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, 389 insertions, 48 deletions

diff --git a/contrib/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/contrib/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index bc5109b..60e5f06 100644
--- a/contrib/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/contrib/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -9,14 +9,12 @@
 //
 // This file implements a simple interprocedural pass which walks the
 // call-graph, looking for functions which do not access or only read
-// non-local memory, and marking them readnone/readonly.  In addition,
-// it marks function arguments (of pointer type) 'nocapture' if a call
-// to the function does not create any copies of the pointer value that
-// outlive the call.  This more or less means that the pointer is only
-// dereferenced, and not returned from the function or stored in a global.
-// Finally, well-known library call declarations are marked with all
-// attributes that are consistent with the function's standard definition.
-// This pass is implemented as a bottom-up traversal of the call-graph.
+// non-local memory, and marking them readnone/readonly.  It does the
+// same with function arguments independently, marking them readonly/
+// readnone/nocapture.  Finally, well-known library call declarations
+// are marked with all attributes that are consistent with the
+// function's standard definition. This pass is implemented as a
+// bottom-up traversal of the call-graph.
 //
 //===----------------------------------------------------------------------===//
 
@@ -40,6 +38,8 @@ using namespace llvm;
 STATISTIC(NumReadNone, "Number of functions marked readnone");
 STATISTIC(NumReadOnly, "Number of functions marked readonly");
 STATISTIC(NumNoCapture, "Number of arguments marked nocapture");
+STATISTIC(NumReadNoneArg, "Number of arguments marked readnone");
+STATISTIC(NumReadOnlyArg, "Number of arguments marked readonly");
 STATISTIC(NumNoAlias, "Number of function returns marked noalias");
 STATISTIC(NumAnnotated, "Number of attributes added to library functions");
 
@@ -56,8 +56,8 @@ namespace {
     // AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
     bool AddReadAttrs(const CallGraphSCC &SCC);
 
-    // AddNoCaptureAttrs - Deduce nocapture attributes for the SCC.
-    bool AddNoCaptureAttrs(const CallGraphSCC &SCC);
+    // AddArgumentAttrs - Deduce nocapture attributes for the SCC.
+    bool AddArgumentAttrs(const CallGraphSCC &SCC);
 
     // IsFunctionMallocLike - Does this function allocate new memory?
     bool IsFunctionMallocLike(Function *F,
@@ -71,36 +71,43 @@ namespace {
 
     void setDoesNotAccessMemory(Function &F) {
       if (!F.doesNotAccessMemory()) {
-	F.setDoesNotAccessMemory();
-	++NumAnnotated;
+        F.setDoesNotAccessMemory();
+        ++NumAnnotated;
       }
     }
 
     void setOnlyReadsMemory(Function &F) {
       if (!F.onlyReadsMemory()) {
-	F.setOnlyReadsMemory();
-	++NumAnnotated;
+        F.setOnlyReadsMemory();
+        ++NumAnnotated;
       }
     }
 
     void setDoesNotThrow(Function &F) {
       if (!F.doesNotThrow()) {
-	F.setDoesNotThrow();
-	++NumAnnotated;
+        F.setDoesNotThrow();
+        ++NumAnnotated;
       }
     }
 
     void setDoesNotCapture(Function &F, unsigned n) {
       if (!F.doesNotCapture(n)) {
-	F.setDoesNotCapture(n);
-	++NumAnnotated;
+        F.setDoesNotCapture(n);
+        ++NumAnnotated;
+      }
+    }
+
+    void setOnlyReadsMemory(Function &F, unsigned n) {
+      if (!F.onlyReadsMemory(n)) {
+        F.setOnlyReadsMemory(n);
+        ++NumAnnotated;
       }
     }
 
     void setDoesNotAlias(Function &F, unsigned n) {
       if (!F.doesNotAlias(n)) {
-	F.setDoesNotAlias(n);
-	++NumAnnotated;
+        F.setDoesNotAlias(n);
+        ++NumAnnotated;
       }
     }
 
@@ -129,7 +136,8 @@ namespace {
 char FunctionAttrs::ID = 0;
 INITIALIZE_PASS_BEGIN(FunctionAttrs, "functionattrs",
                 "Deduce function attributes", false, false)
-INITIALIZE_AG_DEPENDENCY(CallGraph)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(CallGraph)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
 INITIALIZE_PASS_END(FunctionAttrs, "functionattrs",
                 "Deduce function attributes", false, false)
@@ -343,6 +351,7 @@ namespace {
       Function *F = CS.getCalledFunction();
       if (!F || !SCCNodes.count(F)) { Captured = true; return true; }
 
+      bool Found = false;
       Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
       for (CallSite::arg_iterator PI = CS.arg_begin(), PE = CS.arg_end();
            PI != PE; ++PI, ++AI) {
@@ -353,10 +362,12 @@ namespace {
         }
         if (PI == U) {
           Uses.push_back(AI);
+          Found = true;
           break;
         }
       }
-      assert(!Uses.empty() && "Capturing call-site captured nothing?");
+      assert(Found && "Capturing call-site captured nothing?");
+      (void)Found;
       return false;
     }
 
@@ -394,8 +405,100 @@ namespace llvm {
   };
 }
 
-/// AddNoCaptureAttrs - Deduce nocapture attributes for the SCC.
-bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
+// Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.
+static Attribute::AttrKind
+determinePointerReadAttrs(Argument *A,
+                          const SmallPtrSet<Argument*, 8> &SCCNodes) {
+                                                       
+  SmallVector<Use*, 32> Worklist;
+  SmallSet<Use*, 32> Visited;
+  int Count = 0;
+
+  bool IsRead = false;
+  // We don't need to track IsWritten. If A is written to, return immediately.
+
+  for (Value::use_iterator UI = A->use_begin(), UE = A->use_end();
+       UI != UE; ++UI) {
+    if (Count++ >= 20)
+      return Attribute::None;
+
+    Use *U = &UI.getUse();
+    Visited.insert(U);
+    Worklist.push_back(U);
+  }
+
+  while (!Worklist.empty()) {
+    Use *U = Worklist.pop_back_val();
+    Instruction *I = cast<Instruction>(U->getUser());
+    Value *V = U->get();
+
+    switch (I->getOpcode()) {
+    case Instruction::BitCast:
+    case Instruction::GetElementPtr:
+    case Instruction::PHI:
+    case Instruction::Select:
+      // The original value is not read/written via this if the new value isn't.
+      for (Instruction::use_iterator UI = I->use_begin(), UE = I->use_end();
+           UI != UE; ++UI) {
+        Use *U = &UI.getUse();
+        if (Visited.insert(U))
+          Worklist.push_back(U);
+      }
+      break;
+
+    case Instruction::Call:
+    case Instruction::Invoke: {
+      CallSite CS(I);
+      if (CS.doesNotAccessMemory())
+        continue;
+
+      Function *F = CS.getCalledFunction();
+      if (!F) {
+        if (CS.onlyReadsMemory()) {
+          IsRead = true;
+          continue;
+        }
+        return Attribute::None;
+      }
+
+      Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
+      CallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end();
+      for (CallSite::arg_iterator A = B; A != E; ++A, ++AI) {
+        if (A->get() == V) {
+          if (AI == AE) {
+            assert(F->isVarArg() &&
+                   "More params than args in non-varargs call.");
+            return Attribute::None;
+          }
+          if (SCCNodes.count(AI))
+            continue;
+          if (!CS.onlyReadsMemory() && !CS.onlyReadsMemory(A - B))
+            return Attribute::None;
+          if (!CS.doesNotAccessMemory(A - B))
+            IsRead = true;
+        }
+      }
+      break;
+    }
+
+    case Instruction::Load:
+      IsRead = true;
+      break;
+
+    case Instruction::ICmp:
+    case Instruction::Ret:
+      break;
+
+    default:
+      return Attribute::None;
+    }
+  }
+
+  return IsRead ? Attribute::ReadOnly : Attribute::ReadNone;
+}
+
+/// AddArgumentAttrs - Deduce nocapture attributes for the SCC.
+bool FunctionAttrs::AddArgumentAttrs(const CallGraphSCC &SCC) {
   bool Changed = false;
 
   SmallPtrSet<Function*, 8> SCCNodes;
@@ -442,8 +545,11 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
       continue;
     }
 
-    for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end(); A!=E; ++A)
-      if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
+    for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end();
+         A != E; ++A) {
+      if (!A->getType()->isPointerTy()) continue;
+      bool HasNonLocalUses = false;
+      if (!A->hasNoCaptureAttr()) {
         ArgumentUsesTracker Tracker(SCCNodes);
         PointerMayBeCaptured(A, &Tracker);
         if (!Tracker.Captured) {
@@ -458,12 +564,32 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
             // its particulars for Argument-SCC analysis later.
             ArgumentGraphNode *Node = AG[A];
             for (SmallVectorImpl<Argument*>::iterator UI = Tracker.Uses.begin(),
-                   UE = Tracker.Uses.end(); UI != UE; ++UI)
+                     UE = Tracker.Uses.end(); UI != UE; ++UI) {
               Node->Uses.push_back(AG[*UI]);
+              if (*UI != A)
+                HasNonLocalUses = true;
+            }
           }
         }
         // Otherwise, it's captured. Don't bother doing SCC analysis on it.
       }
+      if (!HasNonLocalUses && !A->onlyReadsMemory()) {
+        // Can we determine that it's readonly/readnone without doing an SCC?
+        // Note that we don't allow any calls at all here, or else our result
+        // will be dependent on the iteration order through the functions in the
+        // SCC.
+        SmallPtrSet<Argument*, 8> Self;
+        Self.insert(A);
+        Attribute::AttrKind R = determinePointerReadAttrs(A, Self);
+        if (R != Attribute::None) {
+          AttrBuilder B;
+          B.addAttribute(R);
+          A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
+          Changed = true;
+          R == Attribute::ReadOnly ? ++NumReadOnlyArg : ++NumReadNoneArg;
+        }
+      }
+    }
   }
 
   // The graph we've collected is partial because we stopped scanning for
@@ -482,11 +608,8 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
       // eg. "void f(int* x) { if (...) f(x); }"
       if (ArgumentSCC[0]->Uses.size() == 1 &&
           ArgumentSCC[0]->Uses[0] == ArgumentSCC[0]) {
-        ArgumentSCC[0]->
-          Definition->
-          addAttr(AttributeSet::get(ArgumentSCC[0]->Definition->getContext(),
-                                    ArgumentSCC[0]->Definition->getArgNo() + 1,
-                                    B));
+        Argument *A = ArgumentSCC[0]->Definition;
+        A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
         ++NumNoCapture;
         Changed = true;
       }
@@ -532,6 +655,42 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
       ++NumNoCapture;
       Changed = true;
     }
+
+    // We also want to compute readonly/readnone. With a small number of false
+    // negatives, we can assume that any pointer which is captured isn't going
+    // to be provably readonly or readnone, since by definition we can't
+    // analyze all uses of a captured pointer.
+    //
+    // The false negatives happen when the pointer is captured by a function
+    // that promises readonly/readnone behaviour on the pointer, then the
+    // pointer's lifetime ends before anything that writes to arbitrary memory.
+    // Also, a readonly/readnone pointer may be returned, but returning a
+    // pointer is capturing it.
+
+    Attribute::AttrKind ReadAttr = Attribute::ReadNone;
+    for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
+      Argument *A = ArgumentSCC[i]->Definition;
+      Attribute::AttrKind K = determinePointerReadAttrs(A, ArgumentSCCNodes);
+      if (K == Attribute::ReadNone)
+        continue;
+      if (K == Attribute::ReadOnly) {
+        ReadAttr = Attribute::ReadOnly;
+        continue;
+      }
+      ReadAttr = K;
+      break;
+    }
+
+    if (ReadAttr != Attribute::None) {
+      AttrBuilder B;
+      B.addAttribute(ReadAttr);
+      for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
+        Argument *A = ArgumentSCC[i]->Definition;
+        A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
+        ReadAttr == Attribute::ReadOnly ? ++NumReadOnlyArg : ++NumReadNoneArg;
+        Changed = true;
+      }
+    }
   }
 
   return Changed;
@@ -678,24 +837,32 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setOnlyReadsMemory(F);
     setDoesNotThrow(F);
     break;
-  case LibFunc::strcpy:
-  case LibFunc::stpcpy:
-  case LibFunc::strcat:
   case LibFunc::strtol:
   case LibFunc::strtod:
   case LibFunc::strtof:
   case LibFunc::strtoul:
   case LibFunc::strtoll:
   case LibFunc::strtold:
+  case LibFunc::strtoull:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    break;
+  case LibFunc::strcpy:
+  case LibFunc::stpcpy:
+  case LibFunc::strcat:
   case LibFunc::strncat:
   case LibFunc::strncpy:
   case LibFunc::stpncpy:
-  case LibFunc::strtoull:
     if (FTy->getNumParams() < 2 ||
         !FTy->getParamType(1)->isPointerTy())
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::strxfrm:
     if (FTy->getNumParams() != 3 ||
@@ -705,14 +872,15 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
-    break;
-  case LibFunc::strcmp:
-  case LibFunc::strspn:
-  case LibFunc::strncmp:
-  case LibFunc::strcspn:
-  case LibFunc::strcoll:
-  case LibFunc::strcasecmp:
-  case LibFunc::strncasecmp:
+    setOnlyReadsMemory(F, 2);
+    break;
+  case LibFunc::strcmp: //0,1
+    case LibFunc::strspn: // 0,1
+    case LibFunc::strncmp: // 0,1
+    case LibFunc::strcspn: //0,1
+    case LibFunc::strcoll: //0,1
+    case LibFunc::strcasecmp:  // 0,1
+    case LibFunc::strncasecmp: // 
     if (FTy->getNumParams() < 2 ||
         !FTy->getParamType(0)->isPointerTy() ||
         !FTy->getParamType(1)->isPointerTy())
@@ -736,8 +904,15 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::scanf:
+    if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::setbuf:
   case LibFunc::setvbuf:
     if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
@@ -753,11 +928,31 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::stat:
+  case LibFunc::statvfs:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::sscanf:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
+    break;
   case LibFunc::sprintf:
-  case LibFunc::statvfs:
     if (FTy->getNumParams() < 2 ||
         !FTy->getParamType(0)->isPointerTy() ||
         !FTy->getParamType(1)->isPointerTy())
@@ -765,6 +960,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::snprintf:
     if (FTy->getNumParams() != 3 ||
@@ -774,6 +970,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 3);
+    setOnlyReadsMemory(F, 3);
     break;
   case LibFunc::setitimer:
     if (FTy->getNumParams() != 3 ||
@@ -783,6 +980,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 2);
     setDoesNotCapture(F, 3);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::system:
     if (FTy->getNumParams() != 1 ||
@@ -790,6 +988,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     // May throw; "system" is a valid pthread cancellation point.
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::malloc:
     if (FTy->getNumParams() != 1 ||
@@ -818,6 +1017,12 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
   case LibFunc::modf:
   case LibFunc::modff:
   case LibFunc::modfl:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 2);
+    break;
   case LibFunc::memcpy:
   case LibFunc::memccpy:
   case LibFunc::memmove:
@@ -826,6 +1031,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::memalign:
     if (!FTy->getReturnType()->isPointerTy())
@@ -833,6 +1039,13 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotAlias(F, 0);
     break;
   case LibFunc::mkdir:
+    if (FTy->getNumParams() == 0 ||
+        !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::mktime:
     if (FTy->getNumParams() == 0 ||
         !FTy->getParamType(0)->isPointerTy())
@@ -856,8 +1069,14 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     // May throw; "read" is a valid pthread cancellation point.
     setDoesNotCapture(F, 2);
     break;
-  case LibFunc::rmdir:
   case LibFunc::rewind:
+    if (FTy->getNumParams() < 1 ||
+        !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    break;
+  case LibFunc::rmdir:
   case LibFunc::remove:
   case LibFunc::realpath:
     if (FTy->getNumParams() < 1 ||
@@ -865,8 +1084,19 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::rename:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
+    break;
   case LibFunc::readlink:
     if (FTy->getNumParams() < 2 ||
         !FTy->getParamType(0)->isPointerTy() ||
@@ -875,12 +1105,14 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::write:
     if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
       return false;
     // May throw; "write" is a valid pthread cancellation point.
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::bcopy:
     if (FTy->getNumParams() != 3 ||
@@ -890,6 +1122,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::bcmp:
     if (FTy->getNumParams() != 3 ||
@@ -916,6 +1149,12 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     break;
   case LibFunc::chmod:
   case LibFunc::chown:
+    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::ctermid:
   case LibFunc::clearerr:
   case LibFunc::closedir:
@@ -939,6 +1178,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::fopen:
     if (FTy->getNumParams() != 2 ||
@@ -950,6 +1190,8 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::fdopen:
     if (FTy->getNumParams() != 2 ||
@@ -959,6 +1201,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::feof:
   case LibFunc::free:
@@ -1004,7 +1247,16 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 3);
+    break;
   case LibFunc::fread:
+    if (FTy->getNumParams() != 4 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(3)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 4);
+    break;
   case LibFunc::fwrite:
     if (FTy->getNumParams() != 4 ||
         !FTy->getParamType(0)->isPointerTy() ||
@@ -1013,9 +1265,28 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 4);
+    break;
   case LibFunc::fputs:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::fscanf:
   case LibFunc::fprintf:
+    if (FTy->getNumParams() < 2 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
+    break;
   case LibFunc::fgetpos:
     if (FTy->getNumParams() < 2 ||
         !FTy->getParamType(0)->isPointerTy() ||
@@ -1055,6 +1326,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::ungetc:
     if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
@@ -1063,12 +1335,24 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotCapture(F, 2);
     break;
   case LibFunc::uname:
+    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    break;
   case LibFunc::unlink:
+    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::unsetenv:
     if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::utime:
   case LibFunc::utimes:
@@ -1079,6 +1363,8 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::putc:
     if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
@@ -1093,13 +1379,20 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::pread:
+    if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
+      return false;
+    // May throw; "pread" is a valid pthread cancellation point.
+    setDoesNotCapture(F, 2);
+    break;
   case LibFunc::pwrite:
     if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
       return false;
-    // May throw; these are valid pthread cancellation points.
+    // May throw; "pwrite" is a valid pthread cancellation point.
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::putchar:
     setDoesNotThrow(F);
@@ -1114,6 +1407,8 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::pclose:
     if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
@@ -1126,8 +1421,19 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::vsscanf:
+    if (FTy->getNumParams() != 3 ||
+        !FTy->getParamType(1)->isPointerTy() ||
+        !FTy->getParamType(2)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
+    break;
   case LibFunc::vfscanf:
     if (FTy->getNumParams() != 3 ||
         !FTy->getParamType(1)->isPointerTy() ||
@@ -1136,6 +1442,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::valloc:
     if (!FTy->getReturnType()->isPointerTy())
@@ -1148,6 +1455,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::vfprintf:
   case LibFunc::vsprintf:
@@ -1158,6 +1466,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::vsnprintf:
     if (FTy->getNumParams() != 4 ||
@@ -1167,12 +1476,14 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 3);
+    setOnlyReadsMemory(F, 3);
     break;
   case LibFunc::open:
     if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
       return false;
     // May throw; "open" is a valid pthread cancellation point.
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::opendir:
     if (FTy->getNumParams() != 1 ||
@@ -1182,6 +1493,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::tmpfile:
     if (!FTy->getReturnType()->isPointerTy())
@@ -1210,12 +1522,14 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::lchown:
     if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::qsort:
     if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
@@ -1232,6 +1546,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::dunder_strtok_r:
     if (FTy->getNumParams() != 3 ||
@@ -1239,6 +1554,7 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::under_IO_getc:
     if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
@@ -1258,10 +1574,20 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
   case LibFunc::stat64:
   case LibFunc::lstat64:
   case LibFunc::statvfs64:
+    if (FTy->getNumParams() < 1 ||
+        !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    break;
   case LibFunc::dunder_isoc99_sscanf:
     if (FTy->getNumParams() < 1 ||
         !FTy->getParamType(0)->isPointerTy() ||
@@ -1270,6 +1596,8 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotThrow(F);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::fopen64:
     if (FTy->getNumParams() != 2 ||
@@ -1281,6 +1609,8 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
     setDoesNotAlias(F, 0);
     setDoesNotCapture(F, 1);
     setDoesNotCapture(F, 2);
+    setOnlyReadsMemory(F, 1);
+    setOnlyReadsMemory(F, 2);
     break;
   case LibFunc::fseeko64:
   case LibFunc::ftello64:
@@ -1307,7 +1637,18 @@ bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
       return false;
     // May throw; "open" is a valid pthread cancellation point.
     setDoesNotCapture(F, 1);
+    setOnlyReadsMemory(F, 1);
     break;
+  case LibFunc::gettimeofday:
+    if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
+        !FTy->getParamType(1)->isPointerTy())
+      return false;
+    // Currently some platforms have the restrict keyword on the arguments to
+    // gettimeofday. To be conservative, do not add noalias to gettimeofday's
+    // arguments.
+    setDoesNotThrow(F);
+    setDoesNotCapture(F, 1);
+    setDoesNotCapture(F, 2);
   default:
     // Didn't mark any attributes.
     return false;
@@ -1339,7 +1680,7 @@ bool FunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
 
   bool Changed = annotateLibraryCalls(SCC);
   Changed |= AddReadAttrs(SCC);
-  Changed |= AddNoCaptureAttrs(SCC);
+  Changed |= AddArgumentAttrs(SCC);
   Changed |= AddNoAliasAttrs(SCC);
   return Changed;
 }