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

2 files changed, 1 insertions, 5 deletions

diff --git a/lib/CompilerDriver/CompilationGraph.cpp b/lib/CompilerDriver/CompilationGraph.cpp
index 524607bee7..a36d3fb692 100644
--- a/lib/CompilerDriver/CompilationGraph.cpp
+++ b/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(),
diff --git a/lib/CompilerDriver/Main.cpp b/lib/CompilerDriver/Main.cpp
index 3a3487a0a9..96877077cc 100644
--- a/lib/CompilerDriver/Main.cpp
+++ b/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);