[llvm-cov] Add an option which maps the location of source directories on another machine to your local copies

Summary:
This patch adds the -path-equivalence option (example: llvm-cov show -path-equivalence=/origin/path,/local/path) which maps the source code path from one machine to another when using `llvm-cov show`. This is similar to the -filename-equivalence option, but doesn't require you to specify all the source files on the command line.

This allows you to generate the coverage data on one machine (e.g. in a CI system), and then use llvm-cov on another machine where you have the same code base on a different path.

Reviewers: vsk

Reviewed By: vsk

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D36391

llvm-svn: 310827
diff --git a/llvm/test/tools/llvm-cov/native_separators.c b/llvm/test/tools/llvm-cov/native_separators.c
index adc167b..8ab1a73 100644
--- a/llvm/test/tools/llvm-cov/native_separators.c
+++ b/llvm/test/tools/llvm-cov/native_separators.c
@@ -8,9 +8,9 @@
 // RUN: llvm-profdata merge %S/Inputs/double_dots.proftext -o %t.profdata
 // RUN: llvm-cov show %S/Inputs/native_separators.covmapping -instr-profile=%t.profdata -o %t.dir
 // RUN: FileCheck -check-prefixes=TEXT-INDEX -input-file=%t.dir/index.txt %s
-// RUN: llvm-cov show -format=html %S/Inputs/native_separators.covmapping -instr-profile=%t.profdata -filename-equivalence ../llvm-"config"/../llvm-"cov"/native_separators.c -o %t.dir
+// RUN: llvm-cov show -format=html %S/Inputs/native_separators.covmapping -instr-profile=%t.profdata -path-equivalence=/tmp,%S ../llvm-"config"/../llvm-"cov"/native_separators.c -o %t.dir
 // RUN: FileCheck -check-prefixes=HTML-INDEX -input-file=%t.dir/index.html %s
-// RUN: llvm-cov show -format=html %S/Inputs/native_separators.covmapping -instr-profile=%t.profdata -filename-equivalence %s -o %t.dir
+// RUN: llvm-cov show -format=html %S/Inputs/native_separators.covmapping -instr-profile=%t.profdata -path-equivalence=/tmp,%S %s -o %t.dir
 // RUN: FileCheck -check-prefixes=HTML -input-file=%t.dir/coverage/tmp/native_separators.c.html %s
 
 // TEXT-INDEX: \tmp\native_separators.c