Generate the DWARF stack frame decode operations in the function prologue for ARM/Thumb functions.

Patch by Keith Walker!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201423 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 25 insertions, 2 deletions

diff --git a/lib/CodeGen/AsmPrinter/ARMException.cpp b/lib/CodeGen/AsmPrinter/ARMException.cpp
index 6e79bef8d0..403feb4583 100644
--- a/lib/CodeGen/AsmPrinter/ARMException.cpp
+++ b/lib/CodeGen/AsmPrinter/ARMException.cpp
@@ -37,7 +37,8 @@
 using namespace llvm;
 
 ARMException::ARMException(AsmPrinter *A)
-  : DwarfException(A) {}
+  : DwarfException(A),
+    shouldEmitCFI(false) {}
 
 ARMException::~ARMException() {}
 
@@ -46,7 +47,11 @@ 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);
 }
 
 /// beginFunction - Gather pre-function exception information. Assumes it's
@@ -56,11 +61,22 @@ void ARMException::beginFunction(const MachineFunction *MF) {
   if (Asm->MF->getFunction()->needsUnwindTableEntry())
     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 &&
+         "non-EH CFI not yet supported in prologue with EHABI lowering");
+  if (MoveType == AsmPrinter::CFI_M_Debug) {
+    shouldEmitCFI = true;
+    Asm->OutStreamer.EmitCFIStartProc(false);
+  }
 }
 
 /// endFunction - Gather and emit post-function exception information.
 ///
 void ARMException::endFunction(const MachineFunction *) {
+  if (shouldEmitCFI)
+    Asm->OutStreamer.EmitCFIEndProc();
+
   ARMTargetStreamer &ATS = getTargetStreamer();
   if (!Asm->MF->getFunction()->needsUnwindTableEntry())
     ATS.emitCantUnwind();
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 2f15c97f2d..63b4bb4296 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -697,7 +697,10 @@ bool AsmPrinter::needsSEHMoves() {
 void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
   const MCSymbol *Label = MI.getOperand(0).getMCSymbol();
 
-  if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
+  ExceptionHandling::ExceptionsType ExceptionHandlingType =
+      MAI->getExceptionHandlingType();
+  if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
+      ExceptionHandlingType != ExceptionHandling::ARM)
     return;
 
   if (needsCFIMoves() == CFI_M_None)
diff --git a/lib/CodeGen/AsmPrinter/DwarfException.h b/lib/CodeGen/AsmPrinter/DwarfException.h
index 5a2ee9e490..a28eaf0c14 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.h
+++ b/lib/CodeGen/AsmPrinter/DwarfException.h
@@ -186,6 +186,10 @@ class ARMException : public DwarfException {
   void EmitTypeInfos(unsigned TTypeEncoding);
   ARMTargetStreamer &getTargetStreamer();
 
+  /// shouldEmitCFI - Per-function flag to indicate if frame CFI info
+  /// should be emitted.
+  bool shouldEmitCFI;
+
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.