Implement .cfi_escape. Patch by Brian Anderson!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147352 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCDwarf.h

@@ -271,13 +271,14 @@ namespace llvm {
 
   class MCCFIInstruction {
   public:
-    enum OpType { SameValue, Remember, Restore, Move, RelMove };
+    enum OpType { SameValue, Remember, Restore, Move, RelMove, Escape };
   private:
     OpType Operation;
     MCSymbol *Label;
     // Move to & from location.
     MachineLocation Destination;
     MachineLocation Source;
+    std::vector<char> Values;
   public:
     MCCFIInstruction(OpType Op, MCSymbol *L)
       : Operation(Op), Label(L) {
@@ -296,10 +297,17 @@ namespace llvm {
       : Operation(Op), Label(L), Destination(D), Source(S) {
       assert(Op == RelMove);
     }
+    MCCFIInstruction(OpType Op, MCSymbol *L, StringRef Vals)
+      : Operation(Op), Label(L), Values(Vals.begin(), Vals.end()) {
+      assert(Op == Escape);
+    }
     OpType getOperation() const { return Operation; }
     MCSymbol *getLabel() const { return Label; }
     const MachineLocation &getDestination() const { return Destination; }
     const MachineLocation &getSource() const { return Source; }
+    const StringRef getValues() const {
+      return StringRef(&Values[0], Values.size());
+    }
   };
 
   struct MCDwarfFrameInfo {

include/llvm/MC/MCStreamer.h

@@ -549,6 +549,7 @@ namespace llvm {
     virtual void EmitCFISameValue(int64_t Register);
     virtual void EmitCFIRelOffset(int64_t Register, int64_t Offset);
     virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
+    virtual void EmitCFIEscape(StringRef Values);
 
     virtual void EmitWin64EHStartProc(const MCSymbol *Symbol);
     virtual void EmitWin64EHEndProc();

lib/MC/MCDwarf.cpp

@@ -987,6 +987,10 @@ void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
     Streamer.EmitULEB128IntValue(Reg);
     return;
   }
+  case MCCFIInstruction::Escape:
+    if (VerboseAsm) Streamer.AddComment("Escape bytes");
+    Streamer.EmitBytes(Instr.getValues(), 0);
+    return;
   }
   llvm_unreachable("Unhandled case in switch");
 }

lib/MC/MCParser/AsmParser.cpp

@@ -301,6 +301,8 @@ public:
       &GenericAsmParser::ParseDirectiveCFIRestoreState>(".cfi_restore_state");
     AddDirectiveHandler<
       &GenericAsmParser::ParseDirectiveCFISameValue>(".cfi_same_value");
+    AddDirectiveHandler<
+      &GenericAsmParser::ParseDirectiveCFIEscape>(".cfi_escape");
 
     // Macro directives.
     AddDirectiveHandler<&GenericAsmParser::ParseDirectiveMacrosOnOff>(
@@ -334,6 +336,7 @@ public:
   bool ParseDirectiveCFIRememberState(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFIRestoreState(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveCFISameValue(StringRef, SMLoc DirectiveLoc);
+  bool ParseDirectiveCFIEscape(StringRef, SMLoc DirectiveLoc);
 
   bool ParseDirectiveMacrosOnOff(StringRef, SMLoc DirectiveLoc);
   bool ParseDirectiveMacro(StringRef, SMLoc DirectiveLoc);
@@ -2812,6 +2815,30 @@ bool GenericAsmParser::ParseDirectiveCFISameValue(StringRef IDVal,
   return false;
 }
 
+/// ParseDirectiveCFIEscape
+/// ::= .cfi_escape expression[,...]
+bool GenericAsmParser::ParseDirectiveCFIEscape(StringRef IDVal,
+					       SMLoc DirectiveLoc) {
+  std::string Values;
+  int64_t CurrValue;
+  if (getParser().ParseAbsoluteExpression(CurrValue))
+    return true;
+
+  Values.push_back((uint8_t)CurrValue);
+
+  while (getLexer().is(AsmToken::Comma)) {
+    Lex();
+
+    if (getParser().ParseAbsoluteExpression(CurrValue))
+      return true;
+
+    Values.push_back((uint8_t)CurrValue);
+  }
+
+  getStreamer().EmitCFIEscape(Values);
+  return false;
+}
+
 /// ParseDirectiveMacrosOnOff
 /// ::= .macros_on
 /// ::= .macros_off

lib/MC/MCStreamer.cpp

@@ -408,6 +408,15 @@ void MCStreamer::EmitCFISameValue(int64_t Register) {
   CurFrame->Instructions.push_back(Instruction);
 }
 
+void MCStreamer::EmitCFIEscape(StringRef Values) {
+  EnsureValidFrame();
+  MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
+  MCSymbol *Label = getContext().CreateTempSymbol();
+  EmitLabel(Label);
+  MCCFIInstruction Instruction(MCCFIInstruction::Escape, Label, Values);
+  CurFrame->Instructions.push_back(Instruction);
+}
+
 void MCStreamer::setCurrentW64UnwindInfo(MCWin64EHUnwindInfo *Frame) {
   W64UnwindInfos.push_back(Frame);
   CurrentW64UnwindInfo = W64UnwindInfos.back();

test/MC/ELF/cfi-escape.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_escape 0x15, 7, 0x7f # DW_CFA_val_offset_sf, %esp, 8/-8
+        nop
+	.cfi_endproc
+
+// CHECK:       # Section 4
+// CHECK-NEXT:  (('sh_name', 0x00000011) # '.eh_frame'
+// CHECK-NEXT:   ('sh_type', 0x00000001)
+// CHECK-NEXT:   ('sh_flags', 0x0000000000000002)
+// CHECK-NEXT:   ('sh_addr', 0x0000000000000000)
+// CHECK-NEXT:   ('sh_offset', 0x0000000000000048)
+// CHECK-NEXT:   ('sh_size', 0x0000000000000030)
+// CHECK-NEXT:   ('sh_link', 0x00000000)
+// CHECK-NEXT:   ('sh_info', 0x00000000)
+// CHECK-NEXT:   ('sh_addralign', 0x0000000000000008)
+// CHECK-NEXT:   ('sh_entsize', 0x0000000000000000)
+// CHECK-NEXT:   ('_section_data', '14000000 00000000 017a5200 01781001 1b0c0708 90010000 14000000 1c000000 00000000 02000000 00411507 7f000000')
+// CHECK-NEXT:  ),
+// CHECK-NEXT:  # Section 5
+// CHECK-NEXT:  (('sh_name', 0x0000000c) # '.rela.eh_frame'
+// CHECK-NEXT:   ('sh_type', 0x00000004)
+// CHECK-NEXT:   ('sh_flags', 0x0000000000000000)
+// CHECK-NEXT:   ('sh_addr', 0x0000000000000000)
+// CHECK-NEXT:   ('sh_offset', 0x0000000000000390)
+// CHECK-NEXT:   ('sh_size', 0x0000000000000018)
+// CHECK-NEXT:   ('sh_link', 0x00000007)
+// CHECK-NEXT:   ('sh_info', 0x00000004)
+// CHECK-NEXT:   ('sh_addralign', 0x0000000000000008)
+// CHECK-NEXT:   ('sh_entsize', 0x0000000000000018)
+// CHECK-NEXT:   ('_relocations', [
+// CHECK-NEXT:    # Relocation 0
+// CHECK-NEXT:    (('r_offset', 0x0000000000000020)
+// CHECK-NEXT:     ('r_sym', 0x00000002)
+// CHECK-NEXT:     ('r_type', 0x00000002)
+// CHECK-NEXT:     ('r_addend', 0x0000000000000000)
+// CHECK-NEXT:    ),
+// CHECK-NEXT:   ])
+// CHECK-NEXT:  ),