Commit Graph

12 Commits

Author SHA1 Message Date
Vedant Kumar 859bf4d2be [Coverage] Emit a gap region to cover switch bodies
Emit a gap region beginning where the switch body begins. This sets line
execution counts in the areas between non-overlapping cases to 0.

This also removes some special handling of the first case in a switch:
these are now treated like any other case.

This does not resolve an outstanding issue with case statement regions
that do not end when a region is terminated. But it should address
llvm.org/PR44011.

Differential Revision: https://reviews.llvm.org/D70571
2019-12-03 12:35:54 -08:00
Vedant Kumar 8046d22a36 [Coverage] Complete top-level deferred regions before labels
The area immediately after a terminated region in the function top-level
should have the same count as the label it precedes.

This solves another problem with wrapped segments. Consider:

  1| a:
  2|   return 0;
  3| b:
  4|   return 1;

Without a gap area starting after the first return, the wrapped segment
from line 2 would make it look like line 3 is executed, when it's not.

rdar://35373009

llvm-svn: 317759
2017-11-09 02:33:39 +00:00
Vedant Kumar 2e8c875905 [Coverage] Emit a gap area after if conditions
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
2017-11-09 02:33:38 +00:00
Vedant Kumar 747b0e2905 [Coverage] Precise region termination with deferred regions (reapply)
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
2017-09-08 18:44:56 +00:00
Vedant Kumar a7764adcbb Revert "[Coverage] Precise region termination with deferred regions"
This reverts commit r310010. I don't think there's anything wrong with
this commit, but it's causing clang to generate output that llvm-cov
doesn't do a good job with and the fix isn't immediately clear.

See Eli's comment in D36250 for more context.

I'm reverting the clang change so the coverage bot can revert back to
producing sensible output, and to give myself some time to investigate
what went wrong in llvm.

llvm-svn: 310154
2017-08-05 00:34:10 +00:00
Vedant Kumar 85e6dce1eb [Coverage] Precise region termination with deferred regions
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
llvm-svn: 310010
2017-08-04 00:29:20 +00:00
Alex Lorenz 08780529b3 [Coverage] The coverage region for switch covers the code after the switch.
This patch fixes a regression introduced in r262697 that changed the way the
coverage regions for switches are constructed. The PGO instrumentation counter
for a switch statement refers to the counter at the exit of the switch.
Therefore, the coverage region for the switch statement should cover the code
that comes after the switch, and not the switch statement itself.

rdar://28480997

Differential Revision: https://reviews.llvm.org/D24981

llvm-svn: 282554
2016-09-27 23:30:36 +00:00
Vedant Kumar 3836482abc [Coverage] Fix crash on a switch partially covered by a macro (PR27948)
We have to handle file exits before and after visiting regions in the
switch body. Fixes PR27948.

llvm-svn: 271308
2016-05-31 18:06:19 +00:00
Vedant Kumar 22bd871ea6 [Coverage] Fix the start/end locations of switch statements
While pushing switch statements onto the region stack we neglected to
specify their start/end locations. This results in a crash (PR26825) if
we end up in nested macro expansions without enough information to
handle the relevant file exits.

I added a test in switchmacro.c and fixed up a bunch of incorrect CHECK
lines that specify strange end locations for switches.

llvm-svn: 262697
2016-03-04 08:07:15 +00:00
Rong Xu 9837ef56b4 [PGO] cc1 option name change for profile instrumentation
This patch changes cc1 option -fprofile-instr-generate to an enum option
-fprofile-instrument={clang|none}. It also changes cc1 options
-fprofile-instr-generate= to -fprofile-instrument-path=.
The driver level option -fprofile-instr-generate and -fprofile-instr-generate=
remain intact. This change will pave the way to integrate new PGO
instrumentation in IR level.

Review: http://reviews.llvm.org/D16730
llvm-svn: 259811
2016-02-04 18:39:09 +00:00
Justin Bogner 91f2e3c9c2 InstrProf: Always emit a coverage region for the condition of an if
When tools like llvm-cov show regions, it's much easier to understand
what's happening if the condition of an if shows a counter as well as
the body.

llvm-svn: 229813
2015-02-19 03:10:30 +00:00
Justin Bogner bf42cfd75f InstrProf: Rewrite most of coverage mapping generation in a simpler way
The coverage mapping generation code previously generated a large
number of redundant coverage regions and then tried to merge similar
ones back together. This then relied on some awkward heuristics to
prevent combining of regions that were importantly different but
happened to have the same count. The end result was inefficient and
hard to follow.

Now, we more carefully create the regions we actually want. This makes
it much easier to create regions at precise locations as well as
making the basic approach quite a bit easier to follow. There's still
a fair bit of complexity here dealing with included code and macro
expansions, but that's pretty hard to avoid without significantly
reducing the quality of data we provide.

I had to modify quite a few tests where the source ranges became more
precise or the old ranges seemed to be wrong anyways, and I've added
quite a few new tests since a large number of constructs didn't seem
to be tested before.

llvm-svn: 229748
2015-02-18 21:24:51 +00:00