[llvm-cov] Multi-threaded implementation of prepareFileReports method.
Summary:
Local testing has demonstrated a great speed improvement, compare the following:
1) Existing version:
```
$ time llvm-cov show -format=html -output-dir=report -instr-profile=... ...
The tool has been launched: 00:00:00
Loading coverage data: 00:00:00
Get unique source files: 00:00:33
Creating an index out of the source files: 00:00:34
Going into prepareFileReports: 00:00:34
Going to emit summary information for each file: 00:28:55 <-- 28:21 min!
Going to emit links to files with no function: 00:28:55
Launching 32 threads for generating HTML files: 00:28:55
real 37m43.651s
user 112m5.540s
sys 7m39.872s
```
2) Multi-threaded version with 32 CPUs:
```
$ time llvm-cov show -format=html -output-dir=report -instr-profile=... ...
The tool has been launched: 00:00:00
Loading coverage data: 00:00:00
Get unique source files: 00:00:38
Creating an index out of the source files: 00:00:40
Going into prepareFileReports: 00:00:40
Preparing file reports using 32 threads: 00:00:40
# Creating thread tasks for the following number of files: 16422
Going to emit summary information for each file: 00:01:57 <-- 1:17 min!
Going to emit links to files with no function: 00:01:58
Launching 32 threads for generating HTML files: 00:01:58
real 11m2.044s
user 134m48.124s
sys 7m53.388s
```
Reviewers: vsk, morehouse
Reviewed By: vsk
Subscribers: Dor1s, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D41206
llvm-svn: 321871
diff --git a/llvm/tools/llvm-cov/CoverageReport.h b/llvm/tools/llvm-cov/CoverageReport.h
index 94611bd..f90729b 100644
--- a/llvm/tools/llvm-cov/CoverageReport.h
+++ b/llvm/tools/llvm-cov/CoverageReport.h
@@ -44,6 +44,14 @@
const CoverageViewOptions &Options,
const CoverageFilter &Filters = CoverageFiltersMatchAll());
+ static void
+ prepareSingleFileReport(const StringRef Filename,
+ const coverage::CoverageMapping *Coverage,
+ const CoverageViewOptions &Options,
+ const unsigned LCP,
+ FileCoverageSummary *FileReport,
+ const CoverageFilter *Filters);
+
/// Render file reports for every unique file in the coverage mapping.
void renderFileReports(raw_ostream &OS) const;