MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 19 insertions, 175 deletions

diff --git a/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index c243d34..8371f6d 100644
--- a/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/contrib/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -41,187 +41,31 @@ using namespace llvm;
 STATISTIC(NumSimpl, "Number of blocks simplified");
 
 namespace {
-  struct CFGSimplifyPass : public FunctionPass {
-    static char ID; // Pass identification, replacement for typeid
-    CFGSimplifyPass() : FunctionPass(ID) {
-      initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
-    }
-
-    virtual bool runOnFunction(Function &F);
+struct CFGSimplifyPass : public FunctionPass {
+  static char ID; // Pass identification, replacement for typeid
+  CFGSimplifyPass() : FunctionPass(ID) {
+    initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
+  }
+  virtual bool runOnFunction(Function &F);
 
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<TargetTransformInfo>();
-    }
-  };
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.addRequired<TargetTransformInfo>();
+  }
+};
 }
 
 char CFGSimplifyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(CFGSimplifyPass, "simplifycfg", "Simplify the CFG",
-                      false, false)
+INITIALIZE_PASS_BEGIN(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
+                      false)
 INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
-INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG",
-                    false, false)
+INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
+                    false)
 
 // Public interface to the CFGSimplification pass
 FunctionPass *llvm::createCFGSimplificationPass() {
   return new CFGSimplifyPass();
 }
 
-/// changeToUnreachable - Insert an unreachable instruction before the specified
-/// instruction, making it and the rest of the code in the block dead.
-static void changeToUnreachable(Instruction *I, bool UseLLVMTrap) {
-  BasicBlock *BB = I->getParent();
-  // Loop over all of the successors, removing BB's entry from any PHI
-  // nodes.
-  for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-    (*SI)->removePredecessor(BB);
-
-  // Insert a call to llvm.trap right before this.  This turns the undefined
-  // behavior into a hard fail instead of falling through into random code.
-  if (UseLLVMTrap) {
-    Function *TrapFn =
-      Intrinsic::getDeclaration(BB->getParent()->getParent(), Intrinsic::trap);
-    CallInst *CallTrap = CallInst::Create(TrapFn, "", I);
-    CallTrap->setDebugLoc(I->getDebugLoc());
-  }
-  new UnreachableInst(I->getContext(), I);
-
-  // All instructions after this are dead.
-  BasicBlock::iterator BBI = I, BBE = BB->end();
-  while (BBI != BBE) {
-    if (!BBI->use_empty())
-      BBI->replaceAllUsesWith(UndefValue::get(BBI->getType()));
-    BB->getInstList().erase(BBI++);
-  }
-}
-
-/// changeToCall - Convert the specified invoke into a normal call.
-static void changeToCall(InvokeInst *II) {
-  SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
-  CallInst *NewCall = CallInst::Create(II->getCalledValue(), Args, "", II);
-  NewCall->takeName(II);
-  NewCall->setCallingConv(II->getCallingConv());
-  NewCall->setAttributes(II->getAttributes());
-  NewCall->setDebugLoc(II->getDebugLoc());
-  II->replaceAllUsesWith(NewCall);
-
-  // Follow the call by a branch to the normal destination.
-  BranchInst::Create(II->getNormalDest(), II);
-
-  // Update PHI nodes in the unwind destination
-  II->getUnwindDest()->removePredecessor(II->getParent());
-  II->eraseFromParent();
-}
-
-static bool markAliveBlocks(BasicBlock *BB,
-                            SmallPtrSet<BasicBlock*, 128> &Reachable) {
-
-  SmallVector<BasicBlock*, 128> Worklist;
-  Worklist.push_back(BB);
-  Reachable.insert(BB);
-  bool Changed = false;
-  do {
-    BB = Worklist.pop_back_val();
-
-    // Do a quick scan of the basic block, turning any obviously unreachable
-    // instructions into LLVM unreachable insts.  The instruction combining pass
-    // canonicalizes unreachable insts into stores to null or undef.
-    for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
-      if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
-        if (CI->doesNotReturn()) {
-          // If we found a call to a no-return function, insert an unreachable
-          // instruction after it.  Make sure there isn't *already* one there
-          // though.
-          ++BBI;
-          if (!isa<UnreachableInst>(BBI)) {
-            // Don't insert a call to llvm.trap right before the unreachable.
-            changeToUnreachable(BBI, false);
-            Changed = true;
-          }
-          break;
-        }
-      }
-
-      // Store to undef and store to null are undefined and used to signal that
-      // they should be changed to unreachable by passes that can't modify the
-      // CFG.
-      if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) {
-        // Don't touch volatile stores.
-        if (SI->isVolatile()) continue;
-
-        Value *Ptr = SI->getOperand(1);
-
-        if (isa<UndefValue>(Ptr) ||
-            (isa<ConstantPointerNull>(Ptr) &&
-             SI->getPointerAddressSpace() == 0)) {
-          changeToUnreachable(SI, true);
-          Changed = true;
-          break;
-        }
-      }
-    }
-
-    // Turn invokes that call 'nounwind' functions into ordinary calls.
-    if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
-      Value *Callee = II->getCalledValue();
-      if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
-        changeToUnreachable(II, true);
-        Changed = true;
-      } else if (II->doesNotThrow()) {
-        if (II->use_empty() && II->onlyReadsMemory()) {
-          // jump to the normal destination branch.
-          BranchInst::Create(II->getNormalDest(), II);
-          II->getUnwindDest()->removePredecessor(II->getParent());
-          II->eraseFromParent();
-        } else
-          changeToCall(II);
-        Changed = true;
-      }
-    }
-
-    Changed |= ConstantFoldTerminator(BB, true);
-    for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-      if (Reachable.insert(*SI))
-        Worklist.push_back(*SI);
-  } while (!Worklist.empty());
-  return Changed;
-}
-
-/// removeUnreachableBlocksFromFn - Remove blocks that are not reachable, even
-/// if they are in a dead cycle.  Return true if a change was made, false
-/// otherwise.
-static bool removeUnreachableBlocksFromFn(Function &F) {
-  SmallPtrSet<BasicBlock*, 128> Reachable;
-  bool Changed = markAliveBlocks(F.begin(), Reachable);
-
-  // If there are unreachable blocks in the CFG...
-  if (Reachable.size() == F.size())
-    return Changed;
-
-  assert(Reachable.size() < F.size());
-  NumSimpl += F.size()-Reachable.size();
-
-  // Loop over all of the basic blocks that are not reachable, dropping all of
-  // their internal references...
-  for (Function::iterator BB = ++F.begin(), E = F.end(); BB != E; ++BB) {
-    if (Reachable.count(BB))
-      continue;
-
-    for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-      if (Reachable.count(*SI))
-        (*SI)->removePredecessor(BB);
-    BB->dropAllReferences();
-  }
-
-  for (Function::iterator I = ++F.begin(); I != F.end();)
-    if (!Reachable.count(I))
-      I = F.getBasicBlockList().erase(I);
-    else
-      ++I;
-
-  return true;
-}
-
 /// mergeEmptyReturnBlocks - If we have more than one empty (other than phi
 /// node) return blocks, merge them together to promote recursive block merging.
 static bool mergeEmptyReturnBlocks(Function &F) {
@@ -326,7 +170,7 @@ static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
 bool CFGSimplifyPass::runOnFunction(Function &F) {
   const TargetTransformInfo &TTI = getAnalysis<TargetTransformInfo>();
   const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
-  bool EverChanged = removeUnreachableBlocksFromFn(F);
+  bool EverChanged = removeUnreachableBlocks(F);
   EverChanged |= mergeEmptyReturnBlocks(F);
   EverChanged |= iterativelySimplifyCFG(F, TTI, TD);
 
@@ -334,16 +178,16 @@ bool CFGSimplifyPass::runOnFunction(Function &F) {
   if (!EverChanged) return false;
 
   // iterativelySimplifyCFG can (rarely) make some loops dead.  If this happens,
-  // removeUnreachableBlocksFromFn is needed to nuke them, which means we should
+  // removeUnreachableBlocks is needed to nuke them, which means we should
   // iterate between the two optimizations.  We structure the code like this to
   // avoid reruning iterativelySimplifyCFG if the second pass of
-  // removeUnreachableBlocksFromFn doesn't do anything.
-  if (!removeUnreachableBlocksFromFn(F))
+  // removeUnreachableBlocks doesn't do anything.
+  if (!removeUnreachableBlocks(F))
     return true;
 
   do {
     EverChanged = iterativelySimplifyCFG(F, TTI, TD);
-    EverChanged |= removeUnreachableBlocksFromFn(F);
+    EverChanged |= removeUnreachableBlocks(F);
   } while (EverChanged);
 
   return true;