[llvm-bugs] [Bug 48162] New: llvm-cov gcov does not add "(throw)" to branch statements
via llvm-bugs
llvm-bugs at lists.llvm.org
Thu Nov 12 08:58:07 PST 2020
https://bugs.llvm.org/show_bug.cgi?id=48162
Bug ID: 48162
Summary: llvm-cov gcov does not add "(throw)" to branch
statements
Product: Runtime Libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: libprofile library
Assignee: unassignedbugs at nondot.org
Reporter: John.Forrest at gbgplc.com
CC: llvm-bugs at lists.llvm.org
Created attachment 24158
--> https://bugs.llvm.org/attachment.cgi?id=24158&action=edit
Sample files
I am using clang++ to generate coverage reports as part of Sonarqube analysis.
This expects the output from gcovr and we use the latter telling it to use
"llvm-cov gcov" as documented. We've hit the common(?) problem where the
reported coverage figures are low, due it seems to extra branches being added
for exception support. The recommended approach is to add flags
--exclude-throw-branches --exclude-unreachable-branches to gcovr. This has been
observed to help a little but not much.
Experimentation suggests that this relates to the llvm toolchain. gcov itself
(obviously what gcovr expects) adds extra tags to the branch statements with
"(throw)" and "(fallthrough)". It is these tags that gcovr uses to support
--exclude-throw=branches. llvm-cov does not, so gcovr assumes they are "normal"
branches - it has no option. E.g. compare (gcc/gcov):
branch 1 taken 1 (fallthrough)
branch 2 taken 0 (throw)
with (clang/llvm-cov gcov):
branch 0 taken 1
branch 1 taken 0
The attached zip contains a sample program and the respective output of
compiling (with "-O0 -g --coverage"), running and then extracting coverage with
flags "--branch-counts --branch-probabilities --preserve-paths". gcc is v8.3.1.
llvm is 11.0.
--
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20201112/ed607290/attachment-0001.html>
More information about the llvm-bugs
mailing list