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, 479 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Transforms/Scalar/SampleProfile.cpp b/contrib/llvm/lib/Transforms/Scalar/SampleProfile.cpp
new file mode 100644
index 0000000..9bcd702
--- /dev/null
+++ b/contrib/llvm/lib/Transforms/Scalar/SampleProfile.cpp
@@ -0,0 +1,479 @@
+//===- SampleProfile.cpp - Incorporate sample profiles into the IR --------===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the SampleProfileLoader transformation. This pass
+// reads a profile file generated by a sampling profiler (e.g. Linux Perf -
+// http://perf.wiki.kernel.org/) and generates IR metadata to reflect the
+// profile information in the given profile.
+//
+// This pass generates branch weight annotations on the IR:
+//
+// - prof: Represents branch weights. This annotation is added to branches
+//      to indicate the weights of each edge coming out of the branch.
+//      The weight of each edge is the weight of the target block for
+//      that edge. The weight of a block B is computed as the maximum
+//      number of samples found in B.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sample-profile"
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/DebugInfo/DIContext.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Regex.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
+
+using namespace llvm;
+
+// Command line option to specify the file to read samples from. This is
+// mainly used for debugging.
+static cl::opt<std::string> SampleProfileFile(
+    "sample-profile-file", cl::init(""), cl::value_desc("filename"),
+    cl::desc("Profile file loaded by -sample-profile"), cl::Hidden);
+
+namespace {
+/// \brief Sample-based profile reader.
+///
+/// Each profile contains sample counts for all the functions
+/// executed. Inside each function, statements are annotated with the
+/// collected samples on all the instructions associated with that
+/// statement.
+///
+/// For this to produce meaningful data, the program needs to be
+/// compiled with some debug information (at minimum, line numbers:
+/// -gline-tables-only). Otherwise, it will be impossible to match IR
+/// instructions to the line numbers collected by the profiler.
+///
+/// From the profile file, we are interested in collecting the
+/// following information:
+///
+/// * A list of functions included in the profile (mangled names).
+///
+/// * For each function F:
+///   1. The total number of samples collected in F.
+///
+///   2. The samples collected at each line in F. To provide some
+///      protection against source code shuffling, line numbers should
+///      be relative to the start of the function.
+class SampleProfile {
+public:
+  SampleProfile(StringRef F) : Profiles(0), Filename(F) {}
+
+  void dump();
+  void loadText();
+  void loadNative() { llvm_unreachable("not implemented"); }
+  bool emitAnnotations(Function &F);
+  void printFunctionProfile(raw_ostream &OS, StringRef FName);
+  void dumpFunctionProfile(StringRef FName);
+
+protected:
+  typedef DenseMap<uint32_t, uint32_t> BodySampleMap;
+  typedef DenseMap<BasicBlock *, uint32_t> BlockWeightMap;
+
+  /// \brief Representation of the runtime profile for a function.
+  ///
+  /// This data structure contains the runtime profile for a given
+  /// function. It contains the total number of samples collected
+  /// in the function and a map of samples collected in every statement.
+  struct FunctionProfile {
+    /// \brief Total number of samples collected inside this function.
+    ///
+    /// Samples are cumulative, they include all the samples collected
+    /// inside this function and all its inlined callees.
+    unsigned TotalSamples;
+
+    // \brief Total number of samples collected at the head of the function.
+    unsigned TotalHeadSamples;
+
+    /// \brief Map line offsets to collected samples.
+    ///
+    /// Each entry in this map contains the number of samples
+    /// collected at the corresponding line offset. All line locations
+    /// are an offset from the start of the function.
+    BodySampleMap BodySamples;
+
+    /// \brief Map basic blocks to their computed weights.
+    ///
+    /// The weight of a basic block is defined to be the maximum
+    /// of all the instruction weights in that block.
+    BlockWeightMap BlockWeights;
+  };
+
+  uint32_t getInstWeight(Instruction &I, unsigned FirstLineno,
+                         BodySampleMap &BodySamples);
+  uint32_t computeBlockWeight(BasicBlock *B, unsigned FirstLineno,
+                              BodySampleMap &BodySamples);
+
+  /// \brief Map every function to its associated profile.
+  ///
+  /// The profile of every function executed at runtime is collected
+  /// in the structure FunctionProfile. This maps function objects
+  /// to their corresponding profiles.
+  StringMap<FunctionProfile> Profiles;
+
+  /// \brief Path name to the file holding the profile data.
+  ///
+  /// The format of this file is defined by each profiler
+  /// independently. If possible, the profiler should have a text
+  /// version of the profile format to be used in constructing test
+  /// cases and debugging.
+  StringRef Filename;
+};
+
+/// \brief Loader class for text-based profiles.
+///
+/// This class defines a simple interface to read text files containing
+/// profiles. It keeps track of line number information and location of
+/// the file pointer. Users of this class are responsible for actually
+/// parsing the lines returned by the readLine function.
+///
+/// TODO - This does not really belong here. It is a generic text file
+/// reader. It should be moved to the Support library and made more general.
+class ExternalProfileTextLoader {
+public:
+  ExternalProfileTextLoader(StringRef F) : Filename(F) {
+    error_code EC;
+    EC = MemoryBuffer::getFile(Filename, Buffer);
+    if (EC)
+      report_fatal_error("Could not open profile file " + Filename + ": " +
+                         EC.message());
+    FP = Buffer->getBufferStart();
+    Lineno = 0;
+  }
+
+  /// \brief Read a line from the mapped file.
+  StringRef readLine() {
+    size_t Length = 0;
+    const char *start = FP;
+    while (FP != Buffer->getBufferEnd() && *FP != '\n') {
+      Length++;
+      FP++;
+    }
+    if (FP != Buffer->getBufferEnd())
+      FP++;
+    Lineno++;
+    return StringRef(start, Length);
+  }
+
+  /// \brief Return true, if we've reached EOF.
+  bool atEOF() const { return FP == Buffer->getBufferEnd(); }
+
+  /// \brief Report a parse error message and stop compilation.
+  void reportParseError(Twine Msg) const {
+    report_fatal_error(Filename + ":" + Twine(Lineno) + ": " + Msg + "\n");
+  }
+
+private:
+  /// \brief Memory buffer holding the text file.
+  OwningPtr<MemoryBuffer> Buffer;
+
+  /// \brief Current position into the memory buffer.
+  const char *FP;
+
+  /// \brief Current line number.
+  int64_t Lineno;
+
+  /// \brief Path name where to the profile file.
+  StringRef Filename;
+};
+
+/// \brief Sample profile pass.
+///
+/// This pass reads profile data from the file specified by
+/// -sample-profile-file and annotates every affected function with the
+/// profile information found in that file.
+class SampleProfileLoader : public FunctionPass {
+public:
+  // Class identification, replacement for typeinfo
+  static char ID;
+
+  SampleProfileLoader(StringRef Name = SampleProfileFile)
+      : FunctionPass(ID), Profiler(0), Filename(Name) {
+    initializeSampleProfileLoaderPass(*PassRegistry::getPassRegistry());
+  }
+
+  virtual bool doInitialization(Module &M);
+
+  void dump() { Profiler->dump(); }
+
+  virtual const char *getPassName() const { return "Sample profile pass"; }
+
+  virtual bool runOnFunction(Function &F);
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesCFG();
+  }
+
+protected:
+  /// \brief Profile reader object.
+  OwningPtr<SampleProfile> Profiler;
+
+  /// \brief Name of the profile file to load.
+  StringRef Filename;
+};
+}
+
+/// \brief Print the function profile for \p FName on stream \p OS.
+///
+/// \param OS Stream to emit the output to.
+/// \param FName Name of the function to print.
+void SampleProfile::printFunctionProfile(raw_ostream &OS, StringRef FName) {
+  FunctionProfile FProfile = Profiles[FName];
+  OS << "Function: " << FName << ", " << FProfile.TotalSamples << ", "
+     << FProfile.TotalHeadSamples << ", " << FProfile.BodySamples.size()
+     << " sampled lines\n";
+  for (BodySampleMap::const_iterator SI = FProfile.BodySamples.begin(),
+                                     SE = FProfile.BodySamples.end();
+       SI != SE; ++SI)
+    OS << "\tline offset: " << SI->first
+       << ", number of samples: " << SI->second << "\n";
+  OS << "\n";
+}
+
+/// \brief Dump the function profile for \p FName.
+///
+/// \param FName Name of the function to print.
+void SampleProfile::dumpFunctionProfile(StringRef FName) {
+  printFunctionProfile(dbgs(), FName);
+}
+
+/// \brief Dump all the function profiles found.
+void SampleProfile::dump() {
+  for (StringMap<FunctionProfile>::const_iterator I = Profiles.begin(),
+                                                  E = Profiles.end();
+       I != E; ++I)
+    dumpFunctionProfile(I->getKey());
+}
+
+/// \brief Load samples from a text file.
+///
+/// The file is divided in two segments:
+///
+/// Symbol table (represented with the string "symbol table")
+///    Number of symbols in the table
+///    symbol 1
+///    symbol 2
+///    ...
+///    symbol N
+///
+/// Function body profiles
+///    function1:total_samples:total_head_samples:number_of_locations
+///    location_offset_1: number_of_samples
+///    location_offset_2: number_of_samples
+///    ...
+///    location_offset_N: number_of_samples
+///
+/// Function names must be mangled in order for the profile loader to
+/// match them in the current translation unit.
+///
+/// Since this is a flat profile, a function that shows up more than
+/// once gets all its samples aggregated across all its instances.
+/// TODO - flat profiles are too imprecise to provide good optimization
+/// opportunities. Convert them to context-sensitive profile.
+///
+/// This textual representation is useful to generate unit tests and
+/// for debugging purposes, but it should not be used to generate
+/// profiles for large programs, as the representation is extremely
+/// inefficient.
+void SampleProfile::loadText() {
+  ExternalProfileTextLoader Loader(Filename);
+
+  // Read the symbol table.
+  StringRef Line = Loader.readLine();
+  if (Line != "symbol table")
+    Loader.reportParseError("Expected 'symbol table', found " + Line);
+  int NumSymbols;
+  Line = Loader.readLine();
+  if (Line.getAsInteger(10, NumSymbols))
+    Loader.reportParseError("Expected a number, found " + Line);
+  for (int I = 0; I < NumSymbols; I++) {
+    StringRef FName = Loader.readLine();
+    FunctionProfile &FProfile = Profiles[FName];
+    FProfile.BodySamples.clear();
+    FProfile.TotalSamples = 0;
+    FProfile.TotalHeadSamples = 0;
+  }
+
+  // Read the profile of each function. Since each function may be
+  // mentioned more than once, and we are collecting flat profiles,
+  // accumulate samples as we parse them.
+  Regex HeadRE("^([^:]+):([0-9]+):([0-9]+):([0-9]+)$");
+  Regex LineSample("^([0-9]+): ([0-9]+)$");
+  while (!Loader.atEOF()) {
+    SmallVector<StringRef, 4> Matches;
+    Line = Loader.readLine();
+    if (!HeadRE.match(Line, &Matches))
+      Loader.reportParseError("Expected 'mangled_name:NUM:NUM:NUM', found " +
+                              Line);
+    assert(Matches.size() == 5);
+    StringRef FName = Matches[1];
+    unsigned NumSamples, NumHeadSamples, NumSampledLines;
+    Matches[2].getAsInteger(10, NumSamples);
+    Matches[3].getAsInteger(10, NumHeadSamples);
+    Matches[4].getAsInteger(10, NumSampledLines);
+    FunctionProfile &FProfile = Profiles[FName];
+    FProfile.TotalSamples += NumSamples;
+    FProfile.TotalHeadSamples += NumHeadSamples;
+    BodySampleMap &SampleMap = FProfile.BodySamples;
+    unsigned I;
+    for (I = 0; I < NumSampledLines && !Loader.atEOF(); I++) {
+      Line = Loader.readLine();
+      if (!LineSample.match(Line, &Matches))
+        Loader.reportParseError("Expected 'NUM: NUM', found " + Line);
+      assert(Matches.size() == 3);
+      unsigned LineOffset, NumSamples;
+      Matches[1].getAsInteger(10, LineOffset);
+      Matches[2].getAsInteger(10, NumSamples);
+      SampleMap[LineOffset] += NumSamples;
+    }
+
+    if (I < NumSampledLines)
+      Loader.reportParseError("Unexpected end of file");
+  }
+}
+
+/// \brief Get the weight for an instruction.
+///
+/// The "weight" of an instruction \p Inst is the number of samples
+/// collected on that instruction at runtime. To retrieve it, we
+/// need to compute the line number of \p Inst relative to the start of its
+/// function. We use \p FirstLineno to compute the offset. We then
+/// look up the samples collected for \p Inst using \p BodySamples.
+///
+/// \param Inst Instruction to query.
+/// \param FirstLineno Line number of the first instruction in the function.
+/// \param BodySamples Map of relative source line locations to samples.
+///
+/// \returns The profiled weight of I.
+uint32_t SampleProfile::getInstWeight(Instruction &Inst, unsigned FirstLineno,
+                                      BodySampleMap &BodySamples) {
+  unsigned LOffset = Inst.getDebugLoc().getLine() - FirstLineno + 1;
+  return BodySamples.lookup(LOffset);
+}
+
+/// \brief Compute the weight of a basic block.
+///
+/// The weight of basic block \p B is the maximum weight of all the
+/// instructions in B.
+///
+/// \param B The basic block to query.
+/// \param FirstLineno The line number for the first line in the
+///     function holding B.
+/// \param BodySamples The map containing all the samples collected in that
+///     function.
+///
+/// \returns The computed weight of B.
+uint32_t SampleProfile::computeBlockWeight(BasicBlock *B, unsigned FirstLineno,
+                                           BodySampleMap &BodySamples) {
+  // If we've computed B's weight before, return it.
+  Function *F = B->getParent();
+  FunctionProfile &FProfile = Profiles[F->getName()];
+  std::pair<BlockWeightMap::iterator, bool> Entry =
+      FProfile.BlockWeights.insert(std::make_pair(B, 0));
+  if (!Entry.second)
+    return Entry.first->second;
+
+  // Otherwise, compute and cache B's weight.
+  uint32_t Weight = 0;
+  for (BasicBlock::iterator I = B->begin(), E = B->end(); I != E; ++I) {
+    uint32_t InstWeight = getInstWeight(*I, FirstLineno, BodySamples);
+    if (InstWeight > Weight)
+      Weight = InstWeight;
+  }
+  Entry.first->second = Weight;
+  return Weight;
+}
+
+/// \brief Generate branch weight metadata for all branches in \p F.
+///
+/// For every branch instruction B in \p F, we compute the weight of the
+/// target block for each of the edges out of B. This is the weight
+/// that we associate with that branch.
+///
+/// TODO - This weight assignment will most likely be wrong if the
+/// target branch has more than two predecessors. This needs to be done
+/// using some form of flow propagation.
+///
+/// Once all the branch weights are computed, we emit the MD_prof
+/// metadata on B using the computed values.
+///
+/// \param F The function to query.
+bool SampleProfile::emitAnnotations(Function &F) {
+  bool Changed = false;
+  FunctionProfile &FProfile = Profiles[F.getName()];
+  unsigned FirstLineno = inst_begin(F)->getDebugLoc().getLine();
+  MDBuilder MDB(F.getContext());
+
+  // Clear the block weights cache.
+  FProfile.BlockWeights.clear();
+
+  // When we find a branch instruction: For each edge E out of the branch,
+  // the weight of E is the weight of the target block.
+  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
+    BasicBlock *B = I;
+    TerminatorInst *TI = B->getTerminator();
+    if (TI->getNumSuccessors() == 1)
+      continue;
+    if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
+      continue;
+
+    SmallVector<uint32_t, 4> Weights;
+    unsigned NSuccs = TI->getNumSuccessors();
+    for (unsigned I = 0; I < NSuccs; ++I) {
+      BasicBlock *Succ = TI->getSuccessor(I);
+      uint32_t Weight =
+          computeBlockWeight(Succ, FirstLineno, FProfile.BodySamples);
+      Weights.push_back(Weight);
+    }
+
+    TI->setMetadata(llvm::LLVMContext::MD_prof,
+                    MDB.createBranchWeights(Weights));
+    Changed = true;
+  }
+
+  return Changed;
+}
+
+char SampleProfileLoader::ID = 0;
+INITIALIZE_PASS(SampleProfileLoader, "sample-profile", "Sample Profile loader",
+                false, false)
+
+bool SampleProfileLoader::runOnFunction(Function &F) {
+  return Profiler->emitAnnotations(F);
+}
+
+bool SampleProfileLoader::doInitialization(Module &M) {
+  Profiler.reset(new SampleProfile(Filename));
+  Profiler->loadText();
+  return true;
+}
+
+FunctionPass *llvm::createSampleProfileLoaderPass() {
+  return new SampleProfileLoader(SampleProfileFile);
+}
+
+FunctionPass *llvm::createSampleProfileLoaderPass(StringRef Name) {
+  return new SampleProfileLoader(Name);
+}