This change introduces a GC parseable lowering for element atomic
memcpy/memmove intrinsics. This way runtime can provide an
implementation which can take a safepoint during copy operation.
See "GC-parseable element atomic memcpy/memmove" thread on llvm-dev
for the background and details:
https://groups.google.com/g/llvm-dev/c/NnENHzmX-b8/m/3PyN8Y2pCAAJ
Differential Revision: https://reviews.llvm.org/D88861
It's currently ambiguous in IR whether the source language explicitly
did not want a stack a stack protector (in C, via function attribute
no_stack_protector) or doesn't care for any given function.
It's common for code that manipulates the stack via inline assembly or
that has to set up its own stack canary (such as the Linux kernel) would
like to avoid stack protectors in certain functions. In this case, we've
been bitten by numerous bugs where a callee with a stack protector is
inlined into an __attribute__((__no_stack_protector__)) caller, which
generally breaks the caller's assumptions about not having a stack
protector. LTO exacerbates the issue.
While developers can avoid this by putting all no_stack_protector
functions in one translation unit together and compiling those with
-fno-stack-protector, it's generally not very ergonomic or as
ergonomic as a function attribute, and still doesn't work for LTO. See also:
https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u
Typically, when inlining a callee into a caller, the caller will be
upgraded in its level of stack protection (see adjustCallerSSPLevel()).
By adding an explicit attribute in the IR when the function attribute is
used in the source language, we can now identify such cases and prevent
inlining. Block inlining when the callee and caller differ in the case that one
contains `nossp` when the other has `ssp`, `sspstrong`, or `sspreq`.
Fixes pr/47479.
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D87956
In preparation for potential future concurrency, a FunctionPass
shouldn't modify anything at the module level that other FunctionPasses
can also modify.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D89890
Recently [1], there was an upgrade to the version of buildbot being
deployed. The new setup will still work with old buildslaves but I
thought it might be a good idea to update the documentation to reflect,
that you now can use a newer buildbot version to when setting up your
worker (formely known as slave).
The upgrade from buildbot 0.8.5 to 2.8.5 went a long with a transition
to a new "worker" terminology [2] which is also reflected by this
change.
[1]: http://lists.llvm.org/pipermail/llvm-dev/2020-October/145629.html
[2]: http://docs.buildbot.net/0.9.12/manual/worker-transition.html
Reviewed By: gkistanova
Differential Revision: https://reviews.llvm.org/D89230
LLVM IR currently assumes some form of forward progress. This form is
not explicitly defined anywhere, and is the cause of miscompilations
in most languages that are not C++11 or later. This implicit forward progress
guarantee can not be opted out of on a function level nor on a loop
level. Languages such as C (C11 and later), C++ (pre-C++11), and Rust
have different forward progress requirements and this needs to be
evident in the IR.
Specifically, C11 and onwards (6.8.5, Paragraph 6) states that "An
iteration statement whose controlling expression is not a constant
expression, that performs no input/output operations, does not access
volatile objects, and performs no synchronization or atomic operations
in its body, controlling expression, or (in the case of for statement)
its expression-3, may be assumed by the implementation to terminate."
C++11 and onwards does not have this assumption, and instead assumes
that every thread must make progress as defined in [intro.progress] when
it comes to scheduling.
This was initially brought up in [0] as a bug, a solution was presented
in [1] which is the current workaround, and the predecessor to this
change was [2].
After defining a notion of forward progress for IR, there are two
options to address this:
1) Set the default to assuming Forward Progress and provide an opt-out for functions and an opt-in for loops.
2) Set the default to not assuming Forward Progress and provide an opt-in for functions, and an opt-in for loops.
Option 2) has been selected because only C++11 and onwards have a
forward progress requirement and it makes sense for them to opt-into it
via the defined `mustprogress` function attribute. The `mustprogress`
function attribute indicates that the function is required to make
forward progress as defined. This is sharply in contrast to the status
quo where this is implicitly assumed. In addition, `willreturn` implies `mustprogress`.
The background for why this definition was chosen is in [3] and for why
the option was chosen is in [4] and the corresponding thread(s). The implementation is in D85393, the
clang patch is in D86841, the LoopDeletion patch is in D86844, the
Inliner patches are in D87180 and D87262, and there will be more
incoming.
[0] https://bugs.llvm.org/show_bug.cgi?id=965#c25
[1] https://lists.llvm.org/pipermail/llvm-dev/2017-October/118558.html
[2] https://reviews.llvm.org/D65718
[3] https://lists.llvm.org/pipermail/llvm-dev/2020-September/144919.html
[4] https://lists.llvm.org/pipermail/llvm-dev/2020-September/145023.html
Reviewed By: jdoerfert, efriedma, nikic
Differential Revision: https://reviews.llvm.org/D86233
The langref description for llvm.test.set.loop.iterations.* were
missing the i1 return type.
Differential Revision: https://reviews.llvm.org/D89564
Patch by: Janek van Oirschot
This patch updates the Kaleidoscope and BuildingAJIT tutorial series (chapter
1-4) to OrcV2. Chapter 5 of the BuildingAJIT series is removed -- it will be
re-instated once we have in-tree support for out-of-process JITing.
This patch only updates the tutorial code, not the text. Patches welcome for
that, otherwise I will try to update it in a few weeks.
This patch adds metadata !noundef and makes load instructions can optionally have it.
A load with !noundef always return a well-defined value (has no undef bit or isn't poison).
If the loaded value isn't well defined, the behavior is undefined.
This metadata can be used to encode the assumption from C/C++ that certain reads of variables should have well-defined values.
It is helpful for optimizing freeze instructions away, because freeze can be removed when its operand has well-defined value, and showing that a load from arbitrary location is well-defined is usually hard otherwise.
The same information can be encoded with llvm.assume with operand bundle; using metadata is chosen because I wasn't sure whether code motion can be freely done when llvm.assume is inserted from clang instead.
The existing codebase already is stripping unknown metadata when doing code motion, so using metadata is UB-safe as well.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D89050
LLVM rejects DWARF operator DW_OP_over. This DWARF operator is needed
for Flang to support assumed rank array.
Summary:
Currently LLVM rejects DWARF operator DW_OP_over. Below error is
produced when llvm finds this operator.
[..]
invalid expression
!DIExpression(151, 20, 16, 48, 30, 35, 80, 34, 6)
warning: ignoring invalid debug info in over.ll
[..]
There were some parts missing in support of this operator, which are
now completed.
Testing
-added a unit testcase
-check-debuginfo
-check-llvm
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D89208
The prefix given to --prefix will be added to GNU absolute paths when
used with --source option (source interleaved with the disassembly).
This matches GNU's objdump behavior.
GNU and C++17 rules for absolute paths are different.
Differential Revision: https://reviews.llvm.org/D85024
Fixes PR46368.
Differential Revision: https://reviews.llvm.org/D85024
This reverts commit eb9f7c28e5fe6d75fed3587023e17f2997c8024b.
Previously this was incorrectly handling linking of the contained
type, so this merges the fixes from D88973.
Add some minimal documentation for DILabel, originally introduced in
D45024. Update the name and semantics of the `variables:` field in the
documentation for `DISubprogram`; the field is now called
`retainedNodes:` and is a heterogeneous list of `DILocalVariable` and
`DILabel`.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D89082
Following up on the discussion within the group during the roundtable at
the 2020 LLVM Developers Meeting, this commit adds to the security docs:
* How long we expect acknowledging security reports will take
* The escalation path the reporter can follow if they get no response
A temporary line inviting reporters to directly follow the escalation
path while the mailing list is being setup is also added.
Differential Revision: https://reviews.llvm.org/D89068
Resigning from security group as Azul representative as I have left Azul. Previously communicated via email with security group.
Differential Revision: https://reviews.llvm.org/D88933
At AMD, in an internal audit of our code, we found some corner cases
where we were not quite differentiating targets enough for some old
hardware. This commit is part of fixing that by adding three new
targets:
* The "Oland" and "Hainan" variants of gfx601 are now split out into
gfx602. LLPC (in the GPUOpen driver) and other front-ends could use
that to avoid using the shaderZExport workaround on gfx602.
* One variant of gfx703 is now split out into gfx705. LLPC and other
front-ends could use that to avoid using the
shaderSpiCsRegAllocFragmentation workaround on gfx705.
* The "TongaPro" variant of gfx802 is now split out into gfx805.
TongaPro has a faster 64-bit shift than its former friends in gfx802,
and a subtarget feature could be set up for that to take advantage of
it. This commit does not make that change; it just adds the target.
V2: Add clang changes. Put TargetParser list in order.
V3: AMDGCNGPUs table in TargetParser.cpp needs to be in GPUKind order,
so fix the GPUKind order.
Differential Revision: https://reviews.llvm.org/D88916
Change-Id: Ia901a7157eb2f73ccd9f25dbacec38427312377d
This patch adds support for DWARF attribute DW_AT_rank.
Summary:
Fortran assumed rank arrays have dynamic rank. DWARF attribute
DW_AT_rank is needed to support that.
Testing:
unit test cases added (hand-written)
check llvm
check debug-info
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D89141
This patch introduce files that just enough for lib/Target/CSKY to compile.
Notably a basic CSKYTargetMachine and CSKYTargetInfo.
Differential Revision: https://reviews.llvm.org/D88466
This patch lets the bb_addr_map (renamed to __llvm_bb_addr_map) section use a special section type (SHT_LLVM_BB_ADDR_MAP) instead of SHT_PROGBITS. This would help parsers, dumpers and other tools to use the sh_type ELF field to identify this section rather than relying on string comparison on the section name.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D88199
Have the build work out of the box by forcing an LLD build.
That way, we don't require an external LTO-aware linker,
as we build one.
Also remove reference to the seemingly dead builder.
Differential Revision: https://reviews.llvm.org/D88990
The section on SmallVector has a note about preferring SmallVectorImpl
for APIs but doesn't mention ArrayRef. Although ArrayRef is discussed
elsewhere, let's re-emphasize here.
Differential Revision: https://reviews.llvm.org/D49881
Motivated by D88183, this seeks to clarify the current loop nomenclature with added illustrations, examples for possibly unexpected situations (infinite loops not part of the "parent" loop, logical loops sharing the same header, ...), and clarification on what other sources may consider a loop. The current document also has multiple errors that are fixed here.
Some selected errors:
* Loops a defined as strongly-connected components. A component a partition of all nodes, i.e. a subloop can never be a component. That is, the document as it currently is only covers top-level loops, even it also uses the term SCC for subloops.
* "a block can be the header of two separate loops at the same time" (it is considered a single loop by LoopInfo)
* "execute before some interesting event happens" (some interesting event is not well-defined)
Reviewed By: baziotis, Whitney
Differential Revision: https://reviews.llvm.org/D88408
This reverts commit 55c4ff91bd820d72014f63dcf7f3d5a0d3397986.
Issues were introduced as discussed in https://reviews.llvm.org/D88241
where this change made previous bugs in the linker and BitCodeWriter
visible.
