New experimental/undocumented feature: 'works_on_empty'.

For now, just enough support to make -filelist work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96918 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CompilerDriver/Common.td

@@ -23,6 +23,7 @@ def output_suffix;
 def cmd_line;
 def join;
 def sink;
+def works_on_empty;
 def actions;
 
 // Possible option types.

include/llvm/CompilerDriver/Tool.h

@@ -28,7 +28,7 @@ namespace llvmc {
   typedef std::vector<llvm::sys::Path> PathVector;
   typedef llvm::StringSet<> InputLanguagesSet;
 
-  /// Tool - A class
+  /// Tool - Represents a single tool.
   class Tool : public llvm::RefCountedBaseVPTR<Tool> {
   public:
 
@@ -51,6 +51,7 @@ namespace llvmc {
     virtual const char*  OutputLanguage() const = 0;
 
     virtual bool IsJoin() const = 0;
+    virtual bool WorksOnEmpty() const = 0;
 
   protected:
     /// OutFileName - Generate the output file name.

lib/CompilerDriver/CompilationGraph.cpp

@@ -313,7 +313,7 @@ int CompilationGraph::Build (const sys::Path& TempDir,
     JoinTool* JT = &dynamic_cast<JoinTool&>(*CurNode->ToolPtr.getPtr());
 
     // Are there any files in the join list?
-    if (JT->JoinListEmpty())
+    if (JT->JoinListEmpty() && !(JT->WorksOnEmpty() && InputFilenames.empty()))
       continue;
 
     Action CurAction = JT->GenerateAction(CurNode->HasChildren(),

lib/CompilerDriver/Main.cpp

@@ -126,10 +126,6 @@ int Main(int argc, char** argv) {
       return 0;
     }
 
-    if (InputFilenames.empty()) {
-      throw std::runtime_error("no input files");
-    }
-
     if (Time) {
       GlobalTimeLog = new std::stringstream;
       GlobalTimeLog->precision(2);

tools/llvmc/plugins/Base/Base.td.in

@@ -76,6 +76,8 @@ def OptList : OptionList<[
     (help "Specifies a framework to link against")),
  (parameter_list_option "weak_framework",
     (help "Specifies a framework to weakly link against"), (hidden)),
+ (parameter_option "filelist", (hidden),
+    (help "Link the files listed in file")),
  (prefix_list_option "F",
     (help "Add a directory to framework search path")),
  (prefix_list_option "I",
@@ -242,6 +244,8 @@ class llvm_gcc_based_linker <string cmd_prefix> : Tool<
  (out_language "executable"),
  (output_suffix "out"),
  (cmd_line !strconcat(cmd_prefix, " $INFILE -o $OUTFILE")),
+ (works_on_empty (case (not_empty "filelist"), true,
+                       (default), false)),
  (join),
  (actions (case
           (switch_on "pthread"), (append_cmd "-lpthread"),
@@ -250,6 +254,7 @@ class llvm_gcc_based_linker <string cmd_prefix> : Tool<
           (not_empty "arch"), (forward "arch"),
           (not_empty "framework"), (forward "framework"),
           (not_empty "weak_framework"), (forward "weak_framework"),
+          (not_empty "filelist"), (forward "filelist"),
           (switch_on "m32"), (forward "m32"),
           (switch_on "m64"), (forward "m64"),
           (not_empty "l"), (forward "l"),

utils/TableGen/LLVMCConfigurationEmitter.cpp

@@ -783,6 +783,7 @@ struct ToolDescription : public RefCountedBase<ToolDescription> {
   std::string OutLanguage;
   std::string OutputSuffix;
   unsigned Flags;
+  const Init* OnEmpty;
 
   // Various boolean properties
   void setSink()      { Flags |= ToolFlags::Sink; }
@@ -792,9 +793,9 @@ struct ToolDescription : public RefCountedBase<ToolDescription> {
 
   // Default ctor here is needed because StringMap can only store
   // DefaultConstructible objects
-  ToolDescription() : CmdLine(0), Actions(0), Flags(0) {}
+  ToolDescription() : CmdLine(0), Actions(0), Flags(0), OnEmpty(0) {}
   ToolDescription (const std::string& n)
-  : Name(n), CmdLine(0), Actions(0), Flags(0)
+    : Name(n), CmdLine(0), Actions(0), Flags(0), OnEmpty(0)
   {}
 };
 
@@ -831,6 +832,7 @@ public:
       AddHandler("out_language", &CollectToolProperties::onOutLanguage);
       AddHandler("output_suffix", &CollectToolProperties::onOutputSuffix);
       AddHandler("sink", &CollectToolProperties::onSink);
+      AddHandler("works_on_empty", &CollectToolProperties::onWorksOnEmpty);
 
       staticMembersInitialized_ = true;
     }
@@ -907,6 +909,10 @@ private:
     toolDesc_.setSink();
   }
 
+  void onWorksOnEmpty (const DagInit& d) {
+    toolDesc_.OnEmpty = d.getArg(0);
+  }
+
 };
 
 /// CollectToolDescriptions - Gather information about tool properties
@@ -1509,7 +1515,7 @@ public:
 /// EmitCaseConstructHandler - Emit code that handles the 'case'
 /// construct. Takes a function object that should emit code for every case
 /// clause. Implemented on top of WalkCase.
-/// Callback's type is void F(Init* Statement, unsigned IndentLevel,
+/// Callback's type is void F(const Init* Statement, unsigned IndentLevel,
 /// raw_ostream& O).
 /// EmitElseIf parameter controls the type of condition that is emitted ('if
 /// (..) {..} else if (..) {} .. else {..}' vs. 'if (..) {..} if(..)  {..}
@@ -2221,6 +2227,29 @@ void EmitIsJoinMethod (const ToolDescription& D, raw_ostream& O) {
   O.indent(Indent1) << "}\n\n";
 }
 
+/// EmitWorksOnEmptyCallback - Callback used by EmitWorksOnEmptyMethod in
+/// conjunction with EmitCaseConstructHandler.
+void EmitWorksOnEmptyCallback (const Init* Value,
+                               unsigned IndentLevel, raw_ostream& O) {
+  CheckBooleanConstant(Value);
+  O.indent(IndentLevel) << "return " << Value->getAsString() << ";\n";
+}
+
+/// EmitWorksOnEmptyMethod - Emit the WorksOnEmpty() method for a given Tool
+/// class.
+void EmitWorksOnEmptyMethod (const ToolDescription& D,
+                             const OptionDescriptions& OptDescs,
+                             raw_ostream& O)
+{
+  O.indent(Indent1) << "bool WorksOnEmpty() const {\n";
+  if (D.OnEmpty == 0)
+    O.indent(Indent2) << "return false;\n";
+  else
+    EmitCaseConstructHandler(D.OnEmpty, Indent2, EmitWorksOnEmptyCallback,
+                             /*EmitElseIf = */ true, OptDescs, O);
+  O.indent(Indent1) << "}\n\n";
+}
+
 /// EmitStaticMemberDefinitions - Emit static member definitions for a
 /// given Tool class.
 void EmitStaticMemberDefinitions(const ToolDescription& D, raw_ostream& O) {
@@ -2255,6 +2284,7 @@ void EmitToolClassDefinition (const ToolDescription& D,
   EmitNameMethod(D, O);
   EmitInOutLanguageMethods(D, O);
   EmitIsJoinMethod(D, O);
+  EmitWorksOnEmptyMethod(D, OptDescs, O);
   EmitGenerateActionMethods(D, OptDescs, O);
 
   // Close class definition