Files
clang-p2996/clang/test/Parser/asm.c
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

44 lines
1.5 KiB
C

// RUN: %clang_cc1 -fsyntax-only -fdouble-square-bracket-attributes -verify %s
#if !__has_extension(gnu_asm)
#error Extension 'gnu_asm' should be available by default
#endif
void f1(void) {
// PR7673: Some versions of GCC support an empty clobbers section.
asm ("ret" : : :);
}
void f2(void) {
asm("foo" : "=r" (a)); // expected-error {{use of undeclared identifier 'a'}}
asm("foo" : : "r" (b)); // expected-error {{use of undeclared identifier 'b'}}
[[]] asm("");
[[gnu::deprecated]] asm(""); // expected-warning {{'deprecated' attribute ignored}}
}
void a(void) __asm__(""); // expected-error {{cannot use an empty string literal in 'asm'}}
void a(void) {
__asm__(""); // ok
}
// rdar://5952468
__asm ; // expected-error {{expected '(' after 'asm'}}
// <rdar://problem/10465079> - Don't crash on wide string literals in 'asm'.
int foo asm (L"bar"); // expected-error {{cannot use wide string literal in 'asm'}}
asm() // expected-error {{expected string literal in 'asm'}}
// expected-error@-1 {{expected ';' after top-level asm block}}
asm(; // expected-error {{expected string literal in 'asm'}}
asm("") // expected-error {{expected ';' after top-level asm block}}
// Unterminated asm strings at the end of the file were causing us to crash, so
// this needs to be last. rdar://15624081
// expected-warning@+3 {{missing terminating '"' character}}
// expected-error@+2 {{expected string literal in 'asm'}}
// expected-error@+1 {{expected ';' after top-level asm block}}
asm("