- Rename DW_OP_LLVM_offset_constu to DW_OP_LLVM_offset_uconst to
matches DW_OP_plus_uconst.
- Correct DW_OP_LLVM_call_ref to be DW_OP_call_ref.
- Move proposed changes to a separate section to clarify that the
introduction section is not part of the changes.
- Fix formatting typos and add missing reference.
- Clarify why DW_OP_LLVM_offset et al do not wrap on overflow.
- Correct syntax of augmentation string.
Differential Revision: https://reviews.llvm.org/D70523
Add llvm.call.preallocated.{setup,arg} instrinsics.
Add "preallocated" operand bundle which takes a token produced by llvm.call.preallocated.setup.
Add "preallocated" parameter attribute, which is like byval but without the copy.
Verifier changes for these IR constructs.
See https://github.com/rnk/llvm-project/blob/call-setup-docs/llvm/docs/CallSetup.md
Subscribers: hiraditya, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74651
This change helps improve `dsymutil` documentation.
- Add missing options
- Re-arrange options in alphabetical order
- Wrap inline options in double-back-quote
- `-v` is for `--version` not `--verbose`
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D78479
Summary:
This change mentions CDE assembly in the LLVM release notes and CDE
intrinsics in both Clang and LLVM release notes.
Reviewers: kristof.beyls, simon_tatham
Reviewed By: kristof.beyls
Subscribers: danielkiss, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D78481
Summary:
This patch add the dataflow option to LLVM_USE_SANITIZER and documents
it.
Tested via check-cxx (wip to fix the errors).
Reviewers: morehouse, #libc!
Subscribers: mgorny, cfe-commits, libcxx-commits
Tags: #clang, #libc
Differential Revision: https://reviews.llvm.org/D78390
Summary:
This matches the behavior of GNU addr2line. We previously treated
hexadecimal addresses as binary if they started with 0b, otherwise as
octal if they started with 0, otherwise as decimal.
This only affects llvm-addr2line; the behavior of llvm-symbolize is
unaffected.
Reviewers: ikudrin, rupprecht, jhenderson
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73306
This moves v32i16/v64i8 to a model consistent with how we
treat integer types with avx1.
This does change the ABI for types vXi16/vXi8 vectors larger than
512 bits to pass in multiple zmms instead of multiple ymms. We'd
already hacked some code to make v64i8/v32i16 pass in zmm.
Cost model is still a bit of a mess. In some place I tried to
match existing behavior. But really we need to account for
splitting and concating costs. Cost model for shuffles is
especially pessimistic.
Differential Revision: https://reviews.llvm.org/D76212
- Unify the sections on DWARF expression and location lists.
- Allow a location description to have one or more single location
descriptions.
- Define context of DWARF expression that includes an initial
stack. Allow initial stack to be used when evaluating location list
expression with overlapping PC ranges.
- Reorganize the DWARF proposal in AMDGPUUsage so suitable for
submission to the DWARF site.
- Replace CFI instruction DW_CFA_LLVM_def_cfa_aspace with
DW_CFA_def_aspace_cfa and DW_CFA_def_aspace_cfa_sf. This is to avoid
the problem that DW_CFA_def_cfa and DW_CFA_def_cfa_sf cannot use a
register that is not the size of an address in the CFA address
space.
- Clarify DWARF address class and DWARF address space. Define language
values for DWARF address classes and specify how they are used by
some common source languages.
- Define rules for accessing registers and derefencing memory when the
type size and register size or byte size operand do not match.
- Numerous cleanups for consistency.
Differential Revision: https://reviews.llvm.org/D70523
This patch extracts the RTTI part of llvm::ErrorInfo into its own class
(RTTIExtends) so that it can be used in other non-error hierarchies, and makes
it compatible with the existing LLVM RTTI function templates (isa, cast,
dyn_cast, dyn_cast_or_null) by adding the classof method.
Differential Revision: https://reviews.llvm.org/D39111
LanguageExtensions.rst:2191: WARNING: Title underline too short.
llvm-symbolizer.rst:157: Error in "code-block" directive: maximum 1 argument(s) allowed, 30 supplied.
This patch adds missing description of enable-no-signed-zeros-fp-math
and enable-no-trapping-fp-math options of llc.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D77713
Now compiler defines 5 sets of constants to represent rounding mode.
These are:
1. `llvm::APFloatBase::roundingMode`. It specifies all 5 rounding modes
defined by IEEE-754 and is used in `APFloat` implementation.
2. `clang::LangOptions::FPRoundingModeKind`. It specifies 4 of 5 IEEE-754
rounding modes and a special value for dynamic rounding mode. It is used
in clang frontend.
3. `llvm::fp::RoundingMode`. Defines the same values as
`clang::LangOptions::FPRoundingModeKind` but in different order. It is
used to specify rounding mode in in IR and functions that operate IR.
4. Rounding mode representation used by `FLT_ROUNDS` (C11, 5.2.4.2.2p7).
Besides constants for rounding mode it also uses a special value to
indicate error. It is convenient to use in intrinsic functions, as it
represents platform-independent representation for rounding mode. In this
role it is used in some pending patches.
5. Values like `FE_DOWNWARD` and other, which specify rounding mode in
library calls `fesetround` and `fegetround`. Often they represent bits
of some control register, so they are target-dependent. The same names
(not values) and a special name `FE_DYNAMIC` are used in
`#pragma STDC FENV_ROUND`.
The first 4 sets of constants are target independent and could have the
same numerical representation. It would simplify conversion between the
representations. Also now `clang::LangOptions::FPRoundingModeKind` and
`llvm::fp::RoundingMode` do not contain the value for IEEE-754 rounding
direction `roundTiesToAway`, although it is supported natively on
some targets.
This change defines all the rounding mode type via one `llvm::RoundingMode`,
which also contains rounding mode for IEEE rounding direction `roundTiesToAway`.
Differential Revision: https://reviews.llvm.org/D77379
D72467 updated the shufflevector instruction to include a constant mask
rather than a mask operand. The LangRef text was vague enough to still
make sense, but it is better to update here too, so there's no confusion
about valid mask values. The text here is adapted from the documentation
code comments for "class ShuffleVectorInst".
Differential Revision: https://reviews.llvm.org/D77396
The LitConfig is shared across the whole test suite. However, since
enabling recursive expansion can be a breaking change for some test
suites, it's important to confine the setting to test suites that
enable it explicitly.
Note that other issues were raised with the way recursiveExpansionLimit
operates. However, this commit simply moves the setting to the right
place -- the mechanism by which it works can be improved independently.
Differential Revision: https://reviews.llvm.org/D77415
SUMMARY:
For the llvm-objdump -D, the symbol name is used as a label in the disassembly for the specific address (when a symbol address is equal to the virtual address in the dump).
In XCOFF, multiple symbols may have the same name, being differentiated by their storage mapping class. It is helpful to print the QualName and not just the name when forming the output label for a csect symbol. The symbol index further removes any ambiguity caused by duplicate names.
To maintain compatibility with the binutils objdump, the XCOFF-specific --symbol-description option is added to enable the enhanced format.
Reviewers: hubert.reinterpretcast, James Henderson, Jason Liu ,daltenty
Subscribers: wuzish, nemanjai, hiraditya
Differential Revision: https://reviews.llvm.org/D72973
Summary:
This patch is to teach `llvm-objdump` dump dynamic symbols (`-T` and `--dynamic-syms`). Currently, this patch is not fully compatible with `gnu-objdump`, but I would like to continue working on this in next few patches. It has two issues.
1. Some symbols shouldn't be marked as global(g). (`-t/--syms` has same issue as well) (Fixed by D75659)
2. `gnu-objdump` can dump version information and *dynamically* insert before symbol name field.
`objdump -T a.out` gives:
```
DYNAMIC SYMBOL TABLE:
0000000000000000 w D *UND* 0000000000000000 _ITM_deregisterTMCloneTable
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 printf
0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 __libc_start_main
0000000000000000 w D *UND* 0000000000000000 __gmon_start__
0000000000000000 w D *UND* 0000000000000000 _ITM_registerTMCloneTable
0000000000000000 w DF *UND* 0000000000000000 GLIBC_2.2.5 __cxa_finalize
```
`llvm-objdump -T a.out` gives:
```
DYNAMIC SYMBOL TABLE:
0000000000000000 w D *UND* 0000000000000000 _ITM_deregisterTMCloneTable
0000000000000000 g DF *UND* 0000000000000000 printf
0000000000000000 g DF *UND* 0000000000000000 __libc_start_main
0000000000000000 w D *UND* 0000000000000000 __gmon_start__
0000000000000000 w D *UND* 0000000000000000 _ITM_registerTMCloneTable
0000000000000000 w DF *UND* 0000000000000000 __cxa_finalize
```
Reviewers: jhenderson, grimar, MaskRay, espindola
Reviewed By: jhenderson, grimar
Subscribers: emaste, rupprecht, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75756
Summary: I think it would be better to require the alignment to be >= 1. It is currently confusing to allow both values.
Reviewers: courbet
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77372
This will likely introduce catastrophic performance regressions on
older subtargets, but should be correct. A follow up change will
remove the old fp32-denormals subtarget features, and switch to using
the new denormal-fp-math/denormal-fp-math-f32 attributes. Frontends
should be making sure to add the denormal-fp-math-f32 attribute when
appropriate to avoid performance regressions.
Uploading output from `git format-patch` fails when version has
more than 2 dots, e.g. git version 2.24.1.windows.2 which is
currently recommended by e.g. GitExtensions or 2.24.1.rc on Linux.
Differential Revision: https://reviews.llvm.org/D72374
Add an option to llvm-dwarfdump to calculate the bytes within
the debug sections. Dump this numbers when using --statistics
option as well.
This is an initial patch (e.g. we should support other units,
since we only support 'bytes' now).
Differential Revision: https://reviews.llvm.org/D74205
Summary:
As noted in documentation, different repetition modes have different trade-offs:
> .. option:: -repetition-mode=[duplicate|loop]
>
> Specify the repetition mode. `duplicate` will create a large, straight line
> basic block with `num-repetitions` copies of the snippet. `loop` will wrap
> the snippet in a loop which will be run `num-repetitions` times. The `loop`
> mode tends to better hide the effects of the CPU frontend on architectures
> that cache decoded instructions, but consumes a register for counting
> iterations.
Indeed. Example:
>>! In D74156#1873657, @lebedev.ri wrote:
> At least for `CMOV`, i'm seeing wildly different results
> | | Latency | RThroughput |
> | duplicate | 1 | 0.8 |
> | loop | 2 | 0.6 |
> where latency=1 seems correct, and i'd expect the througput to be close to 1/2 (since there are two execution units).
This isn't great for analysis, at least for schedule model development.
As discussed in excruciating detail in
>>! In D74156#1924514, @gchatelet wrote:
>>>! In D74156#1920632, @lebedev.ri wrote:
>> ... did that explanation of the question i'm having made any sense?
>
> Thx for digging in the conversation !
> Ok it makes more sense now.
>
> I discussed it a bit with @courbet:
> - We want the analysis tool to stay simple so we'd rather not make it knowledgeable of the repetition mode.
> - We'd like to still be able to select either repetition mode to dig into special cases
>
> So we could add a third `min` repetition mode that would run both and take the minimum. It could be the default option.
> Would you have some time to look what it would take to add this third mode?
there appears to be an agreement that it is indeed sub-par,
and that we should provide an optional, measurement (not analysis!) -time
way to rectify the situation.
However, the solutions isn't entirely straight-forward.
We can just add an actual 'multiplexer' `MinSnippetRepetitor`, because
if we just concatenate snippets produced by `DuplicateSnippetRepetitor`
and `LoopSnippetRepetitor` and run+measure that, the measurement will
naturally be different from what we'd get by running+measuring
them separately and taking the min.
([[ https://www.wolframalpha.com/input/?i=%28x%2By%29%2F2+%21%3D+min%28x%2C+y%29 | `time(D+L)/2 != min(time(D), time(L))` ]])
Also, it seems best to me to have a single snippet instead of generating
a snippet per repetition mode, since the only difference here is that the
loop repetition mode reserves one register for loop counter.
As far as i can tell, we can either teach `BenchmarkRunner::runConfiguration()`
to produce a single report given multiple repetitors (as in the patch),
or do that one layer higher - don't modify `BenchmarkRunner::runConfiguration()`,
produce multiple reports, don't actually print each one, but aggregate them somehow
and only print the final one.
Initially i've gone ahead with the latter approach, but it didn't look like a natural fit;
the former (as in the diff) does seem like a better fit to me.
There's also a question of the test coverage. It sure currently does work here:
```
$ ./bin/llvm-exegesis --opcode-name=CMOV64rr --mode=inverse_throughput --repetition-mode=duplicate
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-8fb949.o
---
mode: inverse_throughput
key:
instructions:
- 'CMOV64rr RAX RAX R11 i_0x0'
- 'CMOV64rr RBP RBP R15 i_0x0'
- 'CMOV64rr RBX RBX RBX i_0x0'
- 'CMOV64rr RCX RCX RBX i_0x0'
- 'CMOV64rr RDI RDI R10 i_0x0'
- 'CMOV64rr RDX RDX RAX i_0x0'
- 'CMOV64rr RSI RSI RAX i_0x0'
- 'CMOV64rr R8 R8 R8 i_0x0'
- 'CMOV64rr R9 R9 RDX i_0x0'
- 'CMOV64rr R10 R10 RBX i_0x0'
- 'CMOV64rr R11 R11 R14 i_0x0'
- 'CMOV64rr R12 R12 R9 i_0x0'
- 'CMOV64rr R13 R13 R12 i_0x0'
- 'CMOV64rr R14 R14 R15 i_0x0'
- 'CMOV64rr R15 R15 R13 i_0x0'
config: ''
register_initial_values:
- 'RAX=0x0'
- 'R11=0x0'
- 'EFLAGS=0x0'
- 'RBP=0x0'
- 'R15=0x0'
- 'RBX=0x0'
- 'RCX=0x0'
- 'RDI=0x0'
- 'R10=0x0'
- 'RDX=0x0'
- 'RSI=0x0'
- 'R8=0x0'
- 'R9=0x0'
- 'R14=0x0'
- 'R12=0x0'
- 'R13=0x0'
cpu_name: bdver2
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
- { key: inverse_throughput, value: 0.819, per_snippet_value: 12.285 }
error: ''
info: instruction has tied variables, using static renaming.
assembled_snippet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
...
$ ./bin/llvm-exegesis --opcode-name=CMOV64rr --mode=inverse_throughput --repetition-mode=loop
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-051eb3.o
---
mode: inverse_throughput
key:
instructions:
- 'CMOV64rr RAX RAX R11 i_0x0'
- 'CMOV64rr RBP RBP RSI i_0x0'
- 'CMOV64rr RBX RBX R9 i_0x0'
- 'CMOV64rr RCX RCX RSI i_0x0'
- 'CMOV64rr RDI RDI RBP i_0x0'
- 'CMOV64rr RDX RDX R9 i_0x0'
- 'CMOV64rr RSI RSI RDI i_0x0'
- 'CMOV64rr R9 R9 R12 i_0x0'
- 'CMOV64rr R10 R10 R11 i_0x0'
- 'CMOV64rr R11 R11 R9 i_0x0'
- 'CMOV64rr R12 R12 RBP i_0x0'
- 'CMOV64rr R13 R13 RSI i_0x0'
- 'CMOV64rr R14 R14 R14 i_0x0'
- 'CMOV64rr R15 R15 R10 i_0x0'
config: ''
register_initial_values:
- 'RAX=0x0'
- 'R11=0x0'
- 'EFLAGS=0x0'
- 'RBP=0x0'
- 'RSI=0x0'
- 'RBX=0x0'
- 'R9=0x0'
- 'RCX=0x0'
- 'RDI=0x0'
- 'RDX=0x0'
- 'R12=0x0'
- 'R10=0x0'
- 'R13=0x0'
- 'R14=0x0'
- 'R15=0x0'
cpu_name: bdver2
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
- { key: inverse_throughput, value: 0.6083, per_snippet_value: 8.5162 }
error: ''
info: instruction has tied variables, using static renaming.
assembled_snippet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
...
$ ./bin/llvm-exegesis --opcode-name=CMOV64rr --mode=inverse_throughput --repetition-mode=min
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-c7a47d.o
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-2581f1.o
---
mode: inverse_throughput
key:
instructions:
- 'CMOV64rr RAX RAX R11 i_0x0'
- 'CMOV64rr RBP RBP R10 i_0x0'
- 'CMOV64rr RBX RBX R10 i_0x0'
- 'CMOV64rr RCX RCX RDX i_0x0'
- 'CMOV64rr RDI RDI RAX i_0x0'
- 'CMOV64rr RDX RDX R9 i_0x0'
- 'CMOV64rr RSI RSI RAX i_0x0'
- 'CMOV64rr R9 R9 RBX i_0x0'
- 'CMOV64rr R10 R10 R12 i_0x0'
- 'CMOV64rr R11 R11 RDI i_0x0'
- 'CMOV64rr R12 R12 RDI i_0x0'
- 'CMOV64rr R13 R13 RDI i_0x0'
- 'CMOV64rr R14 R14 R9 i_0x0'
- 'CMOV64rr R15 R15 RBP i_0x0'
config: ''
register_initial_values:
- 'RAX=0x0'
- 'R11=0x0'
- 'EFLAGS=0x0'
- 'RBP=0x0'
- 'R10=0x0'
- 'RBX=0x0'
- 'RCX=0x0'
- 'RDX=0x0'
- 'RDI=0x0'
- 'R9=0x0'
- 'RSI=0x0'
- 'R12=0x0'
- 'R13=0x0'
- 'R14=0x0'
- 'R15=0x0'
cpu_name: bdver2
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
- { key: inverse_throughput, value: 0.6073, per_snippet_value: 8.5022 }
error: ''
info: instruction has tied variables, using static renaming.
assembled_snippet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
...
```
but i open to suggestions as to how test that.
I also have gone with the suggestion to default to this new mode.
This was irking me for some time, so i'm happy to finally see progress here.
Looking forward to feedback.
Reviewers: courbet, gchatelet
Reviewed By: courbet, gchatelet
Subscribers: mstojanovic, RKSimon, llvm-commits, courbet, gchatelet
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76921
The requirement for deopt parameter to be in gc parameter if it can
be modified by GC is very strong and difficult to follow.
The key example of why this can't work:
%p1 = bitcast i8* %p to i8*
statepoint [gc = (%p1)], [deopt = (%p1)]
The optimizer is allowed to replace either use (or both) of %p1 with %p.
If it updates only one of the two (entirely legal), the two sets do not overlap.
So this change removes the strong wording.
Reviewers: reames, dantrushin
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D77122
We already mention that `noalias` is modeled after the C99 `restrict`
qualifier but we did omit one important requirement in the description.
For the restrict guarantees the object affected has to be modified
during the execution of the function, in any way (see 6.7.3.1.4 in [0]).
There are two reasons we want this restriction as well:
1) To match the `restrict` semantics when we lower it to `noalias`.
2) To allow the reasoning that the object pointed to by a `noalias`
pointer is not modified through means not derived from this
pointer. Hence, following the uses of that pointer is sufficient
to determine potential modifications.
The discussion on this came up as part of D73428. In that patch the
Attributor is taught to derive `noalias` for call site arguments based
on alias queries against objects that are accessed in the callee. This
is possible even if the pointer passed at the call site was "not-`noalias`".
To simplify the logic there *and* to allow the use of `noalias` as
described in 2) above, it is beneficial to follow the C `restrict`
semantics in cases where there might be "read-read-aliases". Note that
AliasAnalysis* queries for read only objects already result in
`NoAlias` even if the pointers might "alias".
* From this point of view our Alias Analysis is basically a Dependence
Analysis.
[0] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D74935
Summary:
This patch clarifies the semantics of branching on undef value.
Defining `br undef` as undefined behavior explains optimizations that use branch conditions, such as CVP (D76931) and GVN (propagateEquality).
For `switch cond`, it is defined to raise UB if cond is an expression containing undef && cond is not frozen &&
it may yield different values.
This allows that at the destination block the branch condition can be assumed to be frozen already (otherwise UB was already triggered).
This condition is slightly stricter than MemorySanitizer, which allows undef-y condition if it always leads to the same destination,
but it does not break MemorySanitizer because we are giving stricter constraint.
Reviewers: efriedma, fhahn, nikic, spatel, jdoerfert, nlopes
Reviewed By: nlopes
Subscribers: regehr, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76973
I added a list of options to configure should someone have issues with
long build time or running out of memory. This was added under common
problems in the getting started section of the documentation.
Reviewed By: Meinersbur, dim, e-leclercq
Differential Revision: https://reviews.llvm.org/D75425
This allows defining substitutions in terms of other substitutions. For
example, a %build substitution could be defined in terms of a %cxx
substitution as '%cxx %s -o %t.exe' and the script would be properly
expanded.
Differential Revision: https://reviews.llvm.org/D76178
James Henderson