Default address space (applies when no explicit address space was
specified) maps to generic (4) address space.
Added SYCL named address spaces `sycl_global`, `sycl_local` and
`sycl_private` defined as sub-sets of the default address space.
Static variables without address space now reside in global address
space when compile for SPIR target, unless they have an explicit address
space qualifier in source code.
Differential Revision: https://reviews.llvm.org/D89909
This is a Clang-only change and depends on the existing "musttail"
support already implemented in LLVM.
The [[clang::musttail]] attribute goes on a return statement, not
a function definition. There are several constraints that the user
must follow when using [[clang::musttail]], and these constraints
are verified by Sema.
Tail calls are supported on regular function calls, calls through a
function pointer, member function calls, and even pointer to member.
Future work would be to throw a warning if a users tries to pass
a pointer or reference to a local variable through a musttail call.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D99517
This implements C-style type conversions for matrix types, as specified
in clang/docs/MatrixTypes.rst.
Fixes PR47141.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D99037
This removes some (but not all) uses of type-less CreateGEP()
and CreateInBoundsGEP() APIs, which are incompatible with opaque
pointers.
There are a still a number of tricky uses left, as well as many
more variation APIs for CreateGEP.
These are incompatible with opaque pointers. This is in preparation
of dropping this API on the IRBuilder side as well.
Instead explicitly pass the loaded type.
Currently clang uses stub function to launch kernel. This is inconvenient
to interop with C++ programs since the stub function has different name
as kernel, which is required by ROCm debugger.
This patch emits a variable symbol which has the same name as the kernel
and uses it to register and launch the kernel. This allows C++ program to
launch a kernel by using the original kernel name.
Reviewed by: Artem Belevich
Differential Revision: https://reviews.llvm.org/D86376
This patch responds to a comment from @vitalybuka in D96203: suggestion to
do the change incrementally, and start by modifying this file name. I modified
the file name and made the other changes that follow from that rename.
Reviewers: vitalybuka, echristo, MaskRay, jansvoboda11, aaron.ballman
Differential Revision: https://reviews.llvm.org/D96974
getAs<> can return null if the cast is invalid, which can lead to null pointer deferences. Use castAs<> instead which will assert that the cast is valid.
As mentioned in D93793, there are quite a few places where unary `IRBuilder::CreateShuffleVector(X, Mask)` can be used
instead of `IRBuilder::CreateShuffleVector(X, Undef, Mask)`.
Let's update them.
Actually, it would have been more natural if the patches were made in this order:
(1) let them use unary CreateShuffleVector first
(2) update IRBuilder::CreateShuffleVector to use poison as a placeholder value (D93793)
The order is swapped, but in terms of correctness it is still fine.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D93923
Sometimes people get minimal crash reports after a UBSAN incident. This change
tags each trap with an integer representing the kind of failure encountered,
which can aid in tracking down the root cause of the problem.
In C++ when a reference variable is captured by copy, the lambda
is supposed to make a copy of the referenced variable in the captures
and refer to the copy in the lambda. Therefore, it is valid to capture
a reference to a host global variable in a device lambda since the
device lambda will refer to the copy of the host global variable instead
of access the host global variable directly.
However, clang tries to avoid capturing of reference to a host global variable
if it determines the use of the reference variable in the lambda function is
not odr-use. Clang also tries to emit load of the reference to a global variable
as load of the global variable if it determines that the reference variable is
a compile-time constant.
For a device lambda to capture a reference variable to host global variable
and use the captured value, clang needs to be taught that in such cases the use of the reference
variable is odr-use and the reference variable is not compile-time constant.
This patch fixes that.
Differential Revision: https://reviews.llvm.org/D91088
The strictfp metadata was added to the casting AST nodes in D85960, but
we aren't using that metadata yet. This patch adds that support.
In order to avoid lots of ad-hoc passing around of the strictfp bits I
updated the IRBuilder when moving from a function that has the Expr* to a
function that lacks it. I believe we should switch to this pattern to keep
the strictfp support from being overly invasive.
For the purpose of testing that we're picking up the right metadata, I
also made my tests use a pragma to make the AST's strictfp metadata not
match the global strictfp metadata. This exposes issues that we need to
deal with in subsequent patches, and I believe this is the right method
for most all of our clang strictfp tests.
Differential Revision: https://reviews.llvm.org/D88913
non-type template parameters.
Create a unique TemplateParamObjectDecl instance for each such value,
representing the globally unique template parameter object to which the
template parameter refers.
No IR generation support yet; that will follow in a separate patch.
Using TypeSize::getFixedSize() instead of relying upon the implicit
TypeSize->uint64_cast as the type is always fixed width.
Differential Revision: https://reviews.llvm.org/D89313
This patch resumes the work of D16586.
According to the AAPCS, volatile bit-fields should
be accessed using containers of the widht of their
declarative type. In such case:
```
struct S1 {
short a : 1;
}
```
should be accessed using load and stores of the width
(sizeof(short)), where now the compiler does only load
the minimum required width (char in this case).
However, as discussed in D16586,
that could overwrite non-volatile bit-fields, which
conflicted with C and C++ object models by creating
data race conditions that are not part of the bit-field,
e.g.
```
struct S2 {
short a;
int b : 16;
}
```
Accessing `S2.b` would also access `S2.a`.
The AAPCS Release 2020Q2
(https://documentation-service.arm.com/static/5efb7fbedbdee951c1ccf186?token=)
section 8.1 Data Types, page 36, "Volatile bit-fields -
preserving number and width of container accesses" has been
updated to avoid conflict with the C++ Memory Model.
Now it reads in the note:
```
This ABI does not place any restrictions on the access widths of bit-fields where the container
overlaps with a non-bit-field member or where the container overlaps with any zero length bit-field
placed between two other bit-fields. This is because the C/C++ memory model defines these as being
separate memory locations, which can be accessed by two threads simultaneously. For this reason,
compilers must be permitted to use a narrower memory access width (including splitting the access into
multiple instructions) to avoid writing to a different memory location. For example, in
struct S { int a:24; char b; }; a write to a must not also write to the location occupied by b, this requires at least two
memory accesses in all current Arm architectures. In the same way, in struct S { int a:24; int:0; int b:8; };,
writes to a or b must not overwrite each other.
```
I've updated the patch D16586 to follow such behavior by verifying that we
only change volatile bit-field access when:
- it won't overlap with any other non-bit-field member
- we only access memory inside the bounds of the record
- avoid overlapping zero-length bit-fields.
Regarding the number of memory accesses, that should be preserved, that will
be implemented by D67399.
Reviewed By: ostannard
Differential Revision: https://reviews.llvm.org/D72932
Extend -fsanitize=nullability-arg to handle call sites which accept C++
member pointers.
rdar://62476022
Differential Revision: https://reviews.llvm.org/D88336
This patch resumes the work of D16586.
According to the AAPCS, volatile bit-fields should
be accessed using containers of the widht of their
declarative type. In such case:
```
struct S1 {
short a : 1;
}
```
should be accessed using load and stores of the width
(sizeof(short)), where now the compiler does only load
the minimum required width (char in this case).
However, as discussed in D16586,
that could overwrite non-volatile bit-fields, which
conflicted with C and C++ object models by creating
data race conditions that are not part of the bit-field,
e.g.
```
struct S2 {
short a;
int b : 16;
}
```
Accessing `S2.b` would also access `S2.a`.
The AAPCS Release 2020Q2
(https://documentation-service.arm.com/static/5efb7fbedbdee951c1ccf186?token=)
section 8.1 Data Types, page 36, "Volatile bit-fields -
preserving number and width of container accesses" has been
updated to avoid conflict with the C++ Memory Model.
Now it reads in the note:
```
This ABI does not place any restrictions on the access widths of bit-fields where the container
overlaps with a non-bit-field member or where the container overlaps with any zero length bit-field
placed between two other bit-fields. This is because the C/C++ memory model defines these as being
separate memory locations, which can be accessed by two threads simultaneously. For this reason,
compilers must be permitted to use a narrower memory access width (including splitting the access into
multiple instructions) to avoid writing to a different memory location. For example, in
struct S { int a:24; char b; }; a write to a must not also write to the location occupied by b, this requires at least two
memory accesses in all current Arm architectures. In the same way, in struct S { int a:24; int:0; int b:8; };,
writes to a or b must not overwrite each other.
```
Patch D16586 was updated to follow such behavior by verifying that we
only change volatile bit-field access when:
- it won't overlap with any other non-bit-field member
- we only access memory inside the bounds of the record
- avoid overlapping zero-length bit-fields.
Regarding the number of memory accesses, that should be preserved, that will
be implemented by D67399.
Differential Revision: https://reviews.llvm.org/D72932
The following people contributed to this patch:
- Diogo Sampaio
- Ties Stuij
Provides AMDGCN and NVPTX specific specialization of getGPUWarpSize,
getGPUThreadID, and getGPUNumThreads methods. Adds tests for AMDGCN
codegen for these methods in generic and simd modes. Also changes the
precondition in InitTempAlloca to be slightly more permissive. Useful for
AMDGCN OpenMP codegen where allocas are created with a cast to an
address space.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D84260
Reapply 49e5f603d4
which had been reverted in c94332919b.
Originally reverted because I hadn't updated it in quite a while when I
got around to committing it, so there were a bunch of missing changes to
new code since I'd written the patch.
Reviewers: aaron.ballman
Differential Revision: https://reviews.llvm.org/D76646
There is a version that just tests (also called
isIntegerConstantExpression) & whereas this version is specifically used
when the value is of interest (a few call sites were actually refactored
to calling the test-only version) so let's make the API look more like
it.
Reviewers: aaron.ballman
Differential Revision: https://reviews.llvm.org/D76646
Summary:
D82193 exposed a problem with global type definitions in
`OMPConstants.h`. This causes a race when running in thinLTO mode.
Types now live inside of OpenMPIRBuilder to prevent this from happening.
Reviewers: jdoerfert
Subscribers: yaxunl, hiraditya, guansong, dexonsmith, aaron.ballman, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D83176
Summary:
Modified the OMPBuilderCBHelpers in the following ways:
- Moved location of class definition and deleted all constructors
- Moved OpenMP-specific address allocation of local variables
- Moved threadprivate variable creation for the current thread
Reviewers: jdoerfert
Subscribers: yaxunl, guansong, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D79676
Prevent IR-gen from emitting consteval declarations
Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.
Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D76420
Rather than pushing inactive cleanups for the block captures at the
entry of a full expression and activating them during the creation of
the block literal, just call pushLifetimeExtendedDestroy to ensure the
cleanups are popped at the end of the scope enclosing the block
expression.
rdar://problem/63996471
Differential Revision: https://reviews.llvm.org/D81624
This patch implements matrix index expressions
(matrix[RowIdx][ColumnIdx]).
It does so by introducing a new MatrixSubscriptExpr(Base, RowIdx, ColumnIdx).
MatrixSubscriptExprs are built in 2 steps in ActOnMatrixSubscriptExpr. First,
if the base of a subscript is of matrix type, we create a incomplete
MatrixSubscriptExpr(base, idx, nullptr). Second, if the base is an incomplete
MatrixSubscriptExpr, we create a complete
MatrixSubscriptExpr(base->getBase(), base->getRowIdx(), idx)
Similar to vector elements, it is not possible to take the address of
a MatrixSubscriptExpr.
For CodeGen, a new MatrixElt type is added to LValue, which is very
similar to VectorElt. The only difference is that we may need to cast
the type of the base from an array to a vector type when accessing it.
Reviewers: rjmccall, anemet, Bigcheese, rsmith, martong
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D76791
If we're going to assume references are dereferenceable, we should also
assume they're aligned: otherwise, we can't actually dereference them.
See also D80072.
Differential Revision: https://reviews.llvm.org/D80166
This operator is intended for casting between
pointers to objects in different address spaces
and follows similar logic as const_cast in C++.
Tags: #clang
Differential Revision: https://reviews.llvm.org/D60193
This is D77454, except for stores. All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.
Differential Revision: https://reviews.llvm.org/D79968
This patch adds a matrix type to Clang as described in the draft
specification in clang/docs/MatrixSupport.rst. It introduces a new option
-fenable-matrix, which can be used to enable the matrix support.
The patch adds new MatrixType and DependentSizedMatrixType types along
with the plumbing required. Loads of and stores to pointers to matrix
values are lowered to memory operations on 1-D IR arrays. After loading,
the loaded values are cast to a vector. This ensures matrix values use
the alignment of the element type, instead of LLVM's large vector
alignment.
The operators and builtins described in the draft spec will will be added in
follow-up patches.
Reviewers: martong, rsmith, Bigcheese, anemet, dexonsmith, rjmccall, aaron.ballman
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D72281
Some function declarations like this:
void foo();
do not have a type declaration, for that you'd use:
void foo(void);
Clang internally bitcasts the variadic function declaration to a
function pointer, but doesn't use the correct address space on AVR. This
commit fixes that.
This fix is necessary to let Clang compile compiler-rt for AVR.
Differential Revision: https://reviews.llvm.org/D78125
Summary:
Previously, we treated CXXUuidofExpr as quite a special case: it was the
only kind of expression that could be a canonical template argument, it
could be a constant lvalue base object, and so on. In addition, we
represented the UUID value as a string, whose source form we did not
preserve faithfully, and that we partially parsed in multiple different
places.
With this patch, we create an MSGuidDecl object to represent the
implicit object of type 'struct _GUID' created by a UuidAttr. Each
UuidAttr holds a pointer to its 'struct _GUID' and its original
(as-written) UUID string. A non-value-dependent CXXUuidofExpr behaves
like a DeclRefExpr denoting that MSGuidDecl object. We cache an APValue
representation of the GUID on the MSGuidDecl and use it from constant
evaluation where needed.
This allows removing a lot of the special-case logic to handle these
expressions. Unfortunately, many parts of Clang assume there are only
a couple of interesting kinds of ValueDecl, so the total amount of
special-case logic is not really reduced very much.
This fixes a few bugs and issues:
* PR38490: we now support reading from GUID objects returned from
__uuidof during constant evaluation.
* Our Itanium mangling for a non-instantiation-dependent template
argument involving __uuidof no longer depends on which CXXUuidofExpr
template argument we happened to see first.
* We now predeclare ::_GUID, and permit use of __uuidof without
any header inclusion, better matching MSVC's behavior. We do not
predefine ::__s_GUID, though; that seems like a step too far.
* Our IR representation for GUID constants now uses the correct IR type
wherever possible. We will still fall back to using the
{i32, i16, i16, [8 x i8]}
layout if a definition of struct _GUID is not available. This is not
ideal: in principle the two layouts could have different padding.
Reviewers: rnk, jdoerfert
Subscribers: arphaman, cfe-commits, aeubanks
Tags: #clang
Differential Revision: https://reviews.llvm.org/D78171
Summary:
Remove usages of asserting vector getters in Type in preparation for the
VectorType refactor. The existence of these functions complicates the
refactor while adding little value.
Reviewers: sdesmalen, efriedma, krememek
Reviewed By: sdesmalen, efriedma
Subscribers: dexonsmith, Charusso, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77257
Summary:
We're smart and do constant folding when emitting conditional operators.
Thus we emit the live value as a lvalue. This doesn't work if the live value is a throw expression.
Handle this by emitting the throw and returning the dead value as the lvalue.
Fixes PR28184.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77502
Instead, represent the mask as out-of-line data in the instruction. This
should be more efficient in the places that currently use
getShuffleVector(), and paves the way for further changes to add new
shuffles for scalable vectors.
This doesn't change the syntax in textual IR. And I don't currently plan
to change the bitcode encoding in this patch, although we'll probably
need to do something once we extend shufflevector for scalable types.
I expect that once this is finished, we can then replace the raw "mask"
with something more appropriate for scalable vectors. Not sure exactly
what this looks like at the moment, but there are a few different ways
we could handle it. Maybe we could try to describe specific shuffles.
Or maybe we could define it in terms of a function to convert a fixed-length
array into an appropriate scalable vector, using a "step", or something
like that.
Differential Revision: https://reviews.llvm.org/D72467
Summary:
- https://reviews.llvm.org/D68578 revises the `GlobalDecl` constructors
to ensure all GPU kernels have `ReferenceKenelKind` initialized
properly with an explicit constructor and static one. But, there are
lots of places using the implicit constructor triggering the assertion
on non-GPU kernels. That's found in compilation of many tests and
workloads.
- Fixing all of them may change more code and, more importantly, all of
them assumes the default kernel reference kind. This patch changes
that constructor to tell `CUDAGlobalAttr` and construct `GlobalDecl`
properly.
Reviewers: yaxunl
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D76344
Fix a bug in IRGen where it wasn't destructing compound literals in C
that are ObjC pointer arrays or non-trivial structs. Also diagnose jumps
that enter or exit the lifetime of the compound literals.
rdar://problem/51867864
Differential Revision: https://reviews.llvm.org/D64464
HIP emits a device stub function for each kernel in host code.
The HIP debugger requires device stub function to have a different unmangled name as the kernel.
Currently the name of the device stub function is the mangled name with a postfix .stub. However,
this does not work with the HIP debugger since the unmangled name is the same as the kernel.
This patch adds prefix __device__stub__ to the unmangled name of the device stub before mangling,
therefore the device stub function has a valid mangled name which is different than the device kernel
name. The device side kernel name is kept unchanged. kernels with extern "C" also gets the prefix added
to the corresponding device stub function.
Differential Revision: https://reviews.llvm.org/D68578
Summary:
Following the AAPCS, every store to a volatile bit-field requires to generate one load of that field, even if all the bits are going to be replaced.
This patch allows the user to opt-in in following such rule, whenever the a.
AAPCS Release 2019Q1.1 (https://static.docs.arm.com/ihi0042/g/aapcs32.pdf)
section 8.1 Data Types, page 35, paragraph: Volatile bit-fields – preserving number and width of container accesses
```
When a volatile bit-field is written, and its container does not overlap with any non-bit-field member, its
container must be read exactly once and written exactly once using the access width appropriate to the
type of the container. The two accesses are not atomic.
```
Reviewers: lebedev.ri, ostannard, jfb, eli.friedman
Reviewed By: jfb
Subscribers: rsmith, rjmccall, dexonsmith, kristof.beyls, jfb, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67399
Linux commit
1cf5b23988 (diff-289313b9fec99c6f0acfea19d9cfd949)
uses "#pragma clang attribute push (__attribute__((preserve_access_index)),
apply_to = record)"
to apply CO-RE relocations to all records including the following pattern:
#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
typedef struct {
int a;
} __t;
#pragma clang attribute pop
int test(__t *arg) { return arg->a; }
The current approach to use struct type in the relocation record will
result in an anonymous struct, which make later type matching difficult
in bpf loader. In fact, current BPF backend will fail the above program
with assertion:
clang: ../lib/Target/BPF/BPFAbstractMemberAccess.cpp:796: ...
Assertion `TypeName.size()' failed.
The patch use the base lvalue type for the "base" value to annotate
preservee_{struct,union}_access_index intrinsics. In the above example,
the type will be "__t" which preserved the type name.
Differential Revision: https://reviews.llvm.org/D73900
When T is a class type, only nvsize(T) bytes need be accessible through
the reference. We had matching bugs in the application of the
dereferenceable attribute and in -fsanitize=undefined.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
Summary:
This patch resumes the work of D16586.
According to the AAPCS, volatile bit-fields should
be accessed using containers of the widht of their
declarative type. In such case:
```
struct S1 {
short a : 1;
}
```
should be accessed using load and stores of the width
(sizeof(short)), where now the compiler does only load
the minimum required width (char in this case).
However, as discussed in D16586,
that could overwrite non-volatile bit-fields, which
conflicted with C and C++ object models by creating
data race conditions that are not part of the bit-field,
e.g.
```
struct S2 {
short a;
int b : 16;
}
```
Accessing `S2.b` would also access `S2.a`.
The AAPCS Release 2019Q1.1
(https://static.docs.arm.com/ihi0042/g/aapcs32.pdf)
section 8.1 Data Types, page 35, "Volatile bit-fields -
preserving number and width of container accesses" has been
updated to avoid conflict with the C++ Memory Model.
Now it reads in the note:
```
This ABI does not place any restrictions on the access widths
of bit-fields where the container overlaps with a non-bit-field member.
This is because the C/C++ memory model defines these as being separate
memory locations, which can be accessed by two threads
simultaneously. For this reason, compilers must be permitted to use a
narrower memory access width (including splitting the access
into multiple instructions) to avoid writing to a different memory location.
```
I've updated the patch D16586 to follow such behavior by verifying that we
only change volatile bit-field access when:
- it won't overlap with any other non-bit-field member
- we only access memory inside the bounds of the record
Regarding the number of memory accesses, that should be preserved, that will
be implemented by D67399.
Reviewers: rsmith, rjmccall, eli.friedman, ostannard
Subscribers: ostannard, kristof.beyls, cfe-commits, carwil, olista01
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72932
If a system header provides an (inline) implementation of some of their
function, clang still matches on the function name and generate the appropriate
llvm builtin, e.g. memcpy. This behavior is in line with glibc recommendation «
users may not provide their own version of symbols » but doesn't account for the
fact that glibc itself can provide inline version of some functions.
It is the case for the memcpy function when -D_FORTIFY_SOURCE=1 is on. In that
case an inline version of memcpy calls __memcpy_chk, a function that performs
extra runtime checks. Clang currently ignores the inline version and thus
provides no runtime check.
This code fixes the issue by detecting functions whose name is a builtin name
but also have an inline implementation.
Differential Revision: https://reviews.llvm.org/D71082
Added codegen support for lastprivate conditional. According to the
standard, if when the conditional modifier appears on the clause, if an
assignment to a list item is encountered in the construct then the
original list item is assigned the value that is assigned to the new
list item in the sequentially last iteration or lexically last section
in which such an assignment is encountered.
We look for the assignment operations and check if the left side
references lastprivate conditional variable. Then the next code is
emitted:
if (last_iv_a <= iv) {
last_iv_a = iv;
last_a = lp_a;
}
At the end the implicit barrier is generated to wait for the end of all
threads and then in the check for the last iteration the private copy is
assigned the last value.
if (last_iter) {
lp_a = last_a; // <--- new code
a = lp_a; // <--- store of private value to the original variable.
}
Summary:
Basic codegen for the declarations marked as nontemporal. Also, if the
base declaration in the member expression is marked as nontemporal,
lvalue for member decl access inherits nonteporal flag from the base
lvalue.
Reviewers: rjmccall, hfinkel, jdoerfert
Subscribers: guansong, arphaman, caomhin, kkwli0, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D71708
ExpandTypeFromArgs
This fixes a bug in IRGen where a call to `llvm.objc.storeStrong` was
being emitted to initialize a __strong field of an uninitialized
temporary struct, which caused crashes at runtime.
rdar://problem/51807365
AggValueSlot
This reapplies 8a5b7c3570 after a null
dereference bug in CGOpenMPRuntime::emitUserDefinedMapper.
Original commit message:
This is needed for the pointer authentication work we plan to do in the
near future.
a63a81bd99/clang/docs/PointerAuthentication.rst
This has the main effect of causing target-cpu and target-features to be set
on __cfi_check_fail, causing the function to become ABI-compatible with other
functions in the case where these attributes affect ABI (e.g. reserve-x18).
Technically we only need to call SetLLVMFunctionAttributes to get the target-*
attributes set, but since we're creating a definition we probably ought to
call the ForDefinition function as well.
Fixes PR44094.
Differential Revision: https://reviews.llvm.org/D70692
This patch is a follow-up for commit 4e2ce228ae
[BPF] Add preserve_access_index attribute for record definition
to restrict attribute for C only. A new test case is added
to check for this restriction.
Additional code polishing is done based on
Aaron Ballman's suggestion in https://reviews.llvm.org/D69759/new/.
Differential Revision: https://reviews.llvm.org/D70257
This is a resubmission for the previous reverted commit
9434360401 with the same subject. This commit fixed the
segfault issue and addressed additional review comments.
This patch introduced a new bpf specific attribute which can
be added to struct or union definition. For example,
struct s { ... } __attribute__((preserve_access_index));
union u { ... } __attribute__((preserve_access_index));
The goal is to simplify user codes for cases
where preserve access index happens for certain struct/union,
so user does not need to use clang __builtin_preserve_access_index
for every members.
The attribute has no effect if -g is not specified.
When the attribute is specified and -g is specified, any member
access defined by that structure or union, including array subscript
access and inner records, will be preserved through
__builtin_preserve_{array,struct,union}_access_index()
IR intrinsics, which will enable relocation generation
in bpf backend.
The following is an example to illustrate the usage:
-bash-4.4$ cat t.c
#define __reloc__ __attribute__((preserve_access_index))
struct s1 {
int c;
} __reloc__;
struct s2 {
union {
struct s1 b[3];
};
} __reloc__;
struct s3 {
struct s2 a;
} __reloc__;
int test(struct s3 *arg) {
return arg->a.b[2].c;
}
-bash-4.4$ clang -target bpf -g -S -O2 t.c
A relocation with access string "0:0:0:0:2:0" will be generated
representing access offset of arg->a.b[2].c.
forward declaration with attribute is also handled properly such
that the attribute is copied and populated in real record definition.
Differential Revision: https://reviews.llvm.org/D69759
This patch introduced a new bpf specific attribute which can
be added to struct or union definition. For example,
struct s { ... } __attribute__((preserve_access_index));
union u { ... } __attribute__((preserve_access_index));
The goal is to simplify user codes for cases
where preserve access index happens for certain struct/union,
so user does not need to use clang __builtin_preserve_access_index
for every members.
The attribute has no effect if -g is not specified.
When the attribute is specified and -g is specified, any member
access defined by that structure or union, including array subscript
access and inner records, will be preserved through
__builtin_preserve_{array,struct,union}_access_index()
IR intrinsics, which will enable relocation generation
in bpf backend.
The following is an example to illustrate the usage:
-bash-4.4$ cat t.c
#define __reloc__ __attribute__((preserve_access_index))
struct s1 {
int c;
} __reloc__;
struct s2 {
union {
struct s1 b[3];
};
} __reloc__;
struct s3 {
struct s2 a;
} __reloc__;
int test(struct s3 *arg) {
return arg->a.b[2].c;
}
-bash-4.4$ clang -target bpf -g -S -O2 t.c
A relocation with access string "0:0:0:0:2:0" will be generated
representing access offset of arg->a.b[2].c.
forward declaration with attribute is also handled properly such
that the attribute is copied and populated in real record definition.
Differential Revision: https://reviews.llvm.org/D69759
Summary:
These were the only remaining users of the GetElementPtrInst::getGEPReturnType
method that gets the element type from the pointer type.
Remove that method since its now dead.
Reviewers: jyknight, t.p.northover, arsenm
Reviewed By: arsenm
Subscribers: wdng, arsenm, arphaman, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D69756
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<> directly and if not assert will fire for us.
llvm-svn: 373918
Summary:
* Don't bother using a thread wrapper when the variable is known to
have constant initialization.
* Emit the thread wrapper as discardable-if-unused in TUs that don't
contain a definition of the thread_local variable.
* Don't emit the thread wrapper at all if the thread_local variable
is unused and discardable; it will be emitted by all TUs that need
it.
Reviewers: rjmccall, jdoerfert
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67429
llvm-svn: 371767
constant.
If the constexpr variable is partially initialized, the initializer can
be emitted as the structure, not as an array, because of some early
optimizations. The llvm variable gets the type from this constant and,
thus, gets the type which is pointer to struct rather than pointer to an
array. We need to convert this type to be truely array, otherwise it may
lead to the compiler crash when trying to emit array subscript
expression.
llvm-svn: 371548
Currently, clang accepts a union with a reference member when given the -fms-extensions flag. This change fixes the codegen for this case.
Patch by Dominic Ferreira.
llvm-svn: 370052
I noticed another instance of the issue where references to aliases were
being replaced with aliasees, this time in InstCombine. In the instance that
I saw it turned out to be only a QoI issue (a symbol ended up being missing
from the symbol table due to the last reference to the alias being removed,
preventing HWASAN from symbolizing a global reference), but it could easily
have manifested as incorrect behaviour.
Since this is the third such issue encountered (previously: D65118, D65314)
it seems to be time to address this common error/QoI issue once and for all
and make the strip* family of functions not look through aliases.
Includes a test for the specific issue that I saw, but no doubt there are
other similar bugs fixed here.
As with D65118 this has been tested to make sure that the optimization isn't
load bearing. I built Clang, Chromium for Linux, Android and Windows as well
as the test-suite and there were no size regressions.
Differential Revision: https://reviews.llvm.org/D66606
llvm-svn: 369697
Previously, debuginfo types are annotated to
IR builtin preserve_struct_access_index() and
preserve_union_access_index(), but not
preserve_array_access_index(). The debug info
is useful to identify the root type name which
later will be used for type comparison.
For user access without explicit type conversions,
the previous scheme works as we can ignore intermediate
compiler generated type conversions (e.g., from union types to
union members) and still generate correct access index string.
The issue comes with user explicit type conversions, e.g.,
converting an array to a structure like below:
struct t { int a; char b[40]; };
struct p { int c; int d; };
struct t *var = ...;
... __builtin_preserve_access_index(&(((struct p *)&(var->b[0]))->d)) ...
Although BPF backend can derive the type of &(var->b[0]),
explicit type annotation make checking more consistent
and less error prone.
Another benefit is for multiple dimension array handling.
For example,
struct p { int c; int d; } g[8][9][10];
... __builtin_preserve_access_index(&g[2][3][4].d) ...
It would be possible to calculate the number of "struct p"'s
before accessing its member "d" if array debug info is
available as it contains each dimension range.
This patch enables to annotate IR builtin preserve_array_access_index()
with proper debuginfo type. The unit test case and language reference
is updated as well.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D65664
llvm-svn: 367724
The original commit is r366076. It is temporarily reverted (r366155)
due to test failure. This resubmit makes test more robust by accepting
regex instead of hardcoded names/references in several places.
This is a followup patch for https://reviews.llvm.org/D61809.
Handle unnamed bitfield properly and add more test cases.
Fixed the unnamed bitfield issue. The unnamed bitfield is ignored
by debug info, so we need to ignore such a struct/union member
when we try to get the member index in the debug info.
D61809 contains two test cases but not enough as it does
not checking generated IRs in the fine grain level, and also
it does not have semantics checking tests.
This patch added unit tests for both code gen and semantics checking for
the new intrinsic.
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 366231
i.e., recent 5745eccef54ddd3caca278d1d292a88b2281528b:
* Bump the function_type_mismatch handler version, as its signature has changed.
* The function_type_mismatch handler can return successfully now, so
SanitizerKind::Function must be AlwaysRecoverable (like for
SanitizerKind::Vptr).
* But the minimal runtime would still unconditionally treat a call to the
function_type_mismatch handler as failure, so disallow -fsanitize=function in
combination with -fsanitize-minimal-runtime (like it was already done for
-fsanitize=vptr).
* Add tests.
Differential Revision: https://reviews.llvm.org/D61479
llvm-svn: 366186
This is a followup patch for https://reviews.llvm.org/D61809.
Handle unnamed bitfield properly and add more test cases.
Fixed the unnamed bitfield issue. The unnamed bitfield is ignored
by debug info, so we need to ignore such a struct/union member
when we try to get the member index in the debug info.
D61809 contains two test cases but not enough as it does
not checking generated IRs in the fine grain level, and also
it does not have semantics checking tests.
This patch added unit tests for both code gen and semantics checking for
the new intrinsic.
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 366076
For background of BPF CO-RE project, please refer to
http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.
In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.
Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
addr = preserve_array_access_index(base, index, dimension)
addr = preserve_union_access_index(base, di_index)
addr = preserve_struct_access_index(base, gep_index, di_index)
here,
base: the base pointer for the array/union/struct access.
index: the last access index for array, the same for IR/DebugInfo layout.
dimension: the array dimension.
gep_index: the access index based on IR layout.
di_index: the access index based on user/debuginfo types.
If using these intrinsics blindly, i.e., transforming all GEPs
to these intrinsics and later on reducing them to GEPs, we have
seen up to 7% more instructions generated. To avoid such an overhead,
a clang builtin is proposed:
base = __builtin_preserve_access_index(base)
such that user wraps to-be-relocated GEPs in this builtin
and preserve_*_access_index intrinsics only apply to
those GEPs. Such a buyin will prevent performance degradation
if people do not use CO-RE, even for programs which use
bpf_probe_read().
For example, for the following example,
$ cat test.c
struct sk_buff {
int i;
int b1:1;
int b2:2;
union {
struct {
int o1;
int o2;
} o;
struct {
char flags;
char dev_id;
} dev;
int netid;
} u[10];
};
static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
= (void *) 4;
#define _(x) (__builtin_preserve_access_index(x))
int bpf_prog(struct sk_buff *ctx) {
char dev_id;
bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
return dev_id;
}
$ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
test.c >& log
The generated IR looks like below:
...
define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
%2 = alloca %struct.sk_buff*, align 8
%3 = alloca i8, align 1
store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
%4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
%5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
%6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
%struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
%7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
[10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
%8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
%union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
%9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
%10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
%struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
%11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
%12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
%13 = sext i8 %12 to i32, !dbg !54
call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
ret i32 %13, !dbg !57
}
!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
!26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
!34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)
Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.
For &ctx->u[5].dev.dev_id,
. The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
. The "%7 = ..." represents array subscript "5".
. The "%8 = ..." represents union member "dev" with index 1 for DI layout.
. The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.
Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.
The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D61809
llvm-svn: 365438
Alexey Bader