Print jump tables before exception tables.

In the case where just tables are part of the function section, this produces
more readable assembly by avoiding switching to the eh section and back
to .text.

This would also break with non unique section names, as trying to switch to
a unique section actually creates a new one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231677 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/ARMException.cpp

@@ -36,8 +36,7 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 using namespace llvm;
 
-ARMException::ARMException(AsmPrinter *A)
-  : EHStreamer(A), shouldEmitCFI(false) {}
+ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
 
 ARMException::~ARMException() {}
 
@@ -70,13 +69,7 @@ void ARMException::beginFunction(const MachineFunction *MF) {
 
 /// endFunction - Gather and emit post-function exception information.
 ///
-void ARMException::endFunction(const MachineFunction *) {
-  if (shouldEmitCFI)
-    Asm->OutStreamer.EmitCFIEndProc();
-
-  // Map all labels and get rid of any dead landing pads.
-  MMI->TidyLandingPads();
-
+void ARMException::endFunction(const MachineFunction *MF) {
   ARMTargetStreamer &ATS = getTargetStreamer();
   if (!Asm->MF->getFunction()->needsUnwindTableEntry() &&
       MMI->getLandingPads().empty())

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -900,6 +900,14 @@ void AsmPrinter::EmitFunctionBody() {
     OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
   }
 
+  for (const HandlerInfo &HI : Handlers) {
+    NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
+    HI.Handler->markFunctionEnd();
+  }
+
+  // Print out jump tables referenced by the function.
+  EmitJumpTableInfo();
+
   // Emit post-function debug and/or EH information.
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
@@ -907,9 +915,6 @@ void AsmPrinter::EmitFunctionBody() {
   }
   MMI->EndFunction();
 
-  // Print out jump tables referenced by the function.
-  EmitJumpTableInfo();
-
   OutStreamer.AddBlankLine();
 }
 
@@ -1245,10 +1250,8 @@ void AsmPrinter::EmitJumpTableInfo() {
   bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
       MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
       *F);
-  if (!JTInDiffSection) {
-    OutStreamer.SwitchSection(TLOF.SectionForGlobal(F, *Mang, TM));
-  } else {
-    // Otherwise, drop it in the readonly section.
+  if (JTInDiffSection) {
+    // Drop it in the readonly section.
     const MCSection *ReadOnlySection =
         TLOF.getSectionForJumpTable(*F, *Mang, TM);
     OutStreamer.SwitchSection(ReadOnlySection);
@@ -2504,3 +2507,5 @@ GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
 
 /// Pin vtable to this file.
 AsmPrinterHandler::~AsmPrinterHandler() {}
+
+void AsmPrinterHandler::markFunctionEnd() {}

lib/CodeGen/AsmPrinter/AsmPrinterHandler.h

@@ -41,6 +41,10 @@ public:
   /// call.
   virtual void beginFunction(const MachineFunction *MF) = 0;
 
+  // \brief Emit any of function marker (like .cfi_endproc). This is called
+  // before endFunction and cannot switch sections.
+  virtual void markFunctionEnd();
+
   /// \brief Gather post-function debug information.
   /// Please note that some AsmPrinter implementations may not call
   /// beginFunction at all.

lib/CodeGen/AsmPrinter/DwarfCFIException.cpp

@@ -39,9 +39,24 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 using namespace llvm;
 
+DwarfCFIExceptionBase::DwarfCFIExceptionBase(AsmPrinter *A)
+    : EHStreamer(A), shouldEmitCFI(false) {}
+
+void DwarfCFIExceptionBase::markFunctionEnd() {
+  if (shouldEmitCFI)
+    Asm->OutStreamer.EmitCFIEndProc();
+
+  if (MMI->getLandingPads().empty())
+    return;
+
+  // Map all labels and get rid of any dead landing pads.
+  MMI->TidyLandingPads();
+}
+
 DwarfCFIException::DwarfCFIException(AsmPrinter *A)
-  : EHStreamer(A), shouldEmitPersonality(false), shouldEmitLSDA(false),
-    shouldEmitMoves(false), moveTypeModule(AsmPrinter::CFI_M_None) {}
+    : DwarfCFIExceptionBase(A), shouldEmitPersonality(false),
+      shouldEmitLSDA(false), shouldEmitMoves(false),
+      moveTypeModule(AsmPrinter::CFI_M_None) {}
 
 DwarfCFIException::~DwarfCFIException() {}
 
@@ -100,7 +115,8 @@ void DwarfCFIException::beginFunction(const MachineFunction *MF) {
   shouldEmitLSDA = shouldEmitPersonality &&
     LSDAEncoding != dwarf::DW_EH_PE_omit;
 
-  if (!shouldEmitPersonality && !shouldEmitMoves)
+  shouldEmitCFI = shouldEmitPersonality || shouldEmitMoves;
+  if (!shouldEmitCFI)
     return;
 
   Asm->OutStreamer.EmitCFIStartProc(/*IsSimple=*/false);
@@ -125,16 +141,8 @@ void DwarfCFIException::beginFunction(const MachineFunction *MF) {
 /// endFunction - Gather and emit post-function exception information.
 ///
 void DwarfCFIException::endFunction(const MachineFunction *) {
-  if (!shouldEmitPersonality && !shouldEmitMoves)
-    return;
-
-  Asm->OutStreamer.EmitCFIEndProc();
-
   if (!shouldEmitPersonality)
     return;
 
-  // Map all labels and get rid of any dead landing pads.
-  MMI->TidyLandingPads();
-
   emitExceptionTable();
 }

lib/CodeGen/AsmPrinter/DwarfException.h

@@ -21,7 +21,17 @@ namespace llvm {
 class MachineFunction;
 class ARMTargetStreamer;
 
-class DwarfCFIException : public EHStreamer {
+class DwarfCFIExceptionBase : public EHStreamer {
+protected:
+  DwarfCFIExceptionBase(AsmPrinter *A);
+
+  /// Per-function flag to indicate if frame CFI info should be emitted.
+  bool shouldEmitCFI;
+
+  void markFunctionEnd() override;
+};
+
+class DwarfCFIException : public DwarfCFIExceptionBase {
   /// Per-function flag to indicate if .cfi_personality should be emitted.
   bool shouldEmitPersonality;
 
@@ -51,13 +61,10 @@ public:
   void endFunction(const MachineFunction *) override;
 };
 
-class ARMException : public EHStreamer {
+class ARMException : public DwarfCFIExceptionBase {
   void emitTypeInfos(unsigned TTypeEncoding) override;
   ARMTargetStreamer &getTargetStreamer();
 
-  /// Per-function flag to indicate if frame CFI info should be emitted.
-  bool shouldEmitCFI;
-
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.

test/CodeGen/X86/global-sections.ll

@@ -86,11 +86,13 @@ bb7:
 ; DARWIN64: _F3:
 ; DARWIN64: Lfunc_end
 ; DARWIN64-NEXT: .cfi_endproc
-; DARWIN64-NEXT: .section        __TEXT,__gcc_except_tab
-; DARWIN64-NOT: .section
-; DARWIN64: .section        __TEXT,__text,regular,pure_instructions
 ; DARWIN64-NOT: .section
 ; DARWIN64: LJTI{{.*}}:
+; DARWIN64-NEXT: .long
+; DARWIN64-NEXT: .long
+; DARWIN64-NEXT: .long
+; DARWIN64-NEXT: .long
+; DARWIN64-NEXT: .section        __TEXT,__gcc_except_tab
 
 ; int G1;
 @G1 = common global i32 0