Reland with update on test case ContinuousSyncmode/basic.c.

This reverts commit fe5c2c3ca682b140dd5e640e75948363b6b25ef9.

This reverts commit 2d7374a0c680f96bdcdb3d05034a93bf145d140f.
Breaks ContinuousSyncMode/basic.c in check-profile on macOS.

Differential Revision: https://reviews.llvm.org/D97101

Differential Revision: https://reviews.llvm.org/D84988

Bug filled here: https://bugs.llvm.org/show_bug.cgi?id=45757.
Add comment to skipped regions so we don't track execution count for lines containing only comments.

Differential Revision: https://reviews.llvm.org/D83592

This casued assertions during Chromium builds. See comment on the code review

> Bug filled here: https://bugs.llvm.org/show_bug.cgi?id=45757.
> Add comment to skipped regions so we don't track execution count for lines containing only comments.
>
> Differential Revision: https://reviews.llvm.org/D84208

This reverts commit abd45154bdb6b76c5b480455eacc8c75b08242aa and the
follow-up 87d725473380652bbe845fd2fbd9c0507a55172f.

Bug filled here: https://bugs.llvm.org/show_bug.cgi?id=45757.
Add comment to skipped regions so we don't track execution count for lines containing only comments.

Differential Revision: https://reviews.llvm.org/D84208

Discard the last uncompleted deferred region in a decl, if one exists.
This prevents lines at the end of a function containing only whitespace
or closing braces from being marked as uncovered, if they follow a
region terminator (return/break/etc).

The previous behavior was to heuristically complete deferred regions at
the end of a decl. In practice this ended up being too brittle for too
little gain. Users would complain that there was no way to reach full
code coverage because whitespace at the end of a function would be
marked uncovered.

rdar://40238228

Differential Revision: https://reviews.llvm.org/D46918

llvm-svn: 333609

The area immediately after the closing right-paren of an if condition
should have a count equal to the 'then' block's count. Use a gap region
to set this count, so that region highlighting for the 'then' block
remains precise.

This solves a problem we have with wrapped segments. Consider:

  1| if (false)
  2|   foo();

Without a gap area starting after the condition, the wrapped segment
from line 1 would make it look like line 2 is executed, when it's not.

rdar://35373009

llvm-svn: 317758

The current coverage implementation doesn't handle region termination
very precisely. Take for example an `if' statement with a `return':

  void f() {
    if (true) {
      return; // The `if' body's region is terminated here.
    }
    // This line gets the same coverage as the `if' condition.
  }

If the function `f' is called, the line containing the comment will be
marked as having executed once, which is not correct.

The solution here is to create a deferred region after terminating a
region. The deferred region is completed once the start location of the
next statement is known, and is then pushed onto the region stack.
In the cases where it's not possible to complete a deferred region, it
can safely be dropped.

Testing: lit test updates, a stage2 coverage-enabled build of clang

This is a reapplication but there are no changes from the original commit.
With D36813, the segment builder in llvm will be able to handle deferred
regions correctly.

llvm-svn: 312818