Commit Graph

13 Commits

Author SHA1 Message Date
Richard Smith cdb06f2150 Correctly compute linkage for members of internal linkage classes.
We used to give such members no linkage instead of giving them the linkage of
the class.

llvm-svn: 314054
2017-09-23 04:02:17 +00:00
Richard Smith df963a38a9 DR1113: anonymous namespaces formally give their contents internal linkage.
This doesn't affect our code generation in any material way -- we already give
such declarations internal linkage from a codegen perspective -- but it has
some subtle effects on code validity.

We suppress the 'L' (internal linkage) marker for mangled names in anonymous
namespaces, because it is redundant (the information is already carried by the
namespace); this deviates from GCC's behavior if a variable or function in an
anonymous namespace is redundantly declared 'static' (where GCC does include
the 'L'), but GCC's behavior is incoherent because such a declaration can be
validly declared with or without the 'static'.

We still deviate from the standard in one regard here: extern "C" declarations
in anonymous namespaces are still granted external linkage. Changing those does
not appear to have been an intentional consequence of the standard change in
DR1113.

llvm-svn: 314037
2017-09-22 22:21:44 +00:00
Richard Smith 7ff8304db7 Closure types have no name (and can't have a typedef name for linkage
purposes), so they never formally have linkage.

llvm-svn: 313957
2017-09-22 04:33:20 +00:00
Richard Smith 405e2dbf37 Implement C++ [basic.link]p8.
If a function or variable has a type with no linkage (and is not extern "C"),
any use of it requires a definition within the same translation unit; the idea
is that it is not possible to define the entity elsewhere, so any such use is
necessarily an error.

There is an exception, though: some types formally have no linkage but
nonetheless can be referenced from other translation units (for example, this
happens to anonymous structures defined within inline functions). For entities
with those types, we suppress the diagnostic except under -pedantic.

llvm-svn: 313729
2017-09-20 07:22:00 +00:00
Richard Smith 541b38be7b Switch the semantic DeclContext for a block-scope declaration of a function or
variable from being the function to being the enclosing namespace scope (in
C++) or the TU (in C). This allows us to fix a selection of related issues
where we would build incorrect redeclaration chains for such declarations, and
fail to notice type mismatches.

Such declarations are put into a new IdentifierNamespace, IDNS_LocalExtern,
which is only found when searching scopes, and not found when searching
DeclContexts. Such a declaration is only made visible in its DeclContext if
there are no non-LocalExtern declarations.

llvm-svn: 191064
2013-09-20 01:15:31 +00:00
Richard Smith 1c34fb78e7 Fix implementation of C11 6.2.7/4 and C++11 [dcl.array]p3:
When a local extern declaration redeclares some other entity, the type of that
entity is merged with the prior type if the prior declaration is visible (in C)
or is declared in the same scope (in C++).

 - Make LookupRedeclarationWithLinkage actually work in C++, use it in the right
   set of cases, and make it track whether it found a shadowed declaration.
 - Track whether we found a declaration in the same scope (for C++) including
   across serialization and template instantiation.

llvm-svn: 188307
2013-08-13 18:18:50 +00:00
John McCall b65e8fe143 Only merge down a variable type if the previous declaration was
visible.  There's a lot of potential badness in how we're modelling
these things, but getting this much correct is reasonably easy.

rdar://13535367

llvm-svn: 178488
2013-04-01 18:34:28 +00:00
Richard Smith 8d06f42448 Improve 0-argument -Wvexing-parse diagnostic by adding notes with fix-its:
- If the declarator is at the start of a line, and the previous line contained
   another declarator and ended with a comma, then that comma was probably a
   typo for a semicolon:

   int n = 0, m = 1, l = 2, // k = 5;
   myImportantFunctionCall(); // oops!

 - If removing the parentheses would correctly initialize the object, then
   produce a note suggesting that fix.

 - Otherwise, if there is a simple initializer we can suggest which performs
   value-initialization, then provide a note suggesting a correction to that
   initializer.

Sema::Declarator now tracks the location of the comma prior to the declarator in
the declaration, if there is one, to facilitate providing the note. The code to
determine an appropriate initializer from the -Wuninitialized warning has been
factored out to allow use in both that and -Wvexing-parse.

llvm-svn: 148072
2012-01-12 23:53:29 +00:00
Richard Smith b3851f5ca1 David Blaikie and Chandler would like us to diagnose
int f();

in function scopes under -Wvexing-parse, so now we do.

llvm-svn: 147649
2012-01-06 02:30:50 +00:00
Richard Smith d069d2f6ac Tweak to r147599 for PR10828: Move the check from the parser into sema, and use
the Semantic Powers to only warn on class types (or dependent types), where the
constructor or destructor could do something interesting.

llvm-svn: 147642
2012-01-06 01:31:20 +00:00
Richard Smith 69f90dce49 PR10828: Produce a warning when a no-arguments function is declared in block
scope, when no other indication is provided that the user intended to declare a
function rather than a variable.

Remove some false positives from the existing 'parentheses disambiguated as a
function' warning by suppressing it when the declaration is marked as 'typedef'
or 'extern'.

Add a new warning group -Wvexing-parse containing both of these warnings.

The new warning is enabled by default; despite a number of false positives (and
one bug) in clang's test-suite, I have only found genuine bugs with it when
running it over a significant quantity of real C++ code.

llvm-svn: 147599
2012-01-05 04:12:21 +00:00
Daniel Dunbar 8fbe78f6fc Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- 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
2009-12-15 20:14:24 +00:00
Douglas Gregor f73b282bf0 Implement the rules in C++ [basic.link] and C99 6.2.2 for computing
the linkage of a declaration. Switch the lame (and completely wrong)
NamedDecl::hasLinkage() over to using the new NamedDecl::getLinkage(),
along with the "can this declaration be a template argument?" check
that started all of this.

Fixes -fsyntax-only for PR5597.

llvm-svn: 89891
2009-11-25 22:24:25 +00:00