Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.
Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.
This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.
```c++
// -std=c++14
#define SAFE_STATIC __attribute__((require_constant_initialization)) static
struct T {
constexpr T(int) {}
~T();
};
SAFE_STATIC T x = {42}; // OK.
SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
// copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.
Reviewers: majnemer, rsmith, aaron.ballman
Subscribers: jroelofs, cfe-commits
Differential Revision: https://reviews.llvm.org/D23385
llvm-svn: 280525
Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.
Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.
This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.
```c++
// -std=c++14
#define SAFE_STATIC __attribute__((require_constant_initialization)) static
struct T {
constexpr T(int) {}
~T();
};
SAFE_STATIC T x = {42}; // OK.
SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
// copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.
Reviewers: majnemer, rsmith, aaron.ballman
Subscribers: jroelofs, cfe-commits
Differential Revision: https://reviews.llvm.org/D23385
llvm-svn: 280516
Extend the __declspec(dll*) attribute to cover ObjC interfaces. This was
requested by Microsoft for their ObjC support. Cover both import and export.
This only adds the semantic analysis portion of the support, code-generation
still remains outstanding. Add some basic initial documentation on the
attributes that were previously empty. Tweak the previous tests to use the
relative expected-warnings to make the tests easier to read.
llvm-svn: 275610
Previous attempts to rename the IBOutletCollection argument to something
other than "Interface" were undone (r127127 and r139620). Instead of
renaming it, work around this in tablegen, so the public facing getter
can have the usual name of 'getInterface'.
Fixes PR26682
llvm-svn: 271305
Reduce space in empty constructors and between data members and first public section.
Fix some Include What You Use warnings.
Differential revision: http://reviews.llvm.org/D20213
llvm-svn: 269371
Bitsets, and the compiler features they rely on (vtable opt, CFI),
only have visibility within the LTO'd part of the linkage unit. Therefore,
only enable these features for classes with hidden LTO visibility. This
notion is based on object file visibility or (on Windows)
dllimport/dllexport attributes.
We provide the [[clang::lto_visibility_public]] attribute to override the
compiler's LTO visibility inference in cases where the class is defined
in the non-LTO'd part of the linkage unit, or where the ABI supports
calling classes derived from abstract base classes with hidden visibility
in other linkage units (e.g. COM on Windows).
If the cross-DSO CFI mode is enabled, bitset checks are emitted even for
classes with public LTO visibility, as that mode uses a separate mechanism
to cause bitsets to be exported.
This mechanism replaces the whole-program-vtables blacklist, so remove the
-fwhole-program-vtables-blacklist flag.
Because __declspec(uuid()) now implies [[clang::lto_visibility_public]], the
support for the special attr:uuid blacklist entry is removed.
Differential Revision: http://reviews.llvm.org/D18635
llvm-svn: 267784
exactly the same as clang's existing [[clang::fallthrough]] attribute, which
has been updated to have the same semantics. The one significant difference
is that [[fallthrough]] is ill-formed if it's not used immediately before a
switch label (even when -Wimplicit-fallthrough is disabled). To support that,
we now build a CFG of any function that uses a '[[fallthrough]];' statement
to check.
In passing, fix some bugs with our support for statement attributes -- in
particular, diagnose their use on declarations, rather than asserting.
llvm-svn: 262881
Storing std::strings in attributes simply doesn't work, we never call
the destructor. Use an array of StringRefs instead of std::strings and
copy the data into memory taken from the ASTContext.
llvm-svn: 260831
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html
"This is the way [autoconf] ends
Not with a bang but a whimper."
-T.S. Eliot
Reviewers: chandlerc, grosbach, bob.wilson, echristo
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D16472
llvm-svn: 258862
Fake arguments are automatically handled for serialization, cloning,
and other representational tasks, but aren't included in pretty-printing
or parsing (should we eventually ever automate that).
This is chiefly useful for attributes that can be written by the
user, but which are also frequently synthesized by the compiler,
and which we'd like to remember details of the synthesis for.
As a simple example, use this to narrow the cases in which we were
generating a specialized note for implicitly unavailable declarations.
llvm-svn: 251469
Automatically insert line feed after pretty printing of all pragma-like attributes + fix printing of pragma-like pragmas on declarations.
Differential Revision: http://reviews.llvm.org/D13546
llvm-svn: 250017
We can use the 'H' typespec modifier to use 128-bit vectors directly
in the only two users of this special-case: the vcvt f16 intrinsics.
This also lets us use more meaningful prototype modifiers.
llvm-svn: 245778
We had "vcvt_f16" and "VCVT_HIGH_F16": for other FP types, this naming
is used for intrinsics with integer overloads. The FP->FP conversions,
on the other hand, use the full "vcvt_f32_f64" name instead.
Use the same naming convention for the f16<->f32 conversions.
While there, reorder the definitions a little bit.
llvm-svn: 245763
Improvement to the memory leak fix in 244196.
Address validity is required for the Intrinsic objects, but since the
collections only ever grow (no elements are removed), deque provides
sufficient guarantees (that the objects will never be reallocated/moved
around) for this use case.
llvm-svn: 244241
GenerateHasAttrSpellingStringSwitch and GenerateTargetRequirements had
duplicated code to check the conditions for target-specific attributes.
Refactor the duplicated code into a separate function. NFC.
llvm-svn: 242731
Clang used to silently ignore __declspec(novtable). It is implemented
now, but leaving the vtable uninitialized does not work when using the
Itanium ABI, where the class layout for complex class hierarchies is
stored in the vtable. It might be possible to honor the novtable
attribute in some simple cases and either report an error or ignore
it in more complex situations, but it’s not clear if that would be
worthwhile. There is also value in having a simple and predictable
behavior, so this changes clang to simply ignore novtable when not using
the Microsoft C++ ABI.
llvm-svn: 242730
The patch is generated using this command:
$ tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
work/llvm/tools/clang
To reduce churn, not touching namespaces spanning less than 10 lines.
llvm-svn: 240270
Adds a new warning (under -Wnullability-completeness) that complains
about pointer, block pointer, or member pointer declarations that have
not been annotated with nullability information (directly or inferred)
within a header that contains some nullability annotations. This is
intended to be used to help maintain the completeness of nullability
information within a header that has already been audited.
Note that, for performance reasons, this warning will underrepresent
the number of non-annotated pointers in the case where more than one
pointer is seen before the first nullability type specifier, because
we're only tracking one piece of information per header. Part of
rdar://problem/18868820.
llvm-svn: 240158
On ARM/AArch64, we currently always use EmitScalarExpr for the immediate
builtin arguments, instead of directly emitting the constant. When the
overflow sanitizer is enabled, this generates overflow intrinsics
instead of constants, breaking assumptions in various places.
Instead, use the knowledge of "immediates" to directly emit a constant:
- teach the tablegen backend to emit the "immediate" modifiers
- use those modifiers in the NEON CodeGen, on ARM and AArch64.
Fixes PR23517.
Differential Revision: http://reviews.llvm.org/D10045
llvm-svn: 239002
If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.
Call sites were found with the ASTMatcher + some semi-automated cleanup.
memberCallExpr(
argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
hasArgument(0, bindTemporaryExpr(
hasType(recordDecl(hasNonTrivialDestructor())),
has(constructExpr()))),
unless(isInTemplateInstantiation()))
No functional change intended.
llvm-svn: 238601
The GCC construct __attribute__((aligned)) is defined to set alignment
to "the default alignment for the target architecture" according to
the GCC documentation:
The default alignment is sufficient for all scalar types, but may not be
enough for all vector types on a target that supports vector operations.
The default alignment is fixed for a particular target ABI.
clang currently hard-coded an alignment of 16 bytes for that construct,
which is correct on some platforms (including X86), but wrong on others
(including SystemZ). Since this value is ABI-relevant, it is important
to get correct for compatibility purposes.
This patch adds a new TargetInfo member "DefaultAlignForAttributeAligned"
that targets can set to the appropriate default __attribute__((aligned))
value.
Note that I'm deliberately *not* using the existing "SuitableAlign"
value, which is used to set the pre-defined macro __BIGGEST_ALIGNMENT__,
since those two values may not be the same on all platforms. In fact,
on X86, __attribute__((aligned)) always uses 16-byte alignment, while
__BIGGEST_ALIGNMENT__ may be larger if AVX-2 or AVX-512 are supported.
(This is actually not yet correctly implemented in clang either.)
The patch provides a value for DefaultAlignForAttributeAligned only for
SystemZ, and leaves the default for all other targets at 16, which means
no visible change in behavior on all other targets. (The value is still
wrong for some other targets, but I'd prefer to leave it to the target
maintainers for those platforms to fix.)
llvm-svn: 235397
We know all subclasses in tblgen so just generate a giant switch for
the few virtual methods or turn them into a member variable using spare
bits. The giant jump tables aren't pretty but still much smaller than
a vtable for every attribute, shrinking Release+Asserts clang by ~400k.
Also halves the size of the Attr base class. No functional change
intended.
llvm-svn: 232726
Now that SmallString is a first-class citizen, most SmallString::str()
calls are not required. This patch removes a whole bunch of them, yet
there are lots more.
There are two use cases where str() is really needed:
1) To use one of StringRef member functions which is not available in
SmallString.
2) To convert to std::string, as StringRef implicitly converts while
SmallString do not. We may wish to change this, but it may introduce
ambiguity.
llvm-svn: 232622
We do not implicitly create an OpenCLImageAccessAttr, so this change only affects out of tree users. There is no way to test this behavior specifically that I can see, since this only affects implicit creation of attributes.
Fixes PR22403.
llvm-svn: 231803
This attribute serves as a hint to improve warnings about the ranges of
enumerators used as flag types. It currently has no working C++ implementation
due to different semantics for enums in C++. For more explanation, see the docs
and testcases.
Reviewed by Aaron Ballman.
llvm-svn: 222906
Instead of manually maintaining a flag indicating whether we're about to print
out the last child of the parent node (to determine whether we print "`" or
"|"), capture a callable to print that child and defer printing it until we
either see a next child or finish the parent.
No functionality change intended.
llvm-svn: 220930
Previously loop hints such as #pragma loop vectorize_width(#) required a constant. This patch allows a constant expression to be used as well. Such as a non-type template parameter or an expression (2 * c + 1).
Reviewed by Richard Smith
llvm-svn: 219589
This function might be a bit easier if it were split in two with a lot
of early returns - and that setOptional bit in the outer function, but
anyway.
llvm-svn: 215263
Updating the diagnostics in the launch_bounds test since they have been improved in that case. Adding a test for nonnull since it has little test coverage, but has truly variadic arguments.
llvm-svn: 214407
The NEON intrinsics in arm_neon.h are designed to work on vectors
"as-if" loaded by (V)LDR. We load vectors "as-if" (V)LD1, so the
intrinsics are currently incorrect.
This patch adds big-endian versions of the intrinsics that does the
"obvious but dumb" thing of reversing all vector inputs and all
vector outputs. This will produce extra REVs, but we trust the
optimizer to remove them.
llvm-svn: 211893
There comes a time in the life of any amateur code generator when dumb string
concatenation just won't cut it any more. For NeonEmitter.cpp, that time has
come.
There were a bunch of magic type codes which meant different things depending on
the context. There were a bunch of special cases that really had no reason to be
there but the whole thing was so creaky that removing them would cause something
weird to fall over. There was a 1000 line switch statement for code generation
involving string concatenation, which actually did lexical scoping to an extent
(!!) with a bunch of semi-repeated cases.
I tried to refactor this three times in three different ways without
success. The only way forward was to rewrite the entire thing. Luckily the
testing coverage on this stuff is absolutely massive, both with regression tests
and the "emperor" random test case generator.
The main change is that previously, in arm_neon.td a bunch of "Operation"s were
defined with special names. NeonEmitter.cpp knew about these Operations and
would emit code based on a huge switch. Actually this doesn't make much sense -
the type information was held as strings, so type checking was impossible. Also
TableGen's DAG type actually suits this sort of code generation very well
(surprising that...)
So now every operation is defined in terms of TableGen DAGs. There are a bunch
of operators to use, including "op" (a generic unary or binary operator), "call"
(to call other intrinsics) and "shuffle" (take a guess...). One of the main
advantages of this apart from making it more obvious what is going on, is that
we have proper type inference. This has two obvious advantages:
1) TableGen can error on bad intrinsic definitions easier, instead of just
generating wrong code.
2) Calls to other intrinsics are typechecked too. So
we no longer need to work out whether the thing we call needs to be the Q-lane
version or the D-lane version - TableGen knows that itself!
Here's an example: before:
case OpAbdl: {
std::string abd = MangleName("vabd", typestr, ClassS) + "(__a, __b)";
if (typestr[0] != 'U') {
// vabd results are always unsigned and must be zero-extended.
std::string utype = "U" + typestr.str();
s += "(" + TypeString(proto[0], typestr) + ")";
abd = "(" + TypeString('d', utype) + ")" + abd;
s += Extend(utype, abd) + ";";
} else {
s += Extend(typestr, abd) + ";";
}
break;
}
after:
def OP_ABDL : Op<(cast "R", (call "vmovl", (cast $p0, "U",
(call "vabd", $p0, $p1))))>;
As an example of what happens if you do something wrong now, here's what happens
if you make $p0 unsigned before the call to "vabd" - that is, $p0 -> (cast "U",
$p0):
arm_neon.td:574:1: error: No compatible intrinsic found - looking up intrinsic 'vabd(uint8x8_t, int8x8_t)'
Available overloads:
- float64x2_t vabdq_v(float64x2_t, float64x2_t)
- float64x1_t vabd_v(float64x1_t, float64x1_t)
- float64_t vabdd_f64(float64_t, float64_t)
- float32_t vabds_f32(float32_t, float32_t)
... snip ...
This makes it seriously easy to work out what you've done wrong in fairly nasty
intrinsics.
As part of this I've massively beefed up the documentation in arm_neon.td too.
Things still to do / on the radar:
- Testcase generation. This was implemented in the previous version and not in
the new one, because
- Autogenerated tests are not being run. The testcase in test/ differs from
the autogenerated version.
- There were a whole slew of special cases in the testcase generation that just
felt (and looked) like hacks.
If someone really feels strongly about this, I can try and reimplement it too.
- Big endian. That's coming soon and should be a very small diff on top of this one.
llvm-svn: 211101
By describing system header suppressions directly in tablegen we eliminate
special cases in getDiagnosticSeverity().
Dropping the reliance on builtin diagnostic classes when mapping also gets us
closer to the goal of reusing the diagnostic machinery for custom diagnostics.
No change in functionality.
llvm-svn: 211023
hint attributes. Includes tests for pragma printing and for attribute order
which is incorrectly reversed by ParsedAttributes.
Reviewed by Aaron Ballman
llvm-svn: 210925
This begins to address cognitive dissonance caused by treating the Note
diagnostic level as a severity in the diagnostic engine.
No change in functionality.
llvm-svn: 210758
will never be true in a well-defined context. The checking for null pointers
has been moved into the caller logic so it does not rely on undefined behavior.
llvm-svn: 210498
I was bitten by this when working with the dll attributes: when a dll
attribute was cloned from a class template declaration to its
specialization, the Inherited flag didn't get cloned.
Differential Revision: http://reviews.llvm.org/D3972
llvm-svn: 209950
The attribute emitter was using FunctionTemplate to map the diagnostic to "functions or methods", but that isn't a particularly clear diagnostic in these cases anyway (since they do not apply to ObjC methods). Updated the attribute emitter to remove custom logic for FunctionTemplateDecl, and updated the test cases for the change in diagnostic wording.
llvm-svn: 209209
Replace a large monolitic function, with per-table functions which all nicely
fit on my screen. I also added documentation to each function that describes
what kind of tables are generated and which information is contained and
switched to range based for loops. Finally, I run clang-format over the moved
code.
I spent a significant amount of time to understand this code when reasoning
about possible extensions to the diagnostic interface to support 'remark'
diagnostics. This change will definitely help such an implementation, but
already by itself it will save other people a lot of time when trying to
understand this functionality.
Even though the patch touches the full function, it is mostly mechanical. No
functional change intended. The generated tblgen files are identical.
llvm-svn: 208136
Since the community says that a blacklist is not good enough, and I don't have
enough time now to implement a proper whitelist, let's just remove the
attribute validation.
But, nevertheless, we can still communicate in the generated XML if our parser
found an issue with the HTML. But this bit is best-effort and is specifically
called out in the schema as such.
llvm-svn: 207712
Eric Fiselier