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

1 files changed, 4 insertions, 0 deletions

diff --git a/include/llvm/Analysis/LoopPass.h b/include/llvm/Analysis/LoopPass.h
index 10ff1033dc..6f77d019b6 100644
--- a/include/llvm/Analysis/LoopPass.h
+++ b/include/llvm/Analysis/LoopPass.h
@@ -31,6 +31,10 @@ public:
   explicit LoopPass(intptr_t pid) : Pass(PT_Loop, pid) {}
   explicit LoopPass(void *pid) : Pass(PT_Loop, pid) {}
 
+  /// getPrinterPass - Get a pass to print the function corresponding
+  /// to a Loop.
+  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
+
   // runOnLoop - This method should be implemented by the subclass to perform
   // whatever action is necessary for the specified Loop.
   virtual bool runOnLoop(Loop *L, LPPassManager &LPM) = 0;