If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
llvm-svn: 272709
This enables use of the 'R' and 'T' memory constraints for inline ASM
operands on SystemZ, which allow an index register as well as an
immediate displacement. This patch includes corresponding documentation
and test case updates.
As with the last patch of this kind, I moved the 'm' constraint to the
most general case, which is now 'T' (base + 20-bit signed displacement +
index register).
Author: colpell
Differential Revision: http://reviews.llvm.org/D21239
llvm-svn: 272547
Summary: This also deprecated the get attribute function familly.
Reviewers: Wallbraker, whitequark, joker.eph, echristo, rafael, jyknight
Subscribers: axw, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19181
llvm-svn: 272504
Summary:
This documents the various relocation types that are supported by the
Radeon Open Compute (ROC) runtime (which is essentially the dynamic
linker for AMDGPU).
Only R_AMDGPU_32 is not currently supported by the ROC runtime, but
it will usually be resolved at link time by lld.
Patch by: Konstantin Zhuravlyov
Reviewers: kzhuravl, rafael
Subscribers: rafael, arsenm, llvm-commits, kzhuravl
Differential Revision: http://reviews.llvm.org/D20952
llvm-svn: 272352
This enables use of the 'S' constraint for inline ASM operands on
SystemZ, which allows for a memory reference with a signed 20-bit
immediate displacement. This patch includes corresponding documentation
and test case updates.
I've changed the 'T' constraint to match the new behavior for 'S', as
'T' also uses a long displacement (though index constraints are still
not implemented). I also changed 'm' to match the behavior for 'S' as
this will allow for a wider range of displacements for 'm', though
correct me if that's not the right decision.
Author: colpell
Differential Revision: http://reviews.llvm.org/D21097
llvm-svn: 272266
Changes since the initial commit:
- Use echo instead of printf. This should side-step the character
escaping issues on Windows.
Differential Revision: http://reviews.llvm.org/D20980
llvm-svn: 272068
take into account modernizations in r246002 and r270381.
Patch based on http://reviews.llvm.org/D20954 by Miroslav Hrncir.
Thanks Miroslav!
llvm-svn: 271985
Summary:
This is an initial implementation of a Hardened Allocator based on Sanitizer Common's CombinedAllocator.
It aims at mitigating heap based vulnerabilities by adding several features to the base allocator, while staying relatively fast.
The following were implemented:
- additional consistency checks on the allocation function parameters and on the heap chunks;
- use of checksum protected chunk header, to detect corruption;
- randomness to the allocator base;
- delayed freelist (quarantine), to mitigate use after free and overall determinism.
Additional mitigations are in the works.
Reviewers: eugenis, aizatsky, pcc, krasin, vitalybuka, glider, dvyukov, kcc
Subscribers: kubabrecka, filcab, llvm-commits
Differential Revision: http://reviews.llvm.org/D20084
llvm-svn: 271968
Changes since the initial commit:
- Normalize file paths read from the file to prevent Windows path
separators from escaping parts of the path.
- Since we need to store the normalized file paths in WeightedFile,
don't do tricky things to keep the source MemoryBuffer alive.
- Don't use list-initialization for a std::string in WeightedFile.
Differential Revision: http://reviews.llvm.org/D20980
llvm-svn: 271953
Changes since the initial commit:
- Normalize file paths read from the file to prevent Windows path
separators from escaping parts of the path.
- Since we need to store the normalized file paths in WeightedFile,
don't do tricky things to keep the source MemoryBuffer alive.
Differential Revision: http://reviews.llvm.org/D20980
llvm-svn: 271949
This chapter discusses IR optimizations, the ORC IRTransformLayer, and the ORC
layer concept itself.
The text is still pretty rough, but I think the main ideas are there. Feedback
is very welcome, as always.
llvm-svn: 271865
and/or tests aren't working on Windows currently.
There seems to be some problem with quoting the file paths. I don't
understand the test structure here or the code well enough to try to
come up with a way to correctly handle paths with back slashes in them,
and this has caused the Windows builds to be failing for 7 hours now, so
I'm reverting the whole thing to bring them back to life. Sorry for the
disruption, but a couple of these were bug fixes anyways that can be
folded into a fresh commit.
Reverts the following patches:
r271756: Clean up the way we create the input filenames buffer (NFC)
r271748: Fix use-after-free from discarded MemoryBuffer (NFC)
r271710: Fix option description (NFC)
r271709: Add option to ingest filepaths from a file
llvm-svn: 271760
The new option makes it possible to build external projects as part of
the llvm build without copying (or symlinking) then into llvm/tool with
specifying a few additional cmake variables.
Example usage (2 additional project called foo and bar):
-DLLVM_EXTERNAL_PROJECTS="Foo;Bar"
-DLLVM_EXTERNAL_FOO_SOURCE_DIR=/src/foo
-DLLVM_EXTERNAL_BAR_SOURCE_DIR=/src/bar
Note: This is the extension of the approach we already support for
clang/lldb/poly with adding an option to specify additional supported
projects.
Differential revision: http://reviews.llvm.org/D20838
llvm-svn: 271440
Summary:
It isn't clear what is the operational meaning of loading or storing an
unsized types, since it cannot be lowered into something meaningful.
Since there does not seem to be any practical need for it either, make
such loads and stores illegal IR.
Reviewers: majnemer, chandlerc
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D20846
llvm-svn: 271402
This tidies up some code that was manually constructing RuntimeDyld::SymbolInfo
instances from JITSymbols. It will save more mess in the future when
JITSymbol::getAddress is extended to return an Expected<TargetAddress> rather
than just a TargetAddress, since we'll be able to embed the error checking in
the conversion.
llvm-svn: 271350
This patch adds an IR, assembly and bitcode representation for metadata
attachments for globals. Future patches will port existing features to use
these new attachments.
Differential Revision: http://reviews.llvm.org/D20074
llvm-svn: 271348
* Various tidy-up and streamlining of existing discussion.
* Describes findSymbol and removeModule.
Chapter 1 is now rough but essentially complete in terms of content.
Feedback, patches etc. very welcome.
llvm-svn: 271225
Summary: * docs/WritingAnLLVMBackend.rst: Makefiles are no longer used. The users should use CMakeLists.txt. In order to add the target, the TARGETS_TO_BUILD is replaced with LLVM_ALL_TARGETS.
Reviewers: gribozavr, void, beanz
Subscribers: llvm-commits
Patch By: Visoiu Mistrih Francis (thegameg)
Differential Revision: http://reviews.llvm.org/D20700
llvm-svn: 270921
The memory location that corresponds to a volatile operation is very
special. They are observed by the machine in ways which we cannot
reason about.
Differential Revision: http://reviews.llvm.org/D20555
llvm-svn: 270879
This is a work in progress - the chapter text is incomplete, though
the example code compiles and runs.
Feedback and patches are, as usual, most welcome.
llvm-svn: 270487
Summary: This needs to get in before anything is released concerning attribute. If the old name gets in the wild, then we are stuck with it forever. Putting it in its own diff should getting that part at least in fast.
Reviewers: Wallbraker, whitequark, joker.eph, echristo, rafael, jyknight
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D20417
llvm-svn: 270452
In practice only a few well known appending linkage variables work.
Currently if codegen sees an unknown appending linkage variable it will
just print it as a regular global. That is wrong as the symbol in the
produced object file has different semantics as the one provided by the
appending linkage.
This just errors early instead of producing a broken .o.
llvm-svn: 269706
This new verifier rule lets us unambigously pick a calling convention
when creating a new declaration for
`@llvm.experimental.deoptimize.<ty>`. It is also congruent with our
lowering strategy -- since all calls to `@llvm.experimental.deoptimize`
are lowered to calls to `__llvm_deoptimize`, it is reasonable to enforce
a unique calling convention.
Some of the tests that were breaking this verifier rule have had to be
split up into different .ll files.
The inliner was violating this rule as well, and has been fixed to avoid
producing invalid IR.
llvm-svn: 269261
An oddity of the .ll syntax is that the "@var = " in
@var = global i32 42
is optional. Writing just
global i32 42
is equivalent to
@0 = global i32 42
This means that there is a pretty big First set at the top level. The
current implementation maintains it manually. I was trying to refactor
it, but then started wondering why keep it a all. I personally find the
above syntax confusing. It looks like something is missing.
This patch removes the feature and simplifies the parser.
llvm-svn: 269096
Seems like my sphynx version is different than the one in the bot, as it
accepted everything locally. I think this is the right fix...
llvm-svn: 269062
HowToCrossCompile was outdated and generating too much traffic on the mailing
list with similar queries. This change helps offset most of the problems that
were reported recently including:
* Removing the -ccc-gcc-name, adding --sysroot
* Making references to Debian's multiarch for target libraries
* Expanding -DCMAKE_CXX_FLAGS for both GCC and Clang
* Some formatting and clarifications in the text
llvm-svn: 269054
This is a step towards removing the rampant undefined behaviour in
SelectionDAG, which is a part of llvm.org/PR26808.
We rename SelectionDAGISel::Select to SelectImpl and update targets to
match, and then change Select to return void and consolidate the
sketchy behaviour we're trying to get away from there.
Next, we'll update backends to implement `void Select(...)` instead of
SelectImpl and eventually drop the base Select implementation.
llvm-svn: 268693
This backend was supposed to generate C++ code which will re-construct
the LLVM IR passed as input. This seems to me to have very marginal
usefulness in the first place.
However, the code has never been updated to use IRBuilder, which makes
its current value negative -- people who look at the output may be
steered to use the *wrong* C++ APIs to construct IR.
Furthermore, it's generated code that doesn't compile since at least
2013.
Differential Revision: http://reviews.llvm.org/D19942
llvm-svn: 268631
If a guard call being lowered by LowerGuardIntrinsics has the
`!make.implicit` metadata attached, then reattach the metadata to the
branch in the resulting expanded form of the intrinsic. This allows us
to implement null checks as guards and still get the benefit of implicit
null checks.
llvm-svn: 268148
Summary:
D19403 adds a new pragma for loop distribution. This change adds
support for the corresponding metadata that the pragma is translated to
by the FE.
As part of this I had to rethink the flag -enable-loop-distribute. My
goal was to be backward compatible with the existing behavior:
A1. pass is off by default from the optimization pipeline
unless -enable-loop-distribute is specified
A2. pass is on when invoked directly from opt (e.g. for unit-testing)
The new pragma/metadata overrides these defaults so the new behavior is:
B1. A1 + enable distribution for individual loop with the pragma/metadata
B2. A2 + disable distribution for individual loop with the pragma/metadata
The default value whether the pass is on or off comes from the initiator
of the pass. From the PassManagerBuilder the default is off, from opt
it's on.
I moved -enable-loop-distribute under the pass. If the flag is
specified it overrides the default from above.
Then the pragma/metadata can further modifies this per loop.
As a side-effect, we can now also use -enable-loop-distribute=0 from opt
to emulate the default from the optimization pipeline. So to be precise
this is the new behavior:
C1. pass is off by default from the optimization pipeline
unless -enable-loop-distribute or the pragma/metadata enables it
C2. pass is on when invoked directly from opt
unless -enable-loop-distribute=0 or the pragma/metadata disables it
Reviewers: hfinkel
Subscribers: joker.eph, mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D19431
llvm-svn: 267672
Summary:
This tries to anchor down the concept of domains a bit better. I had
trouble initially relating this to anything. Also talking to David
Majnemer on IRC suggested that I wasn't the only one.
Reviewers: hfinkel
Subscribers: llvm-commits, majnemer
Differential Revision: http://reviews.llvm.org/D18799
llvm-svn: 267647
print-stack-trace.cc test failure of compiler-rt has been fixed by
r266869 (http://reviews.llvm.org/D19148), so reenable sibling call
optimization on ppc64
Reviewers: nemanjai kbarton
llvm-svn: 267527
I really thought we were doing this already, but we were not. Given this input:
void Test(int *res, int *c, int *d, int *p) {
for (int i = 0; i < 16; i++)
res[i] = (p[i] == 0) ? res[i] : res[i] + d[i];
}
we did not vectorize the loop. Even with "assume_safety" the check that we
don't if-convert conditionally-executed loads (to protect against
data-dependent deferenceability) was not elided.
One subtlety: As implemented, it will still prefer to use a masked-load
instrinsic (given target support) over the speculated load. The choice here
seems architecture specific; the best option depends on how expensive the
masked load is compared to a regular load. Ideally, using the masked load still
reduces unnecessary memory traffic, and so should be preferred. If we'd rather
do it the other way, flipping the order of the checks is easy.
The LangRef is updated to make explicit that llvm.mem.parallel_loop_access also
implies that if conversion is okay.
Differential Revision: http://reviews.llvm.org/D19512
llvm-svn: 267514
Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*. It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.
Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType. The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.
This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata. Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.
The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html
llvm-svn: 267296
This intrinsic takes two arguments, ``%ptr`` and ``%offset``. It loads
a 32-bit value from the address ``%ptr + %offset``, adds ``%ptr`` to that
value and returns it. The constant folder specifically recognizes the form of
this intrinsic and the constant initializers it may load from; if a loaded
constant initializer is known to have the form ``i32 trunc(x - %ptr)``,
the intrinsic call is folded to ``x``.
LLVM provides that the calculation of such a constant initializer will
not overflow at link time under the medium code model if ``x`` is an
``unnamed_addr`` function. However, it does not provide this guarantee for
a constant initializer folded into a function body. This intrinsic can be
used to avoid the possibility of overflows when loading from such a constant.
Differential Revision: http://reviews.llvm.org/D18367
llvm-svn: 267223
Amaury Sechet