Make bugpoint *much* more powerful, giving it the capability to delete instructions
out of a large function to reduce it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5408 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/bugpoint/BugDriver.h b/tools/bugpoint/BugDriver.h
index 6398366..3dbb84d 100644
--- a/tools/bugpoint/BugDriver.h
+++ b/tools/bugpoint/BugDriver.h
@@ -15,6 +15,7 @@
class Module;
class Function;
class AbstractInterpreter;
+class Instruction;
class BugDriver {
const std::string ToolName; // Name of bugpoint
@@ -117,6 +118,13 @@
///
Module *extractFunctionFromModule(Function *F) const;
+ /// deleteInstructionFromProgram - This method clones the current Program and
+ /// deletes the specified instruction from the cloned module. It then runs a
+ /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code
+ /// which depends on the value. The modified module is then returned.
+ ///
+ Module *deleteInstructionFromProgram(Instruction *I, unsigned Simp) const;
+
/// initializeExecutionEnvironment - This method is used to set up the
/// environment for executing LLVM programs.
///
diff --git a/tools/bugpoint/CrashDebugger.cpp b/tools/bugpoint/CrashDebugger.cpp
index c69ca45..daf3915 100644
--- a/tools/bugpoint/CrashDebugger.cpp
+++ b/tools/bugpoint/CrashDebugger.cpp
@@ -114,18 +114,63 @@
delete Program;
Program = M;
}
+
+ if (CountFunctions(Program) > 1) {
+ std::cout << "\n*** Couldn't reduce testcase to one function.\n"
+ << " Attempting to remove individual functions.\n";
+ std::cout << "XXX Individual function removal unimplemented!\n";
+ }
}
- if (CountFunctions(Program) > 1) {
- std::cout << "\n*** Couldn't reduce testcase to one function.\n"
- << " Attempting to remove individual functions.\n";
- std::cout << "XXX Individual function removal unimplemented!\n";
- }
+ // FIXME: This should attempt to delete entire basic blocks at a time to speed
+ // up convergence...
- // Now that we have deleted the functions that are unneccesary for the
- // program, try to remove instructions and basic blocks that are not neccesary
- // to cause the crash.
- //
+ unsigned Simplification = 4;
+ do {
+ --Simplification;
+ std::cout << "\n*** Attempting to reduce testcase by deleting instruc"
+ << "tions: Simplification Level #" << Simplification << "\n";
+
+ // Now that we have deleted the functions that are unneccesary for the
+ // program, try to remove instructions that are not neccesary to cause the
+ // crash. To do this, we loop through all of the instructions in the
+ // remaining functions, deleting them (replacing any values produced with
+ // nulls), and then running ADCE and SimplifyCFG. If the transformed input
+ // still triggers failure, keep deleting until we cannot trigger failure
+ // anymore.
+ //
+ TryAgain:
+
+ // Loop over all of the (non-terminator) instructions remaining in the
+ // function, attempting to delete them.
+ for (Module::iterator FI = Program->begin(), E = Program->end();
+ FI != E; ++FI)
+ if (!FI->isExternal()) {
+ for (Function::iterator BI = FI->begin(), E = FI->end(); BI != E; ++BI)
+ for (BasicBlock::iterator I = BI->begin(), E = --BI->end();
+ I != E; ++I) {
+ Module *M = deleteInstructionFromProgram(I, Simplification);
+
+ // Make the function the current program...
+ std::swap(Program, M);
+
+ // Find out if the pass still crashes on this pass...
+ std::cout << "Checking instruction '" << I->getName() << "': ";
+ if (runPass(Pass)) {
+ // Yup, it does, we delete the old module, and continue trying to
+ // reduce the testcase...
+ EmitProgressBytecode(Pass, "reduced-" + I->getName());
+ delete M;
+ goto TryAgain; // I wish I had a multi-level break here!
+ }
+
+ // This pass didn't crash without this instruction, try the next
+ // one.
+ delete Program;
+ Program = M;
+ }
+ }
+ } while (Simplification);
return false;
}
diff --git a/tools/bugpoint/ExtractFunction.cpp b/tools/bugpoint/ExtractFunction.cpp
index 76b2258..9b5440c 100644
--- a/tools/bugpoint/ExtractFunction.cpp
+++ b/tools/bugpoint/ExtractFunction.cpp
@@ -9,7 +9,10 @@
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Type.h"
+#include "llvm/Constant.h"
/// extractFunctionFromModule - This method is used to extract the specified
/// (non-external) function from the current program, slim down the module, and
@@ -19,16 +22,62 @@
Module *Result = CloneModule(Program);
// Translate from the old module to the new copied module...
- F = Result->getFunction(F->getName(), F->getFunctionType());
+ Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
+ std::advance(RFI, std::distance(Program->begin(), Module::iterator(F)));
// In addition to just parsing the input from GCC, we also want to spiff it up
// a little bit. Do this now.
//
PassManager Passes;
- Passes.add(createFunctionExtractionPass(F)); // Extract the function
+ Passes.add(createFunctionExtractionPass(RFI)); // Extract the function
Passes.add(createGlobalDCEPass()); // Delete unreachable globals
Passes.add(createFunctionResolvingPass()); // Delete prototypes
Passes.add(createDeadTypeEliminationPass()); // Remove dead types...
Passes.run(*Result);
return Result;
}
+
+
+/// deleteInstructionFromProgram - This method clones the current Program and
+/// deletes the specified instruction from the cloned module. It then runs a
+/// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
+/// depends on the value. The modified module is then returned.
+///
+Module *BugDriver::deleteInstructionFromProgram(Instruction *I,
+ unsigned Simplification) const {
+ Module *Result = CloneModule(Program);
+
+ BasicBlock *PBB = I->getParent();
+ Function *PF = PBB->getParent();
+
+ Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
+ std::advance(RFI, std::distance(Program->begin(), Module::iterator(PF)));
+
+ Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
+ std::advance(RBI, std::distance(PF->begin(), Function::iterator(PBB)));
+
+ BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
+ std::advance(RI, std::distance(PBB->begin(), BasicBlock::iterator(I)));
+ I = RI; // Got the corresponding instruction!
+
+ // If this instruction produces a value, replace any users with null values
+ if (I->getType() != Type::VoidTy)
+ I->replaceAllUsesWith(Constant::getNullValue(I->getType()));
+
+ // Remove the instruction from the program.
+ I->getParent()->getInstList().erase(I);
+
+ // In addition to just parsing the input from GCC, we also want to spiff it up
+ // a little bit. Do this now.
+ //
+ PassManager Passes;
+ if (Simplification > 2)
+ Passes.add(createAggressiveDCEPass()); // Remove dead code...
+ //Passes.add(createInstructionCombiningPass());
+ if (Simplification > 1)
+ Passes.add(createDeadCodeEliminationPass());
+ if (Simplification)
+ Passes.add(createCFGSimplificationPass()); // Delete dead control flow
+ Passes.run(*Result);
+ return Result;
+}