Profdata Code Coverage

CalabashBackdoor.m

// Forward-declare LLVM (profdata) methods for usage below
// For documentation, see: http://clang.llvm.org/docs/SourceBasedCodeCoverage.html
int __llvm_profile_write_file(void);
void __llvm_profile_initialize_file(void);
void __llvm_profile_set_filename(const char *Name);

/**
 * Generate profraw (profdata) code coverage
 */
- (BOOL)beginCodeCoverage:(NSString*)fullFilePath
{
    __llvm_profile_set_filename([fullFilePath UTF8String]);
    __llvm_profile_initialize_file();
    // llvm_profile_write_file returns 0 on success and 'something else' if unsuccessful
    return (__llvm_profile_write_file() == 0);
}

code_coverage_profdata.rb

# Contains the methods for generating profdata coverage
# First we generate a profraw file, which we then need to convert to the profdata format
# Documentation here: http://clang.llvm.org/docs/SourceBasedCodeCoverage.html

class CodeCoverage
  class Profdata
    @app_name = 'YourAppNameHere'

    @build_path = CODE_COVERAGE_BUILD_PARENT_PATH ||= ''
    @code_coverage_folder_path = File.join(@build_path, 'CodeCoverage/')
    @project_intermediates = CODE_COVERAGE_INTERMEDIATES_DIR ||= nil

    # Check to see if we are set up to collect code coverage
    # @return [Boolean] True if code coverage is on (CODE_COVERAGE_BUILD_PARENT_PATH was set to something), false if not
    def self.on?
      return !@build_path.empty?
    end

    # Generates code coverage at the specified path with the specified filename
    # @param [String] code_coverage_output_path The path to the output file
    # @param [String] code_coverage_filename The name of the file you want to generate
    def self.generate_llvm_coverage(code_coverage_output_path = @code_coverage_folder_path, code_coverage_filename = 'UIAutomationCoverage.profraw')
      if self.on?
        code_coverage_output_full_path = File.join(code_coverage_output_path, code_coverage_filename)
        success = backdoor('beginCodeCoverage:', code_coverage_output_full_path)
        if success
          log_message("[CODE COVERAGE] Code coverage data saved to #{code_coverage_output_full_path}")
        else
          log_failure("[CODE COVERAGE] Attempted to save code coverage to #{code_coverage_output_full_path}, but it was not successful.")
        end
      end
    end
  end
end

globals.rb

# This should be set to the parent directory containing the build folders such as /viewer-ios/
CODE_COVERAGE_BUILD_PARENT_PATH = ENV['CODE_COVERAGE_BUILD_PARENT_PATH']
if CODE_COVERAGE_BUILD_PARENT_PATH
  xc_workspace_path=Dir["#{CODE_COVERAGE_BUILD_PARENT_PATH}/*.xcworkspace"].first
  schema='YourSchemaHere-cal'
  intermediates_dir=`xcodebuild -showBuildSettings -workspace #{xc_workspace_path} -scheme #{schema} | grep -m 1 'PROJECT_TEMP_ROOT' | sed -n -e 's/^.*PROJECT_TEMP_ROOT = //p'`
  CODE_COVERAGE_INTERMEDIATES_DIR=intermediates_dir.strip
end

YourConfig.xcconfig

/////////////////////////////////////
// Apple LLVM 7.0 - Code Generation
/////////////////////////////////////

// Sets -fprofile-instr-generate
CLANG_INSTRUMENT_FOR_OPTIMIZATION_PROFILING = YES

GCC_OPTIMIZATION_LEVEL = 0

// Activating this setting causes a 'notes' file to be produced that the gcov code-coverage utility can use to show program coverage.
GCC_GENERATE_TEST_COVERAGE_FILES = NO

// Activating this setting indicates that code should be added so program flow arcs are instrumented.
GCC_INSTRUMENT_PROGRAM_FLOW_ARCS = NO

Looks like int __llvm_profile_write_file(void) works for Obj C projects in pair with CLANG_INSTRUMENT_FOR_OPTIMIZATION_PROFILING. But as long as you add one swift file in the project swift will complain.. Swift does not support profile guided optimization.. Are there any workarounds?