Add initial implementation of basic-block tracing instrumentation pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13335 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Instrumentation/TraceBasicBlocks.cpp

@@ -0,0 +1,76 @@
+//===- TraceBasicBlocks.cpp - Insert basic-block trace instrumentation ----===//
+// 
+//                      The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This pass instruments the specified program with calls into a runtime
+// library that cause it to output a trace of basic blocks as a side effect
+// of normal execution.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/iOther.h"
+#include "llvm/iMemory.h"
+#include "llvm/iPHINode.h"
+#include "ProfilingUtils.h"
+#include "Support/Debug.h"
+#include <set>
+using namespace llvm;
+
+namespace {
+  class TraceBasicBlocks : public Pass {
+    bool run(Module &M);
+  };
+
+  RegisterOpt<TraceBasicBlocks> X("trace-basic-blocks",
+                              "Insert instrumentation for basic block tracing");
+}
+
+static void InsertInstrumentationCall (BasicBlock *BB,
+                                       const std::string FnName,
+                                       unsigned BBNumber) {
+  DEBUG (std::cerr << "InsertInstrumentationCall (\"" << BB->getName ()
+                   << "\", \"" << FnName << "\", " << BBNumber << ")\n");
+  Module &M = *BB->getParent ()->getParent ();
+  Function *InstrFn = M.getOrInsertFunction (FnName, Type::VoidTy,
+                                             Type::UIntTy, 0);
+  std::vector<Value*> Args (1);
+  Args[0] = ConstantUInt::get (Type::UIntTy, BBNumber);
+
+  // Insert the call after any alloca or PHI instructions...
+  BasicBlock::iterator InsertPos = BB->begin();
+  while (isa<AllocaInst>(InsertPos) || isa<PHINode>(InsertPos))
+    ++InsertPos;
+
+  Instruction *InstrCall = new CallInst (InstrFn, Args, "", InsertPos);
+}
+
+bool TraceBasicBlocks::run(Module &M) {
+  Function *Main = M.getMainFunction();
+  if (Main == 0) {
+    std::cerr << "WARNING: cannot insert basic-block trace instrumentation"
+              << " into a module with no main function!\n";
+    return false;  // No main, no instrumentation!
+  }
+
+  unsigned BBNumber = 0;
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+      InsertInstrumentationCall (BB, "llvm_basic_block_trace", BBNumber);
+      ++BBNumber;
+    }
+
+  // Add the initialization call to main.
+  InsertProfilingInitCall(Main, "llvm_start_basic_block_tracing");
+  return true;
+}
+