This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
This patch teaches clang to parse statements on the global scope to allow:
```
./bin/clang-repl
clang-repl> int i = 12;
clang-repl> ++i;
clang-repl> extern "C" int printf(const char*,...);
clang-repl> printf("%d\n", i);
13
clang-repl> %quit
```
Generally, disambiguating between statements and declarations is a non-trivial
task for a C++ parser. The challenge is to allow both standard C++ to be
translated as if this patch does not exist and in the cases where the user typed
a statement to be executed as if it were in a function body.
Clang's Parser does pretty well in disambiguating between declarations and
expressions. We have added DisambiguatingWithExpression flag which allows us to
preserve the existing and optimized behavior where needed and implement the
extra rules for disambiguating. Only few cases require additional attention:
* Constructors/destructors -- Parser::isConstructorDeclarator was used in to
disambiguate between ctor-looking declarations and statements on the global
scope(eg. `Ns::f()`).
* The template keyword -- the template keyword can appear in both declarations
and statements. This patch considers the template keyword to be a declaration
starter which breaks a few cases in incremental mode which will be tackled
later.
* The inline (and similar) keyword -- looking at the first token in many cases
allows us to classify what is a declaration.
* Other language keywords and specifiers -- ObjC/ObjC++/OpenCL/OpenMP rely on
pragmas or special tokens which will be handled in subsequent patches.
The patch conceptually models a "top-level" statement into a TopLevelStmtDecl.
The TopLevelStmtDecl is lowered into a void function with no arguments.
We attach this function to the global initializer list to execute the statement
blocks in the correct order.
Differential revision: https://reviews.llvm.org/D127284
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.
Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.
KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.
A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:
```
.c:
int f(void);
int (*p)(void) = f;
p();
.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```
Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.
As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.
Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.
Relands 67504c9549 with a fix for
32-bit builds.
Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay
Differential Revision: https://reviews.llvm.org/D119296
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.
Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.
KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.
A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:
```
.c:
int f(void);
int (*p)(void) = f;
p();
.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```
Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.
As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.
Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.
Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay
Differential Revision: https://reviews.llvm.org/D119296
Fixes https://github.com/llvm/llvm-project/issues/55804
The lexing order is already bookkept in DelayedCXXInitPosition but we
were not using it based on the wrong assumption that inline variable is
unordered. This patch fixes it by ordering entries in llvm.global_ctors
by orders in DelayedCXXInitPosition.
for llvm.global_ctors entries without a lexing order, ordering them by
the insertion order.
(This *mostly* orders the template instantiation in
https://reviews.llvm.org/D126341 intuitively, minus one tweak for which I'll
submit a separate patch.)
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D127233
In D130807 we added the `skipprofile` attribute. This commit
changes the format so we can either `forbid` or `skip` profiling
functions by adding the `noprofile` or `skipprofile` attributes,
respectively. The behavior of the original format remains
unchanged.
Also, add the `skipprofile` attribute when using
`-fprofile-function-groups`.
This was originally landed as https://reviews.llvm.org/D130808 but was
reverted due to a Windows test failure.
Differential Revision: https://reviews.llvm.org/D131195
In D130807 we added the `skipprofile` attribute. This commit
changes the format so we can either `forbid` or `skip` profiling
functions by adding the `noprofile` or `skipprofile` attributes,
respectively. The behavior of the original format remains
unchanged.
Also, add the `skipprofile` attribute when using
`-fprofile-function-groups`.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D130808
The re-land fixes module map module dependencies seen on Greendragon, but
not in the clang test suite.
---
Currently we only implement this for the Itanium ABI since the correct
mangling for the initializers in other ABIs is not yet known.
Intended result:
For a module interface [which includes partition interface and implementation
units] (instead of the generic CXX initializer) we emit a module init that:
- wraps the contained initializations in a control variable to ensure that
the inits only happen once, even if a module is imported many times by
imports of the main unit.
- calls module initializers for imported modules first. Note that the
order of module import is not significant, and therefore neither is the
order of imported module initializers.
- We then call initializers for the Global Module Fragment (if present)
- We then call initializers for the current module.
- We then call initializers for the Private Module Fragment (if present)
For a module implementation unit, or a non-module TU that imports at least one
module we emit a regular CXX init that:
- Calls the initializers for any imported modules first.
- Then proceeds as normal with remaining inits.
For all module unit kinds we include a global constructor entry, this allows
for the (in most cases unusual) possibility that a module object could be
included in a final binary without a specific call to its initializer.
Implementation:
- We provide the module pointer in the AST Context so that CodeGen can act
on it and its sub-modules.
- We need to account for module build lines like this:
` clang -cc1 -std=c++20 Foo.pcm -emit-obj -o Foo.o` or
` clang -cc1 -std=c++20 -xc++-module Foo.cpp -emit-obj -o Foo.o`
- in order to do this, we add to ParseAST to set the module pointer in
the ASTContext, once we establish that this is a module build and we
know the module pointer. To be able to do this, we make the query for
current module public in Sema.
- In CodeGen, we determine if the current build requires a CXX20-style module
init and, if so, we defer any module initializers during the "Eagerly
Emitted" phase.
- We then walk the module initializers at the end of the TU but before
emitting deferred inits (which adds any hidden and static ones, fixing
https://github.com/llvm/llvm-project/issues/51873 ).
- We then proceed to emit the deferred inits and continue to emit the CXX
init function.
Differential Revision: https://reviews.llvm.org/D126189
Add two options, `-fprofile-function-groups=N` and `-fprofile-selected-function-group=i` used to partition functions into `N` groups and only instrument the functions in group `i`. Similar options were added to xray in https://reviews.llvm.org/D87953 and the goal is the same; to reduce instrumented size overhead by spreading the overhead across multiple builds. Raw profiles from different groups can be added like normal using the `llvm-profdata merge` command.
Reviewed By: ianlevesque
Differential Revision: https://reviews.llvm.org/D129594
This patch adds a new field called EmittedDeferredDecls in CodeGenModule
that keeps track of decls that were deferred and have been emitted.
The intention of this patch is to solve issues in the incremental c++,
we'll lose info of decls that are lazily emitted when we undo their
usage.
See example below:
clang-repl> inline int foo() { return 42;}
clang-repl> int bar = foo();
clang-repl> %undo
clang-repl> int baz = foo();
JIT session error: Symbols not found: [ _Z3foov ]
error: Failed to materialize symbols: { (main, { baz, $.incr_module_2.inits.0,
orc_init_func.incr_module_2 }) }
Signed-off-by: Jun Zhang <jun@junz.org>
Differential Revision: https://reviews.llvm.org/D128782
Currently we only implement this for the Itanium ABI since the correct
mangling for the initializers in other ABIs is not yet known.
Intended result:
For a module interface [which includes partition interface and implementation
units] (instead of the generic CXX initializer) we emit a module init that:
- wraps the contained initializations in a control variable to ensure that
the inits only happen once, even if a module is imported many times by
imports of the main unit.
- calls module initializers for imported modules first. Note that the
order of module import is not significant, and therefore neither is the
order of imported module initializers.
- We then call initializers for the Global Module Fragment (if present)
- We then call initializers for the current module.
- We then call initializers for the Private Module Fragment (if present)
For a module implementation unit, or a non-module TU that imports at least one
module we emit a regular CXX init that:
- Calls the initializers for any imported modules first.
- Then proceeds as normal with remaining inits.
For all module unit kinds we include a global constructor entry, this allows
for the (in most cases unusual) possibility that a module object could be
included in a final binary without a specific call to its initializer.
Implementation:
- We provide the module pointer in the AST Context so that CodeGen can act
on it and its sub-modules.
- We need to account for module build lines like this:
` clang -cc1 -std=c++20 Foo.pcm -emit-obj -o Foo.o` or
` clang -cc1 -std=c++20 -xc++-module Foo.cpp -emit-obj -o Foo.o`
- in order to do this, we add to ParseAST to set the module pointer in
the ASTContext, once we establish that this is a module build and we
know the module pointer. To be able to do this, we make the query for
current module public in Sema.
- In CodeGen, we determine if the current build requires a CXX20-style module
init and, if so, we defer any module initializers during the "Eagerly
Emitted" phase.
- We then walk the module initializers at the end of the TU but before
emitting deferred inits (which adds any hidden and static ones, fixing
https://github.com/llvm/llvm-project/issues/51873 ).
- We then proceed to emit the deferred inits and continue to emit the CXX
init function.
Differential Revision: https://reviews.llvm.org/D126189
Information in the function `Prologue Data` is intentionally opaque.
When a function with `Prologue Data` is duplicated. The self (global
value) references inside `Prologue Data` is still pointing to the
original function. This may cause errors like `fatal error: error in backend: Cannot represent a difference across sections`.
This patch detaches the information from function `Prologue Data`
and attaches it to a function metadata node.
This and D116130 fix https://github.com/llvm/llvm-project/issues/49689.
Reviewed By: pcc
Differential Revision: https://reviews.llvm.org/D115844
Add option -fhip-kernel-arg-name to emit kernel argument
name metadata, which is needed for certain HIP applications.
Reviewed by: Artem Belevich, Fangrui Song, Brian Sumner
Differential Revision: https://reviews.llvm.org/D128022
This reverts commits:
d3ddc251acd90eecff5c
It turned out there're some options turned on that leaks the memory
intentionally, which fires the asan builds after the patch being
applied. The issue has been fixed in
7bc00ce5cd, so reland it.
Below is the original commit message:
The intent of this patch is to selectively carry some states over to
the Builder so we won't lose the information of the previous symbols.
This used to be several downstream patches of Cling, it aims to fix
errors in Clang Interpreter when trying to use inline functions.
Before this patch:
clang-repl> inline int foo() { return 42;}
clang-repl> int x = foo();
JIT session error: Symbols not found: [ _Z3foov ]
error: Failed to materialize symbols:
{ (main, { x, $.incr_module_1.__inits.0, __orc_init_func.incr_module_1 }) }
Co-authored-by: Axel Naumann <Axel.Naumann@cern.ch>
Signed-off-by: Jun Zhang <jun@junz.org>
This reverts commits:
d3ddc251acd90eecff5c
This relands below commit with asan fix:
The intent of this patch is to selectively carry some states over to
the Builder so we won't lose the information of the previous symbols.
This used to be several downstream patches of Cling, it aims to fix
errors in Clang Interpreter when trying to use inline functions.
Before this patch:
clang-repl> inline int foo() { return 42;}
clang-repl> int x = foo();
JIT session error: Symbols not found: [ _Z3foov ]
error: Failed to materialize symbols:
{ (main, { x, $.incr_module_1.__inits.0, __orc_init_func.incr_module_1 }) }
Co-authored-by: Axel Naumann <Axel.Naumann@cern.ch>
Signed-off-by: Jun Zhang <jun@junz.org>
Differential Revision: https://reviews.llvm.org/D127730
RE-LAND (reverts a revert):
This reverts commit 8e1f47b596.
This patch adds generation of sanitizer metadata attributes (which were
added in D126100) to the clang frontend.
We still currently generate the llvm.asan.globals that's consumed by
the IR pass, but the plan is to eventually migrate off of that onto
purely debuginfo and these IR attributes.
Reviewed By: vitalybuka, kstoimenov
Differential Revision: https://reviews.llvm.org/D126929
This patch adds generation of sanitizer metadata attributes (which were
added in D126100) to the clang frontend.
We still currently generate the `llvm.asan.globals` that's consumed by
the IR pass, but the plan is to eventually migrate off of that onto
purely debuginfo and these IR attributes.
Reviewed By: vitalybuka, kstoimenov
Differential Revision: https://reviews.llvm.org/D126929
The option mdefault-visibility-export-mapping is created to allow
mapping default visibility to an explicit shared library export
(e.g. dllexport). Exactly how and if this is manifested is target
dependent (since it depends on how they map dllexport in the IR).
Three values are provided for the option:
* none: the default and behavior without the option, no additional export linkage information is created.
* explicit: add the export for entities with explict default visibility from the source, including RTTI
* all: add the export for all entities with default visibility
This option is useful for targets which do not export symbols as part of
their usual default linkage behaviour (e.g. AIX), such targets
traditionally specified such information in external files (e.g. export
lists), but this mapping allows them to use the visibility information
typically used for this purpose on other (e.g. ELF) platforms.
This relands commit: 8c8a2679a2
with fixes for the compile time and assert problems that were reported
by:
* making shouldMapVisibilityToDLLExport inline and provide an early return
in the case where no mapping is in effect (aka non-AIX platforms)
* don't try to export RTTI types which we will give internal linkage to
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D126340
The intent of this patch is to selectively carry some states over to
the Builder so we won't lose the information of the previous symbols.
This used to be several downstream patches of Cling, it aims to fix
errors in Clang Interpreter when trying to use inline functions.
Before this patch:
clang-repl> inline int foo() { return 42;}
clang-repl> int x = foo();
JIT session error: Symbols not found: [ _Z3foov ]
error: Failed to materialize symbols:
{ (main, { x, $.incr_module_1.__inits.0, __orc_init_func.incr_module_1 }) }
Co-authored-by: Axel Naumann <Axel.Naumann@cern.ch>
Signed-off-by: Jun Zhang <jun@junz.org>
Differential Revision: https://reviews.llvm.org/D126781
This caused assertions, see comment on the code review:
llvm/clang/lib/AST/Decl.cpp:1510:
clang::LinkageInfo clang::LinkageComputer::getLVForDecl(const clang::NamedDecl *, clang::LVComputationKind):
Assertion `D->getCachedLinkage() == LV.getLinkage()' failed.
> The option mdefault-visibility-export-mapping is created to allow
> mapping default visibility to an explicit shared library export
> (e.g. dllexport). Exactly how and if this is manifested is target
> dependent (since it depends on how they map dllexport in the IR).
>
> Three values are provided for the option:
>
> * none: the default and behavior without the option, no additional export linkage information is created.
> * explicit: add the export for entities with explict default visibility from the source, including RTTI
> * all: add the export for all entities with default visibility
>
> This option is useful for targets which do not export symbols as part of
> their usual default linkage behaviour (e.g. AIX), such targets
> traditionally specified such information in external files (e.g. export
> lists), but this mapping allows them to use the visibility information
> typically used for this purpose on other (e.g. ELF) platforms.
>
> Reviewed By: MaskRay
>
> Differential Revision: https://reviews.llvm.org/D126340
This reverts commit 8c8a2679a2.
The option mdefault-visibility-export-mapping is created to allow
mapping default visibility to an explicit shared library export
(e.g. dllexport). Exactly how and if this is manifested is target
dependent (since it depends on how they map dllexport in the IR).
Three values are provided for the option:
* none: the default and behavior without the option, no additional export linkage information is created.
* explicit: add the export for entities with explict default visibility from the source, including RTTI
* all: add the export for all entities with default visibility
This option is useful for targets which do not export symbols as part of
their usual default linkage behaviour (e.g. AIX), such targets
traditionally specified such information in external files (e.g. export
lists), but this mapping allows them to use the visibility information
typically used for this purpose on other (e.g. ELF) platforms.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D126340
Refactor the code that handles the align clause of 'omp allocate' so
it can be used with globals as well as local variables.
Differential Revision: https://reviews.llvm.org/D126426
CUDA requires that static variables be visible to the host when
offloading. However, The standard semantics of a stiatc variable dictate
that it should not be visible outside of the current file. In order to
access it from the host we need to perform "externalization" on the
static variable on the device. This requires generating a semi-unique
name that can be affixed to the variable as to not cause linker errors.
This is currently done using the CUID functionality, an MD5 hash value
set up by the clang driver. This allows us to achieve is mostly unique
ID that is unique even between multiple compilations of the same file.
However, this is not always availible. Instead, this patch uses the
unique ID from the file to generate a unique symbol name. This will
create a unique name that is consistent between the host and device side
compilations without requiring the CUID to be entered by the driver. The
one downside to this is that we are no longer stable under multiple
compilations of the same file. However, this is a very niche use-case
and is not supported by Nvidia's CUDA compiler so it likely to be good
enough.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D125904
The DXIL validator version option(/validator-version) decide the validator version when compile hlsl.
The format is major.minor like 1.0.
In normal case, the value of validator version should be got from DXIL validator. Before we got DXIL validator ready for llvm/main, DXIL validator version option is added first to set validator version.
It will affect code generation for DXIL, so it is treated as a code gen option.
A new member std::string DxilValidatorVersion is added to clang::CodeGenOptions.
Then CGHLSLRuntime is added to clang::CodeGenModule.
It is used to translate clang::CodeGenOptions::DxilValidatorVersion into a ModuleFlag under key "dx.valver" at end of clang code generation.
Reviewed By: beanz
Differential Revision: https://reviews.llvm.org/D123884
clang to emit DWARF information for global alias variable as
DW_TAG_imported_declaration. This change also handles nested
(recursive) imported declarations.
Reviewed by: dblaikie, aprantl
Differential Revision: https://reviews.llvm.org/D120989
This change merges code for emit of target and target_clones multiversion
resolver functions and, in doing so, corrects handling of target_clones
functions that are declared but not defined. Previously, a use of such
a target_clones function would result in an attempted emit of an ifunc
that referenced an undefined resolver function. Ifunc references to
undefined resolver functions are not allowed and, when the LLVM verifier
is not disabled (via '-disable-llvm-verifier'), resulted in the verifier
issuing a "IFunc resolver must be a definition" error and aborting the
compilation. With this change, ifuncs and resolver function definitions
are always emitted for used target_clones functions regardless of whether
the target_clones function is defined (if the function is defined, then
the ifunc and resolver are emitted regardless of whether the function is
used).
This change has the side effect of causing target_clones variants and
resolver functions to be emitted in a different order than they were
previously. This is harmless and is reflected in the updated tests.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D122958
Previously, GetOrCreateMultiVersionResolver() required the caller to provide
a GlobalDecl along with an llvm::type and FunctionDecl. The latter two can be
cheaply obtained from the first, and the llvm::type parameter is not always
used, so requiring the caller to provide them was unnecessary and created the
possibility that callers would pass an inconsistent set. This change simplifies
the interface to only require the GlobalDecl value.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D122956
We expect that `extern "C"` static functions to be usable in things like
inline assembly, as well as ifuncs:
See the bug report here: https://github.com/llvm/llvm-project/issues/54549
However, we were diagnosing this as 'not defined', because the
ifunc's attempt to look up its resolver would generate a declared IR
function.
Additionally, as background, the way we allow these static extern "C"
functions to work in inline assembly is by making an alias with the C
mangling in MOST situations to the version we emit with
internal-linkage/mangling.
The problem here was multi-fold: First- We generated the alias after the
ifunc was checked, so the function by that name didn't exist yet.
Second, the ifunc's generation caused a symbol to exist under the name
of the alias already (the declared function above), which suppressed the
alias generation.
This patch fixes all of this by moving the checking of ifuncs/CFE aliases
until AFTER we have generated the extern-C alias. Then, it does a
'fixup' around the GlobalIFunc to make sure we correct the reference.
Differential Revision: https://reviews.llvm.org/D122608
This builtin returns the address of a global instance of the
`std::source_location::__impl` type, which must be defined (with an
appropriate shape) before calling the builtin.
It will be used to implement std::source_location in libc++ in a
future change. The builtin is compatible with GCC's implementation,
and libstdc++'s usage. An intentional divergence is that GCC declares
the builtin's return type to be `const void*` (for
ease-of-implementation reasons), while Clang uses the actual type,
`const std::source_location::__impl*`.
In order to support this new functionality, I've also added a new
'UnnamedGlobalConstantDecl'. This artificial Decl is modeled after
MSGuidDecl, and is used to represent a generic concept of an lvalue
constant with global scope, deduplicated by its value. It's possible
that MSGuidDecl itself, or some of the other similar sorts of things
in Clang might be able to be refactored onto this more-generic
concept, but there's enough special-case weirdness in MSGuidDecl that
I gave up attempting to share code there, at least for now.
Finally, for compatibility with libstdc++'s <source_location> header,
I've added a second exception to the "cannot cast from void* to T* in
constant evaluation" rule. This seems a bit distasteful, but feels
like the best available option.
Reviewers: aaron.ballman, erichkeane
Differential Revision: https://reviews.llvm.org/D120159
The default construction of constructor functions by LLVM tends to make
them have internal linkage. When we call a ctor / dtor function in the
target region we are actually creating a kernel that is called at
registration. Because the ctor is a kernel we need to make sure it's
externally visible so we can actually call it. This prevented AMDGPU
from correctly using constructors while NVPTX could use them simply
because it ignored internal visibility.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D122504
CodeGenModule::DeferredDecls std::map::operator[] seem to be hot especially while code generating huge compilation units.
In such cases using DenseMap instead gives observable compile time improvement. Patch was tested on Linux build with default config acting as benchmark.
Build was performed on isolated CPU cores in silent x86-64 Linux environment following: https://llvm.org/docs/Benchmarking.html#linux rules.
Compile time statistics diff produced by perf and time before and after change are following:
instructions -0.15%, cycles -0.7%, max-rss +0.65%.
Using StringMap instead DenseMap doesn't bring any visible gains.
Differential Revision: https://reviews.llvm.org/D118169
Cases where there is a mangling of a cpu-dispatch/cpu-specific function
before the function becomes 'multiversion' (such as a member function)
causes the wrong name to be emitted for one of the variants/resolver,
since the name is cached. Make sure we invalidate the cache in
cpu-dispatch/cpu-specific modes, like we previously did for just target
multiversioning.
Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.
This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.
Link: https://github.com/ClangBuiltLinux/linux/issues/1353
Depends on D108478
Reviewed By: pcc, rjmccall
Differential Revision: https://reviews.llvm.org/D108479
See discussion in D51650, this change was a little aggressive in an
error while doing a 'while we were here', so this removes that error
condition, as it is apparently useful.
This reverts commit bb4934601d.
Kazu Hirata