[llvm-cov] Create syntax to pass source w/o binary.

Since binary ID lookup makes CLI object arguments optional, it should be
possible to pass a list of source files without a binary. Unfortunately,
the current syntax will always interpret the first source file as a
binary. This change adds a `-sources` option to cause all later
positional arguments to be considered sources.

Reviewed By: gulfem

Differential Revision: https://reviews.llvm.org/D144207

(cherry picked from commit 8007bcc)

Author: mysterymath

compiler-rt/test/profile/Linux/binary-id-lookup.c

@@ -9,6 +9,9 @@
 // RUN: cp %t.main %t/.build-id/ab/cd1234.debug
 // RUN: llvm-profdata merge -o %t.profdata %t.profdir/default_*.profraw
 // RUN: llvm-cov show -instr-profile %t.profdata -debug-file-directory %t | FileCheck %s
+// RUN: llvm-cov show -instr-profile %t.profdata %t/libfoo.so -sources %t/foo.c -object %t.main | FileCheck %s --check-prefix=FOO-ONLY
+// RUN: llvm-cov show -instr-profile %t.profdata -debug-file-directory %t -sources %t/foo.c | FileCheck %s --check-prefix=FOO-ONLY
+// RUN: llvm-cov show -instr-profile %t.profdata -debug-file-directory %t %t/libfoo.so -sources %t/foo.c | FileCheck %s --check-prefix=FOO-ONLY
 // RUN: echo "bad" > %t/.build-id/ab/cd1234.debug
 // RUN: llvm-cov show -instr-profile %t.profdata -debug-file-directory %t %t.main | FileCheck %s
 // RUN: not llvm-cov show -instr-profile %t.profdata -debug-file-directory %t/empty 2>&1 | FileCheck %s --check-prefix=NODATA
@@ -17,6 +20,7 @@
 // CHECK: 2| 1|void bar(void) {}
 // CHECK: 3| 1|int main() {
 
+// FOO-ONLY: 1| 1|void foo(void) {}
 // NODATA: error: Failed to load coverage: '': No coverage data found
 
 //--- foo.c

llvm/docs/CommandGuide/llvm-cov.rst

@@ -188,14 +188,14 @@ SHOW COMMAND
 SYNOPSIS
 ^^^^^^^^
 
-:program:`llvm-cov show` [*options*] -instr-profile *PROFILE* *BIN* [*-object BIN,...*] [[*-object BIN*]] [*SOURCES*]
+:program:`llvm-cov show` [*options*] -instr-profile *PROFILE* [*BIN*] [*-object BIN*]... [*-sources*] [*SOURCE*]...
 
 DESCRIPTION
 ^^^^^^^^^^^
 
 The :program:`llvm-cov show` command shows line by line coverage of the
-binaries *BIN*,...  using the profile data *PROFILE*. It can optionally be
-filtered to only show the coverage for the files listed in *SOURCES*.
+binaries *BIN*...  using the profile data *PROFILE*. It can optionally be
+filtered to only show the coverage for the files listed in *SOURCE*....
 
 *BIN* may be an executable, object file, dynamic library, or archive (thin or
 otherwise).
@@ -370,14 +370,14 @@ REPORT COMMAND
 SYNOPSIS
 ^^^^^^^^
 
-:program:`llvm-cov report` [*options*] -instr-profile *PROFILE* *BIN* [*-object BIN,...*] [[*-object BIN*]] [*SOURCES*]
+:program:`llvm-cov report` [*options*] -instr-profile *PROFILE* [*BIN*] [*-object BIN*]... [*-sources*] [*SOURCE*]...
 
 DESCRIPTION
 ^^^^^^^^^^^
 
 The :program:`llvm-cov report` command displays a summary of the coverage of
-the binaries *BIN*,... using the profile data *PROFILE*. It can optionally be
-filtered to only show the coverage for the files listed in *SOURCES*.
+the binaries *BIN*... using the profile data *PROFILE*. It can optionally be
+filtered to only show the coverage for the files listed in *SOURCE*....
 
 *BIN* may be an executable, object file, dynamic library, or archive (thin or
 otherwise).
@@ -451,21 +451,21 @@ EXPORT COMMAND
 SYNOPSIS
 ^^^^^^^^
 
-:program:`llvm-cov export` [*options*] -instr-profile *PROFILE* *BIN* [*-object BIN,...*] [[*-object BIN*]] [*SOURCES*]
+:program:`llvm-cov export` [*options*] -instr-profile *PROFILE* [*BIN*] [*-object BIN*]... [*-sources*] [*SOURCE*]...
 
 DESCRIPTION
 ^^^^^^^^^^^
 
 The :program:`llvm-cov export` command exports coverage data of the binaries
-*BIN*,... using the profile data *PROFILE* in either JSON or lcov trace file
+*BIN*... using the profile data *PROFILE* in either JSON or lcov trace file
 format.
 
 When exporting JSON, the regions, functions, branches, expansions, and
 summaries of the coverage data will be exported. When exporting an lcov trace
 file, the line-based coverage, branch coverage, and summaries will be exported.
 
 The exported data can optionally be filtered to only export the coverage
-for the files listed in *SOURCES*.
+for the files listed in *SOURCE*....
 
 For information on compiling programs for coverage and generating profile data,
 see :ref:`llvm-cov-show`.

llvm/tools/llvm-cov/CodeCoverage.cpp

@@ -635,7 +635,7 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
       "dump-collected-objects", cl::Optional, cl::Hidden,
       cl::desc("Show the collected coverage object files"));
 
-  cl::list<std::string> InputSourceFiles(cl::Positional,
+  cl::list<std::string> InputSourceFiles("sources", cl::Positional,
                                          cl::desc("<Source files>"));
 
   cl::opt<bool> DebugDumpCollectedPaths(