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, 471 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Target/SystemZ/SystemZElimCompare.cpp b/contrib/llvm/lib/Target/SystemZ/SystemZElimCompare.cpp
new file mode 100644
index 0000000..b8a77db
--- /dev/null
+++ b/contrib/llvm/lib/Target/SystemZ/SystemZElimCompare.cpp
@@ -0,0 +1,471 @@
+//===-- SystemZElimCompare.cpp - Eliminate comparison instructions --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass:
+// (1) tries to remove compares if CC already contains the required information
+// (2) fuses compares and branches into COMPARE AND BRANCH instructions
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "systemz-elim-compare"
+
+#include "SystemZTargetMachine.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+using namespace llvm;
+
+STATISTIC(BranchOnCounts, "Number of branch-on-count instructions");
+STATISTIC(EliminatedComparisons, "Number of eliminated comparisons");
+STATISTIC(FusedComparisons, "Number of fused compare-and-branch instructions");
+
+namespace {
+  // Represents the references to a particular register in one or more
+  // instructions.
+  struct Reference {
+    Reference()
+      : Def(false), Use(false), IndirectDef(false), IndirectUse(false) {}
+
+    Reference &operator|=(const Reference &Other) {
+      Def |= Other.Def;
+      IndirectDef |= Other.IndirectDef;
+      Use |= Other.Use;
+      IndirectUse |= Other.IndirectUse;
+      return *this;
+    }
+
+    operator bool() const { return Def || Use; }
+
+    // True if the register is defined or used in some form, either directly or
+    // via a sub- or super-register.
+    bool Def;
+    bool Use;
+
+    // True if the register is defined or used indirectly, by a sub- or
+    // super-register.
+    bool IndirectDef;
+    bool IndirectUse;
+  };
+
+  class SystemZElimCompare : public MachineFunctionPass {
+  public:
+    static char ID;
+    SystemZElimCompare(const SystemZTargetMachine &tm)
+      : MachineFunctionPass(ID), TII(0), TRI(0) {}
+
+    virtual const char *getPassName() const {
+      return "SystemZ Comparison Elimination";
+    }
+
+    bool processBlock(MachineBasicBlock *MBB);
+    bool runOnMachineFunction(MachineFunction &F);
+
+  private:
+    Reference getRegReferences(MachineInstr *MI, unsigned Reg);
+    bool convertToBRCT(MachineInstr *MI, MachineInstr *Compare,
+                       SmallVectorImpl<MachineInstr *> &CCUsers);
+    bool convertToLoadAndTest(MachineInstr *MI);
+    bool adjustCCMasksForInstr(MachineInstr *MI, MachineInstr *Compare,
+                               SmallVectorImpl<MachineInstr *> &CCUsers);
+    bool optimizeCompareZero(MachineInstr *Compare,
+                             SmallVectorImpl<MachineInstr *> &CCUsers);
+    bool fuseCompareAndBranch(MachineInstr *Compare,
+                              SmallVectorImpl<MachineInstr *> &CCUsers);
+
+    const SystemZInstrInfo *TII;
+    const TargetRegisterInfo *TRI;
+  };
+
+  char SystemZElimCompare::ID = 0;
+} // end of anonymous namespace
+
+FunctionPass *llvm::createSystemZElimComparePass(SystemZTargetMachine &TM) {
+  return new SystemZElimCompare(TM);
+}
+
+// Return true if CC is live out of MBB.
+static bool isCCLiveOut(MachineBasicBlock *MBB) {
+  for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+         SE = MBB->succ_end(); SI != SE; ++SI)
+    if ((*SI)->isLiveIn(SystemZ::CC))
+      return true;
+  return false;
+}
+
+// Return true if any CC result of MI would reflect the value of subreg
+// SubReg of Reg.
+static bool resultTests(MachineInstr *MI, unsigned Reg, unsigned SubReg) {
+  if (MI->getNumOperands() > 0 &&
+      MI->getOperand(0).isReg() &&
+      MI->getOperand(0).isDef() &&
+      MI->getOperand(0).getReg() == Reg &&
+      MI->getOperand(0).getSubReg() == SubReg)
+    return true;
+
+  switch (MI->getOpcode()) {
+  case SystemZ::LR:
+  case SystemZ::LGR:
+  case SystemZ::LGFR:
+  case SystemZ::LTR:
+  case SystemZ::LTGR:
+  case SystemZ::LTGFR:
+  case SystemZ::LER:
+  case SystemZ::LDR:
+  case SystemZ::LXR:
+  case SystemZ::LTEBR:
+  case SystemZ::LTDBR:
+  case SystemZ::LTXBR:
+    if (MI->getOperand(1).getReg() == Reg &&
+        MI->getOperand(1).getSubReg() == SubReg)
+      return true;
+  }
+
+  return false;
+}
+
+// Describe the references to Reg in MI, including sub- and super-registers.
+Reference SystemZElimCompare::getRegReferences(MachineInstr *MI, unsigned Reg) {
+  Reference Ref;
+  for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
+    const MachineOperand &MO = MI->getOperand(I);
+    if (MO.isReg()) {
+      if (unsigned MOReg = MO.getReg()) {
+        if (MOReg == Reg || TRI->regsOverlap(MOReg, Reg)) {
+          if (MO.isUse()) {
+            Ref.Use = true;
+            Ref.IndirectUse |= (MOReg != Reg);
+          }
+          if (MO.isDef()) {
+            Ref.Def = true;
+            Ref.IndirectDef |= (MOReg != Reg);
+          }
+        }
+      }
+    }
+  }
+  return Ref;
+}
+
+// Compare compares the result of MI against zero.  If MI is an addition
+// of -1 and if CCUsers is a single branch on nonzero, eliminate the addition
+// and convert the branch to a BRCT(G).  Return true on success.
+bool
+SystemZElimCompare::convertToBRCT(MachineInstr *MI, MachineInstr *Compare,
+                                  SmallVectorImpl<MachineInstr *> &CCUsers) {
+  // Check whether we have an addition of -1.
+  unsigned Opcode = MI->getOpcode();
+  unsigned BRCT;
+  if (Opcode == SystemZ::AHI)
+    BRCT = SystemZ::BRCT;
+  else if (Opcode == SystemZ::AGHI)
+    BRCT = SystemZ::BRCTG;
+  else
+    return false;
+  if (MI->getOperand(2).getImm() != -1)
+    return false;
+
+  // Check whether we have a single JLH.
+  if (CCUsers.size() != 1)
+    return false;
+  MachineInstr *Branch = CCUsers[0];
+  if (Branch->getOpcode() != SystemZ::BRC ||
+      Branch->getOperand(0).getImm() != SystemZ::CCMASK_ICMP ||
+      Branch->getOperand(1).getImm() != SystemZ::CCMASK_CMP_NE)
+    return false;
+
+  // We already know that there are no references to the register between
+  // MI and Compare.  Make sure that there are also no references between
+  // Compare and Branch.
+  unsigned SrcReg = Compare->getOperand(0).getReg();
+  MachineBasicBlock::iterator MBBI = Compare, MBBE = Branch;
+  for (++MBBI; MBBI != MBBE; ++MBBI)
+    if (getRegReferences(MBBI, SrcReg))
+      return false;
+
+  // The transformation is OK.  Rebuild Branch as a BRCT(G).
+  MachineOperand Target(Branch->getOperand(2));
+  Branch->RemoveOperand(2);
+  Branch->RemoveOperand(1);
+  Branch->RemoveOperand(0);
+  Branch->setDesc(TII->get(BRCT));
+  MachineInstrBuilder(*Branch->getParent()->getParent(), Branch)
+    .addOperand(MI->getOperand(0))
+    .addOperand(MI->getOperand(1))
+    .addOperand(Target)
+    .addReg(SystemZ::CC, RegState::ImplicitDefine);
+  MI->removeFromParent();
+  return true;
+}
+
+// If MI is a load instruction, try to convert it into a LOAD AND TEST.
+// Return true on success.
+bool SystemZElimCompare::convertToLoadAndTest(MachineInstr *MI) {
+  unsigned Opcode = TII->getLoadAndTest(MI->getOpcode());
+  if (!Opcode)
+    return false;
+
+  MI->setDesc(TII->get(Opcode));
+  MachineInstrBuilder(*MI->getParent()->getParent(), MI)
+    .addReg(SystemZ::CC, RegState::ImplicitDefine);
+  return true;
+}
+
+// The CC users in CCUsers are testing the result of a comparison of some
+// value X against zero and we know that any CC value produced by MI
+// would also reflect the value of X.  Try to adjust CCUsers so that
+// they test the result of MI directly, returning true on success.
+// Leave everything unchanged on failure.
+bool SystemZElimCompare::
+adjustCCMasksForInstr(MachineInstr *MI, MachineInstr *Compare,
+                      SmallVectorImpl<MachineInstr *> &CCUsers) {
+  int Opcode = MI->getOpcode();
+  const MCInstrDesc &Desc = TII->get(Opcode);
+  unsigned MIFlags = Desc.TSFlags;
+
+  // See which compare-style condition codes are available.
+  unsigned ReusableCCMask = SystemZII::getCompareZeroCCMask(MIFlags);
+
+  // For unsigned comparisons with zero, only equality makes sense.
+  unsigned CompareFlags = Compare->getDesc().TSFlags;
+  if (CompareFlags & SystemZII::IsLogical)
+    ReusableCCMask &= SystemZ::CCMASK_CMP_EQ;
+
+  if (ReusableCCMask == 0)
+    return false;
+
+  unsigned CCValues = SystemZII::getCCValues(MIFlags);
+  assert((ReusableCCMask & ~CCValues) == 0 && "Invalid CCValues");
+
+  // Now check whether these flags are enough for all users.
+  SmallVector<MachineOperand *, 4> AlterMasks;
+  for (unsigned int I = 0, E = CCUsers.size(); I != E; ++I) {
+    MachineInstr *MI = CCUsers[I];
+
+    // Fail if this isn't a use of CC that we understand.
+    unsigned Flags = MI->getDesc().TSFlags;
+    unsigned FirstOpNum;
+    if (Flags & SystemZII::CCMaskFirst)
+      FirstOpNum = 0;
+    else if (Flags & SystemZII::CCMaskLast)
+      FirstOpNum = MI->getNumExplicitOperands() - 2;
+    else
+      return false;
+
+    // Check whether the instruction predicate treats all CC values
+    // outside of ReusableCCMask in the same way.  In that case it
+    // doesn't matter what those CC values mean.
+    unsigned CCValid = MI->getOperand(FirstOpNum).getImm();
+    unsigned CCMask = MI->getOperand(FirstOpNum + 1).getImm();
+    unsigned OutValid = ~ReusableCCMask & CCValid;
+    unsigned OutMask = ~ReusableCCMask & CCMask;
+    if (OutMask != 0 && OutMask != OutValid)
+      return false;
+
+    AlterMasks.push_back(&MI->getOperand(FirstOpNum));
+    AlterMasks.push_back(&MI->getOperand(FirstOpNum + 1));
+  }
+
+  // All users are OK.  Adjust the masks for MI.
+  for (unsigned I = 0, E = AlterMasks.size(); I != E; I += 2) {
+    AlterMasks[I]->setImm(CCValues);
+    unsigned CCMask = AlterMasks[I + 1]->getImm();
+    if (CCMask & ~ReusableCCMask)
+      AlterMasks[I + 1]->setImm((CCMask & ReusableCCMask) |
+                                (CCValues & ~ReusableCCMask));
+  }
+
+  // CC is now live after MI.
+  int CCDef = MI->findRegisterDefOperandIdx(SystemZ::CC, false, true, TRI);
+  assert(CCDef >= 0 && "Couldn't find CC set");
+  MI->getOperand(CCDef).setIsDead(false);
+
+  // Clear any intervening kills of CC.
+  MachineBasicBlock::iterator MBBI = MI, MBBE = Compare;
+  for (++MBBI; MBBI != MBBE; ++MBBI)
+    MBBI->clearRegisterKills(SystemZ::CC, TRI);
+
+  return true;
+}
+
+// Return true if Compare is a comparison against zero.
+static bool isCompareZero(MachineInstr *Compare) {
+  switch (Compare->getOpcode()) {
+  case SystemZ::LTEBRCompare:
+  case SystemZ::LTDBRCompare:
+  case SystemZ::LTXBRCompare:
+    return true;
+
+  default:
+    return (Compare->getNumExplicitOperands() == 2 &&
+            Compare->getOperand(1).isImm() &&
+            Compare->getOperand(1).getImm() == 0);
+  }
+}
+
+// Try to optimize cases where comparison instruction Compare is testing
+// a value against zero.  Return true on success and if Compare should be
+// deleted as dead.  CCUsers is the list of instructions that use the CC
+// value produced by Compare.
+bool SystemZElimCompare::
+optimizeCompareZero(MachineInstr *Compare,
+                    SmallVectorImpl<MachineInstr *> &CCUsers) {
+  if (!isCompareZero(Compare))
+    return false;
+
+  // Search back for CC results that are based on the first operand.
+  unsigned SrcReg = Compare->getOperand(0).getReg();
+  unsigned SrcSubReg = Compare->getOperand(0).getSubReg();
+  MachineBasicBlock *MBB = Compare->getParent();
+  MachineBasicBlock::iterator MBBI = Compare, MBBE = MBB->begin();
+  Reference CCRefs;
+  Reference SrcRefs;
+  while (MBBI != MBBE) {
+    --MBBI;
+    MachineInstr *MI = MBBI;
+    if (resultTests(MI, SrcReg, SrcSubReg)) {
+      // Try to remove both MI and Compare by converting a branch to BRCT(G).
+      // We don't care in this case whether CC is modified between MI and
+      // Compare.
+      if (!CCRefs.Use && !SrcRefs && convertToBRCT(MI, Compare, CCUsers)) {
+        BranchOnCounts += 1;
+        return true;
+      }
+      // Try to eliminate Compare by reusing a CC result from MI.
+      if ((!CCRefs && convertToLoadAndTest(MI)) ||
+          (!CCRefs.Def && adjustCCMasksForInstr(MI, Compare, CCUsers))) {
+        EliminatedComparisons += 1;
+        return true;
+      }
+    }
+    SrcRefs |= getRegReferences(MI, SrcReg);
+    if (SrcRefs.Def)
+      return false;
+    CCRefs |= getRegReferences(MI, SystemZ::CC);
+    if (CCRefs.Use && CCRefs.Def)
+      return false;
+  }
+  return false;
+}
+
+// Try to fuse comparison instruction Compare into a later branch.
+// Return true on success and if Compare is therefore redundant.
+bool SystemZElimCompare::
+fuseCompareAndBranch(MachineInstr *Compare,
+                     SmallVectorImpl<MachineInstr *> &CCUsers) {
+  // See whether we have a comparison that can be fused.
+  unsigned FusedOpcode = TII->getCompareAndBranch(Compare->getOpcode(),
+                                                  Compare);
+  if (!FusedOpcode)
+    return false;
+
+  // See whether we have a single branch with which to fuse.
+  if (CCUsers.size() != 1)
+    return false;
+  MachineInstr *Branch = CCUsers[0];
+  if (Branch->getOpcode() != SystemZ::BRC)
+    return false;
+
+  // Make sure that the operands are available at the branch.
+  unsigned SrcReg = Compare->getOperand(0).getReg();
+  unsigned SrcReg2 = (Compare->getOperand(1).isReg() ?
+                      Compare->getOperand(1).getReg() : 0);
+  MachineBasicBlock::iterator MBBI = Compare, MBBE = Branch;
+  for (++MBBI; MBBI != MBBE; ++MBBI)
+    if (MBBI->modifiesRegister(SrcReg, TRI) ||
+        (SrcReg2 && MBBI->modifiesRegister(SrcReg2, TRI)))
+      return false;
+
+  // Read the branch mask and target.
+  MachineOperand CCMask(MBBI->getOperand(1));
+  MachineOperand Target(MBBI->getOperand(2));
+  assert((CCMask.getImm() & ~SystemZ::CCMASK_ICMP) == 0 &&
+         "Invalid condition-code mask for integer comparison");
+
+  // Clear out all current operands.
+  int CCUse = MBBI->findRegisterUseOperandIdx(SystemZ::CC, false, TRI);
+  assert(CCUse >= 0 && "BRC must use CC");
+  Branch->RemoveOperand(CCUse);
+  Branch->RemoveOperand(2);
+  Branch->RemoveOperand(1);
+  Branch->RemoveOperand(0);
+
+  // Rebuild Branch as a fused compare and branch.
+  Branch->setDesc(TII->get(FusedOpcode));
+  MachineInstrBuilder(*Branch->getParent()->getParent(), Branch)
+    .addOperand(Compare->getOperand(0))
+    .addOperand(Compare->getOperand(1))
+    .addOperand(CCMask)
+    .addOperand(Target)
+    .addReg(SystemZ::CC, RegState::ImplicitDefine);
+
+  // Clear any intervening kills of SrcReg and SrcReg2.
+  MBBI = Compare;
+  for (++MBBI; MBBI != MBBE; ++MBBI) {
+    MBBI->clearRegisterKills(SrcReg, TRI);
+    if (SrcReg2)
+      MBBI->clearRegisterKills(SrcReg2, TRI);
+  }
+  FusedComparisons += 1;
+  return true;
+}
+
+// Process all comparison instructions in MBB.  Return true if something
+// changed.
+bool SystemZElimCompare::processBlock(MachineBasicBlock *MBB) {
+  bool Changed = false;
+
+  // Walk backwards through the block looking for comparisons, recording
+  // all CC users as we go.  The subroutines can delete Compare and
+  // instructions before it.
+  bool CompleteCCUsers = !isCCLiveOut(MBB);
+  SmallVector<MachineInstr *, 4> CCUsers;
+  MachineBasicBlock::iterator MBBI = MBB->end();
+  while (MBBI != MBB->begin()) {
+    MachineInstr *MI = --MBBI;
+    if (CompleteCCUsers &&
+        MI->isCompare() &&
+        (optimizeCompareZero(MI, CCUsers) ||
+         fuseCompareAndBranch(MI, CCUsers))) {
+      ++MBBI;
+      MI->removeFromParent();
+      Changed = true;
+      CCUsers.clear();
+      CompleteCCUsers = true;
+      continue;
+    }
+
+    Reference CCRefs(getRegReferences(MI, SystemZ::CC));
+    if (CCRefs.Def) {
+      CCUsers.clear();
+      CompleteCCUsers = !CCRefs.IndirectDef;
+    }
+    if (CompleteCCUsers && CCRefs.Use)
+      CCUsers.push_back(MI);
+  }
+  return Changed;
+}
+
+bool SystemZElimCompare::runOnMachineFunction(MachineFunction &F) {
+  TII = static_cast<const SystemZInstrInfo *>(F.getTarget().getInstrInfo());
+  TRI = &TII->getRegisterInfo();
+
+  bool Changed = false;
+  for (MachineFunction::iterator MFI = F.begin(), MFE = F.end();
+       MFI != MFE; ++MFI)
+    Changed |= processBlock(MFI);
+
+  return Changed;
+}