[Clang] Add fake use emission to Clang with -fextend-lifetimes (#110102)

Following the previous patch which adds the "extend lifetimes" flag
without (almost) any functionality, this patch adds the r

[Clang] Add fake use emission to Clang with -fextend-lifetimes (#110102)

Following the previous patch which adds the "extend lifetimes" flag
without (almost) any functionality, this patch adds the real feature by
allowing Clang to emit fake uses. These are emitted as a new form of cleanup,
set for variable addresses, which just emits a fake use intrinsic when the
variable falls out of scope. The code for achieving this is simple, with most
of the logic centered on determining whether to emit a fake use for a given
address, and on ensuring that fake uses are ignored in a few cases.

Co-authored-by: Stephen Tozer <stephen.tozer@sony.com>

show more ...

[HLSL] Fix global resource initialization (#123394)

Create separate resource initialization function for each resource and
add them to CodeGenModule's `CXXGlobalInits` list.
Fixes #120636 and addr

[HLSL] Fix global resource initialization (#123394)

Create separate resource initialization function for each resource and
add them to CodeGenModule's `CXXGlobalInits` list.
Fixes #120636 and addresses this [comment
](https://github.com/llvm/llvm-project/pull/119755/files#r1894093603).

show more ...

[Coverage] Introduce the type `CounterPair` for RegionCounterMap. NFC. (#112724)

`CounterPair` can hold `<uint32_t, uint32_t>` instead of current
`unsigned`, to hold also the counter number of SkipP

[Coverage] Introduce the type `CounterPair` for RegionCounterMap. NFC. (#112724)

`CounterPair` can hold `<uint32_t, uint32_t>` instead of current
`unsigned`, to hold also the counter number of SkipPath. For now, this
change provides the skeleton and only `CounterPair::Executed` is used.

Each counter number can have `None` to suppress emitting counter
increment. 2nd element `Skipped` is initialized as `None` by default,
since most `Stmt*` don't have a pair of counters.

This change also provides stubs for the verifier. I'll provide the impl
of verifier for `+Asserts` later.

`markStmtAsUsed(bool, Stmt*)` may be used to inform that other side
counter may not emitted.

`markStmtMaybeUsed(S)` may be used for the `Stmt` and its inner will be
excluded for emission in the case of skipping by constant folding. I put
it into places where I found.

`verifyCounterMap()` will check the coverage map and the counter map,
and can be used to report inconsistency.

These verifier methods shall be eliminated in `-Asserts`.


https://discourse.llvm.org/t/rfc-integrating-singlebytecoverage-with-branch-coverage/82492

show more ...

[clang codegen] Add CreateRuntimeFunction overload that takes a clang type. (#113506)

Correctly computing the LLVM types/attributes is complicated in general,
so add a variant which does that for y

[clang codegen] Add CreateRuntimeFunction overload that takes a clang type. (#113506)

Correctly computing the LLVM types/attributes is complicated in general,
so add a variant which does that for you.

show more ...

[clang] Use {} instead of std::nullopt to initialize empty ArrayRef (#109399)

Follow up to #109133.

[clang] Deduplicate the logic that only warns once when stack is almost full (#112552)

Zero diff in behavior.

Reapply "[clang][CodeGen] Zero init unspecified fields in initializers in C" (#109898) (#110051)

This reverts commit d50eaac12f0cdfe27e942290942b06889ab12a8c. Also fixes
a bug calculating offsets f

Reapply "[clang][CodeGen] Zero init unspecified fields in initializers in C" (#109898) (#110051)

This reverts commit d50eaac12f0cdfe27e942290942b06889ab12a8c. Also fixes
a bug calculating offsets for bit fields in the original patch.

show more ...

[clang] Fix segmentation fault caused by stack overflow on deeply nested expressions (#111701)

Done by calling clang::runWithSufficientStackSpace().
Added CodeGenModule::runWithSufficientStackSpace

[clang] Fix segmentation fault caused by stack overflow on deeply nested expressions (#111701)

Done by calling clang::runWithSufficientStackSpace().
Added CodeGenModule::runWithSufficientStackSpace() method similar to the
one in Sema to provide a single warning when this triggers
Fixes: #111699

show more ...

Revert "[clang][CodeGen] Zero init unspecified fields in initializers in C" (#109898)

Reverts llvm/llvm-project#97121

Causing failures on LNT bots; log shows a crash in
ConstStructBuilder::Build

Revert "[clang][CodeGen] Zero init unspecified fields in initializers in C" (#109898)

Reverts llvm/llvm-project#97121

Causing failures on LNT bots; log shows a crash in
ConstStructBuilder::BuildStruct.

show more ...

[clang][CodeGen] Zero init unspecified fields in initializers in C (#97121)

When an initializer is provided to a variable, the Linux kernel relied
on the compiler to zero-initialize unspecified fie

[clang][CodeGen] Zero init unspecified fields in initializers in C (#97121)

When an initializer is provided to a variable, the Linux kernel relied
on the compiler to zero-initialize unspecified fields, as clarified in
https://www.spinics.net/lists/netdev/msg1007244.html.

But clang doesn't guarantee this:
1. For a union type, if an empty initializer is given, clang only
initializes bytes for the first field, left bytes for other (larger)
fields are marked as undef. Accessing those undef bytes can lead
to undefined behaviors.
2. For a union type, if an initializer explicitly sets a field, left
bytes for other (larger) fields are marked as undef.
3. When an initializer is given, clang doesn't zero initialize padding.

So this patch makes the following change:
1. In C, when an initializer is provided for a variable, zero-initialize
undef and padding fields in the initializer.
2. Document the change in LanguageExtensions.rst.

As suggested in
https://github.com/llvm/llvm-project/issues/78034#issuecomment-2183437928,
the change isn't required by C23, but it's standards conforming to do
so.

Fixes: https://github.com/llvm/llvm-project/issues/97459

show more ...

[clang-repl] [codegen] Reduce the state in TBAA. NFC for static compilation. (#98138)

In incremental compilation clang works with multiple `llvm::Module`s.
Our current approach is to create a CodeG

[clang-repl] [codegen] Reduce the state in TBAA. NFC for static compilation. (#98138)

In incremental compilation clang works with multiple `llvm::Module`s.
Our current approach is to create a CodeGenModule entity for every new
module request (via StartModule). However, some of the state such as the
mangle context needs to be preserved to keep the original semantics in
the ever-growing TU.

Fixes: llvm/llvm-project#95581.

cc: @jeaye

show more ...

[PAC] Implement authentication for C++ member function pointers (#99576)

Introduces type based signing of member function pointers. To support
this discrimination schema we no longer emit member fu

[PAC] Implement authentication for C++ member function pointers (#99576)

Introduces type based signing of member function pointers. To support
this discrimination schema we no longer emit member function pointer to
virtual methods and indices into a vtable but migrate to using thunks.
This does mean member function pointers are no longer necessarily
directly comparable, however as such comparisons are UB this is
acceptable.

We derive the discriminator from the C++ mangling of the type of the
pointer being authenticated.

Co-Authored-By: Akira Hatanaka ahatanaka@apple.com
Co-Authored-By: John McCall rjmccall@apple.com
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>

show more ...

[OpenMP][AMDGPU] Do not attach -fcuda-is-device (#99002)

-fcuda-is-device flag is not used for OpenMP offloading for AMD GPUs and
it does not need to be added as clang cc1 option for OpenMP code.

[OpenMP][AMDGPU] Do not attach -fcuda-is-device (#99002)

-fcuda-is-device flag is not used for OpenMP offloading for AMD GPUs and
it does not need to be added as clang cc1 option for OpenMP code.

This PR has the same functionality as
https://github.com/llvm/llvm-project/pull/96909 but it doesn't introduce
regression for virtual function support.

show more ...

[CUDA][HIP][NFC] add CodeGenModule::shouldEmitCUDAGlobalVar (#98543)

Extract the logic whether to emit a global var based on CUDA/HIP
host/device related attributes to CodeGenModule::shouldEmitCUDA

[CUDA][HIP][NFC] add CodeGenModule::shouldEmitCUDAGlobalVar (#98543)

Extract the logic whether to emit a global var based on CUDA/HIP
host/device related attributes to CodeGenModule::shouldEmitCUDAGlobalVar
to be used by other places.

show more ...

[PAC] Implement function pointer type discrimination (#96992)

Give users an option (-fptrauth-function-pointer-type-discrimination) to
sign a function pointer using a non-zero discriminator based o

[PAC] Implement function pointer type discrimination (#96992)

Give users an option (-fptrauth-function-pointer-type-discrimination) to
sign a function pointer using a non-zero discriminator based on the
function type.

The discriminator is computed by first translating the function type to
a string and then computing the hash value of the string. Two function
types that are compatible in C must be translated to the same string
with the exception of function types that use typedefs of anonymous
structs in their return type or parameter types.

This patch doesn't have the code to resign function pointers, which is
needed when a function pointer is converted to a different function
type. That will be implemented in another patch.

Co-authored-by: John McCall <rjmccall@apple.com>

---------

Co-authored-by: John McCall <rjmccall@apple.com>

show more ...

[PowerPC] Diagnose musttail instead of crash inside backend (#93267)

musttail is not often possible to be generated on PPC targets as when
calling to a function defined in another module, PPC needs

[PowerPC] Diagnose musttail instead of crash inside backend (#93267)

musttail is not often possible to be generated on PPC targets as when
calling to a function defined in another module, PPC needs to restore
the TOC pointer. To restore the TOC pointer, compiler needs to emit a
nop after the call to let linker generate codes to restore TOC pointer.
Tail call cannot generate expected call sequence for this case.

To avoid the crash inside the compiler backend, a diagnosis is added in
the frontend.

Fixes #63214

show more ...

[BPF] Fix linking issues in static map initializers (#91310)

When BPF object files are linked with bpftool, every symbol must be
accompanied by BTF info. Ensure that extern functions referenced by

[BPF] Fix linking issues in static map initializers (#91310)

When BPF object files are linked with bpftool, every symbol must be
accompanied by BTF info. Ensure that extern functions referenced by
global variable initializers are included in BTF.

The primary motivation is "static" initialization of PROG maps:

```c
extern int elsewhere(struct xdp_md *);

struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
__array(values, int (struct xdp_md *));
} prog_map SEC(".maps") = { .values = { elsewhere } };
```

BPF backend needs debug info to produce BTF. Debug info is not
normally generated for external variables and functions. Previously, it
was solved differently for variables (collecting variable declarations
in ExternalDeclarations vector) and functions (logic invoked during
codegen in CGExpr.cpp).

This patch generalises ExternalDefclarations to include both function
and variable declarations. This change ensures that function references
are not missed no matter the context. Previously external functions
referenced in constant expressions lacked debug info.

show more ...

[CodeGen] Use MapVector to stabilize iteration order

Otherwise clang/test/CodeGenCXX/attr-annotate.cpp
output could fail when llvm::hash_value(StringRef) changes
(#96282).

EmitGlobalAnnotations ite

[CodeGen] Use MapVector to stabilize iteration order

Otherwise clang/test/CodeGenCXX/attr-annotate.cpp
output could fail when llvm::hash_value(StringRef) changes
(#96282).

EmitGlobalAnnotations iterates over DeferredAnnotations.

show more ...

[clang] Implement pointer authentication for C++ virtual functions, v-tables, and VTTs (#94056)

Virtual function pointer entries in v-tables are signed with address
discrimination in addition to de

[clang] Implement pointer authentication for C++ virtual functions, v-tables, and VTTs (#94056)

Virtual function pointer entries in v-tables are signed with address
discrimination in addition to declaration-based discrimination, where an
integer discriminator the string hash (see
`ptrauth_string_discriminator`) of the mangled name of the overridden
method. This notably provides diversity based on the full signature of
the overridden method, including the method name and parameter types.
This patch introduces ItaniumVTableContext logic to find the original
declaration of the overridden method.
On AArch64, these pointers are signed using the `IA` key (the
process-independent code key.)

V-table pointers can be signed with either no discrimination, or a
similar scheme using address and decl-based discrimination. In this
case, the integer discriminator is the string hash of the mangled
v-table identifier of the class that originally introduced the vtable
pointer.
On AArch64, these pointers are signed using the `DA` key (the
process-independent data key.)

Not using discrimination allows attackers to simply copy valid v-table
pointers from one object to another. However, using a uniform
discriminator of 0 does have positive performance and code-size
implications on AArch64, and diversity for the most important v-table
access pattern (virtual dispatch) is already better assured by the
signing schemas used on the virtual functions. It is also known that
some code in practice copies objects containing v-tables with `memcpy`,
and while this is not permitted formally, it is something that may be
invasive to eliminate.

This is controlled by:
```
-fptrauth-vtable-pointer-type-discrimination
-fptrauth-vtable-pointer-address-discrimination
```

In addition, this provides fine-grained controls in the
ptrauth_vtable_pointer attribute, which allows overriding the default
ptrauth schema for vtable pointers on a given class hierarchy, e.g.:
```
[[clang::ptrauth_vtable_pointer(no_authentication, no_address_discrimination,
no_extra_discrimination)]]
[[clang::ptrauth_vtable_pointer(default_key, default_address_discrimination,
custom_discrimination, 0xf00d)]]
```

The override is then mangled as a parametrized vendor extension:
```
"__vtptrauth" I
<key>
<addressDiscriminated>
<extraDiscriminator>
E
```

To support this attribute, this patch adds a small extension to the
attribute-emitter tablegen backend.

Note that there are known areas where signing is either missing
altogether or can be strengthened. Some will be addressed in later
changes (e.g., member function pointers, some RTTI).
`dynamic_cast` in particular is handled by emitting an artificial
v-table pointer load (in a way that always authenticates it) before the
runtime call itself, as the runtime doesn't have enough information
today to properly authenticate it. Instead, the runtime is currently
expected to strip the v-table pointer.

---------

Co-authored-by: John McCall <rjmccall@apple.com>
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>

show more ...

[clang] Implement function pointer signing and authenticated function calls (#93906)

The functions are currently always signed/authenticated with zero
discriminator.

Co-Authored-By: John McCall

[clang] Implement function pointer signing and authenticated function calls (#93906)

The functions are currently always signed/authenticated with zero
discriminator.

Co-Authored-By: John McCall <rjmccall@apple.com>

show more ...

[clang] Define ptrauth_sign_constant builtin. (#93904)

This is a constant-expression equivalent to
ptrauth_sign_unauthenticated. Its constant nature lets us guarantee
a non-attackable sequence is

[clang] Define ptrauth_sign_constant builtin. (#93904)

This is a constant-expression equivalent to
ptrauth_sign_unauthenticated. Its constant nature lets us guarantee
a non-attackable sequence is generated, unlike
ptrauth_sign_unauthenticated which we generally discourage using.

It being a constant also allows its usage in global initializers, though
requiring constant pointers and discriminators.

The value must be a constant expression of pointer type which evaluates
to a non-null pointer.

The key must be a constant expression of type ptrauth_key.
The extra data must be a constant expression of pointer or integer type;
if an integer, it will be coerced to ptrauth_extra_data_t.
The result will have the same type as the original value.

This can be used in constant expressions.

Co-authored-by: John McCall <rjmccall@apple.com>

show more ...

[clang] Fix loss of `dllexport` for exported template specialization (#94664)

When dropping DLL attributes, ensure that the most recent declaration is
being checked.

[clang][Modules] Remove unnecessary includes of `Module.h` (#93417)

[clang][SPIR-V] Always add convergence intrinsics (#88918)

PR #80680 added bits in the codegen to lazily add convergence intrinsics
when required. This logic relied on the LoopStack. The issue is w

[clang][SPIR-V] Always add convergence intrinsics (#88918)

PR #80680 added bits in the codegen to lazily add convergence intrinsics
when required. This logic relied on the LoopStack. The issue is when
parsing the condition, the loopstack doesn't yet reflect the correct
values, as expected since we are not yet in the loop.

However, convergence tokens should sometimes already be available. The
solution which seemed the simplest is to greedily generate the tokens
when we generate SPIR-V.

Fixes #88144

---------

Signed-off-by: Nathan Gauër <brioche@google.com>

show more ...

Fix Objective-C++ Sret of non-trivial data types on Windows ARM64 (#88671)

Linked to https://github.com/gnustep/libobjc2/pull/289.

More information can be found in issue: #88273.

My solution i

Fix Objective-C++ Sret of non-trivial data types on Windows ARM64 (#88671)

Linked to https://github.com/gnustep/libobjc2/pull/289.

More information can be found in issue: #88273.

My solution involves creating a new message-send function for this
calling convention when targeting MSVC. Additional information is
available in the libobjc2 pull request.

I am unsure whether we should check for a runtime version where
objc_msgSend_stret2_np is guaranteed to be present or leave it as is,
considering it remains a critical bug. What are your thoughts about this
@davidchisnall?

show more ...