[MSP430] Add support for .refsym directive

Introduces support for '.refsym' assembler directive.

From GCC docs (for MSP430):
'.refsym' - This directive instructs assembler to add an undefined reference
to the symbol following the directive. No relocation is created for this symbol;
it will exist purely for pulling in object files from archives.

Patch by Kristina Bessonova!

Differential Revision: https://reviews.llvm.org/D54618

llvm-svn: 347041

2 files changed, 27 insertions, 0 deletions

diff --git a/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp b/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
index 51b6918105e..3cc6da2c21a 100644
--- a/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
+++ b/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
@@ -51,6 +51,7 @@ class MSP430AsmParser : public MCTargetAsmParser {
                         SMLoc NameLoc, OperandVector &Operands) override;
 
   bool ParseDirective(AsmToken DirectiveID) override;
+  bool ParseDirectiveRefSym(AsmToken DirectiveID);
 
   unsigned validateTargetOperandClass(MCParsedAsmOperand &Op,
                                       unsigned Kind) override;
@@ -407,6 +408,16 @@ bool MSP430AsmParser::ParseInstruction(ParseInstructionInfo &Info,
   return false;
 }
 
+bool MSP430AsmParser::ParseDirectiveRefSym(AsmToken DirectiveID) {
+    StringRef Name;
+    if (getParser().parseIdentifier(Name))
+      return TokError("expected identifier in directive");
+
+    MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
+    getStreamer().EmitSymbolAttribute(Sym, MCSA_Global);
+    return false;
+}
+
 bool MSP430AsmParser::ParseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getIdentifier();
   if (IDVal.lower() == ".long") {
@@ -415,6 +426,8 @@ bool MSP430AsmParser::ParseDirective(AsmToken DirectiveID) {
     ParseLiteralValues(2, DirectiveID.getLoc());
   } else if (IDVal.lower() == ".byte") {
     ParseLiteralValues(1, DirectiveID.getLoc());
+  } else if (IDVal.lower() == ".refsym") {
+    return ParseDirectiveRefSym(DirectiveID);
   }
   return true;
 }
diff --git a/llvm/test/MC/MSP430/refsym.s b/llvm/test/MC/MSP430/refsym.s
new file mode 100644
index 00000000000..684894ca992
--- /dev/null
+++ b/llvm/test/MC/MSP430/refsym.s
@@ -0,0 +1,14 @@
+# RUN: llvm-mc -filetype=obj -triple=msp430 %s | llvm-readobj -t - | FileCheck %s
+
+foo:
+  .refsym __hook
+
+; CHECK:       Symbol {
+; CHECK:         Name: __hook (30)
+; CHECK-NEXT:    Value: 0x0
+; CHECK-NEXT:    Size: 0
+; CHECK-NEXT:    Binding: Global (0x1)
+; CHECK-NEXT:    Type: None (0x0)
+; CHECK-NEXT:    Other: 0
+; CHECK-NEXT:    Section: Undefined (0x0)
+; CHECK-NEXT:  }