Commit Graph

6 Commits

Author SHA1 Message Date
Martin Boehme 8c7b64b5ae [clang] Reject non-declaration C++11 attributes on declarations
For backwards compatiblity, we emit only a warning instead of an error if the
attribute is one of the existing type attributes that we have historically
allowed to "slide" to the `DeclSpec` just as if it had been specified in GNU
syntax. (We will call these "legacy type attributes" below.)

The high-level changes that achieve this are:

- We introduce a new field `Declarator::DeclarationAttrs` (with appropriate
  accessors) to store C++11 attributes occurring in the attribute-specifier-seq
  at the beginning of a simple-declaration (and other similar declarations).
  Previously, these attributes were placed on the `DeclSpec`, which made it
  impossible to reconstruct later on whether the attributes had in fact been
  placed on the decl-specifier-seq or ahead of the declaration.

- In the parser, we propgate declaration attributes and decl-specifier-seq
  attributes separately until we can place them in
  `Declarator::DeclarationAttrs` or `DeclSpec::Attrs`, respectively.

- In `ProcessDeclAttributes()`, in addition to processing declarator attributes,
  we now also process the attributes from `Declarator::DeclarationAttrs` (except
  if they are legacy type attributes).

- In `ConvertDeclSpecToType()`, in addition to processing `DeclSpec` attributes,
  we also process any legacy type attributes that occur in
  `Declarator::DeclarationAttrs` (and emit a warning).

- We make `ProcessDeclAttribute` emit an error if it sees any non-declaration
  attributes in C++11 syntax, except in the following cases:
  - If it is being called for attributes on a `DeclSpec` or `DeclaratorChunk`
  - If the attribute is a legacy type attribute (in which case we only emit
    a warning)

The standard justifies treating attributes at the beginning of a
simple-declaration and attributes after a declarator-id the same. Here are some
relevant parts of the standard:

- The attribute-specifier-seq at the beginning of a simple-declaration
  "appertains to each of the entities declared by the declarators of the
  init-declarator-list" (https://eel.is/c++draft/dcl.dcl#dcl.pre-3)

- "In the declaration for an entity, attributes appertaining to that entity can
  appear at the start of the declaration and after the declarator-id for that
  declaration." (https://eel.is/c++draft/dcl.dcl#dcl.pre-note-2)

- "The optional attribute-specifier-seq following a declarator-id appertains to
  the entity that is declared."
  (https://eel.is/c++draft/dcl.dcl#dcl.meaning.general-1)

The standard contains similar wording to that for a simple-declaration in other
similar types of declarations, for example:

- "The optional attribute-specifier-seq in a parameter-declaration appertains to
  the parameter." (https://eel.is/c++draft/dcl.fct#3)

- "The optional attribute-specifier-seq in an exception-declaration appertains
  to the parameter of the catch clause" (https://eel.is/c++draft/except.pre#1)

The new behavior is tested both on the newly added type attribute
`annotate_type`, for which we emit errors, and for the legacy type attribute
`address_space` (chosen somewhat randomly from the various legacy type
attributes), for which we emit warnings.

Depends On D111548

Reviewed By: aaron.ballman, rsmith

Differential Revision: https://reviews.llvm.org/D126061
2022-06-15 11:58:26 +02:00
Aaron Ballman 7de7161304 Use functions with prototypes when appropriate; NFC
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,

  void func();

becomes

  void func(void);

This is the sixth batch of tests being updated (there are a significant
number of other tests left to be updated).
2022-02-09 17:16:10 -05:00
Jann Horn 6dad7ec539 [clang] Fix noderef for AddrOf on MemberExpr
Committing on behalf of thejh (Jann Horn).

As part of this change, one existing test case has to be adjusted
because it accidentally stripped the NoDeref attribute without
getting caught.

Depends on D92140

Differential Review: https://reviews.llvm.org/D92141
2020-12-07 14:48:41 -08:00
Leonard Chan 155fca3cae [clang] Fix noderef for array member of deref expr
Committing on behalf of thejh (Jann Horn).

    Given an attribute((noderef)) pointer "p" to the struct

    struct s { int a[2]; };
    ensure that the following expressions are treated the same way by the
    noderef logic:

    p->a
    (*p).a
    Until now, the first expression would be treated correctly (nothing is
    added to PossibleDerefs because CheckMemberAccessOfNoDeref() bails out
    on array members), but the second expression would incorrectly warn
    because "*p" creates a PossibleDerefs entry.

    Handle this case the same way as for the AddrOf operator.

    Differential Revision: https://reviews.llvm.org/D92140
2020-12-07 14:39:42 -08:00
Jann Horn 00dad9d028 Ignore noderef attribute in unevaluated context
The noderef attribute is for catching code that accesses pointers in
a different address space. Unevaluated code is always safe in that regard.
2020-11-23 08:10:35 -05:00
Leonard Chan ad7ac964e5 [Sema/Attribute] Check for noderef attribute
This patch adds the noderef attribute in clang and checks for dereferences of
types that have this attribute. This attribute is currently used by sparse and
would like to be ported to clang.

Differential Revision: https://reviews.llvm.org/D49511

llvm-svn: 348442
2018-12-06 01:05:54 +00:00