Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

  Correct lld llvm-tblgen dependency file name

MFC r309169:

  Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
  and llvm-lto.  The mergeinfo confuses Subversion enormously, and these
  directories will just use the mergeinfo for llvm itself.

MFC r312765:

  Pull in r276136 from upstream llvm trunk (by Wei Mi):

    Use ValueOffsetPair to enhance value reuse during SCEV expansion.

    In D12090, the ExprValueMap was added to reuse existing value during
    SCEV expansion. However, const folding and sext/zext distribution can
    make the reuse still difficult.

    A simplified case is: suppose we know S1 expands to V1 in
    ExprValueMap, and
      S1 = S2 + C_a
      S3 = S2 + C_b
    where C_a and C_b are different SCEVConstants. Then we'd like to
    expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
    helpful when S2 is a complex SCEV expr and S2 has no entry in
    ExprValueMap, which is usually caused by the fact that S3 is
    generated from S1 after const folding.

    In order to do that, we represent ExprValueMap as a mapping from SCEV
    to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
    into the ExprValueMap when we create SCEV for V1. When S3 is
    expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
    C_a} in the map, then expand S3 to V1 - C_a + C_b.

    Differential Revision: https://reviews.llvm.org/D21313

  This should fix assertion failures when building OpenCV >= 3.1.

  PR:		215649

MFC r312831:

  Revert r312765 for now, since it causes assertions when building
  lang/spidermonkey24.

  Reported by:	antoine
  PR:		215649

MFC r316511 (by jhb):

  Add an implementation of __ffssi2() derived from __ffsdi2().

  Newer versions of GCC include an __ffssi2() symbol in libgcc and the
  compiler can emit calls to it in generated code.  This is true for at
  least GCC 6.2 when compiling world for mips and mips64.

  Reviewed by:	jmallett, dim
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

  [libcompiler-rt] add bswapdi2/bswapsi2

  This is required for mips gcc 6.3 userland to build/run.

  Reviewed by:	emaste, dim
  Approved by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

  lldb: map TRAP_CAP to a trace trap

  In the absense of a more specific handler for TRAP_CAP (generated by
  ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
  trap.

  Example usage (testing the bug in PR219173):

  % proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
  ...
  (lldb) run
  Process 12980 launching
  Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
  Process 12980 stopped
  * thread #1, stop reason = trace
      frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
  ...

  In the future we should have LLDB control the trapcap procctl itself
  (as it does with ASLR), as well as report a specific stop reason.
  This change eliminates an assertion failure from LLDB for now.

MFC r319796:

  Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

  lld: ELF: Fix ICF crash on absolute symbol relocations.

  If two sections contained relocations to absolute symbols with the same
  value we would crash when trying to access their sections. Add a check that
  both symbols point to sections before accessing their sections, and treat
  absolute symbols as equal if their values are equal.

  Obtained from:	LLD commit r292578

MFC r319918:

  Revert r319796 for now, it can cause undefined references when linking
  in some circumstances.

  Reported by:	Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

  lld: Add armelf emulation mode

  Obtained from:	LLD r305375

MFC r321369:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 (trunk r308421).  Upstream has branched for the 5.0.0 release,
  which should be in about a month.  Please report bugs and regressions,
  so we can get them into the release.

  Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
  support to build; see UPDATING for more information.

MFC r321420:

  Add a few more object files to liblldb, which should solve errors when
  linking the lldb executable in some cases.  In particular, when the
  -ffunction-sections -fdata-sections options are turned off, or
  ineffective.

  Reported by:	Shawn Webb, Mark Millard

MFC r321433:

  Cleanup stale Options.inc files from the previous libllvm build for
  clang 4.0.0.  Otherwise, these can get included before the two newly
  generated ones (which are different) for clang 5.0.0.

  Reported by:	Mark Millard

MFC r321439 (by bdrewery):

  Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

  The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
  sysroot) and are only ever included from a compilation.  So using
  a beforebuild target here removes the file before the compilation
  tries to include it.

MFC r321664:

  Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

    [CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

    This avoids excessive compile time. The case I'm looking at is
    Function.cpp from an old version of LLVM that still had the giant
    memcmp string matcher in it. Before r308322 this compiled in about 2
    minutes, after it, clang takes infinite* time to compile it. With
    this patch we're at 5 min, which is still bad but this is a
    pathological case.

    The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
    for user scanning. It's probably too high, but does the job and is
    very unlikely to regress anything.

    Fixes PR33900.

    * I'm impatient and aborted after 15 minutes, on the bug report it was
      killed after 2h.

  Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

    [X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

    D35067/rL308322 attempted to support up to 4 load pairs for memcmp
    inlining which resulted in regressions for some optimized libc memcmp
    implementations (PR33914).

    Until we can match these more optimal cases, this patch reduces the
    memcmp expansion to a maximum of 2 load pairs (which matches what we
    do for -Os).

    This patch should be considered for the 5.0.0 release branch as well

    Differential Revision: https://reviews.llvm.org/D35830

  These fix a hang (or extremely long compile time) when building older
  LLVM ports.

  Reported by:    antoine
  PR:             219139

MFC r321719:

  Pull in r309503 from upstream clang trunk (by Richard Smith):

    PR33902: Invalidate line number cache when adding more text to
    existing buffer.

    This led to crashes as the line number cache would report a bogus
    line number for a line of code, and we'd try to find a nonexistent
    column within the line when printing diagnostics.

  This fixes an assertion when building the graphics/champlain port.

  Reported by:	antoine, kwm
  PR:		219139

MFC r321723:

  Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
  upstream release_50 branch.  This is just after upstream's 5.0.0-rc1.

MFC r322320:

  Upgrade our copies of clang, llvm and libc++ to r310316 from the
  upstream release_50 branch.

MFC r322326 (by emaste):

  lldb: Make i386-*-freebsd expression work on JIT path

  * Enable i386 ABI creation for freebsd
  * Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
    syscall
  * Unlike linux, the last argument of mmap is actually 64-bit(off_t).
    This requires us to push an additional word for the higher order bits.
  * Prior to this change, ktrace dump will show mmap failures due to
    invalid argument coming from the 6th mmap argument.

  Submitted by:	Karnajit Wangkhem
  Differential Revision:	https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

  lldb: Report inferior signals as signals, not exceptions, on FreeBSD

  This is the FreeBSD equivalent of LLVM r238549.

  This serves 2 purposes:

  * LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
    SIGFPE the way it is suppose to be handled. Prior to this fix these
    signals will neither create a coredump, nor exit from the debugger
    or work for signal handling scenario.
  * eInvalidCrashReason need not report "unknown crash reason" if we have
    a valid si_signo

  llvm.org/pr23699

  Patch by Karnajit Wangkhem

  Differential Revision:  https://reviews.llvm.org/D35223

  Submitted by:	Karnajit Wangkhem
  Obtained from:	LLVM r310591

MFC r322474 (by emaste):

  lld: Add `-z muldefs` option.

  Obtained from:	LLVM r310757

MFC r322740:

  Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
  upstream release_50 branch.

MFC r322855:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
  the upstream release_50 branch.

  As of this version, lib/msun's trig test should also work correctly
  again (see bug 220989 for more information).

  PR:		220989

MFC r323112:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
  the upstream release_50 branch.  This corresponds to 5.0.0 rc4.

  As of this version, the cad/stepcode port should now compile in a more
  reasonable time on i386 (see bug 221836 for more information).

  PR:		221836

MFC r323245:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 release (upstream r312559).

  Release notes for llvm, clang and lld will be available here soon:
  <http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

  Relnotes:	yes

(cherry picked from commit 12cd91cf4c6b96a24427c0de5374916f2808d263)

1 files changed, 678 insertions, 92 deletions

diff --git a/contrib/llvm/lib/Passes/PassBuilder.cpp b/contrib/llvm/lib/Passes/PassBuilder.cpp
index 2994a07..9e0cf27 100644
--- a/contrib/llvm/lib/Passes/PassBuilder.cpp
+++ b/contrib/llvm/lib/Passes/PassBuilder.cpp
@@ -39,6 +39,7 @@
 #include "llvm/Analysis/LoopAccessAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
+#include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/ModuleSummaryAnalysis.h"
 #include "llvm/Analysis/OptimizationDiagnosticInfo.h"
 #include "llvm/Analysis/PostDominators.h"
@@ -61,6 +62,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/GCOVProfiler.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
+#include "llvm/Transforms/IPO/ArgumentPromotion.h"
 #include "llvm/Transforms/IPO/ConstantMerge.h"
 #include "llvm/Transforms/IPO/CrossDSOCFI.h"
 #include "llvm/Transforms/IPO/DeadArgumentElimination.h"
@@ -104,9 +106,12 @@
 #include "llvm/Transforms/Scalar/LoopDistribute.h"
 #include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
 #include "llvm/Transforms/Scalar/LoopInstSimplify.h"
+#include "llvm/Transforms/Scalar/LoopLoadElimination.h"
 #include "llvm/Transforms/Scalar/LoopPassManager.h"
+#include "llvm/Transforms/Scalar/LoopPredication.h"
 #include "llvm/Transforms/Scalar/LoopRotation.h"
 #include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
+#include "llvm/Transforms/Scalar/LoopSink.h"
 #include "llvm/Transforms/Scalar/LoopStrengthReduce.h"
 #include "llvm/Transforms/Scalar/LoopUnrollPass.h"
 #include "llvm/Transforms/Scalar/LowerAtomic.h"
@@ -120,6 +125,7 @@
 #include "llvm/Transforms/Scalar/Reassociate.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
 #include "llvm/Transforms/Scalar/SROA.h"
+#include "llvm/Transforms/Scalar/SimpleLoopUnswitch.h"
 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
 #include "llvm/Transforms/Scalar/Sink.h"
 #include "llvm/Transforms/Scalar/SpeculativeExecution.h"
@@ -131,8 +137,8 @@
 #include "llvm/Transforms/Utils/LoopSimplify.h"
 #include "llvm/Transforms/Utils/LowerInvoke.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
-#include "llvm/Transforms/Utils/MemorySSA.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
+#include "llvm/Transforms/Utils/PredicateInfo.h"
 #include "llvm/Transforms/Utils/SimplifyInstructions.h"
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
 #include "llvm/Transforms/Vectorize/LoopVectorize.h"
@@ -142,7 +148,32 @@
 
 using namespace llvm;
 
-static Regex DefaultAliasRegex("^(default|lto-pre-link|lto)<(O[0123sz])>$");
+static cl::opt<unsigned> MaxDevirtIterations("pm-max-devirt-iterations",
+                                             cl::ReallyHidden, cl::init(4));
+static cl::opt<bool>
+    RunPartialInlining("enable-npm-partial-inlining", cl::init(false),
+                       cl::Hidden, cl::ZeroOrMore,
+                       cl::desc("Run Partial inlinining pass"));
+
+static cl::opt<bool>
+    RunNewGVN("enable-npm-newgvn", cl::init(false),
+              cl::Hidden, cl::ZeroOrMore,
+              cl::desc("Run NewGVN instead of GVN"));
+
+static cl::opt<bool> EnableEarlyCSEMemSSA(
+    "enable-npm-earlycse-memssa", cl::init(true), cl::Hidden,
+    cl::desc("Enable the EarlyCSE w/ MemorySSA pass for the new PM (default = on)"));
+
+static cl::opt<bool> EnableGVNHoist(
+    "enable-npm-gvn-hoist", cl::init(false), cl::Hidden,
+    cl::desc("Enable the GVN hoisting pass for the new PM (default = off)"));
+
+static cl::opt<bool> EnableGVNSink(
+    "enable-npm-gvn-sink", cl::init(false), cl::Hidden,
+    cl::desc("Enable the GVN hoisting pass for the new PM (default = off)"));
+
+static Regex DefaultAliasRegex(
+    "^(default|thinlto-pre-link|thinlto|lto-pre-link|lto)<(O[0123sz])>$");
 
 static bool isOptimizingForSize(PassBuilder::OptimizationLevel Level) {
   switch (Level) {
@@ -250,33 +281,52 @@ AnalysisKey NoOpLoopAnalysis::Key;
 
 } // End anonymous namespace.
 
+void PassBuilder::invokePeepholeEPCallbacks(
+    FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
+  for (auto &C : PeepholeEPCallbacks)
+    C(FPM, Level);
+}
+
 void PassBuilder::registerModuleAnalyses(ModuleAnalysisManager &MAM) {
 #define MODULE_ANALYSIS(NAME, CREATE_PASS)                                     \
   MAM.registerPass([&] { return CREATE_PASS; });
 #include "PassRegistry.def"
+
+  for (auto &C : ModuleAnalysisRegistrationCallbacks)
+    C(MAM);
 }
 
 void PassBuilder::registerCGSCCAnalyses(CGSCCAnalysisManager &CGAM) {
 #define CGSCC_ANALYSIS(NAME, CREATE_PASS)                                      \
   CGAM.registerPass([&] { return CREATE_PASS; });
 #include "PassRegistry.def"
+
+  for (auto &C : CGSCCAnalysisRegistrationCallbacks)
+    C(CGAM);
 }
 
 void PassBuilder::registerFunctionAnalyses(FunctionAnalysisManager &FAM) {
 #define FUNCTION_ANALYSIS(NAME, CREATE_PASS)                                   \
   FAM.registerPass([&] { return CREATE_PASS; });
 #include "PassRegistry.def"
+
+  for (auto &C : FunctionAnalysisRegistrationCallbacks)
+    C(FAM);
 }
 
 void PassBuilder::registerLoopAnalyses(LoopAnalysisManager &LAM) {
 #define LOOP_ANALYSIS(NAME, CREATE_PASS)                                       \
   LAM.registerPass([&] { return CREATE_PASS; });
 #include "PassRegistry.def"
+
+  for (auto &C : LoopAnalysisRegistrationCallbacks)
+    C(LAM);
 }
 
 FunctionPassManager
 PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
-                                                 bool DebugLogging) {
+                                                 bool DebugLogging,
+                                                 bool PrepareForThinLTO) {
   assert(Level != O0 && "Must request optimizations!");
   FunctionPassManager FPM(DebugLogging);
 
@@ -285,7 +335,17 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   FPM.addPass(SROA());
 
   // Catch trivial redundancies
-  FPM.addPass(EarlyCSEPass());
+  FPM.addPass(EarlyCSEPass(EnableEarlyCSEMemSSA));
+
+  // Hoisting of scalars and load expressions.
+  if (EnableGVNHoist)
+    FPM.addPass(GVNHoistPass());
+
+  // Global value numbering based sinking.
+  if (EnableGVNSink) {
+    FPM.addPass(GVNSinkPass());
+    FPM.addPass(SimplifyCFGPass());
+  }
 
   // Speculative execution if the target has divergent branches; otherwise nop.
   FPM.addPass(SpeculativeExecutionPass());
@@ -299,6 +359,8 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   if (!isOptimizingForSize(Level))
     FPM.addPass(LibCallsShrinkWrapPass());
 
+  invokePeepholeEPCallbacks(FPM, Level);
+
   FPM.addPass(TailCallElimPass());
   FPM.addPass(SimplifyCFGPass());
 
@@ -316,19 +378,29 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   // the other we have is `LoopInstSimplify`.
   LoopPassManager LPM1(DebugLogging), LPM2(DebugLogging);
 
-  // FIXME: Enable these when the loop pass manager can support enforcing loop
-  // simplified and LCSSA form as well as updating the loop nest after
-  // transformations and we finsih porting the loop passes.
-#if 0
   // Rotate Loop - disable header duplication at -Oz
   LPM1.addPass(LoopRotatePass(Level != Oz));
   LPM1.addPass(LICMPass());
-  LPM1.addPass(LoopUnswitchPass(/* OptimizeForSize */ Level != O3));
+  LPM1.addPass(SimpleLoopUnswitchPass());
   LPM2.addPass(IndVarSimplifyPass());
-  LPM2.addPass(LoopIdiomPass());
+  LPM2.addPass(LoopIdiomRecognizePass());
+
+  for (auto &C : LateLoopOptimizationsEPCallbacks)
+    C(LPM2, Level);
+
   LPM2.addPass(LoopDeletionPass());
-  LPM2.addPass(SimpleLoopUnrollPass());
-#endif
+  // Do not enable unrolling in PrepareForThinLTO phase during sample PGO
+  // because it changes IR to makes profile annotation in back compile
+  // inaccurate.
+  if (!PrepareForThinLTO || !PGOOpt || PGOOpt->SampleProfileFile.empty())
+    LPM2.addPass(LoopUnrollPass::createFull(Level));
+
+  for (auto &C : LoopOptimizerEndEPCallbacks)
+    C(LPM2, Level);
+
+  // We provide the opt remark emitter pass for LICM to use. We only need to do
+  // this once as it is immutable.
+  FPM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1)));
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
@@ -338,7 +410,10 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   if (Level != O1) {
     // These passes add substantial compile time so skip them at O1.
     FPM.addPass(MergedLoadStoreMotionPass());
-    FPM.addPass(GVN());
+    if (RunNewGVN)
+      FPM.addPass(NewGVNPass());
+    else
+      FPM.addPass(GVN());
   }
 
   // Specially optimize memory movement as it doesn't look like dataflow in SSA.
@@ -357,37 +432,102 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   // Run instcombine after redundancy and dead bit elimination to exploit
   // opportunities opened up by them.
   FPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(FPM, Level);
 
   // Re-consider control flow based optimizations after redundancy elimination,
   // redo DCE, etc.
   FPM.addPass(JumpThreadingPass());
   FPM.addPass(CorrelatedValuePropagationPass());
   FPM.addPass(DSEPass());
-  // FIXME: Enable this when the loop pass manager can support enforcing loop
-  // simplified and LCSSA form as well as updating the loop nest after
-  // transformations and we finsih porting the loop passes.
-#if 0
   FPM.addPass(createFunctionToLoopPassAdaptor(LICMPass()));
-#endif
+
+  for (auto &C : ScalarOptimizerLateEPCallbacks)
+    C(FPM, Level);
 
   // Finally, do an expensive DCE pass to catch all the dead code exposed by
   // the simplifications and basic cleanup after all the simplifications.
   FPM.addPass(ADCEPass());
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(FPM, Level);
 
   return FPM;
 }
 
+void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM, bool DebugLogging,
+                                    PassBuilder::OptimizationLevel Level,
+                                    bool RunProfileGen,
+                                    std::string ProfileGenFile,
+                                    std::string ProfileUseFile) {
+  // Generally running simplification passes and the inliner with an high
+  // threshold results in smaller executables, but there may be cases where
+  // the size grows, so let's be conservative here and skip this simplification
+  // at -Os/Oz.
+  if (!isOptimizingForSize(Level)) {
+    InlineParams IP;
+
+    // In the old pass manager, this is a cl::opt. Should still this be one?
+    IP.DefaultThreshold = 75;
+
+    // FIXME: The hint threshold has the same value used by the regular inliner.
+    // This should probably be lowered after performance testing.
+    // FIXME: this comment is cargo culted from the old pass manager, revisit).
+    IP.HintThreshold = 325;
+
+    CGSCCPassManager CGPipeline(DebugLogging);
+
+    CGPipeline.addPass(InlinerPass(IP));
+
+    FunctionPassManager FPM;
+    FPM.addPass(SROA());
+    FPM.addPass(EarlyCSEPass());    // Catch trivial redundancies.
+    FPM.addPass(SimplifyCFGPass()); // Merge & remove basic blocks.
+    FPM.addPass(InstCombinePass()); // Combine silly sequences.
+    invokePeepholeEPCallbacks(FPM, Level);
+
+    CGPipeline.addPass(createCGSCCToFunctionPassAdaptor(std::move(FPM)));
+
+    MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(std::move(CGPipeline)));
+  }
+
+  // Delete anything that is now dead to make sure that we don't instrument
+  // dead code. Instrumentation can end up keeping dead code around and
+  // dramatically increase code size.
+  MPM.addPass(GlobalDCEPass());
+
+  if (RunProfileGen) {
+    MPM.addPass(PGOInstrumentationGen());
+
+    FunctionPassManager FPM;
+    FPM.addPass(createFunctionToLoopPassAdaptor(LoopRotatePass()));
+    MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+
+    // Add the profile lowering pass.
+    InstrProfOptions Options;
+    if (!ProfileGenFile.empty())
+      Options.InstrProfileOutput = ProfileGenFile;
+    Options.DoCounterPromotion = true;
+    MPM.addPass(InstrProfiling(Options));
+  }
+
+  if (!ProfileUseFile.empty())
+    MPM.addPass(PGOInstrumentationUse(ProfileUseFile));
+}
+
+static InlineParams
+getInlineParamsFromOptLevel(PassBuilder::OptimizationLevel Level) {
+  auto O3 = PassBuilder::O3;
+  unsigned OptLevel = Level > O3 ? 2 : Level;
+  unsigned SizeLevel = Level > O3 ? Level - O3 : 0;
+  return getInlineParams(OptLevel, SizeLevel);
+}
+
 ModulePassManager
-PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
-                                           bool DebugLogging) {
-  assert(Level != O0 && "Must request optimizations for the default pipeline!");
+PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
+                                               bool DebugLogging,
+                                               bool PrepareForThinLTO) {
   ModulePassManager MPM(DebugLogging);
 
-  // Force any function attributes we want the rest of the pipeline te observe.
-  MPM.addPass(ForceFunctionAttrsPass());
-
   // Do basic inference of function attributes from known properties of system
   // libraries and other oracles.
   MPM.addPass(InferFunctionAttrsPass());
@@ -399,7 +539,6 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   EarlyFPM.addPass(SROA());
   EarlyFPM.addPass(EarlyCSEPass());
   EarlyFPM.addPass(LowerExpectIntrinsicPass());
-  EarlyFPM.addPass(GVNHoistPass());
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(EarlyFPM)));
 
   // Interprocedural constant propagation now that basic cleanup has occured
@@ -426,13 +565,36 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // optimizations.
   FunctionPassManager GlobalCleanupPM(DebugLogging);
   GlobalCleanupPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(GlobalCleanupPM, Level);
+
   GlobalCleanupPM.addPass(SimplifyCFGPass());
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(GlobalCleanupPM)));
 
-  // FIXME: Enable this when cross-IR-unit analysis invalidation is working.
-#if 0
-  MPM.addPass(RequireAnalysisPass<GlobalsAA>());
-#endif
+  // Add all the requested passes for PGO, if requested.
+  if (PGOOpt) {
+    assert(PGOOpt->RunProfileGen || !PGOOpt->SampleProfileFile.empty() ||
+           !PGOOpt->ProfileUseFile.empty());
+    if (PGOOpt->SampleProfileFile.empty())
+      addPGOInstrPasses(MPM, DebugLogging, Level, PGOOpt->RunProfileGen,
+                        PGOOpt->ProfileGenFile, PGOOpt->ProfileUseFile);
+    else
+      MPM.addPass(SampleProfileLoaderPass(PGOOpt->SampleProfileFile));
+
+    // Indirect call promotion that promotes intra-module targes only.
+    // Do not enable it in PrepareForThinLTO phase during sample PGO because
+    // it changes IR to makes profile annotation in back compile inaccurate.
+    if (!PrepareForThinLTO || PGOOpt->SampleProfileFile.empty())
+      MPM.addPass(PGOIndirectCallPromotion(
+          false, PGOOpt && !PGOOpt->SampleProfileFile.empty()));
+  }
+
+  // Require the GlobalsAA analysis for the module so we can query it within
+  // the CGSCC pipeline.
+  MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
+
+  // Require the ProfileSummaryAnalysis for the module so we can query it within
+  // the inliner pass.
+  MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
 
   // Now begin the main postorder CGSCC pipeline.
   // FIXME: The current CGSCC pipeline has its origins in the legacy pass
@@ -448,26 +610,63 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // Run the inliner first. The theory is that we are walking bottom-up and so
   // the callees have already been fully optimized, and we want to inline them
   // into the callers so that our optimizations can reflect that.
-  // FIXME; Customize the threshold based on optimization level.
-  MainCGPipeline.addPass(InlinerPass());
+  // For PrepareForThinLTO pass, we disable hot-caller heuristic for sample PGO
+  // because it makes profile annotation in the backend inaccurate.
+  InlineParams IP = getInlineParamsFromOptLevel(Level);
+  if (PrepareForThinLTO && PGOOpt && !PGOOpt->SampleProfileFile.empty())
+    IP.HotCallSiteThreshold = 0;
+  MainCGPipeline.addPass(InlinerPass(IP));
 
   // Now deduce any function attributes based in the current code.
   MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
 
+  // When at O3 add argument promotion to the pass pipeline.
+  // FIXME: It isn't at all clear why this should be limited to O3.
+  if (Level == O3)
+    MainCGPipeline.addPass(ArgumentPromotionPass());
+
   // Lastly, add the core function simplification pipeline nested inside the
   // CGSCC walk.
   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
-      buildFunctionSimplificationPipeline(Level, DebugLogging)));
+      buildFunctionSimplificationPipeline(Level, DebugLogging,
+                                          PrepareForThinLTO)));
+
+  for (auto &C : CGSCCOptimizerLateEPCallbacks)
+    C(MainCGPipeline, Level);
 
+  // We wrap the CGSCC pipeline in a devirtualization repeater. This will try
+  // to detect when we devirtualize indirect calls and iterate the SCC passes
+  // in that case to try and catch knock-on inlining or function attrs
+  // opportunities. Then we add it to the module pipeline by walking the SCCs
+  // in postorder (or bottom-up).
   MPM.addPass(
-      createModuleToPostOrderCGSCCPassAdaptor(std::move(MainCGPipeline)));
+      createModuleToPostOrderCGSCCPassAdaptor(createDevirtSCCRepeatedPass(
+          std::move(MainCGPipeline), MaxDevirtIterations, DebugLogging)));
 
-  // This ends the canonicalization and simplification phase of the pipeline.
-  // At this point, we expect to have canonical and simple IR which we begin
-  // *optimizing* for efficient execution going forward.
+  return MPM;
+}
+
+ModulePassManager
+PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
+                                             bool DebugLogging) {
+  ModulePassManager MPM(DebugLogging);
+
+  // Optimize globals now that the module is fully simplified.
+  MPM.addPass(GlobalOptPass());
 
-  // Eliminate externally available functions now that inlining is over -- we
-  // won't emit these anyways.
+  // Run partial inlining pass to partially inline functions that have
+  // large bodies.
+  if (RunPartialInlining)
+    MPM.addPass(PartialInlinerPass());
+
+  // Remove avail extern fns and globals definitions since we aren't compiling
+  // an object file for later LTO. For LTO we want to preserve these so they
+  // are eligible for inlining at link-time. Note if they are unreferenced they
+  // will be removed by GlobalDCE later, so this only impacts referenced
+  // available externally globals. Eventually they will be suppressed during
+  // codegen, but eliminating here enables more opportunity for GlobalDCE as it
+  // may make globals referenced by available external functions dead and saves
+  // running remaining passes on the eliminated functions.
   MPM.addPass(EliminateAvailableExternallyPass());
 
   // Do RPO function attribute inference across the module to forward-propagate
@@ -475,17 +674,14 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // FIXME: Is this really an optimization rather than a canonicalization?
   MPM.addPass(ReversePostOrderFunctionAttrsPass());
 
-  // Recompute GloblasAA here prior to function passes. This is particularly
+  // Re-require GloblasAA here prior to function passes. This is particularly
   // useful as the above will have inlined, DCE'ed, and function-attr
   // propagated everything. We should at this point have a reasonably minimal
   // and richly annotated call graph. By computing aliasing and mod/ref
   // information for all local globals here, the late loop passes and notably
   // the vectorizer will be able to use them to help recognize vectorizable
   // memory operations.
-  // FIXME: Enable this once analysis invalidation is fully supported.
-#if 0
-  MPM.addPass(Require<GlobalsAA>());
-#endif
+  MPM.addPass(RequireAnalysisPass<GlobalsAA, Module>());
 
   FunctionPassManager OptimizePM(DebugLogging);
   OptimizePM.addPass(Float2IntPass());
@@ -495,36 +691,70 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
   // Optimize the loop execution. These passes operate on entire loop nests
   // rather than on each loop in an inside-out manner, and so they are actually
   // function passes.
+
+  for (auto &C : VectorizerStartEPCallbacks)
+    C(OptimizePM, Level);
+
+  // First rotate loops that may have been un-rotated by prior passes.
+  OptimizePM.addPass(createFunctionToLoopPassAdaptor(LoopRotatePass()));
+
+  // Distribute loops to allow partial vectorization.  I.e. isolate dependences
+  // into separate loop that would otherwise inhibit vectorization.  This is
+  // currently only performed for loops marked with the metadata
+  // llvm.loop.distribute=true or when -enable-loop-distribute is specified.
   OptimizePM.addPass(LoopDistributePass());
-#if 0
-  // FIXME: LoopVectorize relies on "requiring" LCSSA which isn't supported in
-  // the new PM.
+
+  // Now run the core loop vectorizer.
   OptimizePM.addPass(LoopVectorizePass());
-#endif
-  // FIXME: Need to port Loop Load Elimination and add it here.
+
+  // Eliminate loads by forwarding stores from the previous iteration to loads
+  // of the current iteration.
+  OptimizePM.addPass(LoopLoadEliminationPass());
+
+  // Cleanup after the loop optimization passes.
   OptimizePM.addPass(InstCombinePass());
 
+
+  // Now that we've formed fast to execute loop structures, we do further
+  // optimizations. These are run afterward as they might block doing complex
+  // analyses and transforms such as what are needed for loop vectorization.
+
   // Optimize parallel scalar instruction chains into SIMD instructions.
   OptimizePM.addPass(SLPVectorizerPass());
 
-  // Cleanup after vectorizers.
+  // Cleanup after all of the vectorizers.
   OptimizePM.addPass(SimplifyCFGPass());
   OptimizePM.addPass(InstCombinePass());
 
   // Unroll small loops to hide loop backedge latency and saturate any parallel
-  // execution resources of an out-of-order processor.
-  // FIXME: Need to add once loop pass pipeline is available.
-
-  // FIXME: Add the loop sink pass when ported.
-
-  // FIXME: Add cleanup from the loop pass manager when we're forming LCSSA
-  // here.
+  // execution resources of an out-of-order processor. We also then need to
+  // clean up redundancies and loop invariant code.
+  // FIXME: It would be really good to use a loop-integrated instruction
+  // combiner for cleanup here so that the unrolling and LICM can be pipelined
+  // across the loop nests.
+  OptimizePM.addPass(createFunctionToLoopPassAdaptor(LoopUnrollPass::create(Level)));
+  OptimizePM.addPass(InstCombinePass());
+  OptimizePM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
+  OptimizePM.addPass(createFunctionToLoopPassAdaptor(LICMPass()));
 
   // Now that we've vectorized and unrolled loops, we may have more refined
   // alignment information, try to re-derive it here.
   OptimizePM.addPass(AlignmentFromAssumptionsPass());
 
-  // ADd the core optimizing pipeline.
+  // LoopSink pass sinks instructions hoisted by LICM, which serves as a
+  // canonicalization pass that enables other optimizations. As a result,
+  // LoopSink pass needs to be a very late IR pass to avoid undoing LICM
+  // result too early.
+  OptimizePM.addPass(LoopSinkPass());
+
+  // And finally clean up LCSSA form before generating code.
+  OptimizePM.addPass(InstSimplifierPass());
+
+  // LoopSink (and other loop passes since the last simplifyCFG) might have
+  // resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
+  OptimizePM.addPass(SimplifyCFGPass());
+
+  // Add the core optimizing pipeline.
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(OptimizePM)));
 
   // Now we need to do some global optimization transforms.
@@ -538,6 +768,87 @@ PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
 }
 
 ModulePassManager
+PassBuilder::buildPerModuleDefaultPipeline(OptimizationLevel Level,
+                                           bool DebugLogging) {
+  assert(Level != O0 && "Must request optimizations for the default pipeline!");
+
+  ModulePassManager MPM(DebugLogging);
+
+  // Force any function attributes we want the rest of the pipeline to observe.
+  MPM.addPass(ForceFunctionAttrsPass());
+
+  // Add the core simplification pipeline.
+  MPM.addPass(buildModuleSimplificationPipeline(Level, DebugLogging,
+                                                /*PrepareForThinLTO=*/false));
+
+  // Now add the optimization pipeline.
+  MPM.addPass(buildModuleOptimizationPipeline(Level, DebugLogging));
+
+  return MPM;
+}
+
+ModulePassManager
+PassBuilder::buildThinLTOPreLinkDefaultPipeline(OptimizationLevel Level,
+                                                bool DebugLogging) {
+  assert(Level != O0 && "Must request optimizations for the default pipeline!");
+
+  ModulePassManager MPM(DebugLogging);
+
+  // Force any function attributes we want the rest of the pipeline to observe.
+  MPM.addPass(ForceFunctionAttrsPass());
+
+  // If we are planning to perform ThinLTO later, we don't bloat the code with
+  // unrolling/vectorization/... now. Just simplify the module as much as we
+  // can.
+  MPM.addPass(buildModuleSimplificationPipeline(Level, DebugLogging,
+                                                /*PrepareForThinLTO=*/true));
+
+  // Run partial inlining pass to partially inline functions that have
+  // large bodies.
+  // FIXME: It isn't clear whether this is really the right place to run this
+  // in ThinLTO. Because there is another canonicalization and simplification
+  // phase that will run after the thin link, running this here ends up with
+  // less information than will be available later and it may grow functions in
+  // ways that aren't beneficial.
+  if (RunPartialInlining)
+    MPM.addPass(PartialInlinerPass());
+
+  // Reduce the size of the IR as much as possible.
+  MPM.addPass(GlobalOptPass());
+
+  return MPM;
+}
+
+ModulePassManager
+PassBuilder::buildThinLTODefaultPipeline(OptimizationLevel Level,
+                                         bool DebugLogging) {
+  // FIXME: The summary index is not hooked in the new pass manager yet.
+  // When it's going to be hooked, enable WholeProgramDevirt and LowerTypeTest
+  // here.
+
+  ModulePassManager MPM(DebugLogging);
+
+  // Force any function attributes we want the rest of the pipeline to observe.
+  MPM.addPass(ForceFunctionAttrsPass());
+
+  // During the ThinLTO backend phase we perform early indirect call promotion
+  // here, before globalopt. Otherwise imported available_externally functions
+  // look unreferenced and are removed.
+  MPM.addPass(PGOIndirectCallPromotion(
+      true /* InLTO */, PGOOpt && !PGOOpt->SampleProfileFile.empty() &&
+                            !PGOOpt->ProfileUseFile.empty()));
+
+  // Add the core simplification pipeline.
+  MPM.addPass(buildModuleSimplificationPipeline(Level, DebugLogging,
+                                                /*PrepareForThinLTO=*/false));
+
+  // Now add the optimization pipeline.
+  MPM.addPass(buildModuleOptimizationPipeline(Level, DebugLogging));
+
+  return MPM;
+}
+
+ModulePassManager
 PassBuilder::buildLTOPreLinkDefaultPipeline(OptimizationLevel Level,
                                             bool DebugLogging) {
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
@@ -550,13 +861,174 @@ ModulePassManager PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   assert(Level != O0 && "Must request optimizations for the default pipeline!");
   ModulePassManager MPM(DebugLogging);
 
-  // FIXME: Finish fleshing this out to match the legacy LTO pipelines.
-  FunctionPassManager LateFPM(DebugLogging);
-  LateFPM.addPass(InstCombinePass());
-  LateFPM.addPass(SimplifyCFGPass());
+  // Remove unused virtual tables to improve the quality of code generated by
+  // whole-program devirtualization and bitset lowering.
+  MPM.addPass(GlobalDCEPass());
 
-  MPM.addPass(createModuleToFunctionPassAdaptor(std::move(LateFPM)));
+  // Force any function attributes we want the rest of the pipeline to observe.
+  MPM.addPass(ForceFunctionAttrsPass());
 
+  // Do basic inference of function attributes from known properties of system
+  // libraries and other oracles.
+  MPM.addPass(InferFunctionAttrsPass());
+
+  if (Level > 1) {
+    // Indirect call promotion. This should promote all the targets that are
+    // left by the earlier promotion pass that promotes intra-module targets.
+    // This two-step promotion is to save the compile time. For LTO, it should
+    // produce the same result as if we only do promotion here.
+    MPM.addPass(PGOIndirectCallPromotion(
+        true /* InLTO */, PGOOpt && !PGOOpt->SampleProfileFile.empty()));
+
+    // Propagate constants at call sites into the functions they call.  This
+    // opens opportunities for globalopt (and inlining) by substituting function
+    // pointers passed as arguments to direct uses of functions.
+   MPM.addPass(IPSCCPPass());
+  }
+
+  // Now deduce any function attributes based in the current code.
+  MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
+              PostOrderFunctionAttrsPass()));
+
+  // Do RPO function attribute inference across the module to forward-propagate
+  // attributes where applicable.
+  // FIXME: Is this really an optimization rather than a canonicalization?
+  MPM.addPass(ReversePostOrderFunctionAttrsPass());
+
+  // Use inragne annotations on GEP indices to split globals where beneficial.
+  MPM.addPass(GlobalSplitPass());
+
+  // Run whole program optimization of virtual call when the list of callees
+  // is fixed.
+  MPM.addPass(WholeProgramDevirtPass());
+
+  // Stop here at -O1.
+  if (Level == 1)
+    return MPM;
+
+  // Optimize globals to try and fold them into constants.
+  MPM.addPass(GlobalOptPass());
+
+  // Promote any localized globals to SSA registers.
+  MPM.addPass(createModuleToFunctionPassAdaptor(PromotePass()));
+
+  // Linking modules together can lead to duplicate global constant, only
+  // keep one copy of each constant.
+  MPM.addPass(ConstantMergePass());
+
+  // Remove unused arguments from functions.
+  MPM.addPass(DeadArgumentEliminationPass());
+
+  // Reduce the code after globalopt and ipsccp.  Both can open up significant
+  // simplification opportunities, and both can propagate functions through
+  // function pointers.  When this happens, we often have to resolve varargs
+  // calls, etc, so let instcombine do this.
+  FunctionPassManager PeepholeFPM(DebugLogging);
+  PeepholeFPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(PeepholeFPM, Level);
+
+  MPM.addPass(createModuleToFunctionPassAdaptor(std::move(PeepholeFPM)));
+
+  // Note: historically, the PruneEH pass was run first to deduce nounwind and
+  // generally clean up exception handling overhead. It isn't clear this is
+  // valuable as the inliner doesn't currently care whether it is inlining an
+  // invoke or a call.
+  // Run the inliner now.
+  MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
+      InlinerPass(getInlineParamsFromOptLevel(Level))));
+
+  // Optimize globals again after we ran the inliner.
+  MPM.addPass(GlobalOptPass());
+
+  // Garbage collect dead functions.
+  // FIXME: Add ArgumentPromotion pass after once it's ported.
+  MPM.addPass(GlobalDCEPass());
+
+  FunctionPassManager FPM(DebugLogging);
+  // The IPO Passes may leave cruft around. Clean up after them.
+  FPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(FPM, Level);
+
+  FPM.addPass(JumpThreadingPass());
+
+  // Break up allocas
+  FPM.addPass(SROA());
+
+  // Run a few AA driver optimizations here and now to cleanup the code.
+  MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+
+  MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(
+              PostOrderFunctionAttrsPass()));
+  // FIXME: here we run IP alias analysis in the legacy PM.
+
+  FunctionPassManager MainFPM;
+
+  // FIXME: once we fix LoopPass Manager, add LICM here.
+  // FIXME: once we provide support for enabling MLSM, add it here.
+  // FIXME: once we provide support for enabling NewGVN, add it here.
+  if (RunNewGVN)
+    MainFPM.addPass(NewGVNPass());
+  else
+    MainFPM.addPass(GVN());
+
+  // Remove dead memcpy()'s.
+  MainFPM.addPass(MemCpyOptPass());
+
+  // Nuke dead stores.
+  MainFPM.addPass(DSEPass());
+
+  // FIXME: at this point, we run a bunch of loop passes:
+  // indVarSimplify, loopDeletion, loopInterchange, loopUnrool,
+  // loopVectorize. Enable them once the remaining issue with LPM
+  // are sorted out.
+
+  MainFPM.addPass(InstCombinePass());
+  MainFPM.addPass(SimplifyCFGPass());
+  MainFPM.addPass(SCCPPass());
+  MainFPM.addPass(InstCombinePass());
+  MainFPM.addPass(BDCEPass());
+
+  // FIXME: We may want to run SLPVectorizer here.
+  // After vectorization, assume intrinsics may tell us more
+  // about pointer alignments.
+#if 0
+  MainFPM.add(AlignmentFromAssumptionsPass());
+#endif
+
+  // FIXME: Conditionally run LoadCombine here, after it's ported
+  // (in case we still have this pass, given its questionable usefulness).
+
+  MainFPM.addPass(InstCombinePass());
+  invokePeepholeEPCallbacks(MainFPM, Level);
+  MainFPM.addPass(JumpThreadingPass());
+  MPM.addPass(createModuleToFunctionPassAdaptor(std::move(MainFPM)));
+
+  // Create a function that performs CFI checks for cross-DSO calls with
+  // targets in the current module.
+  MPM.addPass(CrossDSOCFIPass());
+
+  // Lower type metadata and the type.test intrinsic. This pass supports
+  // clang's control flow integrity mechanisms (-fsanitize=cfi*) and needs
+  // to be run at link time if CFI is enabled. This pass does nothing if
+  // CFI is disabled.
+  // Enable once we add support for the summary in the new PM.
+#if 0
+  MPM.addPass(LowerTypeTestsPass(Summary ? PassSummaryAction::Export :
+                                           PassSummaryAction::None,
+                                Summary));
+#endif
+
+  // Add late LTO optimization passes.
+  // Delete basic blocks, which optimization passes may have killed.
+  MPM.addPass(createModuleToFunctionPassAdaptor(SimplifyCFGPass()));
+
+  // Drop bodies of available eternally objects to improve GlobalDCE.
+  MPM.addPass(EliminateAvailableExternallyPass());
+
+  // Now that we have optimized the program, discard unreachable functions.
+  MPM.addPass(GlobalDCEPass());
+
+  // FIXME: Enable MergeFuncs, conditionally, after ported, maybe.
   return MPM;
 }
 
@@ -579,12 +1051,8 @@ AAManager PassBuilder::buildDefaultAAPipeline() {
   // Add support for querying global aliasing information when available.
   // Because the `AAManager` is a function analysis and `GlobalsAA` is a module
   // analysis, all that the `AAManager` can do is query for any *cached*
-  // results from `GlobalsAA` through a readonly proxy..
-#if 0
-  // FIXME: Enable once the invalidation logic supports this. Currently, the
-  // `AAManager` will hold stale references to the module analyses.
+  // results from `GlobalsAA` through a readonly proxy.
   AA.registerModuleAnalysis<GlobalsAA>();
-#endif
 
   return AA;
 }
@@ -607,9 +1075,36 @@ static Optional<int> parseDevirtPassName(StringRef Name) {
   return Count;
 }
 
-static bool isModulePassName(StringRef Name) {
+/// Tests whether a pass name starts with a valid prefix for a default pipeline
+/// alias.
+static bool startsWithDefaultPipelineAliasPrefix(StringRef Name) {
+  return Name.startswith("default") || Name.startswith("thinlto") ||
+         Name.startswith("lto");
+}
+
+/// Tests whether registered callbacks will accept a given pass name.
+///
+/// When parsing a pipeline text, the type of the outermost pipeline may be
+/// omitted, in which case the type is automatically determined from the first
+/// pass name in the text. This may be a name that is handled through one of the
+/// callbacks. We check this through the oridinary parsing callbacks by setting
+/// up a dummy PassManager in order to not force the client to also handle this
+/// type of query.
+template <typename PassManagerT, typename CallbacksT>
+static bool callbacksAcceptPassName(StringRef Name, CallbacksT &Callbacks) {
+  if (!Callbacks.empty()) {
+    PassManagerT DummyPM;
+    for (auto &CB : Callbacks)
+      if (CB(Name, DummyPM, {}))
+        return true;
+  }
+  return false;
+}
+
+template <typename CallbacksT>
+static bool isModulePassName(StringRef Name, CallbacksT &Callbacks) {
   // Manually handle aliases for pre-configured pipeline fragments.
-  if (Name.startswith("default") || Name.startswith("lto"))
+  if (startsWithDefaultPipelineAliasPrefix(Name))
     return DefaultAliasRegex.match(Name);
 
   // Explicitly handle pass manager names.
@@ -632,10 +1127,11 @@ static bool isModulePassName(StringRef Name) {
     return true;
 #include "PassRegistry.def"
 
-  return false;
+  return callbacksAcceptPassName<ModulePassManager>(Name, Callbacks);
 }
 
-static bool isCGSCCPassName(StringRef Name) {
+template <typename CallbacksT>
+static bool isCGSCCPassName(StringRef Name, CallbacksT &Callbacks) {
   // Explicitly handle pass manager names.
   if (Name == "cgscc")
     return true;
@@ -656,10 +1152,11 @@ static bool isCGSCCPassName(StringRef Name) {
     return true;
 #include "PassRegistry.def"
 
-  return false;
+  return callbacksAcceptPassName<CGSCCPassManager>(Name, Callbacks);
 }
 
-static bool isFunctionPassName(StringRef Name) {
+template <typename CallbacksT>
+static bool isFunctionPassName(StringRef Name, CallbacksT &Callbacks) {
   // Explicitly handle pass manager names.
   if (Name == "function")
     return true;
@@ -678,10 +1175,11 @@ static bool isFunctionPassName(StringRef Name) {
     return true;
 #include "PassRegistry.def"
 
-  return false;
+  return callbacksAcceptPassName<FunctionPassManager>(Name, Callbacks);
 }
 
-static bool isLoopPassName(StringRef Name) {
+template <typename CallbacksT>
+static bool isLoopPassName(StringRef Name, CallbacksT &Callbacks) {
   // Explicitly handle pass manager names.
   if (Name == "loop")
     return true;
@@ -698,7 +1196,7 @@ static bool isLoopPassName(StringRef Name) {
     return true;
 #include "PassRegistry.def"
 
-  return false;
+  return callbacksAcceptPassName<LoopPassManager>(Name, Callbacks);
 }
 
 Optional<std::vector<PassBuilder::PipelineElement>>
@@ -799,30 +1297,39 @@ bool PassBuilder::parseModulePass(ModulePassManager &MPM,
       MPM.addPass(createRepeatedPass(*Count, std::move(NestedMPM)));
       return true;
     }
+
+    for (auto &C : ModulePipelineParsingCallbacks)
+      if (C(Name, MPM, InnerPipeline))
+        return true;
+
     // Normal passes can't have pipelines.
     return false;
   }
 
   // Manually handle aliases for pre-configured pipeline fragments.
-  if (Name.startswith("default") || Name.startswith("lto")) {
+  if (startsWithDefaultPipelineAliasPrefix(Name)) {
     SmallVector<StringRef, 3> Matches;
     if (!DefaultAliasRegex.match(Name, &Matches))
       return false;
     assert(Matches.size() == 3 && "Must capture two matched strings!");
 
     OptimizationLevel L = StringSwitch<OptimizationLevel>(Matches[2])
-        .Case("O0", O0)
-        .Case("O1", O1)
-        .Case("O2", O2)
-        .Case("O3", O3)
-        .Case("Os", Os)
-        .Case("Oz", Oz);
+                              .Case("O0", O0)
+                              .Case("O1", O1)
+                              .Case("O2", O2)
+                              .Case("O3", O3)
+                              .Case("Os", Os)
+                              .Case("Oz", Oz);
     if (L == O0)
       // At O0 we do nothing at all!
       return true;
 
     if (Matches[1] == "default") {
       MPM.addPass(buildPerModuleDefaultPipeline(L, DebugLogging));
+    } else if (Matches[1] == "thinlto-pre-link") {
+      MPM.addPass(buildThinLTOPreLinkDefaultPipeline(L, DebugLogging));
+    } else if (Matches[1] == "thinlto") {
+      MPM.addPass(buildThinLTODefaultPipeline(L, DebugLogging));
     } else if (Matches[1] == "lto-pre-link") {
       MPM.addPass(buildLTOPreLinkDefaultPipeline(L, DebugLogging));
     } else {
@@ -852,6 +1359,9 @@ bool PassBuilder::parseModulePass(ModulePassManager &MPM,
   }
 #include "PassRegistry.def"
 
+  for (auto &C : ModulePipelineParsingCallbacks)
+    if (C(Name, MPM, InnerPipeline))
+      return true;
   return false;
 }
 
@@ -899,11 +1409,16 @@ bool PassBuilder::parseCGSCCPass(CGSCCPassManager &CGPM,
                                                *MaxRepetitions, DebugLogging));
       return true;
     }
+
+    for (auto &C : CGSCCPipelineParsingCallbacks)
+      if (C(Name, CGPM, InnerPipeline))
+        return true;
+
     // Normal passes can't have pipelines.
     return false;
   }
 
-  // Now expand the basic registered passes from the .inc file.
+// Now expand the basic registered passes from the .inc file.
 #define CGSCC_PASS(NAME, CREATE_PASS)                                          \
   if (Name == NAME) {                                                          \
     CGPM.addPass(CREATE_PASS);                                                 \
@@ -924,6 +1439,9 @@ bool PassBuilder::parseCGSCCPass(CGSCCPassManager &CGPM,
   }
 #include "PassRegistry.def"
 
+  for (auto &C : CGSCCPipelineParsingCallbacks)
+    if (C(Name, CGPM, InnerPipeline))
+      return true;
   return false;
 }
 
@@ -961,11 +1479,16 @@ bool PassBuilder::parseFunctionPass(FunctionPassManager &FPM,
       FPM.addPass(createRepeatedPass(*Count, std::move(NestedFPM)));
       return true;
     }
+
+    for (auto &C : FunctionPipelineParsingCallbacks)
+      if (C(Name, FPM, InnerPipeline))
+        return true;
+
     // Normal passes can't have pipelines.
     return false;
   }
 
-  // Now expand the basic registered passes from the .inc file.
+// Now expand the basic registered passes from the .inc file.
 #define FUNCTION_PASS(NAME, CREATE_PASS)                                       \
   if (Name == NAME) {                                                          \
     FPM.addPass(CREATE_PASS);                                                  \
@@ -985,6 +1508,9 @@ bool PassBuilder::parseFunctionPass(FunctionPassManager &FPM,
   }
 #include "PassRegistry.def"
 
+  for (auto &C : FunctionPipelineParsingCallbacks)
+    if (C(Name, FPM, InnerPipeline))
+      return true;
   return false;
 }
 
@@ -1012,11 +1538,16 @@ bool PassBuilder::parseLoopPass(LoopPassManager &LPM, const PipelineElement &E,
       LPM.addPass(createRepeatedPass(*Count, std::move(NestedLPM)));
       return true;
     }
+
+    for (auto &C : LoopPipelineParsingCallbacks)
+      if (C(Name, LPM, InnerPipeline))
+        return true;
+
     // Normal passes can't have pipelines.
     return false;
   }
 
-  // Now expand the basic registered passes from the .inc file.
+// Now expand the basic registered passes from the .inc file.
 #define LOOP_PASS(NAME, CREATE_PASS)                                           \
   if (Name == NAME) {                                                          \
     LPM.addPass(CREATE_PASS);                                                  \
@@ -1037,6 +1568,9 @@ bool PassBuilder::parseLoopPass(LoopPassManager &LPM, const PipelineElement &E,
   }
 #include "PassRegistry.def"
 
+  for (auto &C : LoopPipelineParsingCallbacks)
+    if (C(Name, LPM, InnerPipeline))
+      return true;
   return false;
 }
 
@@ -1055,6 +1589,9 @@ bool PassBuilder::parseAAPassName(AAManager &AA, StringRef Name) {
   }
 #include "PassRegistry.def"
 
+  for (auto &C : AAParsingCallbacks)
+    if (C(Name, AA))
+      return true;
   return false;
 }
 
@@ -1121,7 +1658,7 @@ bool PassBuilder::parseModulePassPipeline(ModulePassManager &MPM,
   return true;
 }
 
-// Primary pass pipeline description parsing routine.
+// Primary pass pipeline description parsing routine for a \c ModulePassManager
 // FIXME: Should this routine accept a TargetMachine or require the caller to
 // pre-populate the analysis managers with target-specific stuff?
 bool PassBuilder::parsePassPipeline(ModulePassManager &MPM,
@@ -1135,21 +1672,70 @@ bool PassBuilder::parsePassPipeline(ModulePassManager &MPM,
   // automatically.
   StringRef FirstName = Pipeline->front().Name;
 
-  if (!isModulePassName(FirstName)) {
-    if (isCGSCCPassName(FirstName))
+  if (!isModulePassName(FirstName, ModulePipelineParsingCallbacks)) {
+    if (isCGSCCPassName(FirstName, CGSCCPipelineParsingCallbacks)) {
       Pipeline = {{"cgscc", std::move(*Pipeline)}};
-    else if (isFunctionPassName(FirstName))
+    } else if (isFunctionPassName(FirstName,
+                                  FunctionPipelineParsingCallbacks)) {
       Pipeline = {{"function", std::move(*Pipeline)}};
-    else if (isLoopPassName(FirstName))
+    } else if (isLoopPassName(FirstName, LoopPipelineParsingCallbacks)) {
       Pipeline = {{"function", {{"loop", std::move(*Pipeline)}}}};
-    else
+    } else {
+      for (auto &C : TopLevelPipelineParsingCallbacks)
+        if (C(MPM, *Pipeline, VerifyEachPass, DebugLogging))
+          return true;
+
       // Unknown pass name!
       return false;
+    }
   }
 
   return parseModulePassPipeline(MPM, *Pipeline, VerifyEachPass, DebugLogging);
 }
 
+// Primary pass pipeline description parsing routine for a \c CGSCCPassManager
+bool PassBuilder::parsePassPipeline(CGSCCPassManager &CGPM,
+                                    StringRef PipelineText, bool VerifyEachPass,
+                                    bool DebugLogging) {
+  auto Pipeline = parsePipelineText(PipelineText);
+  if (!Pipeline || Pipeline->empty())
+    return false;
+
+  StringRef FirstName = Pipeline->front().Name;
+  if (!isCGSCCPassName(FirstName, CGSCCPipelineParsingCallbacks))
+    return false;
+
+  return parseCGSCCPassPipeline(CGPM, *Pipeline, VerifyEachPass, DebugLogging);
+}
+
+// Primary pass pipeline description parsing routine for a \c
+// FunctionPassManager
+bool PassBuilder::parsePassPipeline(FunctionPassManager &FPM,
+                                    StringRef PipelineText, bool VerifyEachPass,
+                                    bool DebugLogging) {
+  auto Pipeline = parsePipelineText(PipelineText);
+  if (!Pipeline || Pipeline->empty())
+    return false;
+
+  StringRef FirstName = Pipeline->front().Name;
+  if (!isFunctionPassName(FirstName, FunctionPipelineParsingCallbacks))
+    return false;
+
+  return parseFunctionPassPipeline(FPM, *Pipeline, VerifyEachPass,
+                                   DebugLogging);
+}
+
+// Primary pass pipeline description parsing routine for a \c LoopPassManager
+bool PassBuilder::parsePassPipeline(LoopPassManager &CGPM,
+                                    StringRef PipelineText, bool VerifyEachPass,
+                                    bool DebugLogging) {
+  auto Pipeline = parsePipelineText(PipelineText);
+  if (!Pipeline || Pipeline->empty())
+    return false;
+
+  return parseLoopPassPipeline(CGPM, *Pipeline, VerifyEachPass, DebugLogging);
+}
+
 bool PassBuilder::parseAAPipeline(AAManager &AA, StringRef PipelineText) {
   // If the pipeline just consists of the word 'default' just replace the AA
   // manager with our default one.