Allow a header to be part of multiple modules.

This patch changes two things:

a) Allow a header to be part of multiple modules. The reasoning is that
in existing codebases that have a module-like build system, the same
headers might be used in several build targets. Simple reasons might be
that they defined different classes that are declared in the same
header. Supporting a header as a part of multiple modules will make the
transistion easier for those cases. A later step in clang can then
determine whether the two modules are actually compatible and can be
merged and error out appropriately. The later check is similar to what
needs to be done for template specializations anyway.

b) Allow modules to be stored in a directory tree separate from the
headers they describe.

Review: http://llvm-reviews.chandlerc.com/D1951

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193151 91177308-0d34-0410-b5e6-96231b3b80d8
Remove incorrect assert.

If we run into the second preprocessor branch chain, the first branch
chain might have already set the maximum branch count on that level to
something > 0.

Fixes PR17645.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193153 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment typo

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193154 91177308-0d34-0410-b5e6-96231b3b80d8
This patch causes clang to reject alias attributes that point to undefined
names. For example, with this patch we now reject

void f1(void) __attribute__((alias("g1")));

This patch is implemented in CodeGen. It is quiet a bit simpler and more
compatible with gcc than implementing it in Sema. The downside is that the
errors only fire during -emit-llvm.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193161 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "This patch causes clang to reject alias attributes that point to undefined names. For example, with this patch we now reject"

This reverts commit r193161.

It broke

void foo() __attribute__((alias("bar")));
void bar() {}
void zed() __attribute__((alias("foo")));

Looks like we have to fix pr17639 first :-(

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193162 91177308-0d34-0410-b5e6-96231b3b80d8
Drop the unneeded VBase field from MethodInfo in the VFTableBuilder class

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193164 91177308-0d34-0410-b5e6-96231b3b80d8
Use early return. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193166 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format: Improve formatting of ObjC array literals.

Before:
  NSArray *arguments =
      @[ kind == kUserTicket ? @"--user-store" : @"--system-store",
         @"--print-tickets", @"--productid", @"com.google.Chrome" ];
After:
  NSArray *arguments = @[
      kind == kUserTicket ? @"--user-store" : @"--system-store",
      @"--print-tickets",
      @"--productid",
      @"com.google.Chrome"
  ];

This fixes llvm.org/PR15231.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193167 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format: Fix ObjC literal indentation in Google style.

Style guide demands a two-space indent.

Before:
  NSArray *arguments = @[
      kind == kUserTicket ? @"--user-store" : @"--system-store",
      @"--print-tickets",
      @"--productid",
      @"com.google.Chrome"
  ];

After:
  NSArray *arguments = @[
    kind == kUserTicket ? @"--user-store" : @"--system-store",
    @"--print-tickets",
    @"--productid",
    @"com.google.Chrome"
  ];

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193168 91177308-0d34-0410-b5e6-96231b3b80d8
Reenable 'break' in 'for' specifier to allow compilation of QT macro 'foreach'

This is a fix to PR17649, caused by fix in r193073. QT uses 'break' statement
to implement their 'foreach' macro. To enable build of QT, this fix reenables
break but only in 'for' statement specifier and only in the third expression.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193170 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r193073 and the attempt to fix it in r193170.

This patch wasn't reviewed, and isn't correctly preserving the behaviors
relied upon by QT. I don't have a direct example of fallout, but it
should go through the standard code review process. For example, it
should never have removed the QT test case that was added when fixing
those users.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193174 91177308-0d34-0410-b5e6-96231b3b80d8
Use GEPs correctly when adjusting this in MicrosoftCXXABI

Reviewed at http://llvm-reviews.chandlerc.com/D1977

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193176 91177308-0d34-0410-b5e6-96231b3b80d8
[analyzer] scan-build: Handle -m* option wildcard after compiler/linker flags.

Some of the shared compiler/linker flags start with -m, so they've been
getting passed to the compiler only since r180073. Now, the -m* wildcard
is processed after the shared flags and the ignored flags.

Found by Laszlo Nagy!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193184 91177308-0d34-0410-b5e6-96231b3b80d8
_mm_extract_epi16: use "& 7" when index is out of bound.

This is in line with implementation of _mm_extract_pi16.
rdar://15250497


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193187 91177308-0d34-0410-b5e6-96231b3b80d8
New fix for pr17535.

This is a fixed version of r193161. In order to handle

    void foo() __attribute__((alias("bar")));
    void bar() {}
    void zed() __attribute__((alias("foo")));

it is not enough to delay aliases to the end of the TU, we have to do two
passes over them to find if they are defined or not.

This can be implemented by producing alias as we go and just doing the second
pass at the end. This has the advantage that other parts of clang that were
expecting alias to be processed in order don't have to be changed.

This patch also handles cyclic aliases.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193188 91177308-0d34-0410-b5e6-96231b3b80d8
Treat aliases as definitions.

This fixes pr17639.

Before this patch clang would consider

void foo(void) __attribute((alias("__foo")));

a declaration. It now correctly handles it as a definition.

Initial patch by Alp Toker. I added support for variables.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193200 91177308-0d34-0410-b5e6-96231b3b80d8
Consider hidden decls for isUsed checks.

This fixes pr17624.

A FIXME from Richard Smith:

It seems to me that the root cause is that a per-Decl 'used' flag doesn't
really make much sense in the way we use it now. I think we should either track
whether that particular declaration is used (with isUsed scanning the entire
redecl chain), or we should only have one flag for the entire redeclaration
chain (perhaps by always looking at the flag on either the most recent decl or
the canonical decl). Modeling it as "is this declaration or any previous
declaration used" is weird, and requires contortions like the loop at the end
of Sema::MarkFunctionReferenced.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193202 91177308-0d34-0410-b5e6-96231b3b80d8
Sema: Allow IndirectFieldDecl to appear in a non-type template argument

We would not identify pointer-to-member construction in a non-type
template argument if it was either a FieldDecl or a CXXMethodDecl.
However, this would incorrectly reject declarations that were injected
via an IndirectFieldDecl (e.g. a field inside of an anonymous union).

This fixes PR17657.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193203 91177308-0d34-0410-b5e6-96231b3b80d8
Split -fsanitize=bounds to -fsanitize=array-bounds (for the frontend-inserted
check using the ubsan runtime) and -fsanitize=local-bounds (for the middle-end
check which inserts traps).

Remove -fsanitize=local-bounds from -fsanitize=undefined. It does not produce
useful diagnostics and has false positives (PR17635), and is not a good
compromise position between UBSan's checks and ASan's checks.

Map -fbounds-checking to -fsanitize=local-bounds to restore Clang's historical
behavior for that flag.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193205 91177308-0d34-0410-b5e6-96231b3b80d8
Retain previous language linkage of friend function declarations

With this extension, friend function declarations will retain the language
linkage specified for previous declarations instead of emitting an error
diagnostic.

The feature is known to be compatible with GCC and MSVC and permits a
language to be specified indirectly where it cannot otherwise be written
directly in class scope.

Work is ongoing to improve linkage spec diagnostics.

Fixes PR17337.

Reviewed by Richard Smith.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193206 91177308-0d34-0410-b5e6-96231b3b80d8