add a EmitSymbolValue convenience method to MCStreamer.

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

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index fc0838459388b7a1d071f49ae766f90ed0c5a70e..246538b8c202dce001a263b9b378d08fd870483a 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -61,7 +61,7 @@ AsmPrinter::AsmPrinter(formatted_raw_ostream &o, TargetMachine &tm,
   : MachineFunctionPass(&ID), O(o),
     TM(tm), MAI(T), TRI(tm.getRegisterInfo()),
     OutContext(Ctx), OutStreamer(Streamer),
-    LastMI(0), LastFn(0), Counter(~0U), PrevDLT(NULL) {
+    LastMI(0), LastFn(0), Counter(~0U), SetCounter(0), PrevDLT(NULL) {
   DW = 0; MMI = 0;
   VerboseAsm = Streamer.isVerboseAsm();
 }
@@ -335,7 +335,7 @@ static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
     // Print source line info.
     DIScope Scope = DLT.getScope();
     // Omit the directory, because it's likely to be long and uninteresting.
-    if (!Scope.isNull())
+    if (Scope.Verify())
       CommentOS << Scope.getFilename();
     else
       CommentOS << "<unknown>";
@@ -893,6 +893,31 @@ void AsmPrinter::EmitInt64(uint64_t Value) const {
   OutStreamer.EmitIntValue(Value, 8, 0/*addrspace*/);
 }
 
+/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
+/// in bytes of the directive is specified by Size and Hi/Lo specify the
+/// labels.  This implicitly uses .set if it is available.
+void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
+                                     unsigned Size) const {
+  // Get the Hi-Lo expression.
+  const MCExpr *Diff = 
+    MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
+                            MCSymbolRefExpr::Create(Lo, OutContext),
+                            OutContext);
+  
+  if (!MAI->hasSetDirective()) {
+    OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
+    return;
+  }
+
+  // Otherwise, emit with .set (aka assignment).
+  MCSymbol *SetLabel =
+    OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + "set" +
+                                 Twine(SetCounter++));
+  OutStreamer.EmitAssignment(SetLabel, Diff);
+  OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
+}
+
+
 //===----------------------------------------------------------------------===//
 
 // EmitAlignment - Emit an alignment directive to the specified power of
@@ -917,11 +942,10 @@ void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
   
   if (NumBits == 0) return;   // No need to emit alignment.
   
-  unsigned FillValue = 0;
   if (getCurrentSection()->getKind().isText())
-    FillValue = MAI->getTextAlignFillValue();
-  
-  OutStreamer.EmitValueToAlignment(1 << NumBits, FillValue, 1, 0);
+    OutStreamer.EmitCodeAlignment(1 << NumBits);
+  else
+    OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
 }
 
 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
@@ -1288,7 +1312,7 @@ void AsmPrinter::processDebugLoc(const MachineInstr *MI,
   if (DL.isUnknown())
     return;
   DILocation CurDLT = MF->getDILocation(DL);
-  if (CurDLT.getScope().isNull())
+  if (!CurDLT.getScope().Verify())
     return;
 
   if (!BeforePrintingInsn) {
@@ -1717,7 +1741,7 @@ void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
   }
 
   // Print the main label for the block.
-  if (MBB->pred_empty() || MBB->isOnlyReachableByFallthrough()) {
+  if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
     if (VerboseAsm) {
       // NOTE: Want this comment at start of line.
       O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
@@ -1764,6 +1788,39 @@ void AsmPrinter::printOffset(int64_t Offset) const {
     O << Offset;
 }
 
+/// isBlockOnlyReachableByFallthough - Return true if the basic block has
+/// exactly one predecessor and the control transfer mechanism between
+/// the predecessor and this block is a fall-through.
+bool AsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) 
+    const {
+  // If this is a landing pad, it isn't a fall through.  If it has no preds,
+  // then nothing falls through to it.
+  if (MBB->isLandingPad() || MBB->pred_empty())
+    return false;
+  
+  // If there isn't exactly one predecessor, it can't be a fall through.
+  MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
+  ++PI2;
+  if (PI2 != MBB->pred_end())
+    return false;
+  
+  // The predecessor has to be immediately before this block.
+  const MachineBasicBlock *Pred = *PI;
+  
+  if (!Pred->isLayoutSuccessor(MBB))
+    return false;
+  
+  // If the block is completely empty, then it definitely does fall through.
+  if (Pred->empty())
+    return true;
+  
+  // Otherwise, check the last instruction.
+  const MachineInstr &LastInst = Pred->back();
+  return !LastInst.getDesc().isBarrier();
+}
+
+
+
 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
   if (!S->usesMetadata())
     return 0;