Pull in r196939 from upstream llvm trunk (by Reid Kleckner):

  Reland "Fix miscompile of MS inline assembly with stack realignment"

  This re-lands commit r196876, which was reverted in r196879.

  The tests have been fixed to pass on platforms with a stack alignment
  larger than 4.

  Update to clang side tests will land shortly.

Pull in r196986 from upstream llvm trunk (by Reid Kleckner):

  Revert the backend fatal error from r196939

  The combination of inline asm, stack realignment, and dynamic allocas
  turns out to be too common to reject out of hand.

  ASan inserts empy inline asm fragments and uses aligned allocas.
  Compiling any trivial function containing a dynamic alloca with ASan is
  enough to trigger the check.

  XFAIL the test cases that would be miscompiled and add one that uses the
  relevant functionality.

Pull in r202930 from upstream llvm trunk (by Hans Wennborg):

  Check for dynamic allocas and inline asm that clobbers sp before building
  selection dag (PR19012)

  In X86SelectionDagInfo::EmitTargetCodeForMemcpy we check with MachineFrameInfo
  to make sure that ESI isn't used as a base pointer register before we choose to
  emit rep movs (which clobbers esi).

  The problem is that MachineFrameInfo wouldn't know about dynamic allocas or
  inline asm that clobbers the stack pointer until SelectionDAGBuilder has
  encountered them.

  This patch fixes the problem by checking for such things when building the
  FunctionLoweringInfo.

  Differential Revision: http://llvm-reviews.chandlerc.com/D2954

Together, these commits fix the problem encountered in the devel/emacs
port on the i386 architecture, where a combination of stack realignment,
alloca() and memcpy() could incidentally clobber the %esi register,
leading to segfaults in the temacs build-time utility.

See also: http://llvm.org/PR18171 and http://llvm.org/PR19012

Reported by:	ashish
PR:		ports/183064
MFC after:	1 week

10 files changed, 94 insertions, 36 deletions

diff --git a/contrib/llvm/include/llvm/CodeGen/FunctionLoweringInfo.h b/contrib/llvm/include/llvm/CodeGen/FunctionLoweringInfo.h
index 50d320f8e839..854cac250ccd 100644
--- a/contrib/llvm/include/llvm/CodeGen/FunctionLoweringInfo.h
+++ b/contrib/llvm/include/llvm/CodeGen/FunctionLoweringInfo.h
@@ -41,6 +41,7 @@ class MachineBasicBlock;
 class MachineFunction;
 class MachineModuleInfo;
 class MachineRegisterInfo;
+class SelectionDAG;
 class TargetLowering;
 class Value;
 
@@ -125,7 +126,7 @@ public:
   /// set - Initialize this FunctionLoweringInfo with the given Function
   /// and its associated MachineFunction.
   ///
-  void set(const Function &Fn, MachineFunction &MF);
+  void set(const Function &Fn, MachineFunction &MF, SelectionDAG *DAG);
 
   /// clear - Clear out all the function-specific state. This returns this
   /// FunctionLoweringInfo to an empty state, ready to be used for a
diff --git a/contrib/llvm/include/llvm/CodeGen/MachineFrameInfo.h b/contrib/llvm/include/llvm/CodeGen/MachineFrameInfo.h
index 022634df87cf..ba536e72f6cb 100644
--- a/contrib/llvm/include/llvm/CodeGen/MachineFrameInfo.h
+++ b/contrib/llvm/include/llvm/CodeGen/MachineFrameInfo.h
@@ -223,6 +223,10 @@ class MachineFrameInfo {
   /// Whether the "realign-stack" option is on.
   bool RealignOption;
 
+  /// True if the function includes inline assembly that adjusts the stack
+  /// pointer.
+  bool HasInlineAsmWithSPAdjust;
+
   const TargetFrameLowering *getFrameLowering() const;
 public:
     explicit MachineFrameInfo(const TargetMachine &TM, bool RealignOpt)
@@ -240,6 +244,7 @@ public:
     LocalFrameSize = 0;
     LocalFrameMaxAlign = 0;
     UseLocalStackAllocationBlock = false;
+    HasInlineAsmWithSPAdjust = false;
   }
 
   /// hasStackObjects - Return true if there are any stack objects in this
@@ -451,6 +456,10 @@ public:
   bool hasCalls() const { return HasCalls; }
   void setHasCalls(bool V) { HasCalls = V; }
 
+  /// Returns true if the function contains any stack-adjusting inline assembly.
+  bool hasInlineAsmWithSPAdjust() const { return HasInlineAsmWithSPAdjust; }
+  void setHasInlineAsmWithSPAdjust(bool B) { HasInlineAsmWithSPAdjust = B; }
+
   /// getMaxCallFrameSize - Return the maximum size of a call frame that must be
   /// allocated for an outgoing function call.  This is only available if
   /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
@@ -521,7 +530,7 @@ public:
   /// variable sized object is created, whether or not the index returned is
   /// actually used.
   ///
-  int CreateVariableSizedObject(unsigned Alignment);
+  int CreateVariableSizedObject(unsigned Alignment, const AllocaInst *Alloca);
 
   /// getCalleeSavedInfo - Returns a reference to call saved info vector for the
   /// current function.
diff --git a/contrib/llvm/include/llvm/CodeGen/MachineFunction.h b/contrib/llvm/include/llvm/CodeGen/MachineFunction.h
index c886e256e044..43b370cccff7 100644
--- a/contrib/llvm/include/llvm/CodeGen/MachineFunction.h
+++ b/contrib/llvm/include/llvm/CodeGen/MachineFunction.h
@@ -131,8 +131,8 @@ class MachineFunction {
   /// about the control flow of such functions.
   bool ExposesReturnsTwice;
 
-  /// True if the function includes MS-style inline assembly.
-  bool HasMSInlineAsm;
+  /// True if the function includes any inline assembly.
+  bool HasInlineAsm;
 
   MachineFunction(const MachineFunction &) LLVM_DELETED_FUNCTION;
   void operator=(const MachineFunction&) LLVM_DELETED_FUNCTION;
@@ -218,15 +218,14 @@ public:
     ExposesReturnsTwice = B;
   }
 
-  /// Returns true if the function contains any MS-style inline assembly.
-  bool hasMSInlineAsm() const {
-    return HasMSInlineAsm;
+  /// Returns true if the function contains any inline assembly.
+  bool hasInlineAsm() const {
+    return HasInlineAsm;
   }
 
-  /// Set a flag that indicates that the function contains MS-style inline
-  /// assembly.
-  void setHasMSInlineAsm(bool B) {
-    HasMSInlineAsm = B;
+  /// Set a flag that indicates that the function contains inline assembly.
+  void setHasInlineAsm(bool B) {
+    HasInlineAsm = B;
   }
   
   /// getInfo - Keep track of various per-function pieces of information for
diff --git a/contrib/llvm/lib/CodeGen/MachineFunction.cpp b/contrib/llvm/lib/CodeGen/MachineFunction.cpp
index 0703df09a60e..f3be318f29f0 100644
--- a/contrib/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/contrib/llvm/lib/CodeGen/MachineFunction.cpp
@@ -525,13 +525,14 @@ int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
 /// variable sized object is created, whether or not the index returned is
 /// actually used.
 ///
-int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment) {
+int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment,
+                                                const AllocaInst *Alloca) {
   HasVarSizedObjects = true;
   Alignment =
     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
                           !RealignOption,
                         Alignment, getFrameLowering()->getStackAlignment()); 
-  Objects.push_back(StackObject(0, Alignment, 0, false, false, true, 0));
+  Objects.push_back(StackObject(0, Alignment, 0, false, false, true, Alloca));
   ensureMaxAlignment(Alignment);
   return (int)Objects.size()-NumFixedObjects-1;
 }
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index 4309dc1d48cb..e9d23244f4d6 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Target/TargetRegisterInfo.h"
@@ -55,7 +56,8 @@ static bool isUsedOutsideOfDefiningBlock(const Instruction *I) {
   return false;
 }
 
-void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
+void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
+                               SelectionDAG *DAG) {
   const TargetLowering *TLI = TM.getTargetLowering();
 
   Fn = &fn;
@@ -100,6 +102,43 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
   for (; BB != EB; ++BB)
     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
          I != E; ++I) {
+      // Look for dynamic allocas.
+      if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
+        if (!AI->isStaticAlloca()) {
+          unsigned Align = std::max(
+              (unsigned)TLI->getDataLayout()->getPrefTypeAlignment(
+                AI->getAllocatedType()),
+              AI->getAlignment());
+          unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
+          if (Align <= StackAlign)
+            Align = 0;
+          // Inform the Frame Information that we have variable-sized objects.
+          MF->getFrameInfo()->CreateVariableSizedObject(Align ? Align : 1, AI);
+        }
+      }
+
+      // Look for inline asm that clobbers the SP register.
+      if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
+        ImmutableCallSite CS(I);
+        if (const InlineAsm *IA = dyn_cast<InlineAsm>(CS.getCalledValue())) {
+          unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
+          std::vector<TargetLowering::AsmOperandInfo> Ops =
+            TLI->ParseConstraints(CS);
+          for (size_t I = 0, E = Ops.size(); I != E; ++I) {
+            TargetLowering::AsmOperandInfo &Op = Ops[I];
+            if (Op.Type == InlineAsm::isClobber) {
+              // Clobbers don't have SDValue operands, hence SDValue().
+              TLI->ComputeConstraintToUse(Op, SDValue(), DAG);
+              std::pair<unsigned, const TargetRegisterClass*> PhysReg =
+                TLI->getRegForInlineAsmConstraint(Op.ConstraintCode,
+                                                  Op.ConstraintVT);
+              if (PhysReg.first == SP)
+                MF->getFrameInfo()->setHasInlineAsmWithSPAdjust(true);
+            }
+          }
+        }
+      }
+
       // Mark values used outside their block as exported, by allocating
       // a virtual register for them.
       if (isUsedOutsideOfDefiningBlock(I))
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 2b2713d248e5..41662a90469f 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -851,12 +851,20 @@ void RegsForValue::AddInlineAsmOperands(unsigned Code, bool HasMatching,
   SDValue Res = DAG.getTargetConstant(Flag, MVT::i32);
   Ops.push_back(Res);
 
+  unsigned SP = TLI.getStackPointerRegisterToSaveRestore();
   for (unsigned Value = 0, Reg = 0, e = ValueVTs.size(); Value != e; ++Value) {
     unsigned NumRegs = TLI.getNumRegisters(*DAG.getContext(), ValueVTs[Value]);
     MVT RegisterVT = RegVTs[Value];
     for (unsigned i = 0; i != NumRegs; ++i) {
       assert(Reg < Regs.size() && "Mismatch in # registers expected");
-      Ops.push_back(DAG.getRegister(Regs[Reg++], RegisterVT));
+      unsigned TheReg = Regs[Reg++];
+      Ops.push_back(DAG.getRegister(TheReg, RegisterVT));
+
+      if (TheReg == SP && Code == InlineAsm::Kind_Clobber) {
+        // If we clobbered the stack pointer, MFI should know about it.
+        assert(DAG.getMachineFunction().getFrameInfo()->
+            hasInlineAsmWithSPAdjust());
+      }
     }
   }
 }
@@ -3370,9 +3378,7 @@ void SelectionDAGBuilder::visitAlloca(const AllocaInst &I) {
   setValue(&I, DSA);
   DAG.setRoot(DSA.getValue(1));
 
-  // Inform the Frame Information that we have just allocated a variable-sized
-  // object.
-  FuncInfo.MF->getFrameInfo()->CreateVariableSizedObject(Align ? Align : 1);
+  assert(FuncInfo.MF->getFrameInfo()->hasVarSizedObjects());
 }
 
 void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 3a0cfa16aee3..b8b4db42eaf7 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -419,7 +419,7 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
 
   CurDAG->init(*MF, TTI, TLI);
-  FuncInfo->set(Fn, *MF);
+  FuncInfo->set(Fn, *MF, CurDAG);
 
   if (UseMBPI && OptLevel != CodeGenOpt::None)
     FuncInfo->BPI = &getAnalysis<BranchProbabilityInfo>();
@@ -428,7 +428,8 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
 
   SDB->init(GFI, *AA, LibInfo);
 
-  MF->setHasMSInlineAsm(false);
+  MF->setHasInlineAsm(false);
+
   SelectAllBasicBlocks(Fn);
 
   // If the first basic block in the function has live ins that need to be
@@ -511,7 +512,7 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
        ++I) {
 
-    if (MFI->hasCalls() && MF->hasMSInlineAsm())
+    if (MFI->hasCalls() && MF->hasInlineAsm())
       break;
 
     const MachineBasicBlock *MBB = I;
@@ -522,8 +523,8 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
           II->isStackAligningInlineAsm()) {
         MFI->setHasCalls(true);
       }
-      if (II->isMSInlineAsm()) {
-        MF->setHasMSInlineAsm(true);
+      if (II->isInlineAsm()) {
+        MF->setHasInlineAsm(true);
       }
     }
   }
diff --git a/contrib/llvm/lib/MC/MCParser/AsmParser.cpp b/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
index a91bd93105b6..8fe39c8ef878 100644
--- a/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/contrib/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -4192,6 +4192,11 @@ bool AsmParser::parseMSInlineAsm(
         AsmStrRewrites.push_back(AsmRewrite(AOK_Input, Start, SymName.size()));
       }
     }
+
+    // Consider implicit defs to be clobbers.  Think of cpuid and push.
+    const uint16_t *ImpDefs = Desc.getImplicitDefs();
+    for (unsigned I = 0, E = Desc.getNumImplicitDefs(); I != E; ++I)
+      ClobberRegs.push_back(ImpDefs[I]);
   }
 
   // Set the number of Outputs and Inputs.
diff --git a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp
index a06ba9d750a9..0d76534711de 100644
--- a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -50,7 +50,7 @@ bool X86FrameLowering::hasFP(const MachineFunction &MF) const {
   return (MF.getTarget().Options.DisableFramePointerElim(MF) ||
           RegInfo->needsStackRealignment(MF) ||
           MFI->hasVarSizedObjects() ||
-          MFI->isFrameAddressTaken() || MF.hasMSInlineAsm() ||
+          MFI->isFrameAddressTaken() || MFI->hasInlineAsmWithSPAdjust() ||
           MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() ||
           MMI.callsUnwindInit() || MMI.callsEHReturn());
 }
diff --git a/contrib/llvm/lib/Target/X86/X86RegisterInfo.cpp b/contrib/llvm/lib/Target/X86/X86RegisterInfo.cpp
index dbda556b1b5e..e6cd59397cbd 100644
--- a/contrib/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/contrib/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -403,18 +403,15 @@ bool X86RegisterInfo::hasBasePointer(const MachineFunction &MF) const {
    if (!EnableBasePointer)
      return false;
 
-   // When we need stack realignment and there are dynamic allocas, we can't
-   // reference off of the stack pointer, so we reserve a base pointer.
-   //
-   // This is also true if the function contain MS-style inline assembly.  We
-   // do this because if any stack changes occur in the inline assembly, e.g.,
-   // "pusha", then any C local variable or C argument references in the
-   // inline assembly will be wrong because the SP is not properly tracked.
-   if ((needsStackRealignment(MF) && MFI->hasVarSizedObjects()) ||
-       MF.hasMSInlineAsm())
-     return true;
-
-   return false;
+   // When we need stack realignment, we can't address the stack from the frame
+   // pointer.  When we have dynamic allocas or stack-adjusting inline asm, we
+   // can't address variables from the stack pointer.  MS inline asm can
+   // reference locals while also adjusting the stack pointer.  When we can't
+   // use both the SP and the FP, we need a separate base pointer register.
+   bool CantUseFP = needsStackRealignment(MF);
+   bool CantUseSP =
+       MFI->hasVarSizedObjects() || MFI->hasInlineAsmWithSPAdjust();
+   return CantUseFP && CantUseSP;
 }
 
 bool X86RegisterInfo::canRealignStack(const MachineFunction &MF) const {