Implement Jakob's suggestion on how to detect fall thought without calling

[oota-llvm.git] / lib / CodeGen / AsmPrinter / AsmPrinter.cpp

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 86e8bb6c3436515bd91b9ba0cb63f7c9eb72e685..187963c26a1ffeed2e1f351093da42a70b1ecf31 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -38,6 +38,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetOptions.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Assembly/Writer.h"
 #include "llvm/ADT/SmallString.h"
@@ -188,21 +189,22 @@ bool AsmPrinter::doInitialization(Module &M) {
   if (MAI->doesSupportDebugInformation())
     DD = new DwarfDebug(this, &M);
 
-  if (MAI->doesSupportExceptionHandling())
-    switch (MAI->getExceptionHandlingType()) {
-    default:
-    case ExceptionHandling::DwarfTable:
-      DE = new DwarfTableException(this);
-      break;
-    case ExceptionHandling::DwarfCFI:
-      DE = new DwarfCFIException(this);
-      break;
-    case ExceptionHandling::ARM:
-      DE = new ARMException(this);
-      break;
-    }
+  switch (MAI->getExceptionHandlingType()) {
+  case ExceptionHandling::None:
+    return false;
+  case ExceptionHandling::SjLj:
+  case ExceptionHandling::DwarfCFI:
+    DE = new DwarfCFIException(this);
+    return false;
+  case ExceptionHandling::ARM:
+    DE = new ARMException(this);
+    return false;
+  case ExceptionHandling::Win64:
+    DE = new Win64Exception(this);
+    return false;
+  }
 
-  return false;
+  llvm_unreachable("Unknown exception type.");
 }
 
 void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
@@ -267,7 +269,7 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   }
 
   MCSymbol *GVSym = Mang->getSymbol(GV);
-  EmitVisibility(GVSym, GV->getVisibility());
+  EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
 
   if (!GV->hasInitializer())   // External globals require no extra code.
     return;
@@ -591,18 +593,32 @@ static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
   return true;
 }
 
+AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
+  if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
+      MF->getFunction()->needsUnwindTableEntry())
+    return CFI_M_EH;
+
+  if (MMI->hasDebugInfo())
+    return CFI_M_Debug;
+
+  return CFI_M_None;
+}
+
+bool AsmPrinter::needsSEHMoves() {
+  return MAI->getExceptionHandlingType() == ExceptionHandling::Win64 &&
+    MF->getFunction()->needsUnwindTableEntry();
+}
+
 void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
   MCSymbol *Label = MI.getOperand(0).getMCSymbol();
 
-  if (MAI->doesDwarfRequireFrameSection() ||
-      MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
-    OutStreamer.EmitLabel(Label);
-
   if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
     return;
 
-  const MachineFunction &MF = *MI.getParent()->getParent();
-  MachineModuleInfo &MMI = MF.getMMI();
+  if (needsCFIMoves() == CFI_M_None)
+    return;
+
+  MachineModuleInfo &MMI = MF->getMMI();
   std::vector<MachineMove> &Moves = MMI.getFrameMoves();
   bool FoundOne = false;
   (void)FoundOne;
@@ -675,6 +691,9 @@ void AsmPrinter::EmitFunctionBody() {
         if (isVerbose()) EmitKill(II, *this);
         break;
       default:
+        if (!TM.hasMCUseLoc())
+          MCLineEntry::Make(&OutStreamer, getCurrentSection());
+
         EmitInstruction(II);
         break;
       }
@@ -749,30 +768,25 @@ getDebugValueLocation(const MachineInstr *MI) const {
   return MachineLocation();
 }
 
-/// getDwarfRegOpSize - get size required to emit given machine location using
-/// dwarf encoding.
-unsigned AsmPrinter::getDwarfRegOpSize(const MachineLocation &MLoc) const {
-  const TargetRegisterInfo *RI = TM.getRegisterInfo();
-  unsigned DWReg = RI->getDwarfRegNum(MLoc.getReg(), false);
-  if (int Offset = MLoc.getOffset()) {
-    // If the value is at a certain offset from frame register then
-    // use DW_OP_breg.
-    if (DWReg < 32)
-      return 1 + MCAsmInfo::getSLEB128Size(Offset);
-    else
-      return 1 + MCAsmInfo::getULEB128Size(MLoc.getReg()) 
-        + MCAsmInfo::getSLEB128Size(Offset);
-  }
-  if (DWReg < 32)
-    return 1;
-
-  return 1 + MCAsmInfo::getULEB128Size(DWReg);
-}
-
 /// EmitDwarfRegOp - Emit dwarf register operation.
 void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
-  unsigned Reg = TRI->getDwarfRegNum(MLoc.getReg(), false);
+  int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false);
+
+  for (const unsigned *SR = TRI->getSuperRegisters(MLoc.getReg());
+       *SR && Reg < 0; ++SR) {
+    Reg = TRI->getDwarfRegNum(*SR, false);
+    // FIXME: Get the bit range this register uses of the superregister
+    // so that we can produce a DW_OP_bit_piece
+  }
+
+  // FIXME: Handle cases like a super register being encoded as
+  // DW_OP_reg 32 DW_OP_piece 4 DW_OP_reg 33
+
+  // FIXME: We have no reasonable way of handling errors in here. The
+  // caller might be in the middle of an dwarf expression. We should
+  // probably assert that Reg >= 0 once debug info generation is more mature.
+
   if (int Offset =  MLoc.getOffset()) {
     if (Reg < 32) {
       OutStreamer.AddComment(
@@ -797,6 +811,8 @@ void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
       EmitULEB128(Reg);
     }
   }
+
+  // FIXME: Produce a DW_OP_bit_piece if we used a superregister
 }
 
 bool AsmPrinter::doFinalization(Module &M) {
@@ -1909,7 +1925,7 @@ isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
     return false;
 
   // The predecessor has to be immediately before this block.
-  const MachineBasicBlock *Pred = *PI;
+  MachineBasicBlock *Pred = *PI;
 
   if (!Pred->isLayoutSuccessor(MBB))
     return false;
@@ -1918,9 +1934,26 @@ isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
   if (Pred->empty())
     return true;
 
-  // Otherwise, check the last instruction.
-  const MachineInstr &LastInst = Pred->back();
-  return !LastInst.getDesc().isBarrier();
+  // Check the terminators in the previous blocks
+  for (MachineBasicBlock::iterator II = Pred->getFirstTerminator(),
+         IE = Pred->end(); II != IE; ++II) {
+    MachineInstr &MI = *II;
+
+    // If it is not a simple branch, we are in a table somewhere.
+    if (!MI.getDesc().isBranch() || MI.getDesc().isIndirectBranch())
+      return false;
+
+    // If we are the operands of one of the branches, this is not
+    // a fall through.
+    for (MachineInstr::mop_iterator OI = MI.operands_begin(),
+           OE = MI.operands_end(); OI != OE; ++OI) {
+      const MachineOperand& OP = *OI;
+      if (OP.isMBB() && OP.getMBB() == MBB)
+        return false;
+    }
+  }
+
+  return true;
 }