The instruction set first appeared with Westmere, but not all processors
in that and the next few generations have the instructions. According to
Wikipedia[1], the first generation in which all SKUs have AES
instructions are Skylake and Goldmont. I can't find any Skylake,
Kabylake, Kabylake-R or Cannon Lake currently listed at
https://ark.intel.com that says "Intel® AES New Instructions" "No".
This matches GCC commit
https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01940.html
[1] https://en.wikipedia.org/wiki/AES_instruction_set
Patch By: thiagomacieira
Differential Revision: https://reviews.llvm.org/D51510
llvm-svn: 341862
Summary:
Added support of creating a hardlink from one file to another file.
After a hardlink is added between two files, both file will have the same:
1. UniqueID (inode)
2. Size
3. Buffer
This will bring replay of compilation closer to the actual compilation. There are instances where clang checks for the UniqueID of the file/header to be loaded which leads to a different behavior during replay as all files have different UniqueIDs.
Patch by Utkarsh Saxena!
Reviewers: ilya-biryukov
Reviewed By: ilya-biryukov
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D51359
llvm-svn: 341366
ARM_FEATURE_DSP is already set for targets with the +dsp feature. In
the backend, this target feature is also used to represent the
availability of the of the instructions that the ACLE guard through
the __ARM_FEATURE_SIMD32 macro. We don't have any cores that
implement one and not the other, so set this macro for cores later
than V6 or for Cortex-M cores that the target parser, or user, reports
that the 'dsp' instructions are supported.
Differential Revision: https://reviews.llvm.org/D51093
llvm-svn: 340911
As reported on http://lists.llvm.org/pipermail/cfe-dev/2018-August/058760.html,
this broke i386-freebsd11 due to its lack of atomic 64 bit primitives.
While that's not really this commit's fault, let's revert back to the old
behaviour until this can be fixed. This means generating cmpxchg8b etc for i386
and i486 which don't technically support those, but that's been the behaviour
for a long time, so a little longer probably doesn't hurt that much.
> Adjust MaxAtomicInlineWidth for i386/i486 targets.
>
> This is to fix the bug reported in https://bugs.llvm.org/show_bug.cgi?id=34347#c6.
> Currently, all MaxAtomicInlineWidth of x86-32 targets are set to 64. However,
> i386 doesn't support any cmpxchg related instructions. i486 only supports cmpxchg.
> So in this patch MaxAtomicInlineWidth is reset as follows:
> For i386, the MaxAtomicInlineWidth should be 0 because no cmpxchg is supported.
> For i486, the MaxAtomicInlineWidth should be 32 because it supports cmpxchg.
> For others 32 bits x86 cpu, the MaxAtomicInlineWidth should be 64 because of cmpxchg8b.
>
> Differential Revision: https://reviews.llvm.org/D42154
llvm-svn: 340666
Revert to the original behavior: only calculate real file path when
file is opened and avoid using InterndPath for real path calculation.
llvm-svn: 340602
Summary:
This partially rolls back the change in D48903:
89aa7f45a1 (diff-0025af005307891b5429b6a834823d5eR318)
`real_path` can be very expensive on real file systems, and calling it on each
opened file can slow down the compilation. This also slows down deserialized
ASTs for which real paths need to be recalculated for each input files again.
For clangd code completion latency (using preamble):
Before
{F7039629}
After
{F7039630}
Reviewers: ilya-biryukov, simark
Reviewed By: ilya-biryukov
Subscribers: kadircet, cfe-commits
Differential Revision: https://reviews.llvm.org/D51159
llvm-svn: 340598
subtarget features for indirect calls and indirect branches.
This is in preparation for enabling *only* the call retpolines when
using speculative load hardening.
I've continued to use subtarget features for now as they continue to
seem the best fit given the lack of other retpoline like constructs so
far.
The LLVM side is pretty simple. I'd like to eventually get rid of the
old feature, but not sure what backwards compatibility issues that will
cause.
This does remove the "implies" from requesting an external thunk. This
always seemed somewhat questionable and is now clearly not desirable --
you specify a thunk the same way no matter which set of things are
getting retpolines.
I really want to keep this nicely isolated from end users and just an
LLVM implementation detail, so I've moved the `-mretpoline` flag in
Clang to no longer rely on a specific subtarget feature by that name and
instead to be directly handled. In some ways this is simpler, but in
order to preserve existing behavior I've had to add some fallback code
so that users who relied on merely passing -mretpoline-external-thunk
continue to get the same behavior. We should eventually remove this
I suspect (we have never tested that it works!) but I've not done that
in this patch.
Differential Revision: https://reviews.llvm.org/D51150
llvm-svn: 340515
Set __mips_fpr to 0 if o32 ABI is used with either -mfpxx
or none of -mfp32, -mfpxx, -mfp64 being specified.
Introduce additional checks:
-mfpxx is only to be used in conjunction with the o32 ABI.
report an error when incompatible options are provided.
Formerly no errors were raised when combining n32/n64 ABIs
with -mfp32 and -mfpxx.
There are other cases when __mips_fpr should be set to 0
that are not covered, ex. using o32 on a mips64 cpu
which is valid but not supported in the backend as of yet.
Differential Revision: https://reviews.llvm.org/D50557
llvm-svn: 340391
Summary:
Migrate callers to print().
dump() should be useful to downstreams and third parties as a debugging
aid. Everyone trips up on this and creates confusing output.
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D50661
llvm-svn: 339810
Fast FMAF is not a sufficient condition to enable denormals.
Before VI, enabling denormals caused F32 instructions to
run at F64 speeds.
llvm-svn: 339278
First and subsequent iteration steps are similar, capture this similarity.
Reviewers: bruno, benlangmuir
Reviewed By: bruno
Subscribers: dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D50118
llvm-svn: 339199
Entries with only a filename prevent us from building a file system tree and
cause the assertion
> Assertion failed: (NewParentE && "Parent entry must exist"), function uniqueOverlayTree, file clang/lib/Basic/VirtualFileSystem.cpp, line 1303.
Entries with a relative path are simply not discoverable during header search.
rdar://problem/28990865
Reviewers: bruno, benlangmuir
Reviewed By: bruno
Subscribers: dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D49518
llvm-svn: 339164
Summary:
InMemoryFileSystem::status behaves differently than
RealFileSystem::status. The Name contained in the Status returned by
RealFileSystem::status will be the path as requested by the caller,
whereas InMemoryFileSystem::status returns the normalized path.
For example, when requested the status for "../src/first.h",
RealFileSystem returns a Status with "../src/first.h" as the Name.
InMemoryFileSystem returns "/absolute/path/to/src/first.h".
The reason for this change is that I want to make a unit test in the
clangd testsuite (where we use an InMemoryFileSystem) to reproduce a
bug I get with the clangd program (where a RealFileSystem is used).
This difference in behavior "hides" the bug in the unit test version.
An indirect impact of this change is that a -Wnonportable-include-path
warning is now emitted in test PCH/case-insensitive-include.c. This is
because the real path of the included file (with the wrong case) was not
available previously, whereas it is now.
Reviewers: malaperle, ilya-biryukov, bkramer
Reviewed By: ilya-biryukov
Subscribers: eric_niebler, malaperle, omtcyfz, hokein, bkramer, ilya-biryukov, ioeric, cfe-commits
Differential Revision: https://reviews.llvm.org/D48903
llvm-svn: 339063
This patch proposes an abstract type that represents fixed point numbers, similar to APInt or APSInt that was discussed in https://reviews.llvm.org/D48456#inline-425585. This type holds a value, scale, and saturation and is meant to perform intermediate calculations on constant fixed point values.
Currently this class is used as a way for handling the conversions between fixed point numbers with different sizes and radixes. For example, if I'm casting from a signed _Accum to a saturated unsigned short _Accum, I will need to check the value of the signed _Accum to see if it fits into the short _Accum which involves getting and comparing against the max/min values of the short _Accum. The FixedPointNumber class currently handles the radix shifting and extension when converting to a signed _Accum.
Differential Revision: https://reviews.llvm.org/D48661
llvm-svn: 339028
The way address space declarations for builtins currently work
is nearly useless. The code assumes the address spaces used for
builtins is a confusingly named "target address space" from user
code using __attribute__((address_space(N))) that matches
the builtin declaration. There's no way to use this to declare
a builtin that returns a language specific address space.
The terminology used is highly cofusing since it has nothing
to do with the the address space selected by the target to use
for a language address space.
This feature is essentially unused as-is. AMDGPU and NVPTX
are the only in-tree targets attempting to use this. The AMDGPU
builtins certainly do not behave as intended (i.e. all of the
builtins returning pointers can never compile because the numbered
address space never matches the expected named address space).
The NVPTX builtins are missing tests for some, and the others
seem to rely on an implicit addrspacecast.
Change the used address space for builtins based on a target
hook to allow using a language address space for a builtin.
This allows the same builtin declaration to be used for multiple
languages with similarly purposed address spaces (e.g. the same
AMDGPU builtin can be used in OpenCL and CUDA even though the
constant address spaces are arbitarily different).
This breaks the possibility of using arbitrary numbered
address spaces alongside the named address spaces for builtins.
If this is an issue we probably need to introduce another builtin
declaration character to distinguish language address spaces from
so-called "target address spaces".
llvm-svn: 338707
This adds tests for Armv8.4-A, and also some v8.2 and v8.3 tests that were
missing.
Differential Revision: https://reviews.llvm.org/D50068
llvm-svn: 338525
Summary: Microsoft's C++ object model for ARM64 is the same as that for X86_64.
For example, small structs with non-trivial copy constructors or virtual
function tables are passed indirectly. Currently, they are passed in registers
when compiled with clang.
Reviewers: rnk, mstorsjo, TomTan, haripul, javed.absar
Reviewed By: rnk, mstorsjo
Subscribers: kristof.beyls, chrib, llvm-commits, cfe-commits
Differential Revision: https://reviews.llvm.org/D49770
llvm-svn: 338076
Summary:
InMemoryFileSystem::status behaves differently than
RealFileSystem::status. The Name contained in the Status returned by
RealFileSystem::status will be the path as requested by the caller,
whereas InMemoryFileSystem::status returns the normalized path.
For example, when requested the status for "../src/first.h",
RealFileSystem returns a Status with "../src/first.h" as the Name.
InMemoryFileSystem returns "/absolute/path/to/src/first.h".
The reason for this change is that I want to make a unit test in the
clangd testsuite (where we use an InMemoryFileSystem) to reproduce a
bug I get with the clangd program (where a RealFileSystem is used).
This difference in behavior "hides" the bug in the unit test version.
Reviewers: malaperle, ilya-biryukov, bkramer
Subscribers: cfe-commits, ioeric, ilya-biryukov, bkramer, hokein, omtcyfz
Differential Revision: https://reviews.llvm.org/D48903
llvm-svn: 338057
Summary:
- add comments clarifying semantics
- Status::copyWithNewName(Status, Name) --> instance method
- Status::copyWithNewName(fs::file_status, Name) --> constructor (it's not a copy)
- File::getName() -> getRealPath(), reflecting its actual behavior/function
and stop returning status().getName() in the base class (callers can do this
fallback if they want to, it complicates the contracts).
This is mostly NFC, but the behavior of File::getName() affects FileManager's
FileEntry::tryGetRealPathName(), which now fails in more cases:
- non-real file cases
- real-file cases where the underlying vfs::File was opened in a way that
doesn't call realpath().
(In these cases we don't know a distinct real name, so in principle it seems OK)
Reviewers: klimek
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D49724
llvm-svn: 337834
Changing it to unsigned long (which is 32-bit on wasm32) makes it the same
type as wasm64 (where unsigned long is 64-bit), which would eliminate the most
common cause for mangled names being different between wasm32 and wasm64. For
example, export lists containing symbol names could now often be the same
between wasm32 and wasm64.
Differential Revision: https://reviews.llvm.org/D40526
llvm-svn: 337783
As documented here: https://software.intel.com/en-us/node/682969 and
https://software.intel.com/en-us/node/523346. cpu_dispatch multiversioning
is an ICC feature that provides for function multiversioning.
This feature is implemented with two attributes: First, cpu_specific,
which specifies the individual function versions. Second, cpu_dispatch,
which specifies the location of the resolver function and the list of
resolvable functions.
This is valuable since it provides a mechanism where the resolver's TU
can be specified in one location, and the individual implementions
each in their own translation units.
The goal of this patch is to be source-compatible with ICC, so this
implementation diverges from the ICC implementation in a few ways:
1- Linux x86/64 only: This implementation uses ifuncs in order to
properly dispatch functions. This is is a valuable performance benefit
over the ICC implementation. A future patch will be provided to enable
this feature on Windows, but it will obviously more closely fit ICC's
implementation.
2- CPU Identification functions: ICC uses a set of custom functions to identify
the feature list of the host processor. This patch uses the cpu_supports
functionality in order to better align with 'target' multiversioning.
1- cpu_dispatch function def/decl: ICC's cpu_dispatch requires that the function
marked cpu_dispatch be an empty definition. This patch supports that as well,
however declarations are also permitted, since the linker will solve the
issue of multiple emissions.
Differential Revision: https://reviews.llvm.org/D47474
llvm-svn: 337552
This reverts commit r336807. This breaks users of
ClangTool::mapVirtualFile. Will try to investigate a fix. See also the
discussion on https://reviews.llvm.org/D48903
llvm-svn: 336831
Summary:
InMemoryFileSystem::status behaves differently than
RealFileSystem::status. The Name contained in the Status returned by
RealFileSystem::status will be the path as requested by the caller,
whereas InMemoryFileSystem::status returns the normalized path.
For example, when requested the status for "../src/first.h",
RealFileSystem returns a Status with "../src/first.h" as the Name.
InMemoryFileSystem returns "/absolute/path/to/src/first.h".
The reason for this change is that I want to make a unit test in the
clangd testsuite (where we use an InMemoryFileSystem) to reproduce a
bug I get with the clangd program (where a RealFileSystem is used).
This difference in behavior "hides" the bug in the unit test version.
In general, I guess it's good if InMemoryFileSystem works as much as
possible like RealFileSystem.
Doing so made the FileEntry::RealPathName value (assigned in
FileManager::getFile) wrong when using the InMemoryFileSystem. That's
because it assumes that vfs::File::getName will always return the real
path. I changed to to use FileSystem::getRealPath instead.
Subscribers: ilya-biryukov, ioeric, cfe-commits
Differential Revision: https://reviews.llvm.org/D48903
llvm-svn: 336807
This is part of an ongoing attempt at making 512 bit vectors illegal in the X86 backend type legalizer due to CPU frequency penalties associated with wide vectors on Skylake Server CPUs. We want the loop vectorizer to be able to emit IR containing wide vectors as intermediate operations in vectorized code and allow these wide vectors to be legalized to 256 bits by the X86 backend even though we are targetting a CPU that supports 512 bit vectors. This is similar to what happens with an AVX2 CPU, the vectorizer can emit wide vectors and the backend will split them. We want this splitting behavior, but still be able to use new Skylake instructions that work on 256-bit vectors and support things like masking and gather/scatter.
Of course if the user uses explicit vector code in their source code we need to not split those operations. Especially if they have used any of the 512-bit vector intrinsics from immintrin.h. And we need to make it so that merely using the intrinsics produces the expected code in order to be backwards compatible.
To support this goal, this patch adds a new IR function attribute "min-legal-vector-width" that can indicate the need for a minimum vector width to be legal in the backend. We need to ensure this attribute is set to the largest vector width needed by any intrinsics from immintrin.h that the function uses. The inliner will be reponsible for merging this attribute when a function is inlined. We may also need a way to limit inlining in the future as well, but we can discuss that in the future.
To make things more complicated, there are two different ways intrinsics are implemented in immintrin.h. Either as an always_inline function containing calls to builtins(can be target specific or target independent) or vector extension code. Or as a macro wrapper around a taget specific builtin. I believe I've removed all cases where the macro was around a target independent builtin.
To support the always_inline function case this patch adds attribute((min_vector_width(128))) that can be used to tag these functions with their vector width. All x86 intrinsic functions that operate on vectors have been tagged with this attribute.
To support the macro case, all x86 specific builtins have also been tagged with the vector width that they require. Use of any builtin with this property will implicitly increase the min_vector_width of the function that calls it. I've done this as a new property in the attribute string for the builtin rather than basing it on the type string so that we can opt into it on a per builtin basis and avoid any impact to target independent builtins.
There will be future work to support vectors passed as function arguments and supporting inline assembly. And whatever else we can find that isn't covered by this patch.
Special thanks to Chandler who suggested this direction and reviewed a preview version of this patch. And thanks to Eric Christopher who has had many conversations with me about this issue.
Differential Revision: https://reviews.llvm.org/D48617
llvm-svn: 336583
- Rename the `-fsame-fbits` flag to `-fpadding-on-unsigned-fixed-point`
- Move the flag from a driver option to a cc1 option
- Rename the `SameFBits` member in TargetInfo to `PaddingOnUnsignedFixedPoint`
- Updated descriptions
Differential Revision: https://reviews.llvm.org/D48727
llvm-svn: 335993
This diff includes the logic for setting the precision bits for each primary fixed point type in the target info and logic for initializing a fixed point literal.
Fixed point literals are declared using the suffixes
```
hr: short _Fract
uhr: unsigned short _Fract
r: _Fract
ur: unsigned _Fract
lr: long _Fract
ulr: unsigned long _Fract
hk: short _Accum
uhk: unsigned short _Accum
k: _Accum
uk: unsigned _Accum
```
Errors are also thrown for illegal literal values
```
unsigned short _Accum u_short_accum = 256.0uhk; // expected-error{{the integral part of this literal is too large for this unsigned _Accum type}}
```
Differential Revision: https://reviews.llvm.org/D46915
llvm-svn: 335148
The SPIR target currently allows for half precision floating point types to be
emitted using the LLVM intrinsic functions which convert half types to floats
and doubles. However, this is illegal in SPIR as the only intrinsic allowed by
SPIR is memcpy, as per section 3 of the SPIR specification. Currently this is
leading to an assert being hit in the Clang CodeGen when attempting to emit a
constant or literal _Float16 type in a comparison operation on a SPIR or SPIR64
target. This assert stems from the CodeGen attempting to emit a constant half
value as an integer because the backend has specified that it is using these
half conversion intrinsics (which represents half as i16). This patch prevents
SPIR targets from using these intrinsics by overloading the responsible target
info method, marks SPIR targets as having a legal half type and provides
additional regression testing for the _Float16 type on SPIR targets.
Patch by: Stephen McGroarty
Differential Revision: https://reviews.llvm.org/D48188
llvm-svn: 335111
This diff includes changes for the remaining _Fract and _Sat fixed point types.
```
signed short _Fract s_short_fract;
signed _Fract s_fract;
signed long _Fract s_long_fract;
unsigned short _Fract u_short_fract;
unsigned _Fract u_fract;
unsigned long _Fract u_long_fract;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
short _Fract short_fract;
_Fract fract;
long _Fract long_fract;
// Saturated fixed point types
_Sat signed short _Accum sat_s_short_accum;
_Sat signed _Accum sat_s_accum;
_Sat signed long _Accum sat_s_long_accum;
_Sat unsigned short _Accum sat_u_short_accum;
_Sat unsigned _Accum sat_u_accum;
_Sat unsigned long _Accum sat_u_long_accum;
_Sat signed short _Fract sat_s_short_fract;
_Sat signed _Fract sat_s_fract;
_Sat signed long _Fract sat_s_long_fract;
_Sat unsigned short _Fract sat_u_short_fract;
_Sat unsigned _Fract sat_u_fract;
_Sat unsigned long _Fract sat_u_long_fract;
// Aliased saturated fixed point types
_Sat short _Accum sat_short_accum;
_Sat _Accum sat_accum;
_Sat long _Accum sat_long_accum;
_Sat short _Fract sat_short_fract;
_Sat _Fract sat_fract;
_Sat long _Fract sat_long_fract;
```
This diff only allows for declaration of these fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches.
Differential Revision: https://reviews.llvm.org/D46911
llvm-svn: 334718
Diasble the use of the type __float128 for PPC machines older
than Power9.
The use of -mfloat128 for PPC machine older than Power9 will result
in an error.
Differential Revision: https://reviews.llvm.org/D48088
llvm-svn: 334613
Summary:
This kind of functionality is useful to other project apart from clang.
LLDB works with version numbers a lot, but it does not have a convenient
abstraction for this. Moving this class to a lower level library allows
it to be freely used within LLDB.
Since this class is used in a lot of places in clang, and it used to be
in the clang namespace, it seemed appropriate to add it to the list of
adopted classes in LLVM.h to avoid prefixing all uses with "llvm::".
Also, I didn't find any tests specific for this class, so I wrote a
couple of quick ones for the more interesting bits of functionality.
Reviewers: zturner, erik.pilkington
Subscribers: mgorny, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D47887
llvm-svn: 334399
This breaks the OpenFlags enumeration into two separate
enumerations: OpenFlags and CreationDisposition. The first
controls the behavior of the API depending on whether or not
the target file already exists, and is not a flags-based
enum. The second controls more flags-like values.
This yields a more easy to understand API, while also allowing
flags to be passed to the openForRead api, where most of the
values didn't make sense before. This also makes the apis more
testable as it becomes easy to enumerate all the configurations
which make sense, so I've added many new tests to exercise all
the different values.
llvm-svn: 334221
Do not memory map the main file if the flag UserFilesAreVolatile is set to true
in ASTUnit when calling FileSystem::getBufferForFile.
Differential Revision: https://reviews.llvm.org/D47460
llvm-svn: 334070
Adding __attribute__((aligned(32))) to __m256 breaks the implementation
of _mm256_loadu_ps on Windows. On Windows, alignment attributes have
higher precedence than packing attributes.
We also might want to carefully consider the consequences of changing
our vector typedefs, since many users copy them and invent their own
new, non-Intel specific vector type names.
llvm-svn: 333958
// Primary fixed point types
signed short _Accum s_short_accum;
signed _Accum s_accum;
signed long _Accum s_long_accum;
unsigned short _Accum u_short_accum;
unsigned _Accum u_accum;
unsigned long _Accum u_long_accum;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
This diff only allows for declaration of the fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches. The saturated versions of these types and the equivalent _Fract types will also be added in future patches.
The tests included are for asserting that we can declare these types.
Fixed the test that was failing by not checking for dso_local on some
targets.
Differential Revision: https://reviews.llvm.org/D46084
llvm-svn: 333923
```
// Primary fixed point types
signed short _Accum s_short_accum;
signed _Accum s_accum;
signed long _Accum s_long_accum;
unsigned short _Accum u_short_accum;
unsigned _Accum u_accum;
unsigned long _Accum u_long_accum;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
```
This diff only allows for declaration of the fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches. The saturated versions of these types and the equivalent `_Fract` types will also be added in future patches.
The tests included are for asserting that we can declare these types.
Differential Revision: https://reviews.llvm.org/D46084
llvm-svn: 333814
This fixes two major problems:
- We were not capping vector alignment as desired on 32-bit ARM.
- We were using different alignments based on the AVX settings on
Intel, so we did not have a consistent ABI.
This is an ABI break, but we think we can get away with it because
vectors tend to be used mostly in inline code (which is why not having
a consistent ABI has not proven disastrous on Intel).
Intel's AVX types are specified as having 32-byte / 64-byte alignment,
so align them explicitly instead of relying on the base ABI rule.
Note that this sort of attribute is stripped from template arguments
in template substitution, so there's a possibility that code templated
over vectors will produce inadequately-aligned objects. The right
long-term solution for this is for alignment attributes to be
interpreted as true qualifiers and thus preserved in the canonical type.
llvm-svn: 333791
An intrinsic for an old instruction, as described in the Intel SDM.
Reviewers: craig.topper, rnk
Reviewed By: craig.topper, rnk
Differential Revision: https://reviews.llvm.org/D47142
llvm-svn: 333256
in gcc by https://gcc.gnu.org/ml/gcc-cvs/2018-04/msg00534.html.
The -mibt feature flag is being removed, and the -fcf-protection
option now also defines a CET macro and causes errors when used
on non-X86 targets, while X86 targets no longer check for -mibt
and -mshstk to determine if -fcf-protection is supported. -mshstk
is now used only to determine availability of shadow stack intrinsics.
Comes with an LLVM patch (D46882).
Patch by mike.dvoretsky
Differential Revision: https://reviews.llvm.org/D46881
llvm-svn: 332704
E. g. use "10.11" instead of "10_11".
We are maintaining backward compatibility by parsing underscore-delimited version tuples but no longer keep track of the separator and using dot format for output.
Differential Revision: https://reviews.llvm.org/D46747
rdar://problem/39845032
llvm-svn: 332598
When looking at lib/Basic/Targets/OSTargets.h, I noticed that _REENTRANT is defined
unconditionally on Solaris, unlike all other targets and what either Studio cc (only define
it with -mt) or gcc (only define it with -pthread) do.
This patch follows that lead.
Differential Revision: https://reviews.llvm.org/D41241
llvm-svn: 332343
The option enables use of 32-bit pointers for accessing
const/local/shared memory. The feature is disabled by default.
Differential Revision: https://reviews.llvm.org/D46148
llvm-svn: 331938
Summary: This can be used to create a virtual environment (incl. VFS, source manager) for code snippets.
Reviewers: sammccall, klimek
Reviewed By: sammccall
Subscribers: klimek, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D46176
llvm-svn: 331923
Restrict the following keywords in the OpenCL C++ language mode,
according to Sections 2.2 & 2.9 of the OpenCL C++ 1.0 Specification.
- dynamic_cast
- typeid
- register (already restricted in OpenCL C, update the diagnostic)
- thread_local
- exceptions (try/catch/throw)
- access qualifiers read_only, write_only, read_write
Support the `__global`, `__local`, `__constant`, `__private`, and
`__generic` keywords in OpenCL C++. Leave the unprefixed address
space qualifiers such as global available, i.e., do not mark them as
reserved keywords in OpenCL C++. libclcxx provides explicit address
space pointer classes such as `global_ptr` and `global<T>` that are
implemented using the `__`-prefixed qualifiers.
Differential Revision: https://reviews.llvm.org/D46022
llvm-svn: 331874
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
Generate a printable OpenCL language version number in a single place
and select between the OpenCL C or OpenCL C++ version accordingly.
Differential Revision: https://reviews.llvm.org/D46382
llvm-svn: 331766
This is not yet part of any C++ working draft, and so is controlled by the flag
-fchar8_t rather than a -std= flag. (The GCC implementation is controlled by a
flag with the same name.)
This implementation is experimental, and will be removed or revised
substantially to match the proposal as it makes its way through the C++
committee.
llvm-svn: 331244
Summary:
The getConstraintRegister method is used by semantic checking of
inline assembly statements in order to diagnose conflicts between
clobber list and input/output lists. Currently ARM and AArch64 don't
override getConstraintRegister, so conflicts between registers
assigned to variables in asm labels and clobber lists are not
diagnosed. Such conflicts can cause assertion failures in the back end
and even miscompilations.
This patch implements getConstraintRegister for ARM and AArch64
targets. Since these targets don't have single-register constraints,
the implementation is trivial and just returns the register specified
in an asm label (if any).
Reviewers: eli.friedman, javed.absar, thopre
Reviewed By: thopre
Subscribers: rengolin, eraman, rogfer01, myatsina, kristof.beyls, cfe-commits, chrib
Differential Revision: https://reviews.llvm.org/D45965
llvm-svn: 331164
When a '>>' token is split into two '>' tokens (in C++11 onwards), or (as an
extension) when we do the same for other tokens starting with a '>', we can't
just use a location pointing to the first '>' as the location of the split
token, because that would result in our miscomputing the length and spelling
for the token. As a consequence, for example, a refactoring replacing 'A<X>'
with something else would sometimes replace one character too many, and
similarly diagnostics highlighting a template-id source range would highlight
one character too many.
Fix this by creating an expansion range covering the first character of the
'>>' token, whose spelling is '>'. For this to work, we generalize the
expansion range of a macro FileID to be either a token range (the common case)
or a character range (used in this new case).
llvm-svn: 331155
LLVM_ON_WIN32 is set exactly with MSVC and MinGW (but not Cygwin) in
HandleLLVMOptions.cmake, which is where _WIN32 defined too. Just use the
default macro instead of a reinvented one.
See thread "Replacing LLVM_ON_WIN32 with just _WIN32" on llvm-dev and cfe-dev.
No intended behavior change.
llvm-svn: 331069
This adds a pre-defined macro to test if the compiler has support for the
v8.2-A dot rpoduct intrinsics in AArch32 mode.
The AAcrh64 equivalent has already been added by rL330229.
The ACLE spec which describes this macro hasn't been published yet, but this is
based on the final internal draft, and GCC has already implemented this.
Differential revision: https://reviews.llvm.org/D46108
llvm-svn: 331038
Passing the features in random order will lead to unpredictable results
when some of the features are related (like the architecture-version
features on ARM).
It might be possible to fix this particular case in the ARM target code,
to avoid adding overlapping target features. But we should probably be
sorting in any case: the behavior shouldn't depend on StringMap's
hashing algorithm.
Differential Revision: https://reviews.llvm.org/D46030
llvm-svn: 330861
When rebasing https://reviews.llvm.org/D40898 with GCC 5.4 on Solaris 11.4, I ran
into a few instances of
In file included from /vol/llvm/src/compiler-rt/local/test/asan/TestCases/Posix/asan-symbolize-sanity-test.cc:19:
In file included from /usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/string:40:
In file included from /usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/bits/char_traits.h:39:
In file included from /usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/bits/stl_algobase.h:64:
In file included from /usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/bits/stl_pair.h:59:
In file included from /usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/bits/move.h:57:
/usr/gcc/5/lib/gcc/x86_64-pc-solaris2.11/5.4.0/../../../../include/c++/5.4.0/type_traits:311:39: error: __float128 is not supported on this target
struct __is_floating_point_helper<__float128>
^
during make check-all. The line above is inside
#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
template<>
struct __is_floating_point_helper<__float128>
: public true_type { };
#endif
While the libstdc++ header indicates support for __float128, clang does not, but
should. The following patch implements this and fixed those errors.
Differential Revision: https://reviews.llvm.org/D41240
llvm-svn: 330572
Right now we only use this information in one place, immediately after
we calculate it, but it's still nice information to have. The Swift
project is going to use this to tidy up its "API notes" feature (see
past discussion on cfe-dev that never quite converged).
Reviewed by Bruno Cardoso Lopes.
llvm-svn: 330452
Summary:
A clang builtin for xray typed events. Differs from
__xray_customevent(...) by the presence of a type tag that is vended by
compiler-rt in typical usage. This allows xray handlers to expand logged
events with their type description and plugins to process traced events
based on type.
This change depends on D45633 for the intrinsic definition.
Reviewers: dberris, pelikan, rnk, eizan
Subscribers: cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D45716
llvm-svn: 330220
Currently, the interaction between the triple, the CPU, and the
supported features is a mess: the driver edits the triple to indicate
the supported architecture version, and the LLVM backend uses this to
figure out what instructions are legal. This makes it difficult to
understand what's happening, and makes it impossible to LTO together two
modules with different computed architectures.
Instead of relying on triple rewriting to get the correct target
features, we should add the right target features explicitly.
Differential Revision: https://reviews.llvm.org/D45240
llvm-svn: 330169
As reported here: https://bugs.llvm.org/show_bug.cgi?id=37033
Any usage of a builtin function that uses a va_list by reference
will cause an assertion when redeclaring it.
After discussion in the review, it was concluded that the correct
way of accomplishing this fix is to make attempts to redeclare certain
builtins an error. Unfortunately, doing this limitation for all builtins
is likely a breaking change, so this commit simply limits it to
types with custom type checking and those that take a reference.
Two tests needed to be updated to make this work.
Differential Revision: https://reviews.llvm.org/D45383
llvm-svn: 330160
This fixes issues with "class" being reported as an identifier in "enum class" because the construct is not present when using default language options.
Patch by Johann Klähn.
llvm-svn: 330159
Summary:
This change addresses http://llvm.org/PR36926 by allowing users to pick
which instrumentation bundles to use, when instrumenting with XRay. In
particular, the flag `-fxray-instrumentation-bundle=` has four valid
values:
- `all`: the default, emits all instrumentation kinds
- `none`: equivalent to -fnoxray-instrument
- `function`: emits the entry/exit instrumentation
- `custom`: emits the custom event instrumentation
These can be combined either as comma-separated values, or as
repeated flag values.
Reviewers: echristo, kpw, eizan, pelikan
Reviewed By: pelikan
Subscribers: mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D44970
llvm-svn: 329985
The WBNOINVD instruction writes back all modified
cache lines in the processor’s internal cache to main memory
but does not invalidate (flush) the internal caches.
Reviewers: craig.topper, zvi, ashlykov
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D43817
llvm-svn: 329848
When NVPTX TARGET_BUILTIN specifies sm_XX or ptxYY as required feature,
consider those features available if we're compiling for GPU >= sm_XX or have
enabled PTX version >= ptxYY.
Differential Revision: https://reviews.llvm.org/D45061
llvm-svn: 329829
Sometimes when people compile bpf programs with
"clang ... -target bpf ...", the kernel header
files may contain host arch inline assembly codes
as in the patch https://patchwork.kernel.org/patch/10119683/
by Arnaldo Carvaldo de Melo.
The current workaround in the above patch
is to guard the inline assembly with "#ifndef __BPF__"
marco. So when __BPF__ is defined, these macros will
have no use.
Such a method is not extensible. As a matter of fact,
most of these inline assembly codes will be thrown away
at the end of clang compilation.
So for bpf target, this patch accepts all asm register
names in clang AST stage. The name will be checked
again during llc code generation if the inline assembly
code is indeed for bpf programs.
With this patch, the above "#ifndef __BPF__" is not needed
any more in https://patchwork.kernel.org/patch/10119683/.
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 329823
amdgcn targets only support HIP, which does not define __CUDA_ARCH__.
this is a partial unroll of r329232 / D45277.
Differential Revision: https://reviews.llvm.org/D45387
llvm-svn: 329584
Summary:
This change consolidates the always/never lists that may be provided to
clang to externally control which functions should be XRay instrumented
by imbuing attributes. The files follow the same format as defined in
https://clang.llvm.org/docs/SanitizerSpecialCaseList.html for the
sanitizer blacklist.
We also deprecate the existing `-fxray-instrument-always=` and
`-fxray-instrument-never=` flags, in favour of `-fxray-attr-list=`.
This fixes http://llvm.org/PR34721.
Reviewers: echristo, vlad.tsyrklevich, eugenis
Reviewed By: vlad.tsyrklevich
Subscribers: llvm-commits, cfe-commits
Differential Revision: https://reviews.llvm.org/D45357
llvm-svn: 329543
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:
archtype
cas
classs
checkk
compres
definit
frome
iff
inteval
ith
lod
methode
nd
optin
ot
pres
statics
te
thru
Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)
Differential revision: https://reviews.llvm.org/D44188
llvm-svn: 329399
Summary:
This patch extend getTargetDefines and implement handleTargetFeatures
and hasFeature. and define corresponding marco for those features.
Reviewers: asb, apazos, eli.friedman
Differential Revision: https://reviews.llvm.org/D44727
Patch by Kito Cheng.
llvm-svn: 329278
Summary:
In https://reviews.llvm.org/D44960, file status check is executed every
time a real file system directory iterator is constructed or
incremented, and emits an error code. This change list fixes the errors
in VirtualFileSystem caused by https://reviews.llvm.org/D44960.
Patch by Yuke Liao (@liaoyuke).
Reviewers: vsk, pcc, zturner, liaoyuke
Reviewed By: vsk
Subscribers: mgrang, cfe-commits
Differential Revision: https://reviews.llvm.org/D45178
llvm-svn: 329223
Microsoft has reserved 'U' for the PreserveMostCC which is used in the
swift runtime. Add support for this. This allows the swift runtime to
be built for Windows again.
llvm-svn: 329025
Summary:
Allow rN registers to be simply parsed as correspoing xN registers.
The "register ... asm("rN")" is an command to the
compiler's register allocator, not an operand to any individual assembly
instruction. GCC documents this syntax as "...the name of the register
that should be used."
This is needed to support the changes in Linux kernel (see
https://lkml.org/lkml/2018/3/1/268 )
Note: This will add support only for the limited use case of
register ... asm("rN"). Any other uses that make rN leak into assembly
are not supported.
Reviewers: kristof.beyls, rengolin, peter.smith, t.p.northover
Reviewed By: peter.smith
Subscribers: javed.absar, eraman, cfe-commits, srhines
Differential Revision: https://reviews.llvm.org/D44815
llvm-svn: 328829
ObjC and ObjC++ pass non-trivial structs in a way that is incompatible
with each other. For example:
typedef struct {
id f0;
__weak id f1;
} S;
// this code is compiled in c++.
extern "C" {
void foo(S s);
}
void caller() {
// the caller passes the parameter indirectly and destructs it.
foo(S());
}
// this function is compiled in c.
// 'a' is passed directly and is destructed in the callee.
void foo(S a) {
}
This patch fixes the incompatibility by passing and returning structs
with __strong or weak fields using the C ABI in C++ mode. __strong and
__weak fields in a struct do not cause the struct to be destructed in
the caller and __strong fields do not cause the struct to be passed
indirectly.
Also, this patch fixes the microsoft ABI bug mentioned here:
https://reviews.llvm.org/D41039?id=128767#inline-364710
rdar://problem/38887866
Differential Revision: https://reviews.llvm.org/D44908
llvm-svn: 328731
r327219 added wrappers to std::sort which randomly shuffle the container before
sorting. This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.
llvm-svn: 328636
Need to override convertConstraint to recognise amdgpu specific register names.
Differential Revision: https://reviews.llvm.org/D44533
llvm-svn: 328359
For generating NEON intrinsics, this determines the NEON data type, and whether
it should be a half type or an i16 type. I.e., we always pass a half type for
AArch64, this hasn't changed, but now also for ARM but only when FullFP16 is
enabled, and i16 otherwise.
This is intended to be non-functional change, but together with the backend
work in D44538 which adds support for f16 vectors, this enables adding the
AArch32 FP16 (vector) intrinsics.
Differential Revision: https://reviews.llvm.org/D44561
llvm-svn: 327836
This is a partial recommit of r327189 that was reverted
due to test issues. I.e., this recommits minimal functional
change, the FP16 feature test macros, and adds tests that
were missing in the original commit.
llvm-svn: 327455
- Expand GK_*s (i.e. GFX6 -> GFX600, GFX601, etc.)
- This allows us to choose features correctly in some cases (for example, fast fmaf is available on gfx600, but not gfx601)
- Move HasFMAF, HasFP64, HasLDEXPF to GPUInfo tables
- Add HasFastFMA, HasFastFMAF to GPUInfo tables
- Add missing tests
llvm-svn: 326254
Summary:
If the flag -fforce-enable-int128 is passed, it will enable support for __int128_t and __uint128_t types.
This flag can then be used to build compiler-rt for RISCV32.
Reviewers: asb, kito-cheng, apazos, efriedma
Reviewed By: asb, efriedma
Subscribers: shiva0217, efriedma, jfb, dschuff, sdardis, sbc100, jgravelle-google, aheejin, rbar, johnrusso, simoncook, jordy.potman.lists, sabuasal, niosHD, cfe-commits
Differential Revision: https://reviews.llvm.org/D43105
llvm-svn: 326045
LLVM has supported a new target feature "alu32" which could be enabled or
disabled by "-mattr=[+|-]alu32" when using llc.
This patch link Clang with it, so it could be also done by passing related
options to Clang, for example:
-Xclang -target-feature -Xclang +alu32
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Yonghong Song <yhs@fb.com>
llvm-svn: 325996
Cannon Lake does not support CLWB, therefore it
does not include all features listed under SKX.
Patch by Gabor Buella
Differential Revision: https://reviews.llvm.org/D43459
llvm-svn: 325655
This patch provides mitigation for CVE-2017-5715, Spectre variant two,
which affects the P5600 and P6600. It provides the option
-mindirect-jump=hazard, which instructs the LLVM backend to replace
indirect branches with their hazard barrier variants.
This option is accepted when targeting MIPS revision two or later.
The migitation strategy suggested by MIPS for these processors is to
use two hazard barrier instructions. 'jalr.hb' and 'jr.hb' are hazard
barrier variants of the 'jalr' and 'jr' instructions respectively.
These instructions impede the execution of instruction stream until
architecturally defined hazards (changes to the instruction stream,
privileged registers which may affect execution) are cleared. These
instructions in MIPS' designs are not speculated past.
These instructions are used with the option -mindirect-jump=hazard
when branching indirectly and for indirect function calls.
These instructions are defined by the MIPS32R2 ISA, so this mitigation
method is not compatible with processors which implement an earlier
revision of the MIPS ISA.
Implementation note: I've opted to provide this as an
-mindirect-jump={hazard,...} style option in case alternative
mitigation methods are required for other implementations of the MIPS
ISA in future, e.g. retpoline style solutions.
Reviewers: atanasyan
Differential Revision: https://reviews.llvm.org/D43487
llvm-svn: 325651
Summary:
Make clang accept `-msahf` (and `-mno-sahf`) flags to activate the
`+sahf` feature for the backend, for bug 36028 (Incorrect use of
pushf/popf enables/disables interrupts on amd64 kernels). This was
originally submitted in bug 36037 by Jonathan Looney
<jonlooney@gmail.com>.
As described there, GCC also uses `-msahf` for this feature, and the
backend already recognizes the `+sahf` feature. All that is needed is to
teach clang to pass this on to the backend.
The mapping of feature support onto CPUs may not be complete; rather, it
was chosen to match LLVM's idea of which CPUs support this feature (see
lib/Target/X86/X86.td).
I also updated the affected test case (CodeGen/attr-target-x86.c) to
match the emitted output.
Reviewers: craig.topper, coby, efriedma, rsmith
Reviewed By: craig.topper
Subscribers: emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D43394
llvm-svn: 325446
The code for going up the macro arg expansion is duplicated in many
places (and we need it for the analyzer as well, so I did not want to
duplicate it two more times).
This patch is an NFC, so the semantics should remain the same.
Differential Revision: https://reviews.llvm.org/D42458
llvm-svn: 324780
diagnostic settings using _Pragma within a macro.
The AST writer had previously been assuming that all diagnostic state
transitions would occur within a FileID corresponding to a file. When a
diagnostic state change occured within a macro, it was unable to form a
location for that state change and would instead corrupt the diagnostic state
of the "root" node (and thus that of the main compilation).
Also introduce a "#pragma clang __debug diag_mapping" debugging utility
that I added to track this issue down.
llvm-svn: 324695
Apparently storing the pointer to a StringLiteral as
a StringRef caused this section of code to issue a ubsan
warning. This will hopefully fix that.
llvm-svn: 324687
What seems to be a bug in older versions of MSVC, constexpr
member arrays with a redefinition (to force emission) require
their initial definition to have the size between the brackets.
llvm-svn: 324682
When rejecting a march= or target-cpu command line parameter,
the message is quite lacking. This patch adds a note that prints
all possible values for the current target, if the target supports it.
This adds support for the ARM/AArch64 targets (more to come!).
Differential Revision: https://reviews.llvm.org/D42978
llvm-svn: 324673
Previously, RISCV32TargetInfo or RISCV64TargetInfo were created
unconditionally. Use LinuxTargetInfo<RISCV??TargetInfo> to ensure that the
proper OS-specific defines are present.
This patch only adds logic to instantiate LinuxTargetInfo and leaves a TODO,
as I'm reluctant to add logic for other targets (e.g. FreeBSD, RTEMS) until
I've produced and tested at least one binary for that OS+target combo.
Thanks to @mgrang to reporting the issue.
llvm-svn: 324170
Clang can use CUDA-9.1 now, though new APIs (are not implemented yet.
The major change is that headers in CUDA-9.1 went through substantial
changes that started in CUDA-9.0 which required substantial changes
in the cuda compatibility headers provided by clang.
There are two major issues:
* CUDA SDK no longer provides declarations for libdevice functions.
* A lot of device-side functions have become nvcc's builtins and
CUDA headers no longer contain their implementations.
This patch changes the way CUDA headers are handled if we compile
with CUDA 9.x. Both 9.0 and 9.1 are affected.
* Clang provides its own declarations of libdevice functions.
* For CUDA-9.x clang now provides implementation of device-side
'standard library' functions using libdevice.
This patch should not affect compilation with CUDA-8. There may be
some observable differences for CUDA-9.0, though they are not expected
to affect functionality.
Tested: CUDA test-suite tests for all supported combinations of:
CUDA: 7.0,7.5,8.0,9.0,9.1
GPU: sm_20, sm_35, sm_60, sm_70
Differential Revision: https://reviews.llvm.org/D42513
llvm-svn: 323713
This is to fix the bug reported in https://bugs.llvm.org/show_bug.cgi?id=34347#c6.
Currently, all MaxAtomicInlineWidth of x86-32 targets are set to 64. However,
i386 doesn't support any cmpxchg related instructions. i486 only supports cmpxchg.
So in this patch MaxAtomicInlineWidth is reset as follows:
For i386, the MaxAtomicInlineWidth should be 0 because no cmpxchg is supported.
For i486, the MaxAtomicInlineWidth should be 32 because it supports cmpxchg.
For others 32 bits x86 cpu, the MaxAtomicInlineWidth should be 64 because of cmpxchg8b.
Differential Revision: https://reviews.llvm.org/D42154
llvm-svn: 323281
Summary:
First, we need to explain the core of the vulnerability. Note that this
is a very incomplete description, please see the Project Zero blog post
for details:
https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html
The basis for branch target injection is to direct speculative execution
of the processor to some "gadget" of executable code by poisoning the
prediction of indirect branches with the address of that gadget. The
gadget in turn contains an operation that provides a side channel for
reading data. Most commonly, this will look like a load of secret data
followed by a branch on the loaded value and then a load of some
predictable cache line. The attacker then uses timing of the processors
cache to determine which direction the branch took *in the speculative
execution*, and in turn what one bit of the loaded value was. Due to the
nature of these timing side channels and the branch predictor on Intel
processors, this allows an attacker to leak data only accessible to
a privileged domain (like the kernel) back into an unprivileged domain.
The goal is simple: avoid generating code which contains an indirect
branch that could have its prediction poisoned by an attacker. In many
cases, the compiler can simply use directed conditional branches and
a small search tree. LLVM already has support for lowering switches in
this way and the first step of this patch is to disable jump-table
lowering of switches and introduce a pass to rewrite explicit indirectbr
sequences into a switch over integers.
However, there is no fully general alternative to indirect calls. We
introduce a new construct we call a "retpoline" to implement indirect
calls in a non-speculatable way. It can be thought of loosely as
a trampoline for indirect calls which uses the RET instruction on x86.
Further, we arrange for a specific call->ret sequence which ensures the
processor predicts the return to go to a controlled, known location. The
retpoline then "smashes" the return address pushed onto the stack by the
call with the desired target of the original indirect call. The result
is a predicted return to the next instruction after a call (which can be
used to trap speculative execution within an infinite loop) and an
actual indirect branch to an arbitrary address.
On 64-bit x86 ABIs, this is especially easily done in the compiler by
using a guaranteed scratch register to pass the target into this device.
For 32-bit ABIs there isn't a guaranteed scratch register and so several
different retpoline variants are introduced to use a scratch register if
one is available in the calling convention and to otherwise use direct
stack push/pop sequences to pass the target address.
This "retpoline" mitigation is fully described in the following blog
post: https://support.google.com/faqs/answer/7625886
We also support a target feature that disables emission of the retpoline
thunk by the compiler to allow for custom thunks if users want them.
These are particularly useful in environments like kernels that
routinely do hot-patching on boot and want to hot-patch their thunk to
different code sequences. They can write this custom thunk and use
`-mretpoline-external-thunk` *in addition* to `-mretpoline`. In this
case, on x86-64 thu thunk names must be:
```
__llvm_external_retpoline_r11
```
or on 32-bit:
```
__llvm_external_retpoline_eax
__llvm_external_retpoline_ecx
__llvm_external_retpoline_edx
__llvm_external_retpoline_push
```
And the target of the retpoline is passed in the named register, or in
the case of the `push` suffix on the top of the stack via a `pushl`
instruction.
There is one other important source of indirect branches in x86 ELF
binaries: the PLT. These patches also include support for LLD to
generate PLT entries that perform a retpoline-style indirection.
The only other indirect branches remaining that we are aware of are from
precompiled runtimes (such as crt0.o and similar). The ones we have
found are not really attackable, and so we have not focused on them
here, but eventually these runtimes should also be replicated for
retpoline-ed configurations for completeness.
For kernels or other freestanding or fully static executables, the
compiler switch `-mretpoline` is sufficient to fully mitigate this
particular attack. For dynamic executables, you must compile *all*
libraries with `-mretpoline` and additionally link the dynamic
executable and all shared libraries with LLD and pass `-z retpolineplt`
(or use similar functionality from some other linker). We strongly
recommend also using `-z now` as non-lazy binding allows the
retpoline-mitigated PLT to be substantially smaller.
When manually apply similar transformations to `-mretpoline` to the
Linux kernel we observed very small performance hits to applications
running typical workloads, and relatively minor hits (approximately 2%)
even for extremely syscall-heavy applications. This is largely due to
the small number of indirect branches that occur in performance
sensitive paths of the kernel.
When using these patches on statically linked applications, especially
C++ applications, you should expect to see a much more dramatic
performance hit. For microbenchmarks that are switch, indirect-, or
virtual-call heavy we have seen overheads ranging from 10% to 50%.
However, real-world workloads exhibit substantially lower performance
impact. Notably, techniques such as PGO and ThinLTO dramatically reduce
the impact of hot indirect calls (by speculatively promoting them to
direct calls) and allow optimized search trees to be used to lower
switches. If you need to deploy these techniques in C++ applications, we
*strongly* recommend that you ensure all hot call targets are statically
linked (avoiding PLT indirection) and use both PGO and ThinLTO. Well
tuned servers using all of these techniques saw 5% - 10% overhead from
the use of retpoline.
We will add detailed documentation covering these components in
subsequent patches, but wanted to make the core functionality available
as soon as possible. Happy for more code review, but we'd really like to
get these patches landed and backported ASAP for obvious reasons. We're
planning to backport this to both 6.0 and 5.0 release streams and get
a 5.0 release with just this cherry picked ASAP for distros and vendors.
This patch is the work of a number of people over the past month: Eric, Reid,
Rui, and myself. I'm mailing it out as a single commit due to the time
sensitive nature of landing this and the need to backport it. Huge thanks to
everyone who helped out here, and everyone at Intel who helped out in
discussions about how to craft this. Also, credit goes to Paul Turner (at
Google, but not an LLVM contributor) for much of the underlying retpoline
design.
Reviewers: echristo, rnk, ruiu, craig.topper, DavidKreitzer
Subscribers: sanjoy, emaste, mcrosier, mgorny, mehdi_amini, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D41723
llvm-svn: 323155
simd`.
Added host codegen + codegen for devices with default codegen for
`#pragma omp target teams distribute parallel for simd` directive.
llvm-svn: 322515
As RV64 codegen has not yet been upstreamed into LLVM, we focus on RV32 driver
support (RV64 to follow).
Differential Revision: https://reviews.llvm.org/D39963
llvm-svn: 322276
Similarly, make -mno-fma and -mno-f16c imply -mno-avx512f.
Withou this "-mno-sse -mavx512f" ends up with avx512f being enabled in the frontend but disabled in the backend.
llvm-svn: 322245
Cf-protection is a target independent flag that instructs the back-end to instrument control flow mechanisms like: Branch, Return, etc.
For example in X86 this flag will be used to instrument Indirect Branch Tracking instructions.
Differential Revision: https://reviews.llvm.org/D40478
Change-Id: I5126e766c0e6b84118cae0ee8a20fe78cc373dea
llvm-svn: 322063
GCC's attribute 'target', in addition to being an optimization hint,
also allows function multiversioning. We currently have the former
implemented, this is the latter's implementation.
This works by enabling functions with the same name/signature to coexist,
so that they can all be emitted. Multiversion state is stored in the
FunctionDecl itself, and SemaDecl manages the definitions.
Note that it ends up having to permit redefinition of functions so
that they can all be emitted. Additionally, all versions of the function
must be emitted, so this also manages that.
Note that this includes some additional rules that GCC does not, since
defining something as a MultiVersion function after a usage has been made illegal.
The only 'history rewriting' that happens is if a function is emitted before
it has been converted to a multiversion'ed function, at which point its name
needs to be changed.
Function templates and virtual functions are NOT yet supported (not supported
in GCC either).
Additionally, constructors/destructors are disallowed, but the former is
planned.
llvm-svn: 322028
When modules come from module map files explicitly specified by
-fmodule-map-file= arguments, allow those to override/shadow modules
with the same name that are found implicitly by header search. If such a
module is looked up by name (e.g. @import), we will always find the one
from -fmodule-map-file. If we try to use a shadowed module by including
one of its headers report an error.
This enables developers to force use of a specific copy of their module
to be used if there are multiple copies that would otherwise be visible,
for example if they develop modules that are installed in the default
search paths.
Patch originally by Ben Langmuir,
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20151116/143425.html
Based on cfe-dev discussion:
http://lists.llvm.org/pipermail/cfe-dev/2015-November/046164.html
Differential Revision: https://reviews.llvm.org/D31269
rdar://problem/23612102
llvm-svn: 321855
When modules come from module map files explicitly specified by
-fmodule-map-file= arguments, allow those to override/shadow modules
with the same name that are found implicitly by header search. If such a
module is looked up by name (e.g. @import), we will always find the one
from -fmodule-map-file. If we try to use a shadowed module by including
one of its headers report an error.
This enables developers to force use of a specific copy of their module
to be used if there are multiple copies that would otherwise be visible,
for example if they develop modules that are installed in the default
search paths.
Patch originally by Ben Langmuir,
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20151116/143425.html
Based on cfe-dev discussion:
http://lists.llvm.org/pipermail/cfe-dev/2015-November/046164.html
Differential Revision: https://reviews.llvm.org/D31269
rdar://problem/23612102
llvm-svn: 321781
I based that commit on what was in Intel's public documentation here https://software.intel.com/sites/default/files/managed/c5/15/architecture-instruction-set-extensions-programming-reference.pdf
Which specifically said CLWB wasn't until Icelake.
But I've since cross checked with SDE and it thinks these features exist on CNL and ICL. So now I don't know what to believe.
I've added test coverage of the current behavior as part of the revert so at least now have proof of what we're doing.
llvm-svn: 321547
We have cannonlake and icelake inheriting from skylake server in a switch using fallthroughs. But they aren't perfect supersets of skylake server.
llvm-svn: 321504
added vbmi2 feature recognition
added intrinsics support for vbmi2 instructions
_mm[128,256,512]_mask[z]_compress_epi[16,32]
_mm[128,256,512]_mask_compressstoreu_epi[16,32]
_mm[128,256,512]_mask[z]_expand_epi[16,32]
_mm[128,256,512]_mask[z]_expandloadu_epi[16,32]
_mm[128,256,512]_mask[z]_sh[l,r]di_epi[16,32,64]
_mm[128,256,512]_mask_sh[l,r]dv_epi[16,32,64]
matching a similar work on the backend (D40206)
Differential Revision: https://reviews.llvm.org/D41557
llvm-svn: 321487
added vpclmulqdq feature recognition
added intrinsics support for vpclmulqdq instructions
_mm256_clmulepi64_epi128
_mm512_clmulepi64_epi128
matching a similar work on the backend (D40101)
Differential Revision: https://reviews.llvm.org/D41573
llvm-svn: 321480
added vaes feature recognition
added intrinsics support for vaes instructions, matching a similar work on the backend (D40078)
_mm256_aesenc_epi128
_mm512_aesenc_epi128
_mm256_aesenclast_epi128
_mm512_aesenclast_epi128
_mm256_aesdec_epi128
_mm512_aesdec_epi128
_mm256_aesdeclast_epi128
_mm512_aesdeclast_epi128
llvm-svn: 321474
https://bugs.llvm.org/show_bug.cgi?id=35721 reports that x86intrin.h
is issuing a few warnings. This is because attribute target is using
isValidFeatureName for its source. It was also discovered that two of
these were missing from hasFeature.
Additionally, shstk is and ibu are reordered alphabetically, as came
up during code review.
llvm-svn: 321324
The size of the result vector is currently around 4600 with
Flavor::WarningOrError, which makes std::vector a better candidate than
llvm::SmallVector.
Patch by: Andras Leitereg!
Differential Revision: https://reviews.llvm.org/D39372
llvm-svn: 321190
Summary:
llvm has grown a WritableMemoryBuffer class, which is convertible
(inherits from) a MemoryBuffer. We can use it to avoid conts_casting the
buffer contents when we want to write to it.
Reviewers: dblaikie, rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D41387
llvm-svn: 321167
Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.
All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.
llvm-svn: 320707
Erich Keane