Add some switches helpful for debugging:

-print-before=<Pass Name>

Dump IR before running pass <Pass Name>.

-print-before-all

Dump IR before running each pass.

-print-after-all

Dump IR after running each pass.

These are helpful when tracking down a miscompilation.  It is easy to
get IR dumps and do diffs on them, etc.

To make this work well, add a new getPrinterPass API to Pass so that
each kind of pass (ModulePass, FunctionPass, etc.) can create a Pass
suitable for dumping out the kind of object the Pass works on.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100143 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 7 insertions, 2 deletions

diff --git a/include/llvm/CodeGen/MachineFunctionPass.h b/include/llvm/CodeGen/MachineFunctionPass.h
index bac110316d..1a2b12972a 100644
--- a/include/llvm/CodeGen/MachineFunctionPass.h
+++ b/include/llvm/CodeGen/MachineFunctionPass.h
@@ -34,6 +34,9 @@ protected:
   explicit MachineFunctionPass(intptr_t ID) : FunctionPass(ID) {}
   explicit MachineFunctionPass(void *ID) : FunctionPass(ID) {}
 
+  /// createPrinterPass - Get a machine function printer pass.
+  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
+
   /// runOnMachineFunction - This method must be overloaded to perform the
   /// desired machine code transformation or analysis.
   ///
diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h
index 911be223b2..d3c2720c15 100644
--- a/include/llvm/CodeGen/Passes.h
+++ b/include/llvm/CodeGen/Passes.h
@@ -21,6 +21,7 @@
 namespace llvm {
 
   class FunctionPass;
+  class MachineFunctionPass;
   class PassInfo;
   class TargetLowering;
   class RegisterCoalescer;
@@ -36,8 +37,9 @@ namespace llvm {
 
   /// MachineFunctionPrinter pass - This pass prints out the machine function to
   /// the given stream, as a debugging tool.
-  FunctionPass *createMachineFunctionPrinterPass(raw_ostream &OS,
-                                                 const std::string &Banner ="");
+  MachineFunctionPass *
+  createMachineFunctionPrinterPass(raw_ostream &OS,
+                                   const std::string &Banner ="");
 
   /// MachineLoopInfo pass - This pass is a loop analysis pass.
   ///