Emit .cfi_sections before the first .cfi_startproc

GNU as rejects input where .cfi_sections is used after .cfi_startproc,
if the new section differs from the old. Adjust our output to always
emit .cfi_sections before the first .cfi_startproc to minimize necessary
code.

Differential Revision: https://reviews.llvm.org/D28011

llvm-svn: 290817

3 files changed, 17 insertions, 19 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
index fff3f003478..0c79def8793 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
@@ -43,13 +43,6 @@ ARMTargetStreamer &ARMException::getTargetStreamer() {
   return static_cast<ARMTargetStreamer &>(TS);
 }
 
-/// endModule - Emit all exception information that should come after the
-/// content.
-void ARMException::endModule() {
-  if (shouldEmitCFI)
-    Asm->OutStreamer->EmitCFISections(false, true);
-}
-
 void ARMException::beginFunction(const MachineFunction *MF) {
   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
     getTargetStreamer().emitFnStart();
@@ -57,7 +50,13 @@ void ARMException::beginFunction(const MachineFunction *MF) {
   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
   assert(MoveType != AsmPrinter::CFI_M_EH &&
          "non-EH CFI not yet supported in prologue with EHABI lowering");
+
   if (MoveType == AsmPrinter::CFI_M_Debug) {
+    if (!hasEmittedCFISections) {
+      Asm->OutStreamer->EmitCFISections(false, true);
+      hasEmittedCFISections = true;
+    }
+
     shouldEmitCFI = true;
     Asm->OutStreamer->EmitCFIStartProc(false);
   }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index efe7059a3a0..ef30e279aed 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -39,7 +39,7 @@
 using namespace llvm;
 
 DwarfCFIExceptionBase::DwarfCFIExceptionBase(AsmPrinter *A)
-    : EHStreamer(A), shouldEmitCFI(false) {}
+    : EHStreamer(A), shouldEmitCFI(false), hasEmittedCFISections(false) {}
 
 void DwarfCFIExceptionBase::markFunctionEnd() {
   endFragment();
@@ -59,7 +59,7 @@ void DwarfCFIExceptionBase::endFragment() {
 DwarfCFIException::DwarfCFIException(AsmPrinter *A)
     : DwarfCFIExceptionBase(A), shouldEmitPersonality(false),
       forceEmitPersonality(false), shouldEmitLSDA(false),
-      shouldEmitMoves(false), moveTypeModule(AsmPrinter::CFI_M_None) {}
+      shouldEmitMoves(false) {}
 
 DwarfCFIException::~DwarfCFIException() {}
 
@@ -70,9 +70,6 @@ void DwarfCFIException::endModule() {
   if (!Asm->MAI->usesCFIForEH())
     return;
 
-  if (moveTypeModule == AsmPrinter::CFI_M_Debug)
-    Asm->OutStreamer->EmitCFISections(false, true);
-
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
 
   unsigned PerEncoding = TLOF.getPersonalityEncoding();
@@ -102,10 +99,6 @@ void DwarfCFIException::beginFunction(const MachineFunction *MF) {
 
   // See if we need frame move info.
   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
-  if (MoveType == AsmPrinter::CFI_M_EH ||
-      (MoveType == AsmPrinter::CFI_M_Debug &&
-       moveTypeModule == AsmPrinter::CFI_M_None))
-    moveTypeModule = MoveType;
 
   shouldEmitMoves = MoveType != AsmPrinter::CFI_M_None;
 
@@ -143,6 +136,12 @@ void DwarfCFIException::beginFragment(const MachineBasicBlock *MBB,
   if (!shouldEmitCFI)
     return;
 
+  if (!hasEmittedCFISections) {
+    if (Asm->needsCFIMoves() == AsmPrinter::CFI_M_Debug)
+      Asm->OutStreamer->EmitCFISections(false, true);
+    hasEmittedCFISections = true;
+  }
+
   Asm->OutStreamer->EmitCFIStartProc(/*IsSimple=*/false);
 
   // Indicate personality routine, if any.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfException.h b/llvm/lib/CodeGen/AsmPrinter/DwarfException.h
index 8287f289f22..80d5bd208ed 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfException.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfException.h
@@ -28,6 +28,8 @@ protected:
 
   /// Per-function flag to indicate if frame CFI info should be emitted.
   bool shouldEmitCFI;
+  /// Per-module flag to indicate if .cfi_section has beeen emitted.
+  bool hasEmittedCFISections;
 
   void markFunctionEnd() override;
   void endFragment() override;
@@ -46,8 +48,6 @@ class LLVM_LIBRARY_VISIBILITY DwarfCFIException : public DwarfCFIExceptionBase {
   /// Per-function flag to indicate if frame moves info should be emitted.
   bool shouldEmitMoves;
 
-  AsmPrinter::CFIMoveType moveTypeModule;
-
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.
@@ -81,7 +81,7 @@ public:
   ~ARMException() override;
 
   /// Emit all exception information that should come after the content.
-  void endModule() override;
+  void endModule() override {}
 
   /// Gather pre-function exception information.  Assumes being emitted
   /// immediately after the function entry point.