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

4 files changed, 59 insertions, 12 deletions

diff --git a/contrib/llvm/lib/CodeGen/MachineFunction.cpp b/contrib/llvm/lib/CodeGen/MachineFunction.cpp
index 0703df0..f3be318 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 4309dc1..e9d2324 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 2b2713d..41662a9 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 3a0cfa1..b8b4db4 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);
       }
     }
   }