1 files changed, 120 insertions, 0 deletions
diff --git a/tools/bugpoint/CrashDebugger.cpp b/tools/bugpoint/CrashDebugger.cpp
new file mode 100644
index 0000000000..3c4fa2dd47
--- /dev/null
+++ b/tools/bugpoint/CrashDebugger.cpp
@@ -0,0 +1,120 @@
+//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
+//
+// This file defines the bugpoint internals that narrow down compilation crashes
+//
+//===----------------------------------------------------------------------===//
+
+#include "BugDriver.h"
+#include "llvm/Module.h"
+#include "llvm/Bytecode/Writer.h"
+#include "llvm/Pass.h"
+#include <fstream>
+
+/// debugCrash - This method is called when some pass crashes on input.  It
+/// attempts to prune down the testcase to something reasonable, and figure
+/// out exactly which pass is crashing.
+///
+bool BugDriver::debugCrash() {
+  std::cout << "\n*** Debugging optimizer crash!\n";
+
+  // Determine which pass causes the optimizer to crash... using binary search
+  unsigned LastToPass = 0, LastToCrash = PassesToRun.size();
+  while (LastToPass != LastToCrash) {
+    unsigned Mid = (LastToCrash+LastToPass+1) / 2;
+    std::vector<const PassInfo*> P(PassesToRun.begin(),
+                                   PassesToRun.begin()+Mid);
+    std::cout << "Checking to see if the first " << Mid << " passes crash: ";
+
+    if (runPasses(P))
+      LastToCrash = Mid-1;
+    else
+      LastToPass = Mid;
+  }
+
+  // Make sure something crashed.  :)
+  if (LastToCrash >= PassesToRun.size()) {
+    std::cerr << "ERROR: No passes crashed!\n";
+    return true;
+  }
+
+  // Calculate which pass it is that crashes...
+  const PassInfo *CrashingPass = PassesToRun[LastToCrash];
+  
+  std::cout << "\n*** Found crashing pass '-" << CrashingPass->getPassArgument()
+            << "': " << CrashingPass->getPassName() << "\n";
+
+  // Compile the program with just the passes that don't crash.
+  if (LastToPass != 0) {
+    // Don't bother doing this if the first pass crashes...
+    std::vector<const PassInfo*> P(PassesToRun.begin(), 
+                                   PassesToRun.begin()+LastToPass);
+    std::string Filename;
+    std::cout << "Running passes that don't crash to get input for pass: ";
+    if (runPasses(P, Filename)) {
+      std::cerr << "ERROR: Running the first " << LastToPass
+                << " passes crashed this time!\n";
+      return true;
+    }
+
+    // Assuming everything was successful, we now have a valid bytecode file in
+    // OutputName.  Use it for "Program" Instead.
+    delete Program;
+    Program = ParseInputFile(Filename);
+
+    // Delete the file now.
+    removeFile(Filename);
+  }
+
+  return debugPassCrash(CrashingPass);
+}
+
+/// CountFunctions - return the number of non-external functions defined in the
+/// module.
+static unsigned CountFunctions(Module *M) {
+  unsigned N = 0;
+  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
+    if (!I->isExternal())
+      ++N;
+  return N;
+}
+
+/// debugPassCrash - This method is called when the specified pass crashes on
+/// Program as input.  It tries to reduce the testcase to something that still
+/// crashes, but it smaller.
+///
+bool BugDriver::debugPassCrash(const PassInfo *Pass) {
+  EmitProgressBytecode(Pass, "passinput");
+
+  if (CountFunctions(Program) > 1) {
+    // Attempt to reduce the input program down to a single function that still
+    // crashes.
+    //
+    std::cout << "\n*** Attempting to reduce the testcase to one function\n";
+
+    for (Module::iterator I = Program->begin(), E = Program->end(); I != E; ++I)
+      if (!I->isExternal()) {
+        // Extract one function from the module...
+        Module *M = extractFunctionFromModule(I);
+
+        // Make the function the current program...
+        std::swap(Program, M);
+        
+        // Find out if the pass still crashes on this pass...
+        std::cout << "Checking function '" << I->getName() << "': ";
+        if (runPass(Pass)) {
+          // Yup, it does, we delete the old module, and continue trying to
+          // reduce the testcase...
+          delete M;
+
+          EmitProgressBytecode(Pass, "reduced-"+I->getName());
+          break;
+        }
+        
+        // This pass didn't crash on this function, try the next one.
+        delete Program;
+        Program = M;
+      }
+  }
+
+  return false;
+}