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[MLIR][Bufferization] BufferResultsToOutParams: Add an option to eliminate AllocOp and Copy #1

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@Menooker Menooker commented Apr 18, 2024

Add an option elim-alloc-copy to remove the unnecessary memref.alloc and memref.copy after this pass, when the memref in ReturnOp is allocated by memref.alloc. Instead, it replaces the uses of the allocated memref with the memref in the out argument.
By default, BufferResultsToOutParams will result in a memcpy operation to copy the originally returned memref to the output argument memref. This is inefficient when the source of memcpy (the returned memref in the original ReturnOp) is from a local AllocOp. The pass can use the output argument memref to replace the locally allocated memref for better performance. elim-alloc-copy avoids dynamic allocation and memory movement.
This option will be critical for performance-sensivtive applications, which require BufferResultsToOutParams pass for a caller-owned output buffer ABI.

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LGTM.


/// If true, the pass eliminates the memref.alloc and memcpy if the returned
/// memref is allocated in the current function.
bool eliminateAllocCopy = false;
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Maybe eliminateResultCopy is more appropriate?

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It eliminates the allocation as well. :)

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The allocation is eliminated because it's dead code. The key is eliminate result copy. Also there's another allocation in the caller, eliminateAllocCopy is a bit confusing.

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eliminate usually uses for removing something from existing IR. But result copy doesn't exist before this pass, the actual behaviour of this option is to prevent generating extra copy. Thus suggest to rename as avoidResultCopy.

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Besides avoid copying, it also replaces the uses of the allocated memref with the memref in args. avoidResultCopy may surprise the user that it also replaces the memref and removes the AllocOp.

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replace the allocated memref by the memref in arg list is quite straight-forward from the pass name itself, if we have to emphasize removing the alloc and extra copy, how about avoidBufferResultAllocAndCopy ?

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Skipping dynamic shape is due to the original pass doesn't well support this scenario, right?
BTW, the original pass always requires the the caller to allocate the buffer for the result, it might be a bit confusing that we're running with "buffer-results-to-out-params" pass but with "hoist-static-allocs=0".

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Menooker commented Apr 28, 2024

Skipping dynamic shape is due to the original pass doesn't well support this scenario, right? BTW, the original pass always requires the the caller to allocate the buffer for the result, it might be a bit confusing that we're running with "buffer-results-to-out-params" pass but with "hoist-static-allocs=0".

Shall we discuss on the public PR? llvm#90011

BTW, The original pass partially support dynamic shape.

@Menooker Menooker force-pushed the fix_buffer_results_to_arg branch 2 times, most recently from 9170bed to 5a15f77 Compare April 29, 2024 02:45
Menooker pushed a commit that referenced this pull request Apr 29, 2024
Builder alerted me to the failing test, attempt #1 in the blind.
thetruestblue and others added 24 commits May 3, 2024 06:47
…_64 for now (llvm#90750)

Disabling this test on all x86_64 to unblock CI.

rdar://125052424
These two are, from a semantic checking perspective, identical to
first-private/private/etc, other than appertainment. This patch
implements both.
The support for interleaved accesses for scalable vector with a factor
of 2 is enabled in vectorizer. Therefore, the patch removed the
restriction for scalable vector with a factor of 2.
Like present, no_create, and first_private, copy is a clause that takes
just a var-list, and follows the same rules as the others.

The one unique part of this clause is that it ALSO supports two
deprecated/backwards-compatibility spellings, so this patch adds them
and implements them.
…#89848)

Make BasicTTIImplBase's `isTypeLegal` check handle unknown types.
Current behavior is aborting.

Motivated by a use case in SimplifyCFG, where `isTypeLegal` is called on
a struct type and dies, when it could be treated as illegal and skipped.
In general it could make sense for unknown types to be allowed, and by
default just considered not legal, but the behavior can of course be
overriden.
…vm#90915)

Followup to llvm#90759.

Instead of just returning null when the caller scope is not
translatable, "jump over" the current caller scope and use the outer
scope as the caller if that is available. This means that in an inlined
call stack if there are frames without debug scope, those frames are
skipped to preserve what is available. In the original example where
```
func A {
  foo loc(fused<#A>["a":1:1])
}
func B {
  call @A loc("b":1:1)
}
func C {
  call @b loc(fused<#C>["c":1:1])
}
```
is inlined into
```
func C {
  foo loc(callsite(
            callsite(fused<#A>["a":1:1] at loc("b":1:1))
           at
            fused<#C>["c":1:1]))
}
```
The translated result would be `!1`:
```
!0 = !DILocation(line: 1, column: 1, scope: !C)
!1 = !DILocation(line: 1, column: 1, scope: !A, inlinedAt: !0)
```

This has a neat benefit in maintaining callsite associativity: No matter
if we have `callsite(callsite(A at B) at C)` or `callsite(A at
callsite(B at C))`, the translation now is the same. The previous
solution did not provide this guarantee, which meant the callsite
construction would somehow impact this translation.
After a48ebb8, the function is no
longer used. Remove it.
…ruct

Like 'copy', these also have alternate names, so this implements that as
well.  Additionally, these have an optional tag of either 'readonly' or
'zero' depending on the clause.

Otherwise, this is a pretty rote implementation of the clause, as there
aren't any special rules for it.
Summary:
'test_exit_status_message_sigterm' is failing due to 'psutil' dependency
introduced in PR llvm#89405. This fix removes 'deque' dependency and checks
if 'psutil' can be imported before running the test. If 'psutil' cannot
be imported, it emits a warning and skips the test.

Test Plan:
./bin/llvm-lit -sv
/path-to-llvm-project/lldb/test/API/tools/lldb-dap/console/TestDAP_console.py
--filter=tools/lldb-dap/console/TestDAP_console.py

Reviewers:
@jeffreytan81,@clayborg,@kusmour, @JDevlieghere,@walter-erquinigo

Subscribers:

Tasks:
lldb-dap

Tags:
The vector crypto instructions may have different scheduling behavior
compared to VALU operations. Instead of using scheduling resources that
describe VALU operations, we give these instructions their own
scheduling resources. This is similar to what we did for Zb* instructions.

The sifive-p670 has vector crypto, so we model behavior for these instructions
in the P600SchedModel. The numbers are based off of measurements collected
internally. These numbers are a bit old and new measurements show that they may
not be fully accurate. It is likely that we will refine these numbers in a
follow up patch(s) based on new measurements.

This PR is stacked on llvm#89256.
The m68k backend will always emit external calls (including libcalls)
with
PC-relative PLT relocations, even when in non-pic mode or -fno-plt is
used.

This is unexpected, as other function calls are emitted with absolute
addressing, and a static code modes suggests that there is no PLT. It
also
leads to a miscompilation where the call instruction emitted expects an
immediate address, while the relocation emitted for that instruction is
PC-relative.

This miscompilation can even be seen in the default C function in
godbolt:
https://godbolt.org/z/zEoazovzo

Fix the issue by classifying external function references based upon the
pic
mode. This triggers a change in the static code model, making it more in
line
with the expected behaviour and allowing use of this backend in more
bare-metal
situations where a PLT does not exist.

The change avoids the issue where we emit a PLT32 relocation for an
absolute
call, and makes libcalls and other external calls use absolute
addressing modes
when a static code model is desired.

Further work should be done in instruction lowering and validation to
ensure
that miscompilations of the same type don't occur.
This reverts commit 02660e2.

The tests do not pass on AIX, the buildkite precommit CI fails on these
tests. For example, https://buildkite.com/llvm-project/libcxx-ci/builds/35184
This attribute is used in the headers. Not using this in the modules has
led to several issues. Add them to the modules to avoid these errors in
other placed.
Enables vectorization of unpack op in the case of unknown vector size.
The vector sizes are determined by the result's shape.
…m tweak (llvm#88737)

Clangd already implements some utility functions for converting between
`SourceLocation`s, `Position`s and `Offset`s into a buffer.
We have 3 different enums all expressing severity (info, warning,
error). Remove all uses with a new Severity enum in lldb-enumerations.h.
…arseNormalizedArchString (llvm#90895)

If 'z' is given as the complete extension name or with a digit after it,
it will crash in the extension map compare function. Check for these
cases and give an error.
ChuanqiXu9 and others added 14 commits May 7, 2024 11:41
into the current module

Following of llvm#86912. After
llvm#86912, with reduced BMI, the
BMI can keep unchange if the dependent modules only changes the
implementation (without introduing new decls). However, this is not
strictly correct.

For example:

```
// a.cppm
export module a;
export inline int a() { ... }

// b.cppm
export module b;
import a;
export inline int b() { return a(); }
```

Since both `a()` and `b()` are inline, we need to make sure the BMI of
`b.pcm` will change after the implementation of `a()` changes.

We can't get that naturally since we won't record the body of `a()`
during the writing process. We can't reuse ODRHash here since ODRHash
won't calculate the called function recursively. So ODRHash will be
problematic if `a()` calls other inline functions.

Probably we can solve this by a new hash mechanism. But the safety and
efficiency may a problem too. Here we just combine the hash value of the
used modules conservatively.
… helper function (llvm#81024)

* This way the helper function could be re-used by
indirect-call-promotion pass to find out the vtable for an indirect call
and extract the value profiles if any.
* The parent patch is llvm#80762
…7ff9

The test fails after dfa7ff9. I didn't find this locally due to
cache.
Demonstrate that this isn't yet working right.
... even if the storage types are different.
…f.forall (llvm#90189)

-- This commit adds a canonicalization pattern to fold away iter args of
scf.forall if :-
   a. The corresponding tied result has no use.
   b. It is not being modified within the loop.

Signed-off-by: Abhishek Varma <[email protected]>
… VarDecls (llvm#90948)

With the commit d530894, we now
preserve the initializer for invalid decls with the recovery-expr.

However there is a chance that the original init expr is a typo-expr, we
should not preserve it in the final AST, as typo-expr is an internal AST
node. We should use the one after the typo correction.

This is spotted by a clangd hover crash on the testcase.
Cycle is associated with construct-names and not labels. Change name of
a few variables to reflect this. Also add appropriate comment to
describe the else case of error checking.
Only VRs should use $noreg, this GPR was accidentally changed in d392520
…inate AllocOp and avoid Copy

Add an option hoist-static-allocs to remove the unnecessary memref.alloc and memref.copy after this pass, when the memref in ReturnOp is allocated by memref.alloc and is statically shaped. Instead, it replaces the uses of the allocated memref with the memref in the out argument.
By default, BufferResultsToOutParams will result in a memcpy operation to copy the originally returned memref to the output argument memref. This is inefficient when the source of memcpy (the returned memref in the original ReturnOp) is from a local AllocOp. The pass can use the output argument memref to replace the locally allocated memref for better performance. elim-alloc-copy avoids dynamic allocation and memory movement.
This option will be critical for performance-sensivtive applications, which require BufferResultsToOutParams pass for a caller-owned output buffer calling convension.
@Menooker Menooker force-pushed the fix_buffer_results_to_arg branch from 5a15f77 to acdbdbf Compare May 7, 2024 07:54
@Menooker Menooker closed this May 8, 2024
@Menooker Menooker deleted the fix_buffer_results_to_arg branch May 8, 2024 06:25
Menooker pushed a commit that referenced this pull request May 16, 2024
…e exception specification of a function (llvm#90760)

[temp.deduct.general] p6 states:
> At certain points in the template argument deduction process it is
necessary to take a function type that makes use of template parameters
and replace those template parameters with the corresponding template
arguments.
This is done at the beginning of template argument deduction when any
explicitly specified template arguments are substituted into the
function type, and again at the end of template argument deduction when
any template arguments that were deduced or obtained from default
arguments are substituted.

[temp.deduct.general] p7 goes on to say:
> The _deduction substitution loci_ are
> - the function type outside of the _noexcept-specifier_,
> - the explicit-specifier,
> - the template parameter declarations, and
> - the template argument list of a partial specialization
>
> The substitution occurs in all types and expressions that are used in
the deduction substitution loci. [...]

Consider the following:
```cpp
struct A
{
    static constexpr bool x = true;
};

template<typename T, typename U>
void f(T, U) noexcept(T::x); // #1

template<typename T, typename U>
void f(T, U*) noexcept(T::y); // #2

template<>
void f<A>(A, int*) noexcept; // clang currently accepts, GCC and EDG reject
```

Currently, `Sema::SubstituteExplicitTemplateArguments` will substitute
into the _noexcept-specifier_ when deducing template arguments from a
function declaration or when deducing template arguments for taking the
address of a function template (and the substitution is treated as a
SFINAE context). In the above example, `#1` is selected as the primary
template because substitution of the explicit template arguments into
the _noexcept-specifier_ of `#2` failed, which resulted in the candidate
being ignored.

This behavior is incorrect ([temp.deduct.general] note 4 says as much), and
this patch corrects it by deferring all substitution into the
_noexcept-specifier_ until it is instantiated.

As part of the necessary changes to make this patch work, the
instantiation of the exception specification of a function template
specialization when taking the address of a function template is changed
to only occur for the function selected by overload resolution per
[except.spec] p13.1 (as opposed to being instantiated for every candidate).
Menooker pushed a commit that referenced this pull request May 16, 2024
…ined member functions & member function templates (llvm#88963)

Consider the following snippet from the discussion of CWG2847 on the core reflector:
```
template<typename T>
concept C = sizeof(T) <= sizeof(long);

template<typename T>
struct A 
{
    template<typename U>
    void f(U) requires C<U>; // #1, declares a function template 

    void g() requires C<T>; // #2, declares a function

    template<>
    void f(char);  // #3, an explicit specialization of a function template that declares a function
};

template<>
template<typename U>
void A<short>::f(U) requires C<U>; // #4, an explicit specialization of a function template that declares a function template

template<>
template<>
void A<int>::f(int); // llvm#5, an explicit specialization of a function template that declares a function

template<>
void A<long>::g(); // llvm#6, an explicit specialization of a function that declares a function
```

A number of problems exist:
- Clang rejects `#4` because the trailing _requires-clause_ has `U`
substituted with the wrong template parameter depth when
`Sema::AreConstraintExpressionsEqual` is called to determine whether it
matches the trailing _requires-clause_ of the implicitly instantiated
function template.
- Clang rejects `llvm#5` because the function template specialization
instantiated from `A<int>::f` has a trailing _requires-clause_, but `llvm#5`
does not (nor can it have one as it isn't a templated function).
- Clang rejects `llvm#6` for the same reasons it rejects `llvm#5`.

This patch resolves these issues by making the following changes:
- To fix `#4`, `Sema::AreConstraintExpressionsEqual` is passed
`FunctionTemplateDecl`s when comparing the trailing _requires-clauses_
of `#4` and the function template instantiated from `#1`.
- To fix `llvm#5` and `llvm#6`, the trailing _requires-clauses_ are not compared
for explicit specializations that declare functions.

In addition to these changes, `CheckMemberSpecialization` now considers
constraint satisfaction/constraint partial ordering when determining
which member function is specialized by an explicit specialization of a
member function for an implicit instantiation of a class template (we
previously would select the first function that has the same type as the
explicit specialization). With constraints taken under consideration, we
match EDG's behavior for these declarations.
Menooker pushed a commit that referenced this pull request May 16, 2024
...which caused issues like

> ==42==ERROR: AddressSanitizer failed to deallocate 0x32 (50) bytes at
address 0x117e0000 (error code: 28)
> ==42==Cannot dump memory map on emscriptenAddressSanitizer: CHECK
failed: sanitizer_common.cpp:81 "((0 && "unable to unmmap")) != (0)"
(0x0, 0x0) (tid=288045824)
> #0 0x14f73b0c in __asan::CheckUnwind()+0x14f73b0c
(this.program+0x14f73b0c)
> #1 0x14f8a3c2 in __sanitizer::CheckFailed(char const*, int, char
const*, unsigned long long, unsigned long long)+0x14f8a3c2
(this.program+0x14f8a3c2)
> #2 0x14f7d6e1 in __sanitizer::ReportMunmapFailureAndDie(void*,
unsigned long, int, bool)+0x14f7d6e1 (this.program+0x14f7d6e1)
> #3 0x14f81fbd in __sanitizer::UnmapOrDie(void*, unsigned
long)+0x14f81fbd (this.program+0x14f81fbd)
> #4 0x14f875df in __sanitizer::SuppressionContext::ParseFromFile(char
const*)+0x14f875df (this.program+0x14f875df)
> llvm#5 0x14f74eab in __asan::InitializeSuppressions()+0x14f74eab
(this.program+0x14f74eab)
> llvm#6 0x14f73a1a in __asan::AsanInitInternal()+0x14f73a1a
(this.program+0x14f73a1a)

when trying to use an ASan suppressions file under Emscripten: Even
though it would be considered OK by SUSv4, the Emscripten runtime states
"We don't support partial munmapping" (see

<emscripten-core/emscripten@f4115eb>
"Implement MAP_ANONYMOUS on top of malloc in STANDALONE_WASM mode
(llvm#16289)").

Co-authored-by: Stephan Bergmann <[email protected]>
Menooker pushed a commit that referenced this pull request May 16, 2024
…ication as used during partial ordering (llvm#91534)

We do not deduce template arguments from the exception specification
when determining the primary template of a function template
specialization or when taking the address of a function template.
Therefore, this patch changes `isAtLeastAsSpecializedAs` such that we do
not mark template parameters in the exception specification as 'used'
during partial ordering (per [temp.deduct.partial]
p12) to prevent the following from being ambiguous:

```
template<typename T, typename U>
void f(U) noexcept(noexcept(T())); // #1

template<typename T>
void f(T*) noexcept; // #2

template<>
void f<int>(int*) noexcept; // currently ambiguous, selects #2 with this patch applied 
```

Although there is no corresponding wording in the standard (see core issue filed here
cplusplus/CWG#537), this seems
to be the intended behavior given the definition of _deduction
substitution loci_ in [temp.deduct.general] p7 (and EDG does the same thing).
Menooker pushed a commit that referenced this pull request Jun 3, 2024
…erSize (llvm#67657)"

This reverts commit f0b3654.

This commit triggers UB by reading an uninitialized variable.

`UP.PartialThreshold` is used uninitialized in `getUnrollingPreferences()` when
it is called from `LoopVectorizationPlanner::executePlan()`. In this case the
`UP` variable is created on the stack and its fields are not initialized.

```
==8802==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x557c0b081b99 in llvm::BasicTTIImplBase<llvm::X86TTIImpl>::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) llvm-project/llvm/include/llvm/CodeGen/BasicTTIImpl.h
    #1 0x557c0b07a40c in llvm::TargetTransformInfo::Model<llvm::X86TTIImpl>::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h:2277:17
    #2 0x557c0f5d69ee in llvm::TargetTransformInfo::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) const llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp:387:19
    #3 0x557c0e6b96a0 in llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7624:7
    #4 0x557c0e6e4b63 in llvm::LoopVectorizePass::processLoop(llvm::Loop*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10253:13
    llvm#5 0x557c0e6f2429 in llvm::LoopVectorizePass::runImpl(llvm::Function&, llvm::ScalarEvolution&, llvm::LoopInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::BlockFrequencyInfo*, llvm::TargetLibraryInfo*, llvm::DemandedBits&, llvm::AssumptionCache&, llvm::LoopAccessInfoManager&, llvm::OptimizationRemarkEmitter&, llvm::ProfileSummaryInfo*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10344:30
    llvm#6 0x557c0e6f2f97 in llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10383:9

[...]

  Uninitialized value was created by an allocation of 'UP' in the stack frame
    #0 0x557c0e6b961e in llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7623:3
```
Menooker pushed a commit that referenced this pull request Jun 3, 2024
…vm#90820)

This solves some ambuguity introduced in P0522 regarding how
template template parameters are partially ordered, and should reduce
the negative impact of enabling `-frelaxed-template-template-args`
by default.

When performing template argument deduction, a template template
parameter
containing no packs should be more specialized than one that does.

Given the following example:
```C++
template<class T2> struct A;
template<template<class ...T3s> class TT1, class T4> struct A<TT1<T4>>; // #1
template<template<class    T5 > class TT2, class T6> struct A<TT2<T6>>; // #2

template<class T1> struct B;
template struct A<B<char>>;
```

Prior to P0522, candidate `#2` would be more specialized.
After P0522, neither is more specialized, so this becomes ambiguous.
With this change, `#2` becomes more specialized again,
maintaining compatibility with pre-P0522 implementations.

The problem is that in P0522, candidates are at least as specialized
when matching packs to fixed-size lists both ways, whereas before,
a fixed-size list is more specialized.

This patch keeps the original behavior when checking template arguments
outside deduction, but restores this aspect of pre-P0522 matching
during deduction.

---

Since this changes provisional implementation of CWG2398 which has
not been released yet, and already contains a changelog entry,
we don't provide a changelog entry here.
Menooker pushed a commit that referenced this pull request Jun 3, 2024
…llvm#92855)

This solves some ambuguity introduced in P0522 regarding how template
template parameters are partially ordered, and should reduce the
negative impact of enabling `-frelaxed-template-template-args` by
default.

When performing template argument deduction, we extend the provisional
wording introduced in llvm#89807 so
it also covers deduction of class templates.

Given the following example:
```C++
template <class T1, class T2 = float> struct A;
template <class T3> struct B;

template <template <class T4> class TT1, class T5> struct B<TT1<T5>>;   // #1
template <class T6, class T7>                      struct B<A<T6, T7>>; // #2

template struct B<A<int>>;
```
Prior to P0522, `#2` was picked. Afterwards, this became ambiguous. This
patch restores the pre-P0522 behavior, `#2` is picked again.

This has the beneficial side effect of making the following code valid:
```C++
template<class T, class U> struct A {};
A<int, float> v;
template<template<class> class TT> void f(TT<int>);

// OK: TT picks 'float' as the default argument for the second parameter.
void g() { f(v); }
```

---

Since this changes provisional implementation of CWG2398 which has not
been released yet, and already contains a changelog entry, we don't
provide a changelog entry here.
Menooker pushed a commit that referenced this pull request Jun 3, 2024
The problematic program is as follows:

```shell
#define pre_a 0
#define PRE(x) pre_##x

void f(void) {
    PRE(a) && 0;
}

int main(void) { return 0; }
```

in which after token concatenation (`##`), there's another nested macro
`pre_a`.

Currently only the outer expansion region will be produced. ([compiler
explorer
link](https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename:'1',fontScale:14,fontUsePx:'0',j:1,lang:___c,selection:(endColumn:29,endLineNumber:8,positionColumn:29,positionLineNumber:8,selectionStartColumn:29,selectionStartLineNumber:8,startColumn:29,startLineNumber:8),source:'%23define+pre_a+0%0A%23define+PRE(x)+pre_%23%23x%0A%0Avoid+f(void)+%7B%0A++++PRE(a)+%26%26+0%3B%0A%7D%0A%0Aint+main(void)+%7B+return+0%3B+%7D'),l:'5',n:'0',o:'C+source+%231',t:'0')),k:51.69491525423727,l:'4',n:'0',o:'',s:0,t:'0'),(g:!((g:!((h:compiler,i:(compiler:cclang_assertions_trunk,filters:(b:'0',binary:'1',binaryObject:'1',commentOnly:'0',debugCalls:'1',demangle:'0',directives:'0',execute:'0',intel:'0',libraryCode:'1',trim:'1',verboseDemangling:'0'),flagsViewOpen:'1',fontScale:14,fontUsePx:'0',j:2,lang:___c,libs:!(),options:'-fprofile-instr-generate+-fcoverage-mapping+-fcoverage-mcdc+-Xclang+-dump-coverage-mapping+',overrides:!(),selection:(endColumn:1,endLineNumber:1,positionColumn:1,positionLineNumber:1,selectionStartColumn:1,selectionStartLineNumber:1,startColumn:1,startLineNumber:1),source:1),l:'5',n:'0',o:'+x86-64+clang+(assertions+trunk)+(Editor+%231)',t:'0')),k:34.5741843594503,l:'4',m:28.903654485049834,n:'0',o:'',s:0,t:'0'),(g:!((h:output,i:(compilerName:'x86-64+clang+(trunk)',editorid:1,fontScale:14,fontUsePx:'0',j:2,wrap:'1'),l:'5',n:'0',o:'Output+of+x86-64+clang+(assertions+trunk)+(Compiler+%232)',t:'0')),header:(),l:'4',m:71.09634551495017,n:'0',o:'',s:0,t:'0')),k:48.30508474576271,l:'3',n:'0',o:'',t:'0')),l:'2',m:100,n:'0',o:'',t:'0')),version:4))

```text
f:
  File 0, 4:14 -> 6:2 = #0
  Decision,File 0, 5:5 -> 5:16 = M:0, C:2
  Expansion,File 0, 5:5 -> 5:8 = #0 (Expanded file = 1)
  File 0, 5:15 -> 5:16 = #1
  Branch,File 0, 5:15 -> 5:16 = 0, 0 [2,0,0] 
  File 1, 2:16 -> 2:23 = #0
  File 2, 1:15 -> 1:16 = #0
  File 2, 1:15 -> 1:16 = #0
  Branch,File 2, 1:15 -> 1:16 = 0, 0 [1,2,0] 
```

The inner expansion region isn't produced because:

1. In the range-based for loop quoted below, each sloc is processed and
possibly emit a corresponding expansion region.
2. For our sloc in question, its direct parent returned by
`getIncludeOrExpansionLoc()` is a `<scratch space>`, because that's how
`##` is processed.


https://github.com/llvm/llvm-project/blob/88b6186af3908c55b357858eb348b5143f21c289/clang/lib/CodeGen/CoverageMappingGen.cpp#L518-L520

3. This `<scratch space>` cannot be found in the FileID mapping so
`ParentFileID` will be assigned an `std::nullopt`


https://github.com/llvm/llvm-project/blob/88b6186af3908c55b357858eb348b5143f21c289/clang/lib/CodeGen/CoverageMappingGen.cpp#L521-L526

4. As a result this iteration of for loop finishes early and no
expansion region is added for the sloc.

This problem gets worse with MC/DC: as the example shows, there's a
branch from File 2 but File 2 itself is missing. This will trigger
assertion failures.

The fix is more or less a workaround and takes a similar approach as
llvm#89573.

~~Depends on llvm#89573.~~ This includes llvm#89573. Kudos to @chapuni!
This and llvm#89573 together fix llvm#87000: I tested locally, both the reduced
program and my original use case (fwiw, Linux kernel) can run
successfully.

---------

Co-authored-by: NAKAMURA Takumi <[email protected]>
Menooker pushed a commit that referenced this pull request Jun 12, 2024
…des (llvm#94453)

LSR will generate chains of related instructions with a known increment
between them. With SVE, in the case of the test case, this can include
increments like 'vscale * 16 + 8'. The idea of this patch is if we have
a '+8' increment already calculated in the chain, we can generate a
(legal) '+ vscale*16' addressing mode from it, allowing us to use the
'[x16, #1, mul vl]' addressing mode instructions.

In order to do this we keep track of the known 'bases' when generating
chains in GenerateIVChain, checking for each if the accumulated
increment expression from the base neatly folds into a legal addressing
mode. If they do not we fall back to the existing LeftOverExpr, whether
it is legal or not.

This is mostly orthogonal to llvm#88124, dealing with the generation of
chains as opposed to rest of LSR. The existing vscale addressing mode
work has greatly helped compared to the last time I looked at this,
allowing us to check that the addressing modes are indeed legal.
Menooker pushed a commit that referenced this pull request Sep 3, 2024
…lvm#104148)

`hasOperands` does not always execute matchers in the order they are
written. This can cause issue in code using bindings when one operand
matcher is relying on a binding set by the other. With this change, the
first matcher present in the code is always executed first and any
binding it sets are available to the second matcher.

Simple example with current version (1 match) and new version (2
matches):
```bash
> cat tmp.cpp
int a = 13;
int b = ((int) a) - a;
int c = a - ((int) a);

> clang-query tmp.cpp
clang-query> set traversal IgnoreUnlessSpelledInSource
clang-query> m binaryOperator(hasOperands(cStyleCastExpr(has(declRefExpr(hasDeclaration(valueDecl().bind("d"))))), declRefExpr(hasDeclaration(valueDecl(equalsBoundNode("d"))))))

Match #1:

tmp.cpp:1:1: note: "d" binds here
int a = 13;
^~~~~~~~~~
tmp.cpp:2:9: note: "root" binds here
int b = ((int)a) - a;
        ^~~~~~~~~~~~
1 match.

> ./build/bin/clang-query tmp.cpp
clang-query> set traversal IgnoreUnlessSpelledInSource
clang-query> m binaryOperator(hasOperands(cStyleCastExpr(has(declRefExpr(hasDeclaration(valueDecl().bind("d"))))), declRefExpr(hasDeclaration(valueDecl(equalsBoundNode("d"))))))

Match #1:

tmp.cpp:1:1: note: "d" binds here
    1 | int a = 13;
      | ^~~~~~~~~~
tmp.cpp:2:9: note: "root" binds here
    2 | int b = ((int)a) - a;
      |         ^~~~~~~~~~~~

Match #2:

tmp.cpp:1:1: note: "d" binds here
    1 | int a = 13;
      | ^~~~~~~~~~
tmp.cpp:3:9: note: "root" binds here
    3 | int c = a - ((int)a);
      |         ^~~~~~~~~~~~
2 matches.
```

If this should be documented or regression tested anywhere please let me
know where.
Menooker pushed a commit that referenced this pull request Sep 3, 2024
…104523)

Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.

This does not affect the numbering of frames, so `f <N>` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.

My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.

rdar://126629381


Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).

before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
    frame #4: 0x00000001000026bc a.out`std::__1::__function::__func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
    frame llvm#5: 0x0000000100003c38 a.out`std::__1::__function::__value_func<int (int, int)>::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
    frame llvm#6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame llvm#7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame llvm#8: 0x0000000183cdf154 dyld`start + 2476
(lldb) 
```

after

```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame llvm#6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame llvm#7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame llvm#8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```
Menooker pushed a commit that referenced this pull request Sep 3, 2024
`JITDylibSearchOrderResolver` local variable can be destroyed before
completion of all callbacks. Capture it together with `Deps` in
`OnEmitted` callback.

Original error:

```
==2035==ERROR: AddressSanitizer: stack-use-after-return on address 0x7bebfa155b70 at pc 0x7ff2a9a88b4a bp 0x7bec08d51980 sp 0x7bec08d51978
READ of size 8 at 0x7bebfa155b70 thread T87 (tf_xla-cpu-llvm)
    #0 0x7ff2a9a88b49 in operator() llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:58
    #1 0x7ff2a9a88b49 in __invoke<(lambda at llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:9) &, const llvm::DenseMap<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> >, llvm::DenseMapInfo<llvm::orc::JITDylib *, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> > > > &> libcxx/include/__type_traits/invoke.h:149:25
    #2 0x7ff2a9a88b49 in __call<(lambda at llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:55:9) &, const llvm::DenseMap<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> >, llvm::DenseMapInfo<llvm::orc::JITDylib *, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib *, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void> > > > &> libcxx/include/__type_traits/invoke.h:224:5
    #3 0x7ff2a9a88b49 in operator() libcxx/include/__functional/function.h:210:12
    #4 0x7ff2a9a88b49 in void std::__u::__function::__policy_invoker<void (llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr,
```
Menooker pushed a commit that referenced this pull request Sep 3, 2024
Static destructor can race with calls to notify and trigger tsan
warning.

```
WARNING: ThreadSanitizer: data race (pid=5787)
  Write of size 1 at 0x55bec9df8de8 by thread T23:
    #0 pthread_mutex_destroy [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:1344](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=1344&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b12affb) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #1 __libcpp_recursive_mutex_destroy [third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h:91](third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h?l=91&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d4e9) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #2 std::__tsan::recursive_mutex::~recursive_mutex() [third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp:52](third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp?l=52&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d4e9)
    #3 ~SmartMutex [third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h:28](third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h?l=28&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaedfe) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #4 (anonymous namespace)::PerfJITEventListener::~PerfJITEventListener() [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:65](third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=65&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaedfe)
    llvm#5 cxa_at_exit_callback_installed_at(void*) [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:437](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=437&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b172cb9) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    llvm#6 llvm::JITEventListener::createPerfJITEventListener() [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:496](third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=496&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcad8f5) (BuildId: ff25ace8b17d9863348bb1759c47246c)
```
```
Previous atomic read of size 1 at 0x55bec9df8de8 by thread T192 (mutexes: write M0, write M1):
    #0 pthread_mutex_unlock [third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:1387](third_party/llvm/llvm-project/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp?l=1387&cl=669089572):3 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x1b12b6bb) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #1 __libcpp_recursive_mutex_unlock [third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h:87](third_party/crosstool/v18/stable/src/libcxx/include/__thread/support/pthread.h?l=87&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d589) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #2 std::__tsan::recursive_mutex::unlock() [third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp:64](third_party/crosstool/v18/stable/src/libcxx/src/mutex.cpp?l=64&cl=669089572):11 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x4523d589)
    #3 unlock [third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h:47](third_party/llvm/llvm-project/llvm/include/llvm/Support/Mutex.h?l=47&cl=669089572):16 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968) (BuildId: ff25ace8b17d9863348bb1759c47246c)
    #4 ~lock_guard [third_party/crosstool/v18/stable/src/libcxx/include/__mutex/lock_guard.h:39](third_party/crosstool/v18/stable/src/libcxx/include/__mutex/lock_guard.h?l=39&cl=669089572):101 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968)
    llvm#5 (anonymous namespace)::PerfJITEventListener::notifyObjectLoaded(unsigned long, llvm::object::ObjectFile const&, llvm::RuntimeDyld::LoadedObjectInfo const&) [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp:290](https://cs.corp.google.com/piper///depot/google3/third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/PerfJITEvents/PerfJITEventListener.cpp?l=290&cl=669089572):1 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bcaf968)
    llvm#6 llvm::orc::RTDyldObjectLinkingLayer::onObjEmit(llvm::orc::MaterializationResponsibility&, llvm::object::OwningBinary<llvm::object::ObjectFile>, std::__tsan::unique_ptr<llvm::RuntimeDyld::MemoryManager, std::__tsan::default_delete<llvm::RuntimeDyld::MemoryManager>>, std::__tsan::unique_ptr<llvm::RuntimeDyld::LoadedObjectInfo, std::__tsan::default_delete<llvm::RuntimeDyld::LoadedObjectInfo>>, std::__tsan::unique_ptr<llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>, llvm::DenseMapInfo<llvm::orc::JITDylib*, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>>>, std::__tsan::default_delete<llvm::DenseMap<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>, llvm::DenseMapInfo<llvm::orc::JITDylib*, void>, llvm::detail::DenseMapPair<llvm::orc::JITDylib*, llvm::DenseSet<llvm::orc::SymbolStringPtr, llvm::DenseMapInfo<llvm::orc::SymbolStringPtr, void>>>>>>, llvm::Error) [third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp:386](https://cs.corp.google.com/piper///depot/google3/third_party/llvm/llvm-project/llvm/lib/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.cpp?l=386&cl=669089572):10 (be1eb158bb70fc9cf7be2db70407e512890e5c6e20720cd88c69d7d9c26ea531_0200d5f71908+0x2bc404a8) (BuildId: ff25ace8b17d9863348bb1759c47246c)
```
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