemerson, javed.absar, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D37456
llvm-svn: 315869
Summary:
It's possible for a ComplexPattern to be used as an operator in a match
pattern. This is used by the load/store patterns in AArch64 to name the
suboperands returned by ComplexPattern predicate so that they can be broken
apart and referenced independently in the result pattern.
This patch adds support for this in order to enable the import of load/store
patterns.
Depends on D37445
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: aemerson, javed.absar, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D37456
llvm-svn: 315863
In type inference, an empty type set for a specific hw mode is not an
error. In earlier stages of the design it was, but having to use non-
parameterized types with target intrinsics necessarily led to type
contradictions: since the intrinsics used specific types, they were
only valid for a specific hw mode, and the resulting type set for other
modes ended up empty. To accommodate the existence of such intrinsics
individual type sets were allowed to be empty as long as not all sets
were empty.
llvm-svn: 315858
Summary:
There is an important mismatch between ISD::LOAD and G_LOAD (and likewise for
ISD::STORE and G_STORE). In SelectionDAG, ISD::LOAD is a non-atomic load
and atomic loads are handled by a separate node. However, this is not true of
GlobalISel's G_LOAD. For G_LOAD, the MachineMemOperand indicates the atomicity
of the operation. As a result, this mapping must also add a predicate that
checks for non-atomic MachineMemOperands.
This is NFC since these nodes always have predicates in practice and are
therefore always rejected at the moment.
Depends on D37443
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: kristof.beyls, llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37445
llvm-svn: 315843
Summary:
GlobalISel and SelectionDAG require different code for the common
load/store predicates due to differences in the representation.
For example:
SelectionDAG: (load<signext,i8>:i32 GPR32:$addr) // The <> denote properties of the SDNode that are not printed in the DAG
GlobalISel: (G_SEXT:s32 (G_LOAD:s8 GPR32:$addr))
Even without that, differences in the IR (SDNode vs MachineInstr) require
differences in the C++ predicate.
This patch moves the implementation of the common load/store predicates
into tablegen so that it can handle these differences.
It's NFC for SelectionDAG since it emits equivalent code and it's NFC for
GlobalISel since the rules involving the relevant predicates are still
rejected by the importer.
Depends on D36618
Reviewers: ab, qcolombet, t.p.northover, rovka, aditya_nandakumar
Subscribers: llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37443
Includes a partial revert of r315826 since this patch makes it necessary for
getPredCode() to return a std::string and getImmCode() should have the same
interface as getPredCode().
llvm-svn: 315841
"No such file or directory: C:\\...\\tests\\Output\\shared-output.py.tmp/Output/Shared/SHARED.tmp"
And yet other forward-slashes don't seem to be causing the same
problem. I'll see if I can get ahold of a Windows machine to poke at
this directly later.
llvm-svn: 315792
Summary:
Operand variable lookups are now performed by the RuleMatcher rather than
searching the whole matcher hierarchy for a match. This revealed a wrong-code
bug that currently affects ARM and X86 where patterns that use a variable more
than once in the match pattern will be imported but won't check that the
operands are identical. This can cause the tablegen-erated matcher to
accept matches that should be rejected.
Depends on D36569
Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar
Subscribers: aemerson, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D36618
llvm-svn: 315780
Summary:
There's only a tablegen testcase for IntImmLeaf and not a CodeGen one
because the relevant rules are rejected for other reasons at the moment.
On AArch64, it's because there's an SDNodeXForm attached to the operand.
On X86, it's because the rule either emits multiple instructions or has
another predicate using PatFrag which cannot easily be supported at the
same time.
Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: aemerson, javed.absar, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D36569
llvm-svn: 315761
Summary:
The purpose of this patch is to expose more information about ImmLeaf-like
PatLeaf's so that GlobalISel can learn to import them. Previously, ImmLeaf
could only be used to test int64_t's produced by sign-extending an APInt.
Other tests on immediates had to use the generic PatLeaf and extract the
constant using C++.
With this patch, tablegen will know how to generate predicates for APInt,
and APFloat. This will allow it to 'do the right thing' for both SelectionDAG
and GlobalISel which require different methods of extracting the immediate
from the IR.
This is NFC for SelectionDAG since the new code is equivalent to the
previous code. It's also NFC for FastISel because FastIselShouldIgnore is 1
for the ImmLeaf subclasses. Enabling FastIselShouldIgnore == 0 for these new
subclasses will require a significant re-factor of FastISel.
For GlobalISel, it's currently NFC because the relevant code to import the
affected rules is not yet present. This will be added in a later patch.
Depends on D36086
Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar
Reviewed By: qcolombet
Subscribers: bjope, aemerson, rengolin, javed.absar, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D36534
llvm-svn: 315747
I'm about to commit a patch that makes them necessary for getPredCode() and
it would be strange for getPredCode() and getImmCode() to require different
usage.
llvm-svn: 315733
This refers to a temporary path that can be shared across all tests,
identified by a particular label. This can be used for things like
caches.
At the moment, the character set for the LABEL is limited to C
identifier characters, plus '-', '+', '=', and '.'. This is the same
set of characters currently allowed in REQUIRES clause identifiers.
llvm-svn: 315697
This paves the way for other projects which might /use/ clang or
lld but not necessarily need to the full set of functionality
available to clang and lld tests to be able to have a basic set
of substitutions that allow a project to run the clang or lld
executables.
llvm-svn: 315627
Summary:
Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with
LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP.
Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods.
Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so
it'll be picked up by public headers.
Differential Revision: https://reviews.llvm.org/D38406
llvm-svn: 315590
This reverts commit 4e4ee1c507e2707bb3c208e1e1b6551c3015cbf5.
This is failing due to some code that isn't built on MSVC
so I didn't catch. Not immediately obvious how to fix this
at first glance, so I'm reverting for now.
llvm-svn: 315536
There's a lot of misuse of Twine scattered around LLVM. This
ranges in severity from benign (returning a Twine from a function
by value that is just a string literal) to pretty sketchy (storing
a Twine by value in a class). While there are some uses for
copying Twines, most of the very compelling ones are confined
to the Twine class implementation itself, and other uses are
either dubious or easily worked around.
This patch makes Twine's copy constructor private, and fixes up
all callsites.
Differential Revision: https://reviews.llvm.org/D38767
llvm-svn: 315530
This adds debug tracing to the table-generated assembly instruction matcher,
enabled by the -debug-only=asm-matcher option.
The changes in the target AsmParsers are to add an MCInstrInfo reference under
a consistent name, so that we can use it from table-generated code. This was
already being used this way for targets that use deprecation warnings, but 5
targets did not have it, and Hexagon had it under a different name to the other
backends.
llvm-svn: 315445
This allows a DiagnosticType and/or DiagnosticString to be associated
with a RegisterClass in tablegen, so that we can emit diagnostics in the
assembler when a register operand is incorrect.
DiagnosticType creates a predictable enum value, which gets returned as
the error code when an operand does not match, and can be used by the
assembly parser to map to a user-facing diagnostic. DiagnosticString
creates an anonymous enum value (currently based on the tablegen class
name), and a function to map from enum values to strings will be
generated. Both of these work the same was as they do for AsmOperand.
This isn't used by any targets yet, but has one (positive) side-effect.
It improves the diagnostic codes returned by validateOperandClass - we
always want to emit the diagnostic that relates to the expected operand
class, but this wasn't always being done when the expected and actual
classes were completely different (token/register/custom). This causes a
few AArch64 diagnostics to be improved, as Match_InvalidOperand was
being returned instead of a specific diagnostic type.
Differential revision: https://reviews.llvm.org/D36691
llvm-svn: 315295
It's rare but there are a small number of patterns like this:
(set i64:$dst, (add i64:$src1, i64:$src2))
These should be equivalent to register classes except they shouldn't check for
a specific register bank.
This doesn't occur in AArch64/ARM/X86 but does occasionally come up in other
in-tree targets such as BPF.
llvm-svn: 315226
After the original commit ([[ https://reviews.llvm.org/rL304088 | rL304088 ]]) was reverted, a discussion in llvm-dev was opened on 'how to accomplish this task'.
In the discussion we concluded that the best way to achieve our goal (which is to automate the folding tables and remove the manually maintained tables) is:
# Commit the tablegen backend disabled by default.
# Proceed with an incremental updating of the manual tables - while checking the validity of each added entry.
# Repeat previous step until we reach a state where the generated and the manual tables are identical. Then we can safely remove the manual tables and include the generated tables instead.
# Schedule periodical (1 week/2 weeks/1 month) runs of the pass:
- if changes appear (new entries):
- make sure the entries are legal
- If they are not, mark them as illegal to folding
- Commit the changes (if there are any).
CMake flag added for this purpose is "X86_GEN_FOLD_TABLES". Building with this flags will run the pass and emit the X86GenFoldTables.inc file under build/lib/Target/X86/ directory which is a good reference for any developer who wants to take part in the effort of completing the current folding tables.
Differential Revision: https://reviews.llvm.org/D38028
llvm-svn: 315173
The assertion tests were using count() instead of testing the find result, resulting in double the number of searches in debug/assert builds.
Instead, call find once (like the release builds do) and assert the result against end().
llvm-svn: 315151
Avoid unnecessary std::string creations in the TreePredicateFn getters and in CodeGenDAGPatterns::getSDNodeNamed
Differential Revision: https://reviews.llvm.org/D38624
llvm-svn: 315148
This addresses two sources of inconsistency in test configuration
files.
1. Substitution boundaries. Previously you would specify a
substitution, such as 'lli', and then additionally a set
of characters that should fail to match before and after
the tool. This was used, for example, so that matches that
are parts of full paths would not be replaced. But not all
tools did this, and those that did would often re-invent
the set of characters themselves, leading to inconsistency.
Now, every tool substitution defaults to using a sane set
of reasonable defaults and you have to explicitly opt out
of it. This actually fixed a few latent bugs that were
never being surfaced, but only on accident.
2. There was no standard way for the system to decide how to
locate a tool. Sometimes you have an explicit path, sometimes
we would search for it and build up a path ourselves, and
sometimes we would build up a full command line. Furthermore,
there was no standardized way to handle missing tools. Do we
warn, fail, ignore, etc? All of this is now encapsulated in
the ToolSubst class. You either specify an exact command to
run, or an instance of FindTool('<tool-name>') and everything
else just works. Furthermore, you can specify an action to
take if the tool cannot be resolved.
Differential Revision: https://reviews.llvm.org/D38565
llvm-svn: 315085
Summary:
normpath() was being called on an empty string and appended to
the environment variable in the case where the environment variable
was unset. This led to ":." being appended to the path, since
normpath() of an empty string is '.', presumably to represent cwd.
Reviewers: zturner, sqlbyme, modocache
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38542
llvm-svn: 314915
This adds a DiagnosticString member to the AsmOperand tablegen class, so
that the diagnostic text to be used when an assembly operand is
incorrect can be stored in the tablegen description of the operand,
rather than in a separate switch statement in the AsmParser.
If DiagnosticString is used for any operands, tablegen will emit a
getMatchKindDiag function, to map from diagnostic enums to strings.
Differential revision: https://reviews.llvm.org/D31606
llvm-svn: 314803
The current table-generated assembly instruction matcher returns a
64-bit error code when matching fails. Since multiple instruction
encodings with the same mnemonic can fail for different reasons, it uses
some heuristics to decide which message is important.
This heuristic does not work well for targets that have many encodings
with the same mnemonic but different operands, or which have different
versions of instructions controlled by subtarget features, as it is hard
to know which encoding the user was intending to use.
Instead of trying to improve the heuristic in the table-generated
matcher, this patch changes it to report a list of near-miss encodings.
This list contains an entry for each encoding with the correct mnemonic,
but with exactly one thing preventing it from being valid. This thing
could be a single invalid operand, a missing target feature or a failed
target-specific validation function.
The target-specific assembly parser can then report an error message
giving multiple options for instruction variants that the user may have
been trying to use. For example, I am working on a patch to use this for
ARM, which can give this error for an invalid instruction for ARMv6-M:
<stdin>:8:3: error: invalid instruction, multiple near-miss encodings found
adds r0, r1, #0x8
^
<stdin>:8:3: note: for one encoding: instruction requires: thumb2
adds r0, r1, #0x8
^
<stdin>:8:16: note: for one encoding: expected an integer in range [0, 7]
adds r0, r1, #0x8
^
<stdin>:8:16: note: for one encoding: expected a register in range [r0, r7]
adds r0, r1, #0x8
^
This also allows the target-specific assembly parser to apply its own
heuristics to suppress some errors. For example, the error "instruction
requires: arm-mode" is never going to be useful when targeting an
M-profile architecture (which does not have ARM mode).
This patch just adds the target-independent mechanism for doing this,
all targets still use the old mechanism. I've added a bit in the
AsmParser tablegen class to allow targets to switch to this new
mechanism. To use this, the target-specific assembly parser will have to
be modified for the change in signature of MatchInstructionImpl, and to
report errors based on the list of near-misses.
Differential revision: https://reviews.llvm.org/D27620
llvm-svn: 314774
Fix llvm_tools_dir attribute access not to fail when the variable is not
present. This directory is not really necessary to run lit tests,
and the code already accounts for it being None.
The reference was added in r313407, and it breaks the stand-alone lit
package in Gentoo.
Differential Revision: https://reviews.llvm.org/D38442
llvm-svn: 314620
Summary:
Also disables leak checking on lto tests, due to many leaks reported
in the system's ld64.
Reviewers: kcc, pcc, bogner, kubamracek
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D37781
llvm-svn: 314535
Also add operator<< for use with raw_ostream to InfoByHwMode and its
derived classes.
Recommitting r313989 with the fix for unresolved references: explicitly
define the operator<< in namespace llvm.
llvm-svn: 314004
Avoid unnecessary std::string creations during TypeSetByHwMode::writeToStream.
Found during investigations into PR28222
Differential Revision: https://reviews.llvm.org/D38174
llvm-svn: 313983
There were two issues, one Python 3 specific related to Unicode,
and another which is that the tool substitution for lld no longer
rejected matches where a / preceded the tool name.
llvm-svn: 313928
debuginfo-tests has need to reuse a lot of common configuration
from clang and lld, and in general it seems like all of the
projects which are tightly coupled (e.g. lld, clang, llvm, lldb,
etc) can benefit from knowing about one other. For example,
lldb needs to know various things about how to run clang in its
test suite. Since there's a lot of common substitutions and
operations that need to be shared among projects, sinking this
up into LLVM makes sense.
In addition, this patch introduces a function add_tool_substitution
which handles all the dirty intricacies of matching tool names
which was previously copied around the various config files. This
is now a simple straightforward interface which is hard to mess
up.
Differential Revision: https://reviews.llvm.org/D37944
llvm-svn: 313919
This has gone back and forth, but it seems this is necessary
after all. realpath is not sufficient because if you have a
file named 'C:\foo.txt', then both realpath('c:\foo.txt') and
realpath(C:\foo.txt') return the string that was passed to them
exactly as is, meaning the case of the drive-letter won't match.
The problem before was not that we were normalizing the case of
items going into the config map, but rather that we were
normalizing the case of something we needed to print. The value
that is used to key on the config map should never be printed.
llvm-svn: 313918
This makes all paths lowercase on Windows, which seemed like a
good idea at the time, but it means that tests can't properly
use FileCheck to match expected path names.
llvm-svn: 313889
Config map is not exposed through the command line, so testing this
is somewhat tricky. But basically we need a test that if a custom
driver builds a config map and passes it to main, it gets respected.
A config map allows config files in the source tree to be mapped
to alternate config files in the build tree. This particular test
works by having two config files in separate directories, and
setting up a config map to have that redirects A/lit.site.cfg
to B/altconfig. Then, we print a message in A/lit.site.cfg
and B/altconfig and check that we do see the output from B
but don't see the output from A. Additionally we test that
the test suite specified by A's config map is properly discovered.
Differential Revision: https://reviews.llvm.org/D38105
llvm-svn: 313887
Summary:
This appears to break some bots, when getToolsPath fails to find some or
all of the tools (for example, an incomplete GnuWin32 installation).
Reviewers: zturner, modocache
Subscribers: sanjoy, llvm-commits
Differential Revision: https://reviews.llvm.org/D38115
llvm-svn: 313854
Many editors and Python-related diagnostics tools such as
debuggers break or fail in mysterious ways when python files
don't end in .py. This is especially true on Windows, but
still exists on other platforms. I don't want to be too heavy
handed in changing everything across the board, but I do want
to at least *allow* lit configs to have .py extensions. This
patch makes the discovery process first look for a config file
with a .py extension, and if one is not found, then looks for
a config file using the old method. So for existing users, there
should be no functional change.
Differential Revision: https://reviews.llvm.org/D37838
llvm-svn: 313849
This changes some STL data types to corresponding LLVM
data types that have better performance characteristics.
Differential Revision: https://reviews.llvm.org/D37957
llvm-svn: 313783
Bug pointed out by EricWF. This would construct a path where
items would be added in the wrong order, potentially leading
to using the wrong tools for testing.
llvm-svn: 313765
Many svn-based buildbots seem to be getting stuck continually
in tree conflicts due to the output of pyc files. I'm disabling
these as a temporary measure in an attempt to get everything
stable again.
I'll try to remove this code once I understand the problem
better.
llvm-svn: 313698
The generated DAG isel file currently makes use of formatted_raw_ostream primarily for generating a hierarchical representation while also skipping over the initial comment that contains the current index.
It was reported in D37957 that this formatting might be slow due to the need to keep track of column numbers by monitoring all the written data for new lines.
This patch attempts to rewrite the emitter to make use of simpler formatting mechanisms to generate a fairly similar output. The main difference is that the number in the index comment is now right justified and padded with spaces inside the comment. Previously we appended the spaces after the comment.
Differential Revision: https://reviews.llvm.org/D37966
llvm-svn: 313674
Add some member types to MachineValueTypeSet::const_iterator so that
iterator_traits can work with it.
Improve TableGen performance of -gen-dag-isel (motivated by X86 backend)
The introduction of parameterized register classes in r313271 caused the
matcher generation code in TableGen to run much slower, particularly so
in the unoptimized (debug) build. This patch recovers some of the lost
performance.
Summary of changes:
- Cache the set of legal types in TypeInfer::getLegalTypes. The contents
of this set do not change.
- Add LLVM_ATTRIBUTE_ALWAYS_INLINE to several small functions. Normally
this would not be necessary, but in the debug build TableGen is not
optimized, so this helps a little bit.
- Add an early exit from TypeSetByHwMode::operator== for the case when
one or both arguments are "simple", i.e. only have one mode. This
saves some time in GenerateVariants.
- Finally, replace the underlying storage type in TypeSetByHwMode::SetType
with MachineValueTypeSet based on std::array instead of std::set.
This significantly reduces the number of memory allocation calls.
I've done a number of experiments with the underlying type of InfoByHwMode.
The type is a map, and for targets that do not use the parameterization,
this map has only one entry. The best (unoptimized) performance, somewhat
surprisingly came from std::map, followed closely by std::unordered_map.
DenseMap was the slowest by a large margin.
Various hand-crafted solutions (emulating enough of the map interface
not to make sweeping changes to the users) did not yield any observable
improvements.
llvm-svn: 313660
The introduction of parameterized register classes in r313271 caused the
matcher generation code in TableGen to run much slower, particularly so
in the unoptimized (debug) build. This patch recovers some of the lost
performance.
Summary of changes:
- Cache the set of legal types in TypeInfer::getLegalTypes. The contents
of this set do not change.
- Add LLVM_ATTRIBUTE_ALWAYS_INLINE to several small functions. Normally
this would not be necessary, but in the debug build TableGen is not
optimized, so this helps a little bit.
- Add an early exit from TypeSetByHwMode::operator== for the case when
one or both arguments are "simple", i.e. only have one mode. This
saves some time in GenerateVariants.
- Finally, replace the underlying storage type in TypeSetByHwMode::SetType
with MachineValueTypeSet based on std::array instead of std::set.
This significantly reduces the number of memory allocation calls.
I've done a number of experiments with the underlying type of InfoByHwMode.
The type is a map, and for targets that do not use the parameterization,
this map has only one entry. The best (unoptimized) performance, somewhat
surprisingly came from std::map, followed closely by std::unordered_map.
DenseMap was the slowest by a large margin.
Various hand-crafted solutions (emulating enough of the map interface
not to make sweeping changes to the users) did not yield any observable
improvements.
llvm-svn: 313647
Since the path a user specifies to the llvm-lit script might be
different than the source tree they built from (since they could
be behind different symlinks), we need to use realpath to make
sure that path comparisons work as expected.
Even better would be to use a custom dictionary comparison with
actual file equivalence comparison semantics, but this is the
least friction to unbreak things for now.
llvm-svn: 313594
It doesn't make sense to me why these bots are failing as the
traceback does not agree with the source code. It's possible
something is stale or there is some other mysterious error,
but in any case hopefully this fixes it.
llvm-svn: 313469
A few tests were manually constructing a LitConfig object, since
I added a new argument to it this was triggering some failures
I didn't detect. `ninja check-lit` passes now.
llvm-svn: 313461
This is helpful for debugging test failures since it removes
the multiprocessing pool from the picture. This will obviously
slow down the test suite by a few orders of magnitude, so it
should only be used for debugging specific failures.
llvm-svn: 313460
It looks like this is going to be non-trivial to get working
in both Py2 and Py3, so for now I'm reverting until I have time
to fully test it under Python 3.
llvm-svn: 313429