Swift: Omit output-file-map when used as a linker

Swift is used as the linker for non-swift files because it needs to pull
files like swiftrt.o in when swift symbols are present to ensure that
the swift runtime is linked.

The swift driver uses clang as the underlying linker, which pulls in
crtbegin.o and friends when appropriate, so using Swift as a linker for
C/C++ libraries is fine.

The output-file-map was getting passed to all Swift invocations,
regardless of whether or not we generated one. This patch changes it so
that we only include the output-file-map in the Swift compiler
invocation if we have actually generated the file.

5 files changed, 38 insertions, 34 deletions

diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index bda8a5f..895a4c3 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -372,7 +372,6 @@ void cmNinjaNormalTargetGenerator::WriteLinkRule(bool useResponseFile,
       vars.SwiftLibraryName = "$SWIFT_LIBRARY_NAME";
       vars.SwiftModule = "$SWIFT_MODULE";
       vars.SwiftModuleName = "$SWIFT_MODULE_NAME";
-      vars.SwiftOutputFileMap = "$SWIFT_OUTPUT_FILE_MAP";
       vars.SwiftSources = "$SWIFT_SOURCES";
 
       vars.Defines = "$DEFINES";
@@ -1072,12 +1071,6 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement(
         cmOutputConverter::SHELL);
     }(vars["SWIFT_MODULE_NAME"]);
 
-    const std::string map = cmStrCat(gt->GetSupportDirectory(), '/', config,
-                                     '/', "output-file-map.json");
-    vars["SWIFT_OUTPUT_FILE_MAP"] =
-      this->GetLocalGenerator()->ConvertToOutputFormat(
-        this->ConvertToNinjaPath(map), cmOutputConverter::SHELL);
-
     vars["SWIFT_SOURCES"] = [this, config]() -> std::string {
       std::vector<cmSourceFile const*> sources;
       std::stringstream oss;
@@ -1101,6 +1094,7 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement(
     vars["DEFINES"] = this->GetDefines("Swift", config);
     vars["FLAGS"] = this->GetFlags("Swift", config);
     vars["INCLUDES"] = this->GetIncludes("Swift", config);
+    this->GenerateSwiftOutputFileMap(config, vars["FLAGS"]);
   }
 
   // Compute specific libraries to link with.
diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index e4427f5..ae6a510 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -1177,30 +1177,42 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements(
   }
 
   this->GetImplFileStream(fileConfig) << "\n";
+}
 
-  if (!this->Configs[config].SwiftOutputMap.empty()) {
-    std::string const mapFilePath =
-      cmStrCat(this->GeneratorTarget->GetSupportDirectory(), '/', config, '/',
-               "output-file-map.json");
-    std::string const targetSwiftDepsPath = [this, config]() -> std::string {
-      cmGeneratorTarget const* target = this->GeneratorTarget;
-      if (cmValue name = target->GetProperty("Swift_DEPENDENCIES_FILE")) {
-        return *name;
-      }
-      return this->ConvertToNinjaPath(
-        cmStrCat(target->GetSupportDirectory(), '/', config, '/',
-                 target->GetName(), ".swiftdeps"));
-    }();
+void cmNinjaTargetGenerator::GenerateSwiftOutputFileMap(
+  const std::string& config, std::string& flags)
+{
+  if (this->Configs[config].SwiftOutputMap.empty()) {
+    return;
+  }
 
-    // build the global target dependencies
-    // https://github.com/apple/swift/blob/master/docs/Driver.md#output-file-maps
-    Json::Value deps(Json::objectValue);
-    deps["swift-dependencies"] = targetSwiftDepsPath;
-    this->Configs[config].SwiftOutputMap[""] = deps;
+  std::string const targetSwiftDepsPath = [this, config]() -> std::string {
+    cmGeneratorTarget const* target = this->GeneratorTarget;
+    if (cmValue name = target->GetProperty("Swift_DEPENDENCIES_FILE")) {
+      return *name;
+    }
+    return this->ConvertToNinjaPath(cmStrCat(target->GetSupportDirectory(),
+                                             '/', config, '/',
+                                             target->GetName(), ".swiftdeps"));
+  }();
 
-    cmGeneratedFileStream output(mapFilePath);
-    output << this->Configs[config].SwiftOutputMap;
-  }
+  std::string mapFilePath =
+    cmStrCat(this->GeneratorTarget->GetSupportDirectory(), '/', config, '/',
+             "output-file-map.json");
+
+  // build the global target dependencies
+  // https://github.com/apple/swift/blob/master/docs/Driver.md#output-file-maps
+  Json::Value deps(Json::objectValue);
+  deps["swift-dependencies"] = targetSwiftDepsPath;
+  this->Configs[config].SwiftOutputMap[""] = deps;
+
+  cmGeneratedFileStream output(mapFilePath);
+  output << this->Configs[config].SwiftOutputMap;
+
+  // Add flag
+  this->LocalGenerator->AppendFlags(flags, "-output-file-map");
+  this->LocalGenerator->AppendFlagEscape(flags,
+                                         ConvertToNinjaPath(mapFilePath));
 }
 
 namespace {
diff --git a/Source/cmNinjaTargetGenerator.h b/Source/cmNinjaTargetGenerator.h
index 4b4cf8d..c43b650 100644
--- a/Source/cmNinjaTargetGenerator.h
+++ b/Source/cmNinjaTargetGenerator.h
@@ -163,6 +163,9 @@ protected:
   void EmitSwiftDependencyInfo(cmSourceFile const* source,
                                const std::string& config);
 
+  void GenerateSwiftOutputFileMap(const std::string& config,
+                                  std::string& flags);
+
   void ExportObjectCompileCommand(
     std::string const& language, std::string const& sourceFileName,
     std::string const& objectDir, std::string const& objectFileName,
diff --git a/Source/cmRulePlaceholderExpander.cxx b/Source/cmRulePlaceholderExpander.cxx
index b63d11c..638bb42 100644
--- a/Source/cmRulePlaceholderExpander.cxx
+++ b/Source/cmRulePlaceholderExpander.cxx
@@ -119,11 +119,6 @@ std::string cmRulePlaceholderExpander::ExpandVariable(
       return this->ReplaceValues->SwiftModuleName;
     }
   }
-  if (this->ReplaceValues->SwiftOutputFileMap) {
-    if (variable == "SWIFT_OUTPUT_FILE_MAP") {
-      return this->ReplaceValues->SwiftOutputFileMap;
-    }
-  }
   if (this->ReplaceValues->SwiftSources) {
     if (variable == "SWIFT_SOURCES") {
       return this->ReplaceValues->SwiftSources;
diff --git a/Source/cmRulePlaceholderExpander.h b/Source/cmRulePlaceholderExpander.h
index 23ec405..5d1f199 100644
--- a/Source/cmRulePlaceholderExpander.h
+++ b/Source/cmRulePlaceholderExpander.h
@@ -64,7 +64,7 @@ public:
     const char* SwiftLibraryName = nullptr;
     const char* SwiftModule = nullptr;
     const char* SwiftModuleName = nullptr;
-    const char* SwiftOutputFileMap = nullptr;
+    const char* SwiftOutputFileMapOption = nullptr;
     const char* SwiftSources = nullptr;
     const char* ISPCHeader = nullptr;
     const char* CudaCompileMode = nullptr;