Centralize handling of the eh_begin and eh_end labels.

This removes a bit of duplicated code and more importantly, remembers the
labels so that they don't need to be looked up by name.

This in turn allows for any name to be used and avoids a crash if the name
we wanted was already taken.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230772 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -103,6 +103,9 @@ public:
   DenseMap<const MCSymbol *, GOTEquivUsePair> GlobalGOTEquivs;
 
 private:
+  MCSymbol *CurrentFnBegin;
+  MCSymbol *CurrentFnEnd;
+
   // The garbage collection metadata printer table.
   void *GCMetadataPrinters; // Really a DenseMap.
 
@@ -146,6 +149,9 @@ public:
   ///
   unsigned getFunctionNumber() const;
 
+  MCSymbol *getFunctionBegin() const { return CurrentFnBegin; }
+  MCSymbol *getFunctionEnd() const { return CurrentFnEnd; }
+
   /// Return information about object file lowering.
   const TargetLoweringObjectFile &getObjFileLowering() const;
 
@@ -331,6 +337,8 @@ public:
   /// Return an assembler temporary label with the specified stem.
   MCSymbol *GetTempSymbol(const Twine &Name) const;
 
+  MCSymbol *createTempSymbol(const Twine &Name, unsigned ID) const;
+
   /// Return the MCSymbol for a private symbol with global value name as its
   /// base, with the specified suffix.
   MCSymbol *getSymbolWithGlobalValueBase(const GlobalValue *GV,

include/llvm/MC/MCContext.h

@@ -215,6 +215,8 @@ namespace llvm {
     /// with a unique but unspecified name.
     MCSymbol *CreateTempSymbol();
 
+    MCSymbol *createTempSymbol(const Twine &Name);
+
     /// getUniqueSymbolID() - Return a unique identifier for use in constructing
     /// symbol names.
     unsigned getUniqueSymbolID() { return NextUniqueID++; }

lib/CodeGen/AsmPrinter/ARMException.cpp

@@ -58,8 +58,6 @@ void ARMException::endModule() {
 void ARMException::beginFunction(const MachineFunction *MF) {
   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
     getTargetStreamer().emitFnStart();
-  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
-                                                Asm->getFunctionNumber()));
   // See if we need call frame info.
   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
   assert(MoveType != AsmPrinter::CFI_M_EH &&
@@ -84,8 +82,6 @@ void ARMException::endFunction(const MachineFunction *) {
       MMI->getLandingPads().empty())
     ATS.emitCantUnwind();
   else {
-    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
-                                                  Asm->getFunctionNumber()));
     if (!MMI->getLandingPads().empty()) {
       // Emit references to personality.
       if (const Function *Personality = MMI->getPersonality()) {

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -109,6 +109,8 @@ AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
   LI = nullptr;
   MF = nullptr;
   CurrentFnSym = CurrentFnSymForSize = nullptr;
+  CurrentFnBegin = nullptr;
+  CurrentFnEnd = nullptr;
   GCMetadataPrinters = nullptr;
   VerboseAsm = OutStreamer.isVerboseAsm();
 }
@@ -554,6 +556,19 @@ void AsmPrinter::EmitFunctionHeader() {
     OutStreamer.EmitLabel(DeadBlockSyms[i]);
   }
 
+  if (!MMI->getLandingPads().empty()) {
+    CurrentFnBegin = createTempSymbol("eh_func_begin", getFunctionNumber());
+
+    if (MAI->useAssignmentForEHBegin()) {
+      MCSymbol *CurPos = OutContext.CreateTempSymbol();
+      OutStreamer.EmitLabel(CurPos);
+      OutStreamer.EmitAssignment(CurrentFnBegin,
+                                 MCSymbolRefExpr::Create(CurPos, OutContext));
+    } else {
+      OutStreamer.EmitLabel(CurrentFnBegin);
+    }
+  }
+
   // Emit pre-function debug and/or EH information.
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
@@ -867,6 +882,12 @@ void AsmPrinter::EmitFunctionBody() {
   // Emit target-specific gunk after the function body.
   EmitFunctionBodyEnd();
 
+  if (!MMI->getLandingPads().empty()) {
+    // Create a symbol for the end of function.
+    CurrentFnEnd = createTempSymbol("eh_func_end", getFunctionNumber());
+    OutStreamer.EmitLabel(CurrentFnEnd);
+  }
+
   // If the target wants a .size directive for the size of the function, emit
   // it.
   if (MAI->hasDotTypeDotSizeDirective()) {
@@ -2273,6 +2294,9 @@ MCSymbol *AsmPrinter::GetTempSymbol(const Twine &Name) const {
                                       Name);
 }
 
+MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name, unsigned ID) const {
+  return OutContext.createTempSymbol(Name + Twine(ID));
+}
 
 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
   return MMI->getAddrLabelSymbol(BA->getBasicBlock());

lib/CodeGen/AsmPrinter/DwarfCFIException.cpp

@@ -113,18 +113,6 @@ void DwarfCFIException::beginFunction(const MachineFunction *MF) {
       TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
   Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
 
-  MCSymbol *EHBegin =
-      Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
-  if (Asm->MAI->useAssignmentForEHBegin()) {
-    MCContext &Ctx = Asm->OutContext;
-    MCSymbol *CurPos = Ctx.CreateTempSymbol();
-    Asm->OutStreamer.EmitLabel(CurPos);
-    Asm->OutStreamer.EmitAssignment(EHBegin,
-                                    MCSymbolRefExpr::Create(CurPos, Ctx));
-  } else {
-    Asm->OutStreamer.EmitLabel(EHBegin);
-  }
-
   // Provide LSDA information.
   if (!shouldEmitLSDA)
     return;
@@ -145,9 +133,6 @@ void DwarfCFIException::endFunction(const MachineFunction *) {
   if (!shouldEmitPersonality)
     return;
 
-  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
-                                                Asm->getFunctionNumber()));
-
   // Map all labels and get rid of any dead landing pads.
   MMI->TidyLandingPads();
 

lib/CodeGen/AsmPrinter/EHStreamer.cpp

@@ -552,16 +552,14 @@ void EHStreamer::emitExceptionTable() {
          I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
       const CallSiteEntry &S = *I;
 
-      MCSymbol *EHFuncBeginSym =
-        Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
+      MCSymbol *EHFuncBeginSym = Asm->getFunctionBegin();
 
       MCSymbol *BeginLabel = S.BeginLabel;
       if (!BeginLabel)
         BeginLabel = EHFuncBeginSym;
       MCSymbol *EndLabel = S.EndLabel;
       if (!EndLabel)
-        EndLabel = Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber());
-
+        EndLabel = Asm->getFunctionEnd();
 
       // 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

lib/CodeGen/AsmPrinter/Win64Exception.cpp

@@ -80,9 +80,6 @@ void Win64Exception::beginFunction(const MachineFunction *MF) {
   const MCSymbol *PersHandlerSym =
       TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
   Asm->OutStreamer.EmitWinEHHandler(PersHandlerSym, true, true);
-
-  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
-                                                Asm->getFunctionNumber()));
 }
 
 /// endFunction - Gather and emit post-function exception information.
@@ -91,9 +88,6 @@ void Win64Exception::endFunction(const MachineFunction *) {
   if (!shouldEmitPersonality && !shouldEmitMoves)
     return;
 
-  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
-                                                Asm->getFunctionNumber()));
-
   // Map all labels and get rid of any dead landing pads.
   MMI->TidyLandingPads();
 
@@ -170,10 +164,8 @@ void Win64Exception::emitCSpecificHandlerTable() {
   SmallVector<CallSiteEntry, 64> CallSites;
   computeCallSiteTable(CallSites, LandingPads, FirstActions);
 
-  MCSymbol *EHFuncBeginSym =
-      Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
-  MCSymbol *EHFuncEndSym =
-      Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber());
+  MCSymbol *EHFuncBeginSym = Asm->getFunctionBegin();
+  MCSymbol *EHFuncEndSym = Asm->getFunctionEnd();
 
   // Emit the number of table entries.
   unsigned NumEntries = 0;

lib/MC/MCContext.cpp

@@ -160,6 +160,12 @@ MCSymbol *MCContext::CreateSymbol(StringRef Name) {
   return Result;
 }
 
+MCSymbol *MCContext::createTempSymbol(const Twine &Name) {
+  SmallString<128> NameSV;
+  raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
+  return CreateSymbol(NameSV);
+}
+
 MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
   SmallString<128> NameSV;
   return GetOrCreateSymbol(Name.toStringRef(NameSV));

test/CodeGen/Mips/mips16ex.ll

@@ -1,8 +1,10 @@
 ; RUN: llc  -march=mipsel -mcpu=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16
 
-;16: .cfi_personality
+;16: main:
 ;16-NEXT: [[TMP:.*]]:
 ;16-NEXT: $eh_func_begin0 = ([[TMP]])
+;16-NEXT: .cfi_startproc
+;16-NEXT: .cfi_personality
 @.str = private unnamed_addr constant [7 x i8] c"hello\0A\00", align 1
 @_ZTIi = external constant i8*
 @.str1 = private unnamed_addr constant [15 x i8] c"exception %i \0A\00", align 1

test/CodeGen/X86/eh-label.ll

@@ -0,0 +1,24 @@
+; RUN: llc < %s -mtriple=x86_64-pc-linux | FileCheck %s
+; Test that we don't crashe if the .Leh_func_end0 name is taken.
+
+declare void @g()
+
+define void @f() {
+bb0:
+  call void asm ".Leh_func_end0:", ""()
+; CHECK: #APP
+; CHECK-NEXT: .Leh_func_end0:
+; CHECK-NEXT: #NO_APP
+
+  invoke void @g() to label %bb2 unwind label %bb1
+bb1:
+  landingpad { i8*, i32 } personality i8* bitcast (void ()* @g to i8*)
+          catch i8* null
+  call void @g()
+  ret void
+bb2:
+  ret void
+
+; CHECK: [[END:.Leh_func_end.*]]:
+; CHECK: .long	[[END]]-
+}

test/CodeGen/X86/global-sections.ll

@@ -84,8 +84,8 @@ bb7:
 }
 
 ; DARWIN64: _F3:
-; DARWIN64: .cfi_endproc
-; DARWIN64-NEXT: Leh_func_end
+; DARWIN64: Leh_func_end
+; DARWIN64-NEXT: .cfi_endproc
 ; DARWIN64-NEXT: .section        __TEXT,__gcc_except_tab
 ; DARWIN64-NOT: .section
 ; DARWIN64: .section        __TEXT,__text,regular,pure_instructions

test/CodeGen/X86/patchpoint-invoke.ll

@@ -5,8 +5,8 @@
 define i64 @patchpoint_invoke(i64 %p1, i64 %p2) {
 entry:
 ; CHECK-LABEL: patchpoint_invoke:
+; CHECK-NEXT:  [[FUNC_BEGIN:.L.*]]:
 ; CHECK-NEXT: .cfi_startproc
-; CHECK:      [[FUNC_BEGIN:.L.*]]:
 ; CHECK:      .cfi_lsda 3, [[EXCEPTION_LABEL:.L[^ ]*]]
 ; CHECK:      pushq %rbp
 

test/CodeGen/XCore/exception.ll

@@ -39,10 +39,10 @@ entry:
   unreachable
 }
 
-; CHECK-LABEL: fn_catch
+; CHECK-LABEL: fn_catch:
+; CHECK-NEXT: [[START:.L[a-zA-Z0-9_]+]]
 ; CHECK: .cfi_startproc
 ; CHECK: .cfi_personality 0, __gxx_personality_v0
-; CHECK: [[START:.L[a-zA-Z0-9_]+]]
 ; CHECK: .cfi_lsda 0, [[LSDA:.L[a-zA-Z0-9_]+]]
 ; CHECK: entsp 4
 ; CHECK: .cfi_def_cfa_offset 16
@@ -91,8 +91,8 @@ lpad:
 ; CHECK: bf r0, [[RETURN]]
 ; CHECK: mov r0, r4
 ; CHECK: bl _Unwind_Resume
-; CHECK: .cfi_endproc
 ; CHECK: [[END:.L[a-zA-Z0-9_]+]]
+; CHECK: .cfi_endproc
   %6 = icmp eq i32 %5, %2
   br i1 %6, label %Resume, label %Exit
 Resume: