Implement cfi_restore. Patch by Brian Anderson!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147356 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 34 insertions, 0 deletions

diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index 881fed4690..986b8b67df 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -987,6 +987,15 @@ void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
     Streamer.EmitULEB128IntValue(Reg);
     return;
   }
+  case MCCFIInstruction::Restore: {
+    unsigned Reg = Instr.getDestination().getReg();
+    if (VerboseAsm) {
+      Streamer.AddComment("DW_CFA_restore");
+      Streamer.AddComment(Twine("Reg ") + Twine(Reg));
+    }
+    Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
+    return;
+  }
   case MCCFIInstruction::Escape:
     if (VerboseAsm) Streamer.AddComment("Escape bytes");
     Streamer.EmitBytes(Instr.getValues(), 0);
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 2ccea786c7..5a69bea2fe 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -302,6 +302,8 @@ public:
     AddDirectiveHandler<
       &GenericAsmParser::ParseDirectiveCFISameValue>(".cfi_same_value");
     AddDirectiveHandler<
+      &GenericAsmParser::ParseDirectiveCFIRestore>(".cfi_restore");
+    AddDirectiveHandler<
       &GenericAsmParser::ParseDirectiveCFIEscape>(".cfi_escape");
 
     // Macro directives.
@@ -336,6 +338,7 @@ public:
   bool ParseDirectiveCFIRememberState(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFIRestoreState(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFISameValue(StringRef, SMLoc DirectiveLoc);
+  bool ParseDirectiveCFIRestore(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFIEscape(StringRef, SMLoc DirectiveLoc);
 
   bool ParseDirectiveMacrosOnOff(StringRef, SMLoc DirectiveLoc);
@@ -2815,6 +2818,19 @@ bool GenericAsmParser::ParseDirectiveCFISameValue(StringRef IDVal,
   return false;
 }
 
+/// ParseDirectiveCFIRestore
+/// ::= .cfi_restore register
+bool GenericAsmParser::ParseDirectiveCFIRestore(StringRef IDVal,
+						SMLoc DirectiveLoc) {
+  int64_t Register = 0;
+  if (ParseRegisterOrRegisterNumber(Register, DirectiveLoc))
+    return true;
+
+  getStreamer().EmitCFIRestore(Register);
+
+  return false;
+}
+
 /// ParseDirectiveCFIEscape
 /// ::= .cfi_escape expression[,...]
 bool GenericAsmParser::ParseDirectiveCFIEscape(StringRef IDVal,
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 4169188cbb..8567941c45 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -408,6 +408,15 @@ void MCStreamer::EmitCFISameValue(int64_t Register) {
   CurFrame->Instructions.push_back(Instruction);
 }
 
+void MCStreamer::EmitCFIRestore(int64_t Register) {
+  EnsureValidFrame();
+  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
+  MCSymbol *Label = getContext().CreateTempSymbol();
+  EmitLabel(Label);
+  MCCFIInstruction Instruction(MCCFIInstruction::Restore, Label, Register);
+  CurFrame->Instructions.push_back(Instruction);
+}
+
 void MCStreamer::EmitCFIEscape(StringRef Values) {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();