This reverts commit bfd2c21.
This appears to be causing stage2 msan failures on buildbots:
  FAIL: LLVM :: Transforms/SimplifyCFG/X86/bug-25299.ll (65872 of 71835)
  ******************** TEST 'LLVM :: Transforms/SimplifyCFG/X86/bug-25299.ll' FAILED ********************
  Script:
  --
  : 'RUN: at line 1';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll -simplifycfg -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll
  --
  Exit Code: 2
  Command Output (stderr):
  --
  ==87374==WARNING: MemorySanitizer: use-of-uninitialized-value
      #0 0x9de47b6 in getBasicBlockIndex /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/IR/Instructions.h:2749:5
      #1 0x9de47b6 in simplifyCommonResume /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:4112:23
      rust-lang#2 0x9de47b6 in simplifyResume /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:4039:12
      rust-lang#3 0x9de47b6 in (anonymous namespace)::SimplifyCFGOpt::simplifyOnce(llvm::BasicBlock*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:6330:16
      rust-lang#4 0x9dcca13 in run /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:6358:16
      rust-lang#5 0x9dcca13 in llvm::simplifyCFG(llvm::BasicBlock*, llvm::TargetTransformInfo const&, llvm::SimplifyCFGOptions const&, llvm::SmallPtrSetImpl<llvm::BasicBlock*>*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:6369:8
      rust-lang#6 0x974643d in iterativelySimplifyCFG(

…e tools

This is the #1 of 2 changes that make remarks hotness threshold option
available in more tools. The changes also allow the threshold to sync with
hotness threshold from profile summary with special value 'auto'.

This change modifies the interface of lto::setupLLVMOptimizationRemarks() to
accept remarks hotness threshold. Update all the tools that use it with remarks
hotness threshold options:

* lld: '--opt-remarks-hotness-threshold='
* llvm-lto2: '--pass-remarks-hotness-threshold='
* llvm-lto: '--lto-pass-remarks-hotness-threshold='
* gold plugin: '-plugin-opt=opt-remarks-hotness-threshold='

Differential Revision: https://reviews.llvm.org/D85809

CXXDeductionGuideDecl with a local typedef has its own copy of the
TypedefDecl with the CXXDeductionGuideDecl as the DeclContext of that
TypedefDecl.
```
      template <typename T> struct A {
        typedef T U;
        A(U, T);
      };
      A a{(int)0, (int)0};
```
Related discussion on cfe-dev:
http://lists.llvm.org/pipermail/cfe-dev/2020-November/067252.html

Without this fix, when we import the CXXDeductionGuideDecl (via
VisitFunctionDecl) then before creating the Decl we must import the
FunctionType. However, the first parameter's type is the afore mentioned
local typedef. So, we then start importing the TypedefDecl whose
DeclContext is the CXXDeductionGuideDecl itself. The infinite loop is
formed.
```
 #0 clang::ASTNodeImporter::VisitCXXDeductionGuideDecl(clang::CXXDeductionGuideDecl*) clang/lib/AST/ASTImporter.cpp:3543:0
 #1 clang::declvisitor::Base<std::add_pointer, clang::ASTNodeImporter, llvm::Expected<clang::Decl*> >::Visit(clang::Decl*) /home/egbomrt/WORK/llvm5/build/debug/tools/clang/include/clang/AST/DeclNodes.inc:405:0
 rust-lang#2 clang::ASTImporter::ImportImpl(clang::Decl*) clang/lib/AST/ASTImporter.cpp:8038:0
 rust-lang#3 clang::ASTImporter::Import(clang::Decl*) clang/lib/AST/ASTImporter.cpp:8200:0
 rust-lang#4 clang::ASTImporter::ImportContext(clang::DeclContext*) clang/lib/AST/ASTImporter.cpp:8297:0
 rust-lang#5 clang::ASTNodeImporter::ImportDeclContext(clang::Decl*, clang::DeclContext*&, clang::DeclContext*&) clang/lib/AST/ASTImporter.cpp:1852:0
 rust-lang#6 clang::ASTNodeImporter::ImportDeclParts(clang::NamedDecl*, clang::DeclContext*&, clang::DeclContext*&, clang::DeclarationName&, clang::NamedDecl*&, clang::SourceLocation&) clang/lib/AST/ASTImporter.cpp:1628:0
 rust-lang#7 clang::ASTNodeImporter::VisitTypedefNameDecl(clang::TypedefNameDecl*, bool) clang/lib/AST/ASTImporter.cpp:2419:0
 rust-lang#8 clang::ASTNodeImporter::VisitTypedefDecl(clang::TypedefDecl*) clang/lib/AST/ASTImporter.cpp:2500:0
 rust-lang#9 clang::declvisitor::Base<std::add_pointer, clang::ASTNodeImporter, llvm::Expected<clang::Decl*> >::Visit(clang::Decl*) /home/egbomrt/WORK/llvm5/build/debug/tools/clang/include/clang/AST/DeclNodes.inc:315:0
 rust-lang#10 clang::ASTImporter::ImportImpl(clang::Decl*) clang/lib/AST/ASTImporter.cpp:8038:0
 rust-lang#11 clang::ASTImporter::Import(clang::Decl*) clang/lib/AST/ASTImporter.cpp:8200:0
 rust-lang#12 llvm::Expected<clang::TypedefNameDecl*> clang::ASTNodeImporter::import<clang::TypedefNameDecl>(clang::TypedefNameDecl*) clang/lib/AST/ASTImporter.cpp:165:0
 rust-lang#13 clang::ASTNodeImporter::VisitTypedefType(clang::TypedefType const*) clang/lib/AST/ASTImporter.cpp:1304:0
 rust-lang#14 clang::TypeVisitor<clang::ASTNodeImporter, llvm::Expected<clang::QualType> >::Visit(clang::Type const*) /home/egbomrt/WORK/llvm5/build/debug/tools/clang/include/clang/AST/TypeNodes.inc:74:0
 rust-lang#15 clang::ASTImporter::Import(clang::QualType) clang/lib/AST/ASTImporter.cpp:8071:0
 rust-lang#16 llvm::Expected<clang::QualType> clang::ASTNodeImporter::import<clang::QualType>(clang::QualType const&) clang/lib/AST/ASTImporter.cpp:179:0
 rust-lang#17 clang::ASTNodeImporter::VisitFunctionProtoType(clang::FunctionProtoType const*) clang/lib/AST/ASTImporter.cpp:1244:0
 rust-lang#18 clang::TypeVisitor<clang::ASTNodeImporter, llvm::Expected<clang::QualType> >::Visit(clang::Type const*) /home/egbomrt/WORK/llvm5/build/debug/tools/clang/include/clang/AST/TypeNodes.inc:47:0
 rust-lang#19 clang::ASTImporter::Import(clang::QualType) clang/lib/AST/ASTImporter.cpp:8071:0
 rust-lang#20 llvm::Expected<clang::QualType> clang::ASTNodeImporter::import<clang::QualType>(clang::QualType const&) clang/lib/AST/ASTImporter.cpp:179:0
 rust-lang#21 clang::QualType clang::ASTNodeImporter::importChecked<clang::QualType>(llvm::Error&, clang::QualType const&) clang/lib/AST/ASTImporter.cpp:198:0
 rust-lang#22 clang::ASTNodeImporter::VisitFunctionDecl(clang::FunctionDecl*) clang/lib/AST/ASTImporter.cpp:3313:0
 rust-lang#23 clang::ASTNodeImporter::VisitCXXDeductionGuideDecl(clang::CXXDeductionGuideDecl*) clang/lib/AST/ASTImporter.cpp:3543:0
```

The fix is to first create the TypedefDecl and only then start to import
the DeclContext.
Basically, we could do this during the import of all other Decls (not
just for typedefs). But it seems, there is only one another AST
construct that has a similar cycle: a struct defined as a function
parameter:
```
int struct_in_proto(struct data_t{int a;int b;} *d);

```
In that case, however, we had decided to return simply with an error
back then because that seemed to be a very rare construct.

Differential Revision: https://reviews.llvm.org/D92209

… disabled for a PCH vs a module file

This addresses an issue with how the PCH preable works, specifically:

1. When using a PCH/preamble the module hash changes and a different cache directory is used
2. When the preamble is used, PCH & PCM validation is disabled.

Due to combination of #1 and rust-lang#2, reparsing with preamble enabled can end up loading a stale module file before a header change and using it without updating it because validation is disabled and it doesn’t check that the header has changed and the module file is out-of-date.

rdar://72611253

Differential Revision: https://reviews.llvm.org/D95159

The IR/MIR pseudo probe intrinsics don't get materialized into real machine instructions and therefore they don't incur runtime cost directly. However, they come with indirect cost by blocking certain optimizations. Some of the blocking are intentional (such as blocking code merge) for better counts quality while the others are accidental. This change unblocks perf-critical optimizations that do not affect counts quality. They include:

1. IR InstCombine, sinking load operation to shorten lifetimes.
2. MIR LiveRangeShrink, similar to #1
3. MIR TwoAddressInstructionPass, i.e, opeq transform
4. MIR function argument copy elision
5. IR stack protection. (though not perf-critical but nice to have).

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D95982

The IR/MIR pseudo probe intrinsics don't get materialized into real machine instructions and therefore they don't incur runtime cost directly. However, they come with indirect cost by blocking certain optimizations. Some of the blocking are intentional (such as blocking code merge) for better counts quality while the others are accidental. This change unblocks perf-critical optimizations that do not affect counts quality. They include:

1. IR InstCombine, sinking load operation to shorten lifetimes.
2. MIR LiveRangeShrink, similar to #1
3. MIR TwoAddressInstructionPass, i.e, opeq transform
4. MIR function argument copy elision
5. IR stack protection. (though not perf-critical but nice to have).

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D95982

/home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.cpp:77:25: runtime error: left shift of 0x0000000000000000fffffffffffffffb by 96 places cannot be represented in type '__int128'
    #0 0x7ffff754edfe in __ubsan::Value::getSIntValue() const /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.cpp:77
    #1 0x7ffff7548719 in __ubsan::Value::isNegative() const /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_value.h:190
    rust-lang#2 0x7ffff7542a34 in handleShiftOutOfBoundsImpl /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_handlers.cpp:338
    rust-lang#3 0x7ffff75431b7 in __ubsan_handle_shift_out_of_bounds /home/marxin/Programming/gcc2/libsanitizer/ubsan/ubsan_handlers.cpp:370
    rust-lang#4 0x40067f in main (/home/marxin/Programming/testcases/a.out+0x40067f)
    rust-lang#5 0x7ffff72c8b24 in __libc_start_main (/lib64/libc.so.6+0x27b24)
    rust-lang#6 0x4005bd in _start (/home/marxin/Programming/testcases/a.out+0x4005bd)

Differential Revision: https://reviews.llvm.org/D97263

Previously, SyntheticSections.cpp did not have a top-level `using namespace
llvm::MachO` because it caused a naming conflict: `llvm::MachO::Symbol` would
collide with `lld::macho::Symbol`.

`MachO::Symbol` represents the symbols defined in InterfaceFiles (TBDs). By
moving the inclusion of InterfaceFile.h into our .cpp files, we can avoid this
name collision in other files where we are only dealing with LLD's own symbols.

Along the way, I removed all unnecessary "MachO::" prefixes in our code.

Cons of this approach: If TextAPI/MachO/Symbol.h gets included via some other
header file in the future, we could run into this collision again.

Alternative 1: Have either TextAPI/MachO or BinaryFormat/MachO.h use a different
namespace. Most of the benefit of `using namespace llvm::MachO` comes from being
able to use things in BinaryFormat/MachO.h conveniently; if TextAPI was under a
different (and fully-qualified) namespace like `llvm::tapi` that would solve our
problems. Cons: lots of files across llvm-project will need to be updated, and
folks who own the TextAPI code need to agree to the name change.

Alternative 2: Rename our Symbol to something like `LldSymbol`. I think this is
ugly.

Personally I think alternative #1 is ideal, but I'm not sure the effort to do it is
worthwhile, this diff's halfway solution seems good enough to me. Thoughts?

Reviewed By: #lld-macho, oontvoo, MaskRay

Differential Revision: https://reviews.llvm.org/D98149

Somewhat surprisingly, signature help is emitted as a side-effect of
computing the expected type of a function argument.
The reason is that both actions require enumerating the possible
function signatures and running partial overload resolution, and doing
this twice would be wasteful and complicated.

Change #1: document this, it's subtle :-)

However, sometimes we need to compute the expected type without having
reached the code completion cursor yet - in particular to allow
completion of designators.
eb4ab33 did this but introduced a
regression - it emits signature help in the wrong location as a side-effect.

Change rust-lang#2: only emit signature help if the code completion cursor was reached.

Currently there is PP.isCodeCompletionReached(), but we can't use it
because it's set *after* running code completion.
It'd be nice to set this implicitly when the completion token is lexed,
but ConsumeCodeCompletionToken() makes this complicated.

Change rust-lang#3: call cutOffParsing() *first* when seeing a completion token.

After this, the fact that the Sema::Produce*SignatureHelp() functions
are even more confusing, as they only sometimes do that.
I don't want to rename them in this patch as it's another large
mechanical change, but we should soon.

Change rust-lang#4: prepare to rename ProduceSignatureHelp() to GuessArgumentType() etc.

Differential Revision: https://reviews.llvm.org/D98488

This reverts commit 9be8f8b.
This breaks tsan on Ubuntu 16.04:

    $ cat tiny_race.c
    #include <pthread.h>
    int Global;
    void *Thread1(void *x) {
      Global = 42;
      return x;
    }
    int main() {
      pthread_t t;
      pthread_create(&t, NULL, Thread1, NULL);
      Global = 43;
      pthread_join(t, NULL);
      return Global;
    }
    $ out/gn/bin/clang -fsanitize=thread -g -O1 tiny_race.c --sysroot ~/src/chrome/src/build/linux/debian_sid_amd64-sysroot/
    $ docker run -v $PWD:/foo ubuntu:xenial /foo/a.out
    FATAL: ThreadSanitizer CHECK failed: ../../compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:447 "((thr_beg)) >= ((tls_addr))" (0x7fddd76beb80, 0xfffffffffffff980)
        #0 <null> <null> (a.out+0x4960b6)
        #1 <null> <null> (a.out+0x4b677f)
        rust-lang#2 <null> <null> (a.out+0x49cf94)
        rust-lang#3 <null> <null> (a.out+0x499bd2)
        rust-lang#4 <null> <null> (a.out+0x42aaf1)
        rust-lang#5 <null> <null> (libpthread.so.0+0x76b9)
        rust-lang#6 <null> <null> (libc.so.6+0x1074dc)

(Get the sysroot from here: https://commondatastorage.googleapis.com/chrome-linux-sysroot/toolchain/500976182686961e34974ea7bdc0a21fca32be06/debian_sid_amd64_sysroot.tar.xz)

Also reverts follow-on commits:
This reverts commit 58c62fd.
This reverts commit 31e541e.

This adds support for swapping comparison operands when it may introduce new
folding opportunities.

This is roughly the same as the code added to AArch64ISelLowering in
162435e.

For an example of a testcase which exercises this, see
llvm/test/CodeGen/AArch64/swap-compare-operands.ll

(Godbolt for that testcase: https://godbolt.org/z/43WEMb)

The idea behind this is that sometimes, we may be able to fold away, say, a
shift or extend in a compare by swapping its operands.

e.g. in the case of this compare:

```
lsl x8, x0, #1
cmp x8, x1
cset w0, lt
```

The following is equivalent:

```
cmp x1, x0, lsl #1
cset w0, gt
```

Most of the code here is just a reimplementation of what already exists in
AArch64ISelLowering.

(See `getCmpOperandFoldingProfit` and `getAArch64Cmp` for the equivalent code.)

Note that most of the AND code in the testcase doesn't actually fold. It seems
like we're missing selection support for that sort of fold right now, since SDAG
happily folds these away (e.g testSwapCmpWithShiftedZeroExtend8_32 in the
original .ll testcase)

Differential Revision: https://reviews.llvm.org/D89422

Comparisons to zero or one after cset instructions can be safely
removed in examples like:

cset w9, eq          cset w9, eq
cmp  w9, #1   --->   <removed>
b.ne    .L1          b.ne    .L1

cset w9, eq          cset w9, eq
cmp  w9, #0   --->   <removed>
b.ne    .L1          b.eq    .L1

Peephole optimization to detect suitable cases and get rid of that
comparisons added.

Differential Revision: https://reviews.llvm.org/D98564

…s...

when the predicate used by last{a,b} specifies a known vector length.

For example:
  aarch64_sve_lasta(VL1, D) -> extractelement(D, #1)
  aarch64_sve_lastb(VL1, D) -> extractelement(D, #0)

Co-authored-by: Paul Walker <paul.walker@arm.com>

Differential Revision: https://reviews.llvm.org/D100476

Commit e3d8ee3 ("reland "[DebugInfo] Support to emit debugInfo
for extern variables"") added support to emit debugInfo for
extern variables if requested by the target. Currently, only
BPF target enables this feature by default.

As BPF ecosystem grows, callback function started to get
support, e.g., recently bpf_for_each_map_elem() is introduced
(https://lwn.net/Articles/846504/) with a callback function as an
argument. In the future we may have something like below as
a demonstration of use case :
    extern int do_work(int);
    long bpf_helper(void *callback_fn, void *callback_ctx, ...);
    long prog_main() {
        struct { ... } ctx = { ... };
        return bpf_helper(&do_work, &ctx, ...);
    }
Basically bpf helper may have a callback function and the
callback function is defined in another file or in the kernel.
In this case, we would like to know the debuginfo types for
do_work(), so the verifier can proper verify the safety of
bpf_helper() call.

For the following example,
    extern int do_work(int);
    long bpf_helper(void *callback_fn);
    long prog() {
        return bpf_helper(&do_work);
    }

Currently, there is no debuginfo generated for extern function do_work().
In the IR, we have,
    ...
    define dso_local i64 @prog() local_unnamed_addr #0 !dbg !7 {
    entry:
      %call = tail call i64 @bpf_helper(i8* bitcast (i32 (i32)* @do_work to i8*)) rust-lang#2, !dbg !11
      ret i64 %call, !dbg !12
    }
    ...
    declare dso_local i32 @do_work(i32) #1
    ...

This patch added support for the above callback function use case, and
the generated IR looks like below:
    ...
    declare !dbg !17 dso_local i32 @do_work(i32) #1
    ...
    !17 = !DISubprogram(name: "do_work", scope: !1, file: !1, line: 1, type: !18, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
    !18 = !DISubroutineType(types: !19)
    !19 = !{!20, !20}
    !20 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)

The TargetInfo.allowDebugInfoForExternalVar is renamed to
TargetInfo.allowDebugInfoForExternalRef as now it guards
both extern variable and extern function debuginfo generation.

Differential Revision: https://reviews.llvm.org/D100567

…rtial type

llvm-dwarfdump crashed for Unit header with DW_UT_partial type.
-------------
llvm-dwarfdump: /tmp/llvm/include/llvm/ADT/Optional.h:197: T& llvm::optional_detail::OptionalStorage<T, true>::getValue() &
[with T = long unsigned int]: Assertion `hasVal' failed.
PLEASE submit a bug report to the technical support section of https://developer.amd.com/amd-aocc and include the crash backtrace.
Stack dump:
0.      Program arguments: llvm-dwarfdump -v /tmp/test/DebugInfo/X86/Output/dwarfdump-he
ader.s.tmp.o
 #0 0x00007f37d5ad8838 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /tmp/llvm/lib/Support/Unix/Signals.inc:565:0
 #1 0x00007f37d5ad88ef PrintStackTraceSignalHandler(void*) /tmp/llvm/lib/Support/Unix/Signals.inc:632:0
 rust-lang#2 0x00007f37d5ad65bd llvm::sys::RunSignalHandlers() /tmp/llvm/lib/Support/Signals.cpp:71:0
 rust-lang#3 0x00007f37d5ad81b9 SignalHandler(int) /tmp/llvm/lib/Support/Unix/Signals.inc:407:0
 rust-lang#4 0x00007f37d4c26040 (/lib/x86_64-linux-gnu/libc.so.6+0x3f040)
 rust-lang#5 0x00007f37d4c25fb7 raise /build/glibc-S9d2JN/glibc-2.27/signal/../sysdeps/unix/sysv/linux/raise.c:51:0
 rust-lang#6 0x00007f37d4c27921 abort /build/glibc-S9d2JN/glibc-2.27/stdlib/abort.c:81:0
 rust-lang#7 0x00007f37d4c1748a __assert_fail_base /build/glibc-S9d2JN/glibc-2.27/assert/assert.c:89:0
 rust-lang#8 0x00007f37d4c17502 (/lib/x86_64-linux-gnu/libc.so.6+0x30502)
 rust-lang#9 0x00007f37d7576b81 llvm::optional_detail::OptionalStorage<unsigned long, true>::getValue() & /tmp/llvm/include/llvm/ADT/Optional.h:198:0
 rust-lang#10 0x00007f37d75726ac llvm::Optional<unsigned long>::operator*() && /tmp/llvm/include/llvm/ADT/Optional.h:309:0
 rust-lang#11 0x00007f37d7582968 llvm::DWARFCompileUnit::dump(llvm::raw_ostream&, llvm::DIDumpOptions) /tmp/llvm/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp:30:0
--------------

Patch by: @jini.susan

Reviewed By: @probinson

Differential Revision: https://reviews.llvm.org/D101255

…ing it

Having nested macros in the C code could cause clangd to fail an assert in clang::Preprocessor::setLoadedMacroDirective() and crash.

 #1 0x00000000007ace30 PrintStackTraceSignalHandler(void*) /qdelacru/llvm-project/llvm/lib/Support/Unix/Signals.inc:632:1
 rust-lang#2 0x00000000007aaded llvm::sys::RunSignalHandlers() /qdelacru/llvm-project/llvm/lib/Support/Signals.cpp:76:20
 rust-lang#3 0x00000000007ac7c1 SignalHandler(int) /qdelacru/llvm-project/llvm/lib/Support/Unix/Signals.inc:407:1
 rust-lang#4 0x00007f096604db20 __restore_rt (/lib64/libpthread.so.0+0x12b20)
 rust-lang#5 0x00007f0964b307ff raise (/lib64/libc.so.6+0x377ff)
 rust-lang#6 0x00007f0964b1ac35 abort (/lib64/libc.so.6+0x21c35)
 rust-lang#7 0x00007f0964b1ab09 _nl_load_domain.cold.0 (/lib64/libc.so.6+0x21b09)
 rust-lang#8 0x00007f0964b28de6 (/lib64/libc.so.6+0x2fde6)
 rust-lang#9 0x0000000001004d1a clang::Preprocessor::setLoadedMacroDirective(clang::IdentifierInfo*, clang::MacroDirective*, clang::MacroDirective*) /qdelacru/llvm-project/clang/lib/Lex/PPMacroExpansion.cpp:116:5

An example of the code that causes the assert failure:
```
...
```

During code completion in clangd, the macros will be loaded in loadMainFilePreambleMacros() by iterating over the macro names and calling PreambleIdentifiers->get(). Since these macro names are store in a StringSet (has StringMap underlying container), the order of the iterator is not guaranteed to be same as the order seen in the source code.

When clangd is trying to resolve nested macros it sometimes attempts to load them out of order which causes a macro to be stored twice. In the example above, ECHO2 macro gets resolved first, but since it uses another macro that has not been resolved it will try to resolve/store that as well. Now there are two MacroDirectives stored in the Preprocessor, ECHO and ECHO2. When clangd tries to load the next macro, ECHO, the preprocessor fails an assert in clang::Preprocessor::setLoadedMacroDirective() because there is already a MacroDirective stored for that macro name.

In this diff, I check if the macro is already inside the IdentifierTable and if it is skip it so that it is not resolved twice.

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D101870

Sample profile loader can be run in both LTO prelink and postlink. Currently the counts annoation in postilnk doesn't fully overwrite what's done in prelink. I'm adding a switch (`-overwrite-existing-weights=1`) to enable a full overwrite, which includes:

1. Clear old metadata for calls when their parent block has a zero count. This could be caused by prelink code duplication.

2. Clear indirect call metadata if somehow all the rest targets have a sum of zero count.

3. Overwrite branch weight for basic blocks.

With a CS profile, I was seeing #1 and rust-lang#2 help reduce code size by preventing post-sample ICP and CGSCC inliner working on obsolete metadata, which come from a partial global inlining in prelink.  It's not expected to work well for non-CS case with a less-accurate post-inline count quality.

It's worth calling out that some prelink optimizations can damage counts quality in an irreversible way. One example is the loop rotate optimization. Due to lack of exact loop entry count (profiling can only give loop iteration count and loop exit count), moving one iteration out of the loop body leaves the rest iteration count unknown. We had to turn off prelink loop rotate to achieve a better postlink counts quality. A even better postlink counts quality can be archived by turning off prelink CGSCC inlining which is not context-sensitive.

Reviewed By: wenlei, wmi

Differential Revision: https://reviews.llvm.org/D102537

1: Add CI. r=ltratt a=vext01



Co-authored-by: Edd Barrett <vext01@gmail.com>

Previously dangling samples were represented by INT64_MAX in sample profile while probes never executed were not reported. This was based on an observation that dangling probes were only at a smaller portion than zero-count probes. However, with compiler optimizations, dangling probes end up becoming at large portion of all probes in general and reporting them does not make sense from profile size point of view. This change flips sample reporting by reporting zero-count probes instead. This enabled dangling probe to be represented by none (missing entry in profile). This has a couple benefits:

1. Reducing sample profile size in optimize mode, even when the number of non-executed probes outperform the number of dangling probes, since INT64_MAX takes more space over 0 to encode.

2. Binary size savings. No need to encode dangling probe anymore, since missing probes are treated as dangling in the profile reader.

3. Reducing compiler work to track dangling probes. However, for probes that are real dead and removed, we still need the compiler to identify them so that they can be reported as zero-count, instead of mistreated as dangling probes.

4. Improving counts quality by respecting the counts already collected on the non-dangling copy of a probe. A probe, when duplicated, gets two copies at runtime. If one of them is dangling while the other is not, merging the two probes at profile generation time will cause the real samples collected on the non-dangling one to be discarded. Not reporting the dangling counterpart will keep the real samples.

5. Better readability.

6. Be consistent with non-CS dwarf line number based profile. Zero counts are trusted by the compiler counts inferencer while missing counts will be inferred by the compiler.

Note that the current patch does include any work for rust-lang#3. There will be follow-up changes.

For #1, I've seen for a large Facebook service, the text profile is reduced by 7%. For extbinary profile, the size of  LBRProfileSection is reduced by 35%.

For rust-lang#4, I have seen general counts quality for SPEC2017 is improved by 10%.

Reviewed By: wenlei, wlei, wmi

Differential Revision: https://reviews.llvm.org/D104129

Rust's v0 name mangling scheme [1] is easy to disambiguate from other
name mangling schemes because symbols always start with `_R`. The llvm
Demangle library supports demangling the Rust v0 scheme. Use it to
demangle Rust symbols.

Added unit tests that check simple symbols. Ran LLDB built with this
patch to debug some Rust programs compiled with the v0 name mangling
scheme. Confirmed symbol names were demangled as expected.

Note: enabling the new name mangling scheme requires a nightly
toolchain:

```
$ cat main.rs
fn main() {
    println!("Hello world!");
}
$ $(rustup which --toolchain nightly rustc) -Z symbol-mangling-version=v0 main.rs -g
$ /home/asm/hacking/llvm/build/bin/lldb ./main --one-line 'b main.rs:2'
(lldb) target create "./main"
Current executable set to '/home/asm/hacking/llvm/rust/main' (x86_64).
(lldb) b main.rs:2
Breakpoint 1: where = main`main::main + 4 at main.rs:2:5, address = 0x00000000000076a4
(lldb) r
Process 948449 launched: '/home/asm/hacking/llvm/rust/main' (x86_64)
warning: (x86_64) /lib64/libgcc_s.so.1 No LZMA support found for reading .gnu_debugdata section
Process 948449 stopped
* thread #1, name = 'main', stop reason = breakpoint 1.1
    frame #0: 0x000055555555b6a4 main`main::main at main.rs:2:5
   1    fn main() {
-> 2        println!("Hello world!");
   3    }
(lldb) bt
error: need to add support for DW_TAG_base_type '()' encoded with DW_ATE = 0x7, bit_size = 0
* thread #1, name = 'main', stop reason = breakpoint 1.1
  * frame #0: 0x000055555555b6a4 main`main::main at main.rs:2:5
    frame #1: 0x000055555555b78b main`<fn() as core::ops::function::FnOnce<()>>::call_once((null)=(main`main::main at main.rs:1), (null)=<unavailable>) at function.rs:227:5
    frame rust-lang#2: 0x000055555555b66e main`std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>(f=(main`main::main at main.rs:1)) at backtrace.rs:125:18
    frame rust-lang#3: 0x000055555555b851 main`std::rt::lang_start::<()>::{closure#0} at rt.rs:49:18
    frame rust-lang#4: 0x000055555556c9f9 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$F$GT$::call_once::h04259e4a34d07c2f at function.rs:259:13
    frame rust-lang#5: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panicking::try::do_call::hb8da45704d5cfbbf at panicking.rs:401:40
    frame rust-lang#6: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panicking::try::h4beadc19a78fec52 at panicking.rs:365:19
    frame rust-lang#7: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panic::catch_unwind::hc58016cd36ba81a4 at panic.rs:433:14
    frame rust-lang#8: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a at rt.rs:34:21
    frame rust-lang#9: 0x000055555555b830 main`std::rt::lang_start::<()>(main=(main`main::main at main.rs:1), argc=1, argv=0x00007fffffffcb18) at rt.rs:48:5
    frame rust-lang#10: 0x000055555555b6fc main`main + 28
    frame rust-lang#11: 0x00007ffff73f2493 libc.so.6`__libc_start_main + 243
    frame rust-lang#12: 0x000055555555b59e main`_start + 46
(lldb)
```

[1]: rust-lang/rust#60705

Reviewed By: clayborg, teemperor

Differential Revision: https://reviews.llvm.org/D104054

This patch adds the new system registers introduced in SME:

  - ID_AA64SMFR0_EL1 (ro) SME feature identifier.
  - SMCR_ELx (r/w) streaming mode control register for configuring
    effective SVE Streaming SVE Vector length when the PE is in
    Streaming SVE mode.
  - SVCR (r/w) streaming vector control register, visible at all
    exception levels. Provides access to PSTATE.SM and PSTATE.ZA
    using MSR and MRS instructions.
  - SMPRI_EL1 (r/w) streaming mode execution priority register.
  - SMPRIMAP_EL2 (r/w) streaming mode priority mapping register.
  - SMIDR_EL1 (ro) streaming mode identification register.
  - TPIDR2_EL0 (r/w) for use by SME software to manage per-thread
    SME context.
  - MPAMSM_EL1 (r/w) MPAM (v8.4) streaming mode register, for
    labelling memory accesses performed in streaming mode.

Also added in this patch are the SME mode change instructions.
Three MSR immediate instructions are implemented to set or clear
PSTATE.SM, PSTATE.ZA, or both respectively:

  - MSR SVCRSM, #<imm1>
  - MSR SVCRZA, #<imm1>
  - MSR SVCRSMZA, #<imm1>

The following smstart/smstop aliases are also implemented for
convenience:

  smstart    -> MSR SVCRSMZA, #1
  smstart sm -> MSR SVCRSM,   #1
  smstart za -> MSR SVCRZA,   #1

  smstop     -> MSR SVCRSMZA, #0
  smstop sm  -> MSR SVCRSM,   #0
  smstop za  -> MSR SVCRZA,   #0

The reference can be found here:
https://developer.arm.com/documentation/ddi0602/2021-06

Reviewed By: david-arm

Differential Revision: https://reviews.llvm.org/D105576

Since d564cfb moved
__hwasan_tag_mismatch4 this test has been reporting
a frame 0 of __hwasan_tag_mismatch_v2.

This failure can be seen on our bots:
https://lab.llvm.org/buildbot/#/builders/185/builds/170

Before the change:
 #0 0xaaaaba100e40 in main <...>/register-dump-read.c:21:10
After the change:
 #0 0xaaaab8494bec in __hwasan_tag_mismatch_v2 <...>/hwasan/hwasan_tag_mismatch_aarch64.S:147
 #1 0xaaaab84b4df8 in main <..>/register-dump-read.c:14:10

Update the test to check for a main frame as either frame
0 or frame 1.

In the latest Linux kernels synchronous tag faults
include the tag bits in their address.
This change adds logical and allocation tags to the
description of synchronous tag faults.
(asynchronous faults have no address)

Process 1626 stopped
* thread #1, name = 'a.out', stop reason = signal SIGSEGV: sync tag check fault (fault address: 0x900fffff7ff9010 logical tag: 0x9 allocation tag: 0x0)

This extends the existing description and will
show as much as it can on the rare occasion something
fails.

This change supports AArch64 MTE only but other
architectures could be added by extending the
switch at the start of AnnotateSyncTagCheckFault.
The rest of the function is generic code.

Tests have been added for synchronous and asynchronous
MTE faults.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105178

This commit contains two mildly separate concepts.

First, sending out reviews for things like this is a bit of a
complicated endeavor, since the reviewer list is relatively long, and I
generally rely on prior CLs in this area to find an authoritative list.
Life's quite a bit easier if phab usernames are readily available on the
doc. So part 1 is making those available.

Second, it seems to me that, at the moment, Phabricator makes the most
sense for membership changes (incl. security group nominations). My
reasoning for this is detailed in the diff, and to some extent in
comment #1 of this bug
<https://bugs.chromium.org/p/llvm/issues/detail?id=12#c1>. This change
adds prose to recommend the use of Phabricator for nominations as a
result.

Differential Revision: https://reviews.llvm.org/D106917

There is a SIGSEGV at `DeduceTemplateArgumentsByTypeMatch`. The bug [llvm#51171](https://bugs.llvm.org/show_bug.cgi?id=51171) was filled. The reproducer can be found at the bug description.

LIT test for the issue was added:
```
./bin/llvm-lit -v ../clang/test/SemaCXX/pr51171-crash.cpp
```

The debug stack trace is below:
```
 #0 0x00000000055afcb9 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/ivanmurashko/local/llvm-project/llvm/lib/Support/Unix/Signals.inc:565:22
 #1 0x00000000055afd70 PrintStackTraceSignalHandler(void*) /home/ivanmurashko/local/llvm-project/llvm/lib/Support/Unix/Signals.inc:632:1
 rust-lang#2 0x00000000055add2d llvm::sys::RunSignalHandlers() /home/ivanmurashko/local/llvm-project/llvm/lib/Support/Signals.cpp:97:20
 rust-lang#3 0x00000000055af701 SignalHandler(int) /home/ivanmurashko/local/llvm-project/llvm/lib/Support/Unix/Signals.inc:407:1
 rust-lang#4 0x00007ffff7bc2b20 __restore_rt sigaction.c:0:0
 rust-lang#5 0x00007ffff66a337f raise (/lib64/libc.so.6+0x3737f)
 rust-lang#6 0x00007ffff668ddb5 abort (/lib64/libc.so.6+0x21db5)
 rust-lang#7 0x00007ffff668dc89 _nl_load_domain.cold.0 loadmsgcat.c:0:0
 rust-lang#8 0x00007ffff669ba76 .annobin___GI___assert_fail.end assert.c:0:0
 rust-lang#9 0x000000000594b210 clang::QualType::getCommonPtr() const /home/ivanmurashko/local/llvm-project/clang/include/clang/AST/Type.h:684:5
rust-lang#10 0x0000000005a12ca6 clang::QualType::getCanonicalType() const /home/ivanmurashko/local/llvm-project/clang/include/clang/AST/Type.h:6467:36
rust-lang#11 0x0000000005a137a6 clang::ASTContext::getCanonicalType(clang::QualType) const /home/ivanmurashko/local/llvm-project/clang/include/clang/AST/ASTContext.h:2433:58
rust-lang#12 0x0000000009204584 DeduceTemplateArgumentsByTypeMatch(clang::Sema&, clang::TemplateParameterList*, clang::QualType, clang::QualType, clang::sema::TemplateDeductionInfo&, llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&, unsigned int, bool, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaTemplateDeduction.cpp:1355:54
rust-lang#13 0x000000000920df0d clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*, clang::TemplateArgumentListInfo*, clang::QualType, clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaTemplateDeduction.cpp:4354:47
rust-lang#14 0x0000000009012b09 (anonymous namespace)::AddressOfFunctionResolver::AddMatchingTemplateFunction(clang::FunctionTemplateDecl*, clang::DeclAccessPair const&) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:12026:38
rust-lang#15 0x0000000009013030 (anonymous namespace)::AddressOfFunctionResolver::FindAllFunctionsThatMatchTargetTypeExactly() /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:12119:9
rust-lang#16 0x0000000009012679 (anonymous namespace)::AddressOfFunctionResolver::AddressOfFunctionResolver(clang::Sema&, clang::Expr*, clang::QualType const&, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:11931:5
rust-lang#17 0x0000000009013c91 clang::Sema::ResolveAddressOfOverloadedFunction(clang::Expr*, clang::QualType, bool, clang::DeclAccessPair&, bool*) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:12286:42
rust-lang#18 0x0000000008fed85d IsStandardConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::StandardConversionSequence&, bool, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:1712:49
rust-lang#19 0x0000000008fec8ea TryImplicitConversion(clang::Sema&, clang::Expr*, clang::QualType, bool, clang::Sema::AllowedExplicit, bool, bool, bool, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:1433:27
rust-lang#20 0x0000000008ff90ba TryCopyInitialization(clang::Sema&, clang::Expr*, clang::QualType, bool, bool, bool, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:5273:71
rust-lang#21 0x00000000090024fb clang::Sema::AddBuiltinCandidate(clang::QualType*, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, unsigned int) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:7755:32
rust-lang#22 0x000000000900513f (anonymous namespace)::BuiltinOperatorOverloadBuilder::addGenericBinaryArithmeticOverloads() /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:8633:30
rust-lang#23 0x0000000009007624 clang::Sema::AddBuiltinOperatorCandidates(clang::OverloadedOperatorKind, clang::SourceLocation, llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:9205:51
rust-lang#24 0x0000000009018734 clang::Sema::LookupOverloadedBinOp(clang::OverloadCandidateSet&, clang::OverloadedOperatorKind, clang::UnresolvedSetImpl const&, llvm::ArrayRef<clang::Expr*>, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:13469:1
rust-lang#25 0x0000000009018d56 clang::Sema::CreateOverloadedBinOp(clang::SourceLocation, clang::BinaryOperatorKind, clang::UnresolvedSetImpl const&, clang::Expr*, clang::Expr*, bool, bool, clang::FunctionDecl*) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaOverload.cpp:13568:24
rust-lang#26 0x0000000008b24797 BuildOverloadedBinOp(clang::Sema&, clang::Scope*, clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaExpr.cpp:14606:65
rust-lang#27 0x0000000008b24ed5 clang::Sema::BuildBinOp(clang::Scope*, clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaExpr.cpp:14691:73
rust-lang#28 0x0000000008b245d4 clang::Sema::ActOnBinOp(clang::Scope*, clang::SourceLocation, clang::tok::TokenKind, clang::Expr*, clang::Expr*) /home/ivanmurashko/local/llvm-project/clang/lib/Sema/SemaExpr.cpp:14566:1
rust-lang#29 0x00000000085bfafb clang::Parser::ParseRHSOfBinaryExpression(clang::ActionResult<clang::Expr*, true>, clang::prec::Level) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseExpr.cpp:630:71
rust-lang#30 0x00000000085bd922 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseExpr.cpp:177:1
rust-lang#31 0x00000000085cbbcd clang::Parser::ParseExpressionList(llvm::SmallVectorImpl<clang::Expr*>&, llvm::SmallVectorImpl<clang::SourceLocation>&, llvm::function_ref<void ()>) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseExpr.cpp:3368:40
rust-lang#32 0x000000000857f49c clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseDecl.cpp:2416:5
rust-lang#33 0x000000000857df16 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::SourceLocation*, clang::Parser::ForRangeInit*) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseDecl.cpp:2092:65
rust-lang#34 0x000000000855f07b clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/Parser.cpp:1138:1
rust-lang#35 0x000000000855f136 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/Parser.cpp:1153:57
rust-lang#36 0x000000000855e644 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/Parser.cpp:975:58
rust-lang#37 0x000000000855d717 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/Parser.cpp:720:42
rust-lang#38 0x0000000008558e01 clang::ParseAST(clang::Sema&, bool, bool) /home/ivanmurashko/local/llvm-project/clang/lib/Parse/ParseAST.cpp:158:37
rust-lang#39 0x000000000627a221 clang::ASTFrontendAction::ExecuteAction() /home/ivanmurashko/local/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1058:11
rust-lang#40 0x0000000006bdcc31 clang::CodeGenAction::ExecuteAction() /home/ivanmurashko/local/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:1045:5
rust-lang#41 0x0000000006279b4d clang::FrontendAction::Execute() /home/ivanmurashko/local/llvm-project/clang/lib/Frontend/FrontendAction.cpp:955:38
rust-lang#42 0x00000000061c3fe9 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /home/ivanmurashko/local/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:974:42
rust-lang#43 0x00000000063f9c5e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /home/ivanmurashko/local/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:278:38
rust-lang#44 0x0000000002603a03 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /home/ivanmurashko/local/llvm-project/clang/tools/driver/cc1_main.cpp:246:40
rust-lang#45 0x00000000025f8a39 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /home/ivanmurashko/local/llvm-project/clang/tools/driver/driver.cpp:338:20
rust-lang#46 0x00000000025f9107 main /home/ivanmurashko/local/llvm-project/clang/tools/driver/driver.cpp:415:26
rust-lang#47 0x00007ffff668f493 __libc_start_main (/lib64/libc.so.6+0x23493)
rust-lang#48 0x00000000025f729e _start (/data/users/ivanmurashko/llvm-project/build/bin/clang-13+0x25f729e)
```

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D106583

In the latest Linux kernels synchronous tag faults
include the tag bits in their address.
This change adds logical and allocation tags to the
description of synchronous tag faults.
(asynchronous faults have no address)

Process 1626 stopped
* thread #1, name = 'a.out', stop reason = signal SIGSEGV: sync tag check fault (fault address: 0x900fffff7ff9010 logical tag: 0x9 allocation tag: 0x0)

This extends the existing description and will
show as much as it can on the rare occasion something
fails.

This change supports AArch64 MTE only but other
architectures could be added by extending the
switch at the start of AnnotateSyncTagCheckFault.
The rest of the function is generic code.

Tests have been added for synchronous and asynchronous
MTE faults.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105178

(cherry picked from commit d510b5f)

A libfuzzer run has discovered some inputs for which the demangler does
not terminate. When minimized, it looks like this: _Zcv1BIRT_EIS1_E

Deciphered:

_Z
cv    - conversion operator

      * result type
 1B   - "B"
 I    - template args begin
  R   - reference type              <.
   T_ - forward template reference   |  *
 E    - template args end            |  |
                                     |  |
      * parameter type               |  |
 I    - template args begin          |  |
  S1_ - substitution #1              * <'
 E    - template args end

The reason is: template-parameter refs in conversion operator result type
create forward-references, while substitutions are instantly resolved via
back-references. Together these can create a reference loop. It causes an
infinite loop in ReferenceType::collapse().

I see three possible ways to avoid these loops:

1. check if resolving a forward reference creates a loop and reject the
   invalid input (hard to traverse AST at this point)
2. check if a substitution contains a malicious forward reference and
   reject the invalid input (hard to traverse AST at this point;
   substitutions are quite common: may affect performance; hard to
   clearly detect loops at this point)
3. detect loops in ReferenceType::collapse() (cannot reject the input)

This patch implements (3) as seemingly the least-impact change. As a
side effect, such invalid input strings are not rejected and produce
garbage, however there are already similar guards in
`if (Printing) return;` checks.

Fixes https://llvm.org/PR51407

Differential Revision: https://reviews.llvm.org/D107712

Change 636428c enabled BlockingRegion hooks for pthread_once().
Unfortunately this seems to cause crashes on Mac OS X which uses
pthread_once() from locations that seem to result in crashes:

| ThreadSanitizer:DEADLYSIGNAL
| ==31465==ERROR: ThreadSanitizer: stack-overflow on address 0x7ffee73fffd8 (pc 0x00010807fd2a bp 0x7ffee7400050 sp 0x7ffee73fffb0 T93815)
|     #0 __tsan::MetaMap::GetSync(__tsan::ThreadState*, unsigned long, unsigned long, bool, bool) tsan_sync.cpp:195 (libclang_rt.tsan_osx_dynamic.dylib:x86_64+0x78d2a)
|     #1 __tsan::MutexPreLock(__tsan::ThreadState*, unsigned long, unsigned long, unsigned int) tsan_rtl_mutex.cpp:143 (libclang_rt.tsan_osx_dynamic.dylib:x86_64+0x6cefc)
|     rust-lang#2 wrap_pthread_mutex_lock sanitizer_common_interceptors.inc:4240 (libclang_rt.tsan_osx_dynamic.dylib:x86_64+0x3dae0)
|     rust-lang#3 flockfile <null>:2 (libsystem_c.dylib:x86_64+0x38a69)
|     rust-lang#4 puts <null>:2 (libsystem_c.dylib:x86_64+0x3f69b)
|     rust-lang#5 wrap_puts sanitizer_common_interceptors.inc (libclang_rt.tsan_osx_dynamic.dylib:x86_64+0x34d83)
|     rust-lang#6 __tsan::OnPotentiallyBlockingRegionBegin() cxa_guard_acquire.cpp:8 (foo:x86_64+0x100000e48)
|     rust-lang#7 wrap_pthread_once tsan_interceptors_posix.cpp:1512 (libclang_rt.tsan_osx_dynamic.dylib:x86_64+0x2f6e6)

From the stack trace it can be seen that the caller is unknown, and the
resulting stack-overflow seems to indicate that whoever the caller is
does not have enough stack space or otherwise is running in a limited
environment not yet ready for full instrumentation.

Fix it by reverting behaviour on Mac OS X to not call BlockingRegion
hooks from pthread_once().

Reported-by: azharudd

Reviewed By: glider

Differential Revision: https://reviews.llvm.org/D108305

The semantics of tail predication loops means that the value of LR as an
instruction is executed determines the predicate. In other words:

mov r3, rust-lang#3
DLSTP lr, r3        // Start tail predication, lr==3
VADD.s32 q0, q1, q2 // Lanes 0,1 and 2 are updated in q0.
mov lr, #1
VADD.s32 q0, q1, q2 // Only first lane is updated.

This means that the value of lr cannot be spilled and re-used in tail
predication regions without potentially altering the behaviour of the
program. More lanes than required could be stored, for example, and in
the case of a gather those lanes might not have been setup, leading to
alignment exceptions.

This patch adds a new lr predicate operand to MVE instructions in order
to keep a reference to the lr that they use as a tail predicate. It will
usually hold the zeroreg meaning not predicated, being set to the LR phi
value in the MVETPAndVPTOptimisationsPass. This will prevent it from
being spilled anywhere that it needs to be used.

A lot of tests needed updating.

Differential Revision: https://reviews.llvm.org/D107638

This reverts commit a2768b4.

Breaks sanitizer-x86_64-linux-fast buildbot:
https://lab.llvm.org/buildbot/#/builders/5/builds/11334

Log snippet:
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80
FAIL: LLVM :: Transforms/SampleProfile/early-inline.ll (65549 of 78729)
******************** TEST 'LLVM :: Transforms/SampleProfile/early-inline.ll' FAILED ********************
Script:
--
: 'RUN: at line 1';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/early-inline.ll -instcombine -sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/einline.prof -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/early-inline.ll
--
Exit Code: 2
Command Output (stderr):
--
/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53: runtime error: member call on null pointer of type 'llvm::sampleprof::FunctionSamples'
    #0 0x5a730f8 in shouldInlineCandidate /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53
    #1 0x5a730f8 in (anonymous namespace)::SampleProfileLoader::tryInlineCandidate((anonymous namespace)::InlineCandidate&, llvm::SmallVector<llvm::CallBase*, 8u>*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1178:21
    rust-lang#2 0x5a6cda6 in inlineHotFunctions /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1105:13
    rust-lang#3 0x5a6cda6 in (anonymous namespace)::SampleProfileLoader::emitAnnotations(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1633:16
    rust-lang#4 0x5a5fcbe in runOnFunction /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:2008:12
    rust-lang#5 0x5a5fcbe in (anonymous namespace)::SampleProfileLoader::runOnModule(llvm::Module&, llvm::AnalysisManager<llvm::Module>*, llvm::ProfileSummaryInfo*, llvm::CallGraph*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1922:15
    rust-lang#6 0x5a5de55 in llvm::SampleProfileLoaderPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:2038:21
    rust-lang#7 0x6552a01 in llvm::detail::PassModel<llvm::Module, llvm::SampleProfileLoaderPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:88:17
    rust-lang#8 0x57f807c in llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/IR/PassManager.h:526:21
    rust-lang#9 0x37c8522 in llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::StringRef>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/opt/NewPMDriver.cpp:489:7
    rust-lang#10 0x37e7c11 in main /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/opt/opt.cpp:830:12
    rust-lang#11 0x7fbf4de4009a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)
    rust-lang#12 0x379e519 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt+0x379e519)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53 in
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/early-inline.ll
--
********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80
FAIL: LLVM :: Transforms/SampleProfile/inline-cold.ll (65643 of 78729)
******************** TEST 'LLVM :: Transforms/SampleProfile/inline-cold.ll' FAILED ********************
Script:
--
: 'RUN: at line 4';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll -sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/inline-cold.prof -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=NOTINLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
: 'RUN: at line 5';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll -passes=sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/inline-cold.prof -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=NOTINLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
: 'RUN: at line 8';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll -sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/inline-cold.prof -sample-profile-inline-size -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=INLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
: 'RUN: at line 11';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll -passes=sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/inline-cold.prof -sample-profile-inline-size -sample-profile-cold-inline-threshold=9999999 -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=INLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
: 'RUN: at line 14';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt < /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll -passes=sample-profile -sample-profile-file=/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/Inputs/inline-cold.prof -sample-profile-inline-size -sample-profile-cold-inline-threshold=-500 -S | /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=NOTINLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
--
Exit Code: 2
Command Output (stderr):
--
/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53: runtime error: member call on null pointer of type 'llvm::sampleprof::FunctionSamples'
    #0 0x5a730f8 in shouldInlineCandidate /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53
    #1 0x5a730f8 in (anonymous namespace)::SampleProfileLoader::tryInlineCandidate((anonymous namespace)::InlineCandidate&, llvm::SmallVector<llvm::CallBase*, 8u>*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1178:21
    rust-lang#2 0x5a6cda6 in inlineHotFunctions /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1105:13
    rust-lang#3 0x5a6cda6 in (anonymous namespace)::SampleProfileLoader::emitAnnotations(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1633:16
    rust-lang#4 0x5a5fcbe in runOnFunction /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:2008:12
    rust-lang#5 0x5a5fcbe in (anonymous namespace)::SampleProfileLoader::runOnModule(llvm::Module&, llvm::AnalysisManager<llvm::Module>*, llvm::ProfileSummaryInfo*, llvm::CallGraph*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1922:15
    rust-lang#6 0x5a5de55 in llvm::SampleProfileLoaderPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:2038:21
    rust-lang#7 0x6552a01 in llvm::detail::PassModel<llvm::Module, llvm::SampleProfileLoaderPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:88:17
    rust-lang#8 0x57f807c in llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/IR/PassManager.h:526:21
    rust-lang#9 0x37c8522 in llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::StringRef>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/opt/NewPMDriver.cpp:489:7
    rust-lang#10 0x37e7c11 in main /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/opt/opt.cpp:830:12
    rust-lang#11 0x7fcd534a209a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)
    rust-lang#12 0x379e519 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/opt+0x379e519)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Transforms/IPO/SampleProfile.cpp:1309:53 in
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /b/sanitizer-x86_64-linux-fast/build/llvm_build_ubsan/bin/FileCheck -check-prefix=INLINE /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/Transforms/SampleProfile/inline-cold.ll
--
********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
********************
Failed Tests (2):
  LLVM :: Transforms/SampleProfile/early-inline.ll
  LLVM :: Transforms/SampleProfile/inline-cold.ll