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

3 files changed, 108 insertions, 5 deletions

diff --git a/lib/VMCore/Pass.cpp b/lib/VMCore/Pass.cpp
index a782e5a..6093750 100644
--- a/lib/VMCore/Pass.cpp
+++ b/lib/VMCore/Pass.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Module.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/Assembly/PrintModulePass.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PassNameParser.h"
@@ -42,6 +43,11 @@ Pass::~Pass() {
 // Force out-of-line virtual method.
 ModulePass::~ModulePass() { }
 
+Pass *ModulePass::createPrinterPass(raw_ostream &O,
+                                    const std::string &Banner) const {
+  return createPrintModulePass(&O, false, Banner);
+}
+
 PassManagerType ModulePass::getPotentialPassManagerType() const {
   return PMT_ModulePassManager;
 }
@@ -113,6 +119,11 @@ void ImmutablePass::initializePass() {
 // FunctionPass Implementation
 //
 
+Pass *FunctionPass::createPrinterPass(raw_ostream &O,
+                                      const std::string &Banner) const {
+  return createPrintFunctionPass(Banner, &O);
+}
+
 // run - On a module, we run this pass by initializing, runOnFunction'ing once
 // for every function in the module, then by finalizing.
 //
@@ -155,6 +166,13 @@ PassManagerType FunctionPass::getPotentialPassManagerType() const {
 // BasicBlockPass Implementation
 //
 
+Pass *BasicBlockPass::createPrinterPass(raw_ostream &O,
+                                        const std::string &Banner) const {
+  
+  llvm_unreachable("BasicBlockPass printing unsupported.");
+  return 0;
+}
+
 // To run this pass on a function, we simply call runOnBasicBlock once for each
 // function.
 //
diff --git a/lib/VMCore/PassManager.cpp b/lib/VMCore/PassManager.cpp
index 6774cec..6ca35ac0 100644
--- a/lib/VMCore/PassManager.cpp
+++ b/lib/VMCore/PassManager.cpp
@@ -13,6 +13,7 @@
 
 
 #include "llvm/PassManagers.h"
+#include "llvm/Assembly/PrintModulePass.h"
 #include "llvm/Assembly/Writer.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -20,6 +21,7 @@
 #include "llvm/Module.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PassNameParser.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/System/Mutex.h"
 #include "llvm/System/Threading.h"
@@ -55,6 +57,57 @@ PassDebugging("debug-pass", cl::Hidden,
   clEnumVal(Executions, "print pass name before it is executed"),
   clEnumVal(Details   , "print pass details when it is executed"),
                              clEnumValEnd));
+
+typedef llvm::cl::list<const llvm::PassInfo *, bool, PassNameParser>
+PassOptionList;
+
+// Print IR out before/after specified passes.
+static PassOptionList
+PrintBefore("print-before",
+            llvm::cl::desc("Print IR before specified passes"));
+
+static PassOptionList
+PrintAfter("print-after",
+           llvm::cl::desc("Print IR after specified passes"));
+
+static cl::opt<bool>
+PrintBeforeAll("print-before-all",
+               llvm::cl::desc("Print IR before each pass"),
+               cl::init(false));
+static cl::opt<bool>
+PrintAfterAll("print-after-all",
+              llvm::cl::desc("Print IR after each pass"),
+              cl::init(false));
+
+/// This is a helper to determine whether to print IR before or
+/// after a pass.
+
+static bool ShouldPrintBeforeOrAfterPass(Pass *P,
+                                         PassOptionList &PassesToPrint) {
+  for (unsigned i = 0, ie = PassesToPrint.size(); i < ie; ++i) {
+    const llvm::PassInfo *PassInf = PassesToPrint[i];
+    if (PassInf && P->getPassInfo())
+      if (PassInf->getPassArgument() ==
+          P->getPassInfo()->getPassArgument()) {
+        return true;
+      }
+  }
+  return false;
+}
+  
+
+/// This is a utility to check whether a pass should have IR dumped
+/// before it.
+static bool ShouldPrintBeforePass(Pass *P) {
+  return PrintBeforeAll || ShouldPrintBeforeOrAfterPass(P, PrintBefore);
+}
+
+/// This is a utility to check whether a pass should have IR dumped
+/// after it.
+static bool ShouldPrintAfterPass(Pass *P) {
+  return PrintAfterAll || ShouldPrintBeforeOrAfterPass(P, PrintAfter);
+}
+
 } // End of llvm namespace
 
 /// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
@@ -182,6 +235,11 @@ public:
     schedulePass(P);
   }
  
+  /// createPrinterPass - Get a function printer pass. 
+  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const {
+    return createPrintFunctionPass(Banner, &O);
+  }
+
   // Prepare for running an on the fly pass, freeing memory if needed
   // from a previous run.
   void releaseMemoryOnTheFly();
@@ -252,6 +310,11 @@ public:
     }
   }
 
+  /// createPrinterPass - Get a module printer pass. 
+  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const {
+    return createPrintModulePass(&O, false, Banner);
+  }
+
   /// run - Execute all of the passes scheduled for execution.  Keep track of
   /// whether any of the passes modifies the module, and if so, return true.
   bool runOnModule(Module &M);
@@ -331,6 +394,11 @@ public:
     schedulePass(P);
   }
  
+  /// createPrinterPass - Get a module printer pass. 
+  Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const {
+    return createPrintModulePass(&O, false, Banner);
+  }
+
   /// run - Execute all of the passes scheduled for execution.  Keep track of
   /// whether any of the passes modifies the module, and if so, return true.
   bool run(Module &M);
@@ -1208,7 +1276,14 @@ FunctionPassManager::~FunctionPassManager() {
 /// there is no need to delete the pass. (TODO delete passes.)
 /// This implies that all passes MUST be allocated with 'new'.
 void FunctionPassManager::add(Pass *P) { 
+  if (ShouldPrintBeforePass(P))
+    add(P->createPrinterPass(dbgs(), std::string("*** IR Dump Before ")
+                             + P->getPassName() + " ***"));
   FPM->add(P);
+
+  if (ShouldPrintAfterPass(P))
+    add(P->createPrinterPass(dbgs(), std::string("*** IR Dump After ")
+                             + P->getPassName() + " ***"));
 }
 
 /// run - Execute all of the passes scheduled for execution.  Keep
@@ -1519,7 +1594,15 @@ PassManager::~PassManager() {
 /// will be destroyed as well, so there is no need to delete the pass.  This
 /// implies that all passes MUST be allocated with 'new'.
 void PassManager::add(Pass *P) {
+  if (ShouldPrintBeforePass(P))
+    add(P->createPrinterPass(dbgs(), std::string("*** IR Dump Before ")
+                             + P->getPassName() + " ***"));
+
   PM->add(P);
+
+  if (ShouldPrintAfterPass(P))
+    add(P->createPrinterPass(dbgs(), std::string("*** IR Dump After ")
+                             + P->getPassName() + " ***"));
 }
 
 /// run - Execute all of the passes scheduled for execution.  Keep track of
diff --git a/lib/VMCore/PrintModulePass.cpp b/lib/VMCore/PrintModulePass.cpp
index f0f6e7a..2d69dce 100644
--- a/lib/VMCore/PrintModulePass.cpp
+++ b/lib/VMCore/PrintModulePass.cpp
@@ -23,21 +23,22 @@ using namespace llvm;
 namespace {
 
   class PrintModulePass : public ModulePass {
+    std::string Banner;
     raw_ostream *Out;       // raw_ostream to print on
     bool DeleteStream;      // Delete the ostream in our dtor?
   public:
     static char ID;
     PrintModulePass() : ModulePass(&ID), Out(&dbgs()), 
       DeleteStream(false) {}
-    PrintModulePass(raw_ostream *o, bool DS)
-      : ModulePass(&ID), Out(o), DeleteStream(DS) {}
+    PrintModulePass(const std::string &B, raw_ostream *o, bool DS)
+        : ModulePass(&ID), Banner(B), Out(o), DeleteStream(DS) {}
     
     ~PrintModulePass() {
       if (DeleteStream) delete Out;
     }
     
     bool runOnModule(Module &M) {
-      (*Out) << M;
+      (*Out) << Banner << M;
       return false;
     }
     
@@ -85,8 +86,9 @@ Y("print-function","Print function to stderr");
 /// createPrintModulePass - Create and return a pass that writes the
 /// module to the specified raw_ostream.
 ModulePass *llvm::createPrintModulePass(llvm::raw_ostream *OS, 
-                                        bool DeleteStream) {
-  return new PrintModulePass(OS, DeleteStream);
+                                        bool DeleteStream,
+                                        const std::string &Banner) {
+  return new PrintModulePass(Banner, OS, DeleteStream);
 }
 
 /// createPrintFunctionPass - Create and return a pass that prints