[llvm-cov] Improve error message by printing the object file name that produces error

If error occurs on constructing coverage info for one of the object files, it prints the name of the object file, so that users know which one is the cause of error.

Differential Revision: https://reviews.llvm.org/D130196

llvm/lib/ProfileData/Coverage/CoverageMapping.cpp

@@ -349,7 +349,7 @@ CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
                       StringRef CompilationDir) {
   auto ProfileReaderOrErr = IndexedInstrProfReader::create(ProfileFilename);
   if (Error E = ProfileReaderOrErr.takeError())
-    return std::move(E);
+    return createFileError(ProfileFilename, std::move(E));
   auto ProfileReader = std::move(ProfileReaderOrErr.get());
   auto Coverage = std::unique_ptr<CoverageMapping>(new CoverageMapping());
   bool DataFound = false;
@@ -358,7 +358,7 @@ CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
     auto CovMappingBufOrErr = MemoryBuffer::getFileOrSTDIN(
         File.value(), /*IsText=*/false, /*RequiresNullTerminator=*/false);
     if (std::error_code EC = CovMappingBufOrErr.getError())
-      return errorCodeToError(EC);
+      return createFileError(File.value(), errorCodeToError(EC));
     StringRef Arch = Arches.empty() ? StringRef() : Arches[File.index()];
     MemoryBufferRef CovMappingBufRef =
         CovMappingBufOrErr.get()->getMemBufferRef();
@@ -368,7 +368,7 @@ CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
     if (Error E = CoverageReadersOrErr.takeError()) {
       E = handleMaybeNoDataFoundError(std::move(E));
       if (E)
-        return std::move(E);
+        return createFileError(File.value(), std::move(E));
       // E == success (originally a no_data_found error).
       continue;
     }
@@ -378,12 +378,14 @@ CoverageMapping::load(ArrayRef<StringRef> ObjectFilenames,
       Readers.push_back(std::move(Reader));
     DataFound |= !Readers.empty();
     if (Error E = loadFromReaders(Readers, *ProfileReader, *Coverage))
-      return std::move(E);
+      return createFileError(File.value(), std::move(E));
   }
   // If no readers were created, either no objects were provided or none of them
   // had coverage data. Return an error in the latter case.
   if (!DataFound && !ObjectFilenames.empty())
-    return make_error<CoverageMapError>(coveragemap_error::no_data_found);
+    return createFileError(
+        join(ObjectFilenames.begin(), ObjectFilenames.end(), ", "),
+        make_error<CoverageMapError>(coveragemap_error::no_data_found));
   return std::move(Coverage);
 }
 

llvm/test/tools/llvm-cov/missing-binaries.test

@@ -0,0 +1,4 @@
+RUN: llvm-profdata merge %S/Inputs/binary-formats.proftext -o %t.profdata
+RUN: not llvm-cov show -instr-profile=%t.profdata --object=%t.nonexistent.binary.1 --object=%t.nonexistent.binary.2 2>&1 | FileCheck %s
+
+CHECK: Failed to load coverage: '{{.*}}nonexistent.binary.1':

llvm/test/tools/llvm-cov/universal-binary.c

@@ -14,7 +14,7 @@ int main(int argc, const char *argv[]) {}
 
 // RUN: not llvm-cov show %S/Inputs/universal-binary -instr-profile %t.profdata -path-equivalence=/tmp,%S %s 2>&1 | FileCheck --check-prefix=WRONG-ARCH %s
 // RUN: not llvm-cov show %S/Inputs/universal-binary -instr-profile %t.profdata -path-equivalence=/tmp,%S %s -arch i386 2>&1 | FileCheck --check-prefix=WRONG-ARCH %s
-// WRONG-ARCH: Failed to load coverage: `-arch` specifier is invalid or missing for universal binary
+// WRONG-ARCH: Failed to load coverage: '{{.*}}universal-binary': `-arch` specifier is invalid or missing for universal binary
 
 // RUN: not llvm-cov show %S/Inputs/universal-binary -instr-profile %t.profdata -path-equivalence=/tmp,%S %s -arch definitly_a_made_up_architecture 2>&1 | FileCheck --check-prefix=MADE-UP-ARCH %s
 // MADE-UP-ARCH: Unknown architecture: definitly_a_made_up_architecture

llvm/test/tools/llvm-cov/warnings.h

@@ -13,4 +13,4 @@
 // FAKE-FUNC-STDERR: Could not read coverage for '{{.*}}'.
 
 // RUN: not llvm-cov report %S/Inputs/malformedRegions.covmapping -instr-profile %S/Inputs/elf_binary_comdat.profdata 2>&1 | FileCheck %s -check-prefix=MALFORMED-REGION
-// MALFORMED-REGION: malformedRegions.covmapping: Failed to load coverage: Malformed coverage data
+// MALFORMED-REGION: Failed to load coverage: '{{.*}}malformedRegions.covmapping': Malformed coverage data

llvm/tools/llvm-cov/CodeCoverage.cpp

@@ -436,8 +436,7 @@ std::unique_ptr<CoverageMapping> CodeCoverageTool::load() {
       CoverageMapping::load(ObjectFilenames, PGOFilename, CoverageArches,
                             ViewOpts.CompilationDirectory);
   if (Error E = CoverageOrErr.takeError()) {
-    error("Failed to load coverage: " + toString(std::move(E)),
+    error("Failed to load coverage: " + toString(std::move(E)));
-          join(ObjectFilenames.begin(), ObjectFilenames.end(), ", "));
     return nullptr;
   }
   auto Coverage = std::move(CoverageOrErr.get());