1 files changed, 140 insertions, 0 deletions
diff --git a/lib/Analysis/AssumptionCache.cpp b/lib/Analysis/AssumptionCache.cpp
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--- /dev/null
+++ b/lib/Analysis/AssumptionCache.cpp
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+//===- AssumptionCache.cpp - Cache finding @llvm.assume calls -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a pass that keeps track of @llvm.assume intrinsics in
+// the functions of a module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+using namespace llvm::PatternMatch;
+
+void AssumptionCache::scanFunction() {
+  assert(!Scanned && "Tried to scan the function twice!");
+  assert(AssumeHandles.empty() && "Already have assumes when scanning!");
+
+  // Go through all instructions in all blocks, add all calls to @llvm.assume
+  // to this cache.
+  for (BasicBlock &B : F)
+    for (Instruction &II : B)
+      if (match(&II, m_Intrinsic<Intrinsic::assume>()))
+        AssumeHandles.push_back(&II);
+
+  // Mark the scan as complete.
+  Scanned = true;
+}
+
+void AssumptionCache::registerAssumption(CallInst *CI) {
+  assert(match(CI, m_Intrinsic<Intrinsic::assume>()) &&
+         "Registered call does not call @llvm.assume");
+
+  // If we haven't scanned the function yet, just drop this assumption. It will
+  // be found when we scan later.
+  if (!Scanned)
+    return;
+
+  AssumeHandles.push_back(CI);
+
+#ifndef NDEBUG
+  assert(CI->getParent() &&
+         "Cannot register @llvm.assume call not in a basic block");
+  assert(&F == CI->getParent()->getParent() &&
+         "Cannot register @llvm.assume call not in this function");
+
+  // We expect the number of assumptions to be small, so in an asserts build
+  // check that we don't accumulate duplicates and that all assumptions point
+  // to the same function.
+  SmallPtrSet<Value *, 16> AssumptionSet;
+  for (auto &VH : AssumeHandles) {
+    if (!VH)
+      continue;
+
+    assert(&F == cast<Instruction>(VH)->getParent()->getParent() &&
+           "Cached assumption not inside this function!");
+    assert(match(cast<CallInst>(VH), m_Intrinsic<Intrinsic::assume>()) &&
+           "Cached something other than a call to @llvm.assume!");
+    assert(AssumptionSet.insert(VH).second &&
+           "Cache contains multiple copies of a call!");
+  }
+#endif
+}
+
+char AssumptionAnalysis::PassID;
+
+PreservedAnalyses AssumptionPrinterPass::run(Function &F,
+                                             AnalysisManager<Function> *AM) {
+  AssumptionCache &AC = AM->getResult<AssumptionAnalysis>(F);
+
+  OS << "Cached assumptions for function: " << F.getName() << "\n";
+  for (auto &VH : AC.assumptions())
+    if (VH)
+      OS << "  " << *cast<CallInst>(VH)->getArgOperand(0) << "\n";
+
+  return PreservedAnalyses::all();
+}
+
+void AssumptionCacheTracker::FunctionCallbackVH::deleted() {
+  auto I = ACT->AssumptionCaches.find_as(cast<Function>(getValPtr()));
+  if (I != ACT->AssumptionCaches.end())
+    ACT->AssumptionCaches.erase(I);
+  // 'this' now dangles!
+}
+
+AssumptionCache &AssumptionCacheTracker::getAssumptionCache(Function &F) {
+  // We probe the function map twice to try and avoid creating a value handle
+  // around the function in common cases. This makes insertion a bit slower,
+  // but if we have to insert we're going to scan the whole function so that
+  // shouldn't matter.
+  auto I = AssumptionCaches.find_as(&F);
+  if (I != AssumptionCaches.end())
+    return *I->second;
+
+  // Ok, build a new cache by scanning the function, insert it and the value
+  // handle into our map, and return the newly populated cache.
+  auto IP = AssumptionCaches.insert(std::make_pair(
+      FunctionCallbackVH(&F, this), llvm::make_unique<AssumptionCache>(F)));
+  assert(IP.second && "Scanning function already in the map?");
+  return *IP.first->second;
+}
+
+void AssumptionCacheTracker::verifyAnalysis() const {
+#ifndef NDEBUG
+  SmallPtrSet<const CallInst *, 4> AssumptionSet;
+  for (const auto &I : AssumptionCaches) {
+    for (auto &VH : I.second->assumptions())
+      if (VH)
+        AssumptionSet.insert(cast<CallInst>(VH));
+
+    for (const BasicBlock &B : cast<Function>(*I.first))
+      for (const Instruction &II : B)
+        if (match(&II, m_Intrinsic<Intrinsic::assume>()))
+          assert(AssumptionSet.count(cast<CallInst>(&II)) &&
+                 "Assumption in scanned function not in cache");
+  }
+#endif
+}
+
+AssumptionCacheTracker::AssumptionCacheTracker() : ImmutablePass(ID) {
+  initializeAssumptionCacheTrackerPass(*PassRegistry::getPassRegistry());
+}
+
+AssumptionCacheTracker::~AssumptionCacheTracker() {}
+
+INITIALIZE_PASS(AssumptionCacheTracker, "assumption-cache-tracker",
+                "Assumption Cache Tracker", false, true)
+char AssumptionCacheTracker::ID = 0;