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, 60 insertions, 0 deletions

diff --git a/lib/CodeGen/MachineFunctionPrinterPass.cpp b/lib/CodeGen/MachineFunctionPrinterPass.cpp
new file mode 100644
index 0000000000..547c4febc8
--- /dev/null
+++ b/lib/CodeGen/MachineFunctionPrinterPass.cpp
@@ -0,0 +1,60 @@
+//===-- MachineFunctionPrinterPass.cpp ------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// MachineFunctionPrinterPass implementation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+/// MachineFunctionPrinterPass - This is a pass to dump the IR of a
+/// MachineFunction.
+///
+struct MachineFunctionPrinterPass : public MachineFunctionPass {
+  static char ID;
+
+  raw_ostream &OS;
+  const std::string Banner;
+
+  MachineFunctionPrinterPass(raw_ostream &os, const std::string &banner) 
+      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
+
+  const char *getPassName() const { return "MachineFunction Printer"; }
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesAll();
+    MachineFunctionPass::getAnalysisUsage(AU);
+  }
+
+  bool runOnMachineFunction(MachineFunction &MF) {
+    OS << "# " << Banner << ":\n";
+    MF.print(OS);
+    return false;
+  }
+};
+
+char MachineFunctionPrinterPass::ID = 0;
+}
+
+namespace llvm {
+/// Returns a newly-created MachineFunction Printer pass. The
+/// default banner is empty.
+///
+MachineFunctionPass *createMachineFunctionPrinterPass(raw_ostream &OS,
+                                                      const std::string &Banner){
+  return new MachineFunctionPrinterPass(OS, Banner);
+}
+
+}