By allowing AnnotateAttr to be applied to statements, users can place arbitrary information in the AST for later use.
For example, this can be used for HW-targeted language extensions that involve specialized loop annotations.
The attributes changes were left out of Clang 17.
Attributes that used to take a string literal now accept an unevaluated
string literal instead, which means they reject numeric escape sequences
and strings literal with an encoding prefix - but the later was already
ill-formed in most cases.
We need to know that we are going to parse an unevaluated string literal
before we do - so we can reject numeric escape sequence,
so we derive from Attrs.td which attributes parameters are expected
to be string literals.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D156237
These changes make the Clang parser recognize expression parameter pack
expansion and initializer lists in attribute arguments. Because
expression parameter pack expansion requires additional handling while
creating and instantiating templates, the support for them must be
explicitly supported through the AcceptsExprPack flag.
Handling expression pack expansions may require a delay to when the
arguments of an attribute are correctly populated. To this end,
attributes that are set to accept these - through setting the
AcceptsExprPack flag - will automatically have an additional variadic
expression argument member named DelayedArgs. This member is not
exposed the same way other arguments are but is set through the new
CreateWithDelayedArgs creator function generated for applicable
attributes.
To illustrate how to implement support for expression pack expansion
support, clang::annotate is made to support pack expansions. This is
done by making handleAnnotationAttr delay setting the actual attribute
arguments until after template instantiation if it was unable to
populate the arguments due to dependencies in the parsed expressions.
This allows using annotation in a much more contexts than it currently has.
especially when annotation with template or constexpr.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D88645
This patch adds support to the attribute tablegen for specifying a [[]] attribute is allowed in C mode. This patch also adds the annotate attribute to the list of double square bracket attributes we support in C mode.
Eventually, I anticipate that this logic will be reversed (you have to opt out of allowing an attribute in C rather than opting in), but I want to see how the design plays out as more attributes are considered.
llvm-svn: 321763
i32 __builtin_annotation(i32, string);
Applying it to i64 (e.g., long long) generates the following IR.
trunc i64 {{.*}} to i32
call i32 @llvm.annotation.i32
zext i32 {{.*}} to i64
The redundant truncation and extension make the result difficult to use.
This patch makes __builtin_annotation() generic.
type __builtin_annotation(type, string);
For the i64 example, it simplifies the generated IR to:
call i64 @llvm.annotation.i64
Patch by Xi Wang!
llvm-svn: 155764
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
