change EH related stuff (other than EH_LABEL) to use MCSymbol

instead of label ID's.  This cleans up and regularizes a bunch 
of code and makes way for future progress.

Unfortunately, this pointed out to me that JITDwarfEmitter.cpp
is largely copy and paste from DwarfException/MachineModuleInfo
and other places.  This is very sad and disturbing. :(

One major change here is that TidyLandingPads moved from being
called in DwarfException::BeginFunction to being called in
DwarfException::EndFunction.  There should not be any 
functionality change from doing this, but I'm not an EH expert.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98459 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 72 insertions, 82 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfException.cpp b/lib/CodeGen/AsmPrinter/DwarfException.cpp
index 16c9aa38e3..ff0aa80b1d 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfException.cpp
@@ -454,7 +454,7 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
                      const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
                      const SmallVectorImpl<unsigned> &FirstActions) {
   // The end label of the previous invoke or nounwind try-range.
-  unsigned LastLabel = 0;
+  MCSymbol *LastLabel = 0;
 
   // Whether there is a potentially throwing instruction (currently this means
   // an ordinary call) between the end of the previous try-range and now.
@@ -475,8 +475,9 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
         continue;
       }
 
-      unsigned BeginLabel = MI->getOperand(0).getImm();
-      assert(BeginLabel && "Invalid label!");
+      unsigned BeginLabelNo = MI->getOperand(0).getImm();
+      assert(BeginLabelNo && "Invalid label!");
+      MCSymbol *BeginLabel = getDWLabel("label", BeginLabelNo);
 
       // End of the previous try-range?
       if (BeginLabel == LastLabel)
@@ -580,7 +581,6 @@ void DwarfException::EmitExceptionTable() {
   const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
   const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
-  if (PadInfos.empty()) return;
 
   // Sort the landing pads in order of their type ids.  This is used to fold
   // duplicate actions.
@@ -605,7 +605,7 @@ void DwarfException::EmitExceptionTable() {
   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
     const LandingPadInfo *LandingPad = LandingPads[i];
     for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
-      unsigned BeginLabel = LandingPad->BeginLabels[j];
+      MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
       assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
       PadRange P = { i, j };
       PadMap[BeginLabel] = P;
@@ -790,45 +790,33 @@ void DwarfException::EmitExceptionTable() {
     for (SmallVectorImpl<CallSiteEntry>::const_iterator
          I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
       const CallSiteEntry &S = *I;
-      const char *BeginTag;
-      unsigned BeginNumber;
-
-      if (!S.BeginLabel) {
-        BeginTag = "eh_func_begin";
-        BeginNumber = SubprogramCount;
-      } else {
-        BeginTag = "label";
-        BeginNumber = S.BeginLabel;
-      }
-
+      
+      MCSymbol *EHFuncBeginSym = getDWLabel("eh_func_begin", SubprogramCount);
+      
+      MCSymbol *BeginLabel = S.BeginLabel;
+      if (BeginLabel == 0)
+        BeginLabel = EHFuncBeginSym;
+      MCSymbol *EndLabel = S.EndLabel;
+      if (EndLabel == 0)
+        EndLabel = getDWLabel("eh_func_end", SubprogramCount);
+        
       // Offset of the call site relative to the previous call site, counted in
       // number of 16-byte bundles. The first call site is counted relative to
       // the start of the procedure fragment.
       Asm->OutStreamer.AddComment("Region start");
-      EmitSectionOffset(getDWLabel(BeginTag, BeginNumber),
-                        getDWLabel("eh_func_begin", SubprogramCount),
-                        true, true);
-
+      EmitSectionOffset(EHFuncBeginSym, EndLabel, true);
+      
       Asm->OutStreamer.AddComment("Region length");
-      if (!S.EndLabel)
-        EmitDifference(getDWLabel("eh_func_end", SubprogramCount),
-                       getDWLabel(BeginTag, BeginNumber),
-                       true);
-      else
-        EmitDifference(getDWLabel("label", S.EndLabel), 
-                       getDWLabel(BeginTag, BeginNumber), true);
+      EmitDifference(EndLabel, BeginLabel, true);
 
 
       // Offset of the landing pad, counted in 16-byte bundles relative to the
       // @LPStart address.
       Asm->OutStreamer.AddComment("Landing pad");
-      if (!S.PadLabel) {
+      if (!S.PadLabel)
         Asm->OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
-      } else {
-        EmitSectionOffset(getDWLabel("label", S.PadLabel),
-                          getDWLabel("eh_func_begin", SubprogramCount),
-                          true, true);
-      }
+      else
+        EmitSectionOffset(S.PadLabel, EHFuncBeginSym, true, true);
 
       // Offset of the first associated action record, relative to the start of
       // the action table. This value is biased by 1 (1 indicates the start of
@@ -928,16 +916,11 @@ void DwarfException::BeginFunction(const MachineFunction *MF) {
   this->MF = MF;
   shouldEmitTable = shouldEmitMoves = false;
 
-  // Map all labels and get rid of any dead landing pads.
-  MMI->TidyLandingPads();
-
   // If any landing pads survive, we need an EH table.
-  if (!MMI->getLandingPads().empty())
-    shouldEmitTable = true;
+  shouldEmitTable = !MMI->getLandingPads().empty();
 
   // See if we need frame move info.
-  if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
-    shouldEmitMoves = true;
+  shouldEmitMoves = !MF->getFunction()->doesNotThrow() || UnwindTablesMandatory;
 
   if (shouldEmitMoves || shouldEmitTable)
     // Assumes in correct section after the entry point.
@@ -959,7 +942,16 @@ void DwarfException::EndFunction() {
     ExceptionTimer->startTimer();
 
   Asm->OutStreamer.EmitLabel(getDWLabel("eh_func_end", SubprogramCount));
-  EmitExceptionTable();
+
+  // Record if this personality index uses a landing pad.
+  bool HasLandingPad = !MMI->getLandingPads().empty();
+  UsesLSDA[MMI->getPersonalityIndex()] |= HasLandingPad;
+  
+  // Map all labels and get rid of any dead landing pads.
+  MMI->TidyLandingPads();
+
+  if (HasLandingPad)
+    EmitExceptionTable();
 
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
   MCSymbol *FunctionEHSym =
@@ -974,9 +966,6 @@ void DwarfException::EndFunction() {
                                          MMI->getFrameMoves(),
                                          MF->getFunction()));
 
-  // Record if this personality index uses a landing pad.
-  UsesLSDA[MMI->getPersonalityIndex()] |= !MMI->getLandingPads().empty();
-
   if (TimePassesIsEnabled)
     ExceptionTimer->stopTimer();
 }
diff --git a/lib/CodeGen/AsmPrinter/DwarfException.h b/lib/CodeGen/AsmPrinter/DwarfException.h
index 274d1a4b7e..4bc4a458c0 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.h
+++ b/lib/CodeGen/AsmPrinter/DwarfException.h
@@ -111,13 +111,6 @@ class DwarfException : public DwarfPrinter {
   /// PadLT - Order landing pads lexicographically by type id.
   static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
 
-  struct KeyInfo {
-    static inline unsigned getEmptyKey() { return -1U; }
-    static inline unsigned getTombstoneKey() { return -2U; }
-    static unsigned getHashValue(const unsigned &Key) { return Key; }
-    static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
-  };
-
   /// PadRange - Structure holding a try-range and the associated landing pad.
   struct PadRange {
     // The index of the landing pad.
@@ -126,7 +119,7 @@ class DwarfException : public DwarfPrinter {
     unsigned RangeIndex;
   };
 
-  typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
+  typedef DenseMap<MCSymbol *, PadRange> RangeMapType;
 
   /// ActionEntry - Structure describing an entry in the actions table.
   struct ActionEntry {
@@ -138,11 +131,11 @@ class DwarfException : public DwarfPrinter {
   /// CallSiteEntry - Structure describing an entry in the call-site table.
   struct CallSiteEntry {
     // The 'try-range' is BeginLabel .. EndLabel.
-    unsigned BeginLabel; // zero indicates the start of the function.
-    unsigned EndLabel;   // zero indicates the end of the function.
+    MCSymbol *BeginLabel; // zero indicates the start of the function.
+    MCSymbol *EndLabel;   // zero indicates the end of the function.
 
     // The landing pad starts at PadLabel.
-    unsigned PadLabel;   // zero indicates that there is no landing pad.
+    MCSymbol *PadLabel;   // zero indicates that there is no landing pad.
     unsigned Action;
   };
 
diff --git a/lib/CodeGen/ELFCodeEmitter.h b/lib/CodeGen/ELFCodeEmitter.h
index b5e9c844ec..2ec1f6e873 100644
--- a/lib/CodeGen/ELFCodeEmitter.h
+++ b/lib/CodeGen/ELFCodeEmitter.h
@@ -57,13 +57,13 @@ namespace llvm {
     bool finishFunction(MachineFunction &F);
 
     /// emitLabel - Emits a label
-    virtual void emitLabel(uint64_t LabelID) {
+    virtual void emitLabel(MCSymbol *Label) {
       assert("emitLabel not implemented");
     }
 
     /// getLabelAddress - Return the address of the specified LabelID, 
     /// only usable after the LabelID has been emitted.
-    virtual uintptr_t getLabelAddress(uint64_t Label) const {
+    virtual uintptr_t getLabelAddress(MCSymbol *Label) const {
       assert("getLabelAddress not implemented");
       return 0;
     }
diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp
index e326ecd756..27c138789d 100644
--- a/lib/CodeGen/MachineModuleInfo.cpp
+++ b/lib/CodeGen/MachineModuleInfo.cpp
@@ -10,6 +10,11 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 
 #include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -17,11 +22,8 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/Instructions.h"
-#include "llvm/Module.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
@@ -68,6 +70,12 @@ bool MachineModuleInfo::doFinalization() {
   return false;
 }
 
+/// getLabelSym - Turn a label ID into a symbol.
+MCSymbol *MachineModuleInfo::getLabelSym(unsigned ID) {
+  return Context.GetOrCreateTemporarySymbol
+    (Twine(Context.getAsmInfo().getPrivateGlobalPrefix()) + "Label" +Twine(ID));
+}
+
 /// EndFunction - Discard function meta information.
 ///
 void MachineModuleInfo::EndFunction() {
@@ -123,7 +131,7 @@ LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
 /// addInvoke - Provide the begin and end labels of an invoke style call and
 /// associate it with a try landing pad block.
 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
-                                  unsigned BeginLabel, unsigned EndLabel) {
+                                  MCSymbol *BeginLabel, MCSymbol *EndLabel) {
   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
   LP.BeginLabels.push_back(BeginLabel);
   LP.EndLabels.push_back(EndLabel);
@@ -132,10 +140,11 @@ void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
 /// addLandingPad - Provide the label of a try LandingPad block.
 ///
 unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
-  unsigned LandingPadLabel = NextLabelID();
+  unsigned LandingPadID = NextLabelID();
+  MCSymbol *LandingPadLabel = getLabelSym(LandingPadID);
   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
   LP.LandingPadLabel = LandingPadLabel;
-  return LandingPadLabel;
+  return LandingPadID;
 }
 
 /// addPersonality - Provide the personality function for the exception
@@ -189,7 +198,7 @@ void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
 void MachineModuleInfo::TidyLandingPads() {
   for (unsigned i = 0; i != LandingPads.size(); ) {
     LandingPadInfo &LandingPad = LandingPads[i];
-    if (isLabelDeleted(LandingPad.LandingPadLabel))
+    if (LandingPad.LandingPadLabel && !LandingPad.LandingPadLabel->isDefined())
       LandingPad.LandingPadLabel = 0;
 
     // Special case: we *should* emit LPs with null LP MBB. This indicates
@@ -199,16 +208,14 @@ void MachineModuleInfo::TidyLandingPads() {
       continue;
     }
 
-    for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
-      unsigned BeginLabel = LandingPad.BeginLabels[j];
-      unsigned EndLabel = LandingPad.EndLabels[j];
-      if (isLabelDeleted(BeginLabel) || isLabelDeleted(EndLabel)) {
-        LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
-        LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
-        continue;
-      }
-
-      ++j;
+    for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
+      MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
+      MCSymbol *EndLabel = LandingPad.EndLabels[j];
+      if (BeginLabel->isDefined() && EndLabel->isDefined()) continue;
+      
+      LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
+      LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
+      --j, --e;
     }
 
     // Remove landing pads with no try-ranges.
@@ -222,7 +229,6 @@ void MachineModuleInfo::TidyLandingPads() {
     if (!LandingPad.LandingPadBlock ||
         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
       LandingPad.TypeIds.clear();
-
     ++i;
   }
 }
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index f4d3c34e68..08ba62b659 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4302,7 +4302,7 @@ void SelectionDAGBuilder::LowerCallTo(CallSite CS, SDValue Callee,
   const FunctionType *FTy = cast<FunctionType>(PT->getElementType());
   const Type *RetTy = FTy->getReturnType();
   MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
-  unsigned BeginLabel = 0, EndLabel = 0;
+  MCSymbol *BeginLabel = 0;
 
   TargetLowering::ArgListTy Args;
   TargetLowering::ArgListEntry Entry;
@@ -4362,7 +4362,8 @@ void SelectionDAGBuilder::LowerCallTo(CallSite CS, SDValue Callee,
   if (LandingPad && MMI) {
     // Insert a label before the invoke call to mark the try range.  This can be
     // used to detect deletion of the invoke via the MachineModuleInfo.
-    BeginLabel = MMI->NextLabelID();
+    unsigned BeginLabelID = MMI->NextLabelID();
+    BeginLabel = MMI->getLabelSym(BeginLabelID);
 
     // For SjLj, keep track of which landing pads go with which invokes
     // so as to maintain the ordering of pads in the LSDA.
@@ -4377,7 +4378,7 @@ void SelectionDAGBuilder::LowerCallTo(CallSite CS, SDValue Callee,
     // this call might not return.
     (void)getRoot();
     DAG.setRoot(DAG.getLabel(ISD::EH_LABEL, getCurDebugLoc(),
-                             getControlRoot(), BeginLabel));
+                             getControlRoot(), BeginLabelID));
   }
 
   // Check if target-independent constraints permit a tail call here.
@@ -4465,9 +4466,10 @@ void SelectionDAGBuilder::LowerCallTo(CallSite CS, SDValue Callee,
   if (LandingPad && MMI) {
     // Insert a label at the end of the invoke call to mark the try range.  This
     // can be used to detect deletion of the invoke via the MachineModuleInfo.
-    EndLabel = MMI->NextLabelID();
+    unsigned EndLabelID = MMI->NextLabelID();
+    MCSymbol *EndLabel = MMI->getLabelSym(EndLabelID);
     DAG.setRoot(DAG.getLabel(ISD::EH_LABEL, getCurDebugLoc(),
-                             getRoot(), EndLabel));
+                             getRoot(), EndLabelID));
 
     // Inform MachineModuleInfo of range.
     MMI->addInvoke(LandingPad, BeginLabel, EndLabel);