llc: Add a 'run-pass' option.

This commit adds a 'run-pass' option to llc, which instructs the compiler to run
one specific code generation pass only.

Llc already has the 'start-after' and the 'stop-after' options, and this new
option complements the other two by making it easier to write tests that want
to invoke a single pass only.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10776


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241476 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/CppBackend/CPPBackend.cpp

@@ -2148,8 +2148,8 @@ char CppWriter::ID = 0;
 
 bool CPPTargetMachine::addPassesToEmitFile(
     PassManagerBase &PM, raw_pwrite_stream &o, CodeGenFileType FileType,
-    bool DisableVerify, AnalysisID StartAfter, AnalysisID StopAfter,
-    MachineFunctionInitializer *MFInitializer) {
+    bool DisableVerify, AnalysisID StartBefore, AnalysisID StartAfter,
+    AnalysisID StopAfter, MachineFunctionInitializer *MFInitializer) {
   if (FileType != TargetMachine::CGFT_AssemblyFile)
     return true;
   auto FOut = llvm::make_unique<formatted_raw_ostream>(o);

lib/Target/CppBackend/CPPTargetMachine.h

@@ -31,7 +31,8 @@ struct CPPTargetMachine : public TargetMachine {
 public:
   bool addPassesToEmitFile(PassManagerBase &PM, raw_pwrite_stream &Out,
                            CodeGenFileType FileType, bool DisableVerify,
-                           AnalysisID StartAfter, AnalysisID StopAfter,
+                           AnalysisID StartBefore, AnalysisID StartAfter,
+                           AnalysisID StopAfter,
                            MachineFunctionInitializer *MFInitializer) override;
 };