The bitset metadata currently used in LLVM has a few problems:
1. It has the wrong name. The name "bitset" refers to an implementation
detail of one use of the metadata (i.e. its original use case, CFI).
This makes it harder to understand, as the name makes no sense in the
context of virtual call optimization.
2. It is represented using a global named metadata node, rather than
being directly associated with a global. This makes it harder to
manipulate the metadata when rebuilding global variables, summarise it
as part of ThinLTO and drop unused metadata when associated globals are
dropped. For this reason, CFI does not currently work correctly when
both CFI and vcall opt are enabled, as vcall opt needs to rebuild vtable
globals, and fails to associate metadata with the rebuilt globals. As I
understand it, the same problem could also affect ASan, which rebuilds
globals with a red zone.
This patch solves both of those problems in the following way:
1. Rename the metadata to "type metadata". This new name reflects how
the metadata is currently being used (i.e. to represent type information
for CFI and vtable opt). The new name is reflected in the name for the
associated intrinsic (llvm.type.test) and pass (LowerTypeTests).
2. Attach metadata directly to the globals that it pertains to, rather
than using the "llvm.bitsets" global metadata node as we are doing now.
This is done using the newly introduced capability to attach
metadata to global variables (r271348 and r271358).
See also: http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html
Differential Revision: http://reviews.llvm.org/D21053
llvm-svn: 273729
Summary:
We will start generating this in a future patch.
Reviewers: arsenm, kzhuravl, rafael, ruiu, tony-tye
Subscribers: arsenm, llvm-commits, kzhuravl
Differential Revision: http://reviews.llvm.org/D21482
llvm-svn: 273628
This change is motivated by an upcoming change to the metadata representation
used for CFI. The indirect function call checker needs type information for
external function declarations in order to correctly generate jump table
entries for such declarations. We currently associate such type information
with declarations using a global metadata node, but I plan [1] to move all
such metadata to global object attachments.
In bitcode, metadata attachments for function declarations appear in the
global metadata block. This seems reasonable to me because I expect metadata
attachments on declarations to be uncommon. In the long term I'd also expect
this to be the case for CFI, because we'd want to use some specialized bitcode
format for this metadata that could be read as part of the ThinLTO thin-link
phase, which would mean that it would not appear in the global metadata block.
To solve the lazy loaded metadata issue I was seeing with D20147, I use the
same bitcode representation for metadata attachments for global variables as I
do for function declarations. Since there's a use case for metadata attachments
in the global metadata block, we might as well use that representation for
global variables as well, at least until we have a mechanism for lazy loading
global variables.
In the assembly format, the metadata attachments appear after the "declare"
keyword in order to avoid a parsing ambiguity.
[1] http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html
Differential Revision: http://reviews.llvm.org/D21052
llvm-svn: 273336
Nearly all the changes to this pass have been done while maintaining and
updating other parts of LLVM. LLVM has had another pass, SROA, which
has superseded ScalarReplAggregates for quite some time.
Differential Revision: http://reviews.llvm.org/D21316
llvm-svn: 272737
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
