Revert "[llvm-cov] Add support for baseline coverage" (#144121)

Reverts llvm/llvm-project#117910

```
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/ProfileData/CoverageMappingTest.cpp:281:28: error: 'std::reference_wrapper' may not intend to support class template argument deduction [-Werror,-Wctad-maybe-unsupported]
  281 |         std::make_optional(std::reference_wrapper(*ProfileReader));
      |                            ^
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/bits/refwrap.h:289:11: note: add a deduction guide to suppress this warning
  289 |     class reference_wrapper
      |           ^
```

1 files changed, 28 insertions, 50 deletions

diff --git a/llvm/tools/llvm-cov/CodeCoverage.cpp b/llvm/tools/llvm-cov/CodeCoverage.cpp
index 6c66858..1f2484c 100644
--- a/llvm/tools/llvm-cov/CodeCoverage.cpp
+++ b/llvm/tools/llvm-cov/CodeCoverage.cpp
@@ -153,7 +153,7 @@ private:
   bool HadSourceFiles = false;
 
   /// The path to the indexed profile.
-  std::optional<std::string> PGOFilename;
+  std::string PGOFilename;
 
   /// A list of input source files.
   std::vector<std::string> SourceFiles;
@@ -455,12 +455,10 @@ static bool modifiedTimeGT(StringRef LHS, StringRef RHS) {
 }
 
 std::unique_ptr<CoverageMapping> CodeCoverageTool::load() {
-  if (PGOFilename) {
-    for (StringRef ObjectFilename : ObjectFilenames)
-      if (modifiedTimeGT(ObjectFilename, PGOFilename.value()))
-        warning("profile data may be out of date - object is newer",
-                ObjectFilename);
-  }
+  for (StringRef ObjectFilename : ObjectFilenames)
+    if (modifiedTimeGT(ObjectFilename, PGOFilename))
+      warning("profile data may be out of date - object is newer",
+              ObjectFilename);
   auto FS = vfs::getRealFileSystem();
   auto CoverageOrErr = CoverageMapping::load(
       ObjectFilenames, PGOFilename, *FS, CoverageArches,
@@ -670,16 +668,11 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
       "dump-collected-paths", cl::Optional, cl::Hidden,
       cl::desc("Show the collected paths to source files"));
 
-  cl::opt<std::string> PGOFilename(
-      "instr-profile", cl::Optional,
+  cl::opt<std::string, true> PGOFilename(
+      "instr-profile", cl::Required, cl::location(this->PGOFilename),
       cl::desc(
           "File with the profile data obtained after an instrumented run"));
 
-  cl::opt<bool> EmptyProfile(
-      "empty-profile", cl::Optional,
-      cl::desc("Use a synthetic profile with no data to generate "
-               "baseline coverage"));
-
   cl::list<std::string> Arches(
       "arch", cl::desc("architectures of the coverage mapping binaries"));
 
@@ -812,15 +805,6 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
     }
     this->CheckBinaryIDs = CheckBinaryIDs;
 
-    if (!PGOFilename.empty() == EmptyProfile) {
-      error(
-          "exactly one of -instr-profile and -empty-profile must be specified");
-      return 1;
-    }
-    if (!PGOFilename.empty()) {
-      this->PGOFilename = std::make_optional(PGOFilename.getValue());
-    }
-
     if (!CovFilename.empty())
       ObjectFilenames.emplace_back(CovFilename);
     for (const std::string &Filename : CovFilenames)
@@ -1132,22 +1116,20 @@ int CodeCoverageTool::doShow(int argc, const char **argv,
     }
   }
 
-  if (PGOFilename) {
-    sys::fs::file_status Status;
-    if (std::error_code EC = sys::fs::status(PGOFilename.value(), Status)) {
-      error("could not read profile data!" + EC.message(), PGOFilename.value());
-      return 1;
-    }
+  sys::fs::file_status Status;
+  if (std::error_code EC = sys::fs::status(PGOFilename, Status)) {
+    error("could not read profile data!" + EC.message(), PGOFilename);
+    return 1;
+  }
 
-    if (ShowCreatedTime) {
-      auto ModifiedTime = Status.getLastModificationTime();
-      std::string ModifiedTimeStr = to_string(ModifiedTime);
-      size_t found = ModifiedTimeStr.rfind(':');
-      ViewOpts.CreatedTimeStr =
-          (found != std::string::npos)
-              ? "Created: " + ModifiedTimeStr.substr(0, found)
-              : "Created: " + ModifiedTimeStr;
-    }
+  if (ShowCreatedTime) {
+    auto ModifiedTime = Status.getLastModificationTime();
+    std::string ModifiedTimeStr = to_string(ModifiedTime);
+    size_t found = ModifiedTimeStr.rfind(':');
+    ViewOpts.CreatedTimeStr =
+        (found != std::string::npos)
+            ? "Created: " + ModifiedTimeStr.substr(0, found)
+            : "Created: " + ModifiedTimeStr;
   }
 
   auto Coverage = load();
@@ -1256,12 +1238,10 @@ int CodeCoverageTool::doReport(int argc, const char **argv,
     return 1;
   }
 
-  if (PGOFilename) {
-    sys::fs::file_status Status;
-    if (std::error_code EC = sys::fs::status(PGOFilename.value(), Status)) {
-      error("could not read profile data!" + EC.message(), PGOFilename.value());
-      return 1;
-    }
+  sys::fs::file_status Status;
+  if (std::error_code EC = sys::fs::status(PGOFilename, Status)) {
+    error("could not read profile data!" + EC.message(), PGOFilename);
+    return 1;
   }
 
   auto Coverage = load();
@@ -1323,12 +1303,10 @@ int CodeCoverageTool::doExport(int argc, const char **argv,
     return 1;
   }
 
-  if (PGOFilename) {
-    sys::fs::file_status Status;
-    if (std::error_code EC = sys::fs::status(PGOFilename.value(), Status)) {
-      error("could not read profile data!" + EC.message(), PGOFilename.value());
-      return 1;
-    }
+  sys::fs::file_status Status;
+  if (std::error_code EC = sys::fs::status(PGOFilename, Status)) {
+    error("could not read profile data!" + EC.message(), PGOFilename);
+    return 1;
   }
 
   auto Coverage = load();