Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

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

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 45 insertions, 10 deletions

diff --git a/contrib/llvm/lib/CodeGen/LiveRangeCalc.h b/contrib/llvm/lib/CodeGen/LiveRangeCalc.h
index 9de48b7..1a7598f 100644
--- a/contrib/llvm/lib/CodeGen/LiveRangeCalc.h
+++ b/contrib/llvm/lib/CodeGen/LiveRangeCalc.h
@@ -22,6 +22,7 @@
 #ifndef LLVM_LIB_CODEGEN_LIVERANGECALC_H
 #define LLVM_LIB_CODEGEN_LIVERANGECALC_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/IndexedMap.h"
 #include "llvm/CodeGen/LiveInterval.h"
@@ -53,6 +54,19 @@ class LiveRangeCalc {
   /// when switching live ranges.
   BitVector Seen;
 
+  /// Map LiveRange to sets of blocks (represented by bit vectors) that
+  /// in the live range are defined on entry and undefined on entry.
+  /// A block is defined on entry if there is a path from at least one of
+  /// the defs in the live range to the entry of the block, and conversely,
+  /// a block is undefined on entry, if there is no such path (i.e. no
+  /// definition reaches the entry of the block). A single LiveRangeCalc
+  /// object is used to track live-out information for multiple registers
+  /// in live range splitting (which is ok, since the live ranges of these
+  /// registers do not overlap), but the defined/undefined information must
+  /// be kept separate for each individual range.
+  /// By convention, EntryInfoMap[&LR] = { Defined, Undefined }.
+  std::map<LiveRange*,std::pair<BitVector,BitVector>> EntryInfoMap;
+
   /// Map each basic block where a live range is live out to the live-out value
   /// and its defining block.
   ///
@@ -101,18 +115,31 @@ class LiveRangeCalc {
   /// used to add entries directly.
   SmallVector<LiveInBlock, 16> LiveIn;
 
-  /// Assuming that @p LR is live-in to @p UseMBB, find the set of defs that can
-  /// reach it.
+  /// Check if the entry to block @p MBB can be reached by any of the defs
+  /// in @p LR. Return true if none of the defs reach the entry to @p MBB.
+  bool isDefOnEntry(LiveRange &LR, ArrayRef<SlotIndex> Undefs,
+                    MachineBasicBlock &MBB, BitVector &DefOnEntry,
+                    BitVector &UndefOnEntry);
+
+  /// Find the set of defs that can reach @p Kill. @p Kill must belong to
+  /// @p UseMBB.
   ///
-  /// If only one def can reach @p UseMBB, all paths from the def to @p UseMBB
-  /// are added to @p LR, and the function returns true.
+  /// If exactly one def can reach @p UseMBB, and the def dominates @p Kill,
+  /// all paths from the def to @p UseMBB are added to @p LR, and the function
+  /// returns true.
   ///
   /// If multiple values can reach @p UseMBB, the blocks that need @p LR to be
   /// live in are added to the LiveIn array, and the function returns false.
   ///
+  /// The array @p Undef provides the locations where the range @p LR becomes
+  /// undefined by <def,read-undef> operands on other subranges. If @p Undef
+  /// is non-empty and @p Kill is jointly dominated only by the entries of
+  /// @p Undef, the function returns false.
+  ///
   /// PhysReg, when set, is used to verify live-in lists on basic blocks.
   bool findReachingDefs(LiveRange &LR, MachineBasicBlock &UseMBB,
-                        SlotIndex Kill, unsigned PhysReg);
+                        SlotIndex Kill, unsigned PhysReg,
+                        ArrayRef<SlotIndex> Undefs);
 
   /// updateSSA - Compute the values that will be live in to all requested
   /// blocks in LiveIn.  Create PHI-def values as required to preserve SSA form.
@@ -127,9 +154,16 @@ class LiveRangeCalc {
 
   /// Extend the live range of @p LR to reach all uses of Reg.
   ///
-  /// All uses must be jointly dominated by existing liveness.  PHI-defs are
-  /// inserted as needed to preserve SSA form.
-  void extendToUses(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask);
+  /// If @p LR is a main range, or if @p LI is null, then all uses must be
+  /// jointly dominated by the definitions from @p LR. If @p LR is a subrange
+  /// of the live interval @p LI, corresponding to lane mask @p LaneMask,
+  /// all uses must be jointly dominated by the definitions from @p LR
+  /// together with definitions of other lanes where @p LR becomes undefined
+  /// (via <def,read-undef> operands).
+  /// If @p LR is a main range, the @p LaneMask should be set to ~0, i.e.
+  /// LaneBitmask::getAll().
+  void extendToUses(LiveRange &LR, unsigned Reg, LaneBitmask LaneMask,
+                    LiveInterval *LI = nullptr);
 
   /// Reset Map and Seen fields.
   void resetLiveOutMap();
@@ -169,7 +203,8 @@ public:
   /// inserted as required to preserve SSA form.
   ///
   /// PhysReg, when set, is used to verify live-in lists on basic blocks.
-  void extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg = 0);
+  void extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg,
+              ArrayRef<SlotIndex> Undefs);
 
   /// createDeadDefs - Create a dead def in LI for every def operand of Reg.
   /// Each instruction defining Reg gets a new VNInfo with a corresponding
@@ -181,7 +216,7 @@ public:
   /// All uses must be jointly dominated by existing liveness.  PHI-defs are
   /// inserted as needed to preserve SSA form.
   void extendToUses(LiveRange &LR, unsigned PhysReg) {
-    extendToUses(LR, PhysReg, ~0u);
+    extendToUses(LR, PhysReg, LaneBitmask::getAll());
   }
 
   /// Calculates liveness for the register specified in live interval @p LI.