From 11ee007384e14ee8517f6f90b83452ea59a979c4 Mon Sep 17 00:00:00 2001
From: Iain Sandoe <iain@codesourcery.com>
Date: Sat, 7 Dec 2013 02:42:06 +0000
Subject: [PATCH] part 3 after review

---
 lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp | 60 ++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 2 deletions(-)

diff --git a/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp b/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
index bd1ceca..c698408 100644
--- a/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
+++ b/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
@@ -197,6 +197,7 @@ class PPCAsmParser : public MCTargetAsmParser {
                                         PPCMCExpr::VariantKind &Variant);
   const MCExpr *FixupVariantKind(const MCExpr *E);
   bool ParseExpression(const MCExpr *&EVal);
+  bool ParseDarwinExpression(const MCExpr *&EVal);
 
   bool ParseOperand(SmallVectorImpl<MCParsedAsmOperand*> &Operands);
 
@@ -1085,10 +1086,16 @@ FixupVariantKind(const MCExpr *E) {
   llvm_unreachable("Invalid expression kind!");
 }
 
-/// Parse an expression.  This differs from the default "parseExpression"
-/// in that it handles complex \code @l/@ha \endcode modifiers.
+/// ParseExpression.  This differs from the default "parseExpression" in that
+/// it handles modifiers.
 bool PPCAsmParser::
 ParseExpression(const MCExpr *&EVal) {
+
+  if (isDarwin())
+    return ParseDarwinExpression(EVal);
+
+  // (ELF Platforms)
+  // Handle \code @l/@ha \endcode
   if (getParser().parseExpression(EVal))
     return true;
 
@@ -1102,6 +1109,55 @@ ParseExpression(const MCExpr *&EVal) {
   return false;
 }
 
+/// ParseDarwinExpression.  (MachO Platforms)
+/// This differs from the default "parseExpression" in that it handles detection
+/// of the \code hi16(), ha16() and lo16() \endcode modifiers.  At present,
+/// parseExpression() doesn't recognise the modifiers when in the Darwin/MachO
+/// syntax form so it is done here.  TODO: Determine if there is merit in arranging
+/// for this to be done at a higher level.
+bool PPCAsmParser::
+ParseDarwinExpression(const MCExpr *&EVal) {
+  PPCMCExpr::VariantKind Variant = PPCMCExpr::VK_PPC_None;
+  switch (getLexer().getKind()) {
+  default:
+    break;
+  case AsmToken::Identifier:
+    // Compiler-generated Darwin identifiers begin with L,l,_ or "; thus
+    // something starting with any other char should be part of the
+    // asm syntax.  If handwritten asm includes an identifier like lo16,
+    // then all bets are off - but no-one would do that, right?
+    StringRef poss = Parser.getTok().getString();
+    if (poss.equals_lower("lo16")) {
+      Variant = PPCMCExpr::VK_PPC_LO;
+    } else if (poss.equals_lower("hi16")) {
+      Variant = PPCMCExpr::VK_PPC_HI;
+    } else if (poss.equals_lower("ha16")) {
+      Variant = PPCMCExpr::VK_PPC_HA;
+    }
+    if (Variant != PPCMCExpr::VK_PPC_None) {
+      Parser.Lex(); // Eat the xx16
+      if (getLexer().isNot(AsmToken::LParen))
+        return Error(Parser.getTok().getLoc(), "expected '('");
+      Parser.Lex(); // Eat the '('
+    }
+    break;
+  }
+
+  if (getParser().parseExpression(EVal))
+    return true;
+
+  if (Variant != PPCMCExpr::VK_PPC_None) {
+    if (getLexer().isNot(AsmToken::RParen))
+      return Error(Parser.getTok().getLoc(), "expected ')'");
+    Parser.Lex(); // Eat the ')'
+    EVal = PPCMCExpr::Create(Variant, EVal, false, getParser().getContext());
+  }
+  return false;
+}
+
+/// ParseOperand
+/// This handles registers in the form 'NN', '%rNN' for ELF platforms and
+/// rNN for MachO.
 bool PPCAsmParser::
 ParseOperand(SmallVectorImpl<MCParsedAsmOperand*> &Operands) {
   SMLoc S = Parser.getTok().getLoc();
-- 
1.7.11.1