Simplify the code that adds passes so compilation can stop after any step

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2775 91177308-0d34-0410-b5e6-96231b3b80d8

tools/gccas/gccas.cpp

@@ -15,17 +15,69 @@
 #include "llvm/Transforms/ConstantMerge.h"
 #include "llvm/Transforms/ChangeAllocations.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Analysis/Verifier.h"
 #include "llvm/Bytecode/WriteBytecodePass.h"
 #include "Support/CommandLine.h"
 #include "Support/Signals.h"
 #include <memory>
 #include <fstream>
 
-cl::String InputFilename ("", "Parse <arg> file, compile to bytecode",
-                          cl::Required, "");
-cl::String OutputFilename("o", "Override output filename", cl::NoFlags, "");
-cl::Flag   StopAtLevelRaise("stopraise", "Stop optimization before level raise",
-                            cl::Hidden);
+static cl::String InputFilename   ("", "Parse <arg> file, compile to bytecode",
+                                   cl::Required, "");
+static cl::String OutputFilename  ("o", "Override output filename");
+static cl::Int    RunNPasses      ("stopAfterNPasses", "Only run the first N "
+                                   "passes of gccas", cl::Hidden);
+static cl::Flag   StopAtLevelRaise("stopraise", "Stop optimization before "
+                                   "level raise", cl::Hidden);
+static cl::Flag   Verify          ("verify", "Verify each pass result");
+
+static inline void addPass(PassManager &PM, Pass *P) {
+  static int NumPassesCreated = 0;
+  
+  // If we haven't already created the number of passes that was requested...
+  if (RunNPasses == 0 || RunNPasses > NumPassesCreated) {
+    // Add the pass to the pass manager...
+    PM.add(P);
+
+    // If we are verifying all of the intermediate steps, add the verifier...
+    if (Verify) PM.add(createVerifierPass());
+
+    // Keep track of how many passes we made for -stopAfterNPasses
+    ++NumPassesCreated;
+  }
+}
+
+
+void AddConfiguredTransformationPasses(PassManager &PM) {
+  if (Verify) PM.add(createVerifierPass());
+
+  addPass(PM, createFunctionResolvingPass());     // Resolve (...) functions
+  addPass(PM, createConstantMergePass());         // Merge dup global constants
+  addPass(PM, createDeadInstEliminationPass());   // Remove Dead code/vars
+  addPass(PM, createRaiseAllocationsPass());      // call %malloc -> malloc inst
+  addPass(PM, createCleanupGCCOutputPass());      // Fix gccisms
+  addPass(PM, createIndVarSimplifyPass());        // Simplify indvars
+
+  // Level raise is eternally buggy/in need of enhancements.  Allow
+  // transformation to stop right before it runs.
+  if (StopAtLevelRaise) return;
+
+  addPass(PM, createRaisePointerReferencesPass());// Eliminate casts
+  addPass(PM, createPromoteMemoryToRegister());   // Promote alloca's to regs
+  addPass(PM, createReassociatePass());           // Reassociate expressions
+  addPass(PM, createInstructionCombiningPass());  // Combine silly seq's
+  addPass(PM, createDeadInstEliminationPass());   // Kill InstCombine remnants
+  addPass(PM, createLICMPass());                  // Hoist loop invariants
+  addPass(PM, createGCSEPass());                  // Remove common subexprs
+  addPass(PM, createSCCPPass());                  // Constant prop with SCCP
+
+  // Run instcombine after redundancy elimination to exploit opportunities
+  // opened up by them.
+  addPass(PM, createInstructionCombiningPass());
+  addPass(PM, createAggressiveDCEPass());          // SSA based 'Agressive DCE'
+  addPass(PM, createCFGSimplificationPass());      // Merge & remove BBs
+}
+
 
 int main(int argc, char **argv) {
   cl::ParseCommandLineOptions(argc, argv, " llvm .s -> .o assembler for GCC\n");
@@ -68,31 +120,16 @@ int main(int argc, char **argv) {
   // a little bit.  Do this now.
   //
   PassManager Passes;
-  Passes.add(createFunctionResolvingPass());      // Resolve (...) functions
-  Passes.add(createConstantMergePass());          // Merge dup global constants
-  Passes.add(createDeadInstEliminationPass());    // Remove Dead code/vars
-  Passes.add(createRaiseAllocationsPass());       // call %malloc -> malloc inst
-  Passes.add(createCleanupGCCOutputPass());       // Fix gccisms
-  Passes.add(createIndVarSimplifyPass());         // Simplify indvars
-  if (!StopAtLevelRaise) {
-    Passes.add(createRaisePointerReferencesPass()); // Eliminate casts
-    Passes.add(createPromoteMemoryToRegister());    // Promote alloca's to regs
-    Passes.add(createReassociatePass());            // Reassociate expressions
-    Passes.add(createInstructionCombiningPass());   // Combine silly seq's
-    Passes.add(createDeadInstEliminationPass());    // Kill InstCombine remnants
-    Passes.add(createLICMPass());                   // Hoist loop invariants
-    Passes.add(createGCSEPass());                   // Remove common subexprs
-    Passes.add(createSCCPPass());                   // Constant prop with SCCP
 
-    // Run instcombine after redundancy elimination to exploit opportunities
-    // opened up by them.
-    Passes.add(createInstructionCombiningPass());
-    Passes.add(createAggressiveDCEPass());          // SSA based 'Agressive DCE'
-    Passes.add(createCFGSimplificationPass());      // Merge & remove BBs
-  }
-  Passes.add(new WriteBytecodePass(&Out));        // Write bytecode to file...
+  // Add all of the transformation passes to the pass manager to do the cleanup
+  // and optimization of the GCC output.
+  //
+  AddConfiguredTransformationPasses(Passes);
+
+  // Write bytecode to file...
+  Passes.add(new WriteBytecodePass(&Out));
 
   // Run our queue of passes all at once now, efficiently.
-  Passes.run(M.get());
+  Passes.run(*M.get());
   return 0;
 }