Implement .cfi_same_value.

llvm-svn: 129361

llvm/include/llvm/MC/MCDwarf.h

@@ -230,7 +230,7 @@ namespace llvm {
 
   class MCCFIInstruction {
   public:
-    enum OpType { Remember, Restore, Move };
+    enum OpType { SameValue, Remember, Restore, Move };
   private:
     OpType Operation;
     MCSymbol *Label;
@@ -242,6 +242,10 @@ namespace llvm {
       : Operation(Op), Label(L) {
       assert(Op == Remember || Op == Restore);
     }
+    MCCFIInstruction(OpType Op, MCSymbol *L, unsigned Register)
+      : Operation(Op), Label(L), Destination(Register) {
+      assert(Op == SameValue);
+    }
     MCCFIInstruction(MCSymbol *L, const MachineLocation &D,
                      const MachineLocation &S)
       : Operation(Move), Label(L), Destination(D), Source(S) {

llvm/include/llvm/MC/MCStreamer.h

@@ -446,6 +446,7 @@ namespace llvm {
     virtual bool EmitCFILsda(const MCSymbol *Sym, unsigned Encoding);
     virtual bool EmitCFIRememberState();
     virtual bool EmitCFIRestoreState();
+    void EmitCFISameValue(int64_t Register);
 
     /// EmitInstruction - Emit the given @p Instruction into the current
     /// section.

llvm/lib/MC/MCDwarf.cpp

@@ -493,6 +493,12 @@ static void EmitCFIInstruction(MCStreamer &Streamer,
   case MCCFIInstruction::Restore:
     Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
     return;
+  case MCCFIInstruction::SameValue: {
+    unsigned Reg = Instr.getDestination().getReg();
+    Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
+    Streamer.EmitULEB128IntValue(Reg, 1);
+    return;
+  }
   }
   llvm_unreachable("Unhandled case in switch");
 }

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -283,6 +283,8 @@ public:
       &GenericAsmParser::ParseDirectiveCFIRememberState>(".cfi_remember_state");
     AddDirectiveHandler<
       &GenericAsmParser::ParseDirectiveCFIRestoreState>(".cfi_restore_state");
+    AddDirectiveHandler<
+      &GenericAsmParser::ParseDirectiveCFISameValue>(".cfi_same_value");
 
     // Macro directives.
     AddDirectiveHandler<&GenericAsmParser::ParseDirectiveMacrosOnOff>(
@@ -314,6 +316,7 @@ public:
   bool ParseDirectiveCFIPersonalityOrLsda(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFIRememberState(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFIRestoreState(StringRef, SMLoc DirectiveLoc);
+  bool ParseDirectiveCFISameValue(StringRef, SMLoc DirectiveLoc);
 
   bool ParseDirectiveMacrosOnOff(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveMacro(StringRef, SMLoc DirectiveLoc);
@@ -2472,6 +2475,20 @@ bool GenericAsmParser::ParseDirectiveCFIRestoreState(StringRef IDVal,
   return getStreamer().EmitCFIRestoreState();
 }
 
+/// ParseDirectiveCFISameValue
+/// ::= .cfi_same_value register
+bool GenericAsmParser::ParseDirectiveCFISameValue(StringRef IDVal,
+                                                  SMLoc DirectiveLoc) {
+  int64_t Register = 0;
+
+  if (ParseRegisterOrRegisterNumber(Register, DirectiveLoc))
+    return true;
+
+  getStreamer().EmitCFISameValue(Register);
+
+  return false;
+}
+
 /// ParseDirectiveMacrosOnOff
 /// ::= .macros_on
 /// ::= .macros_off

llvm/lib/MC/MCStreamer.cpp

@@ -259,6 +259,15 @@ bool MCStreamer::EmitCFIRestoreState() {
   return false;
 }
 
+void MCStreamer::EmitCFISameValue(int64_t Register) {
+  EnsureValidFrame();
+  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
+  MCSymbol *Label = getContext().CreateTempSymbol();
+  EmitLabel(Label);
+  MCCFIInstruction Instruction(MCCFIInstruction::SameValue, Label, Register);
+  CurFrame->Instructions.push_back(Instruction);
+}
+
 void MCStreamer::EmitFnStart() {
   errs() << "Not implemented yet\n";
   abort();

llvm/test/MC/ELF/cfi-same-value.s

@@ -0,0 +1,42 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump  --dump-section-data | FileCheck %s
+
+f:
+	.cfi_startproc
+        nop
+        .cfi_same_value 6
+        nop
+	.cfi_endproc
+
+// CHECK:       # Section 0x00000004
+// CHECK-NEXT:  (('sh_name', 0x00000011) # '.eh_frame'
+// CHECK-NEXT:   ('sh_type', 0x00000001)
+// CHECK-NEXT:   ('sh_flags', 0x00000002)
+// CHECK-NEXT:   ('sh_addr', 0x00000000)
+// CHECK-NEXT:   ('sh_offset', 0x00000048)
+// CHECK-NEXT:   ('sh_size', 0x00000030)
+// CHECK-NEXT:   ('sh_link', 0x00000000)
+// CHECK-NEXT:   ('sh_info', 0x00000000)
+// CHECK-NEXT:   ('sh_addralign', 0x00000008)
+// CHECK-NEXT:   ('sh_entsize', 0x00000000)
+// CHECK-NEXT:   ('_section_data', '14000000 00000000 017a5200 01781001 1b0c0708 90010000 14000000 1c000000 00000000 02000000 00410806 00000000')
+// CHECK-NEXT:  ),
+// CHECK-NEXT:  # Section 0x00000005
+// CHECK-NEXT:  (('sh_name', 0x0000000c) # '.rela.eh_frame'
+// CHECK-NEXT:   ('sh_type', 0x00000004)
+// CHECK-NEXT:   ('sh_flags', 0x00000000)
+// CHECK-NEXT:   ('sh_addr', 0x00000000)
+// CHECK-NEXT:   ('sh_offset', 0x00000390)
+// CHECK-NEXT:   ('sh_size', 0x00000018)
+// CHECK-NEXT:   ('sh_link', 0x00000007)
+// CHECK-NEXT:   ('sh_info', 0x00000004)
+// CHECK-NEXT:   ('sh_addralign', 0x00000008)
+// CHECK-NEXT:   ('sh_entsize', 0x00000018)
+// CHECK-NEXT:   ('_relocations', [
+// CHECK-NEXT:    # Relocation 0x00000000
+// CHECK-NEXT:    (('r_offset', 0x00000020)
+// CHECK-NEXT:     ('r_sym', 0x00000002)
+// CHECK-NEXT:     ('r_type', 0x00000002)
+// CHECK-NEXT:     ('r_addend', 0x00000000)
+// CHECK-NEXT:    ),
+// CHECK-NEXT:   ])
+// CHECK-NEXT:  ),