From c7f552c33efdf246fa26415631e106432f3de0f3 Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Tue, 12 Feb 2013 21:33:51 +0000
Subject: [PATCH] [ms-inline-asm] Implement align directive (which is roughly
 equivalent to .align).

Also, allow _EMIT and __EMIT for the emit directive.  We already do the same
for TYPE, SIZE, and LENGTH.
rdar://13200215

llvm-svn: 175008
---
 llvm/include/llvm/MC/MCTargetAsmParser.h |  1 +
 llvm/lib/MC/MCParser/AsmParser.cpp       | 52 ++++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/llvm/include/llvm/MC/MCTargetAsmParser.h b/llvm/include/llvm/MC/MCTargetAsmParser.h
index 84585d6..4c5b176 100644
--- a/llvm/include/llvm/MC/MCTargetAsmParser.h
+++ b/llvm/include/llvm/MC/MCTargetAsmParser.h
@@ -22,6 +22,7 @@ class MCInst;
 template <typename T> class SmallVectorImpl;
 
 enum AsmRewriteKind {
+  AOK_Align,          // Rewrite align as .align.
   AOK_DotOperator,    // Rewrite a dot operator expression as an immediate.
                       // E.g., [eax].foo.bar -> [eax].8
   AOK_Emit,           // Rewrite _emit as .byte.
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index bd2c65e..7aa3812 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -443,9 +443,12 @@ private:
   bool ParseDirectiveIrpc(SMLoc DirectiveLoc); // ".irpc"
   bool ParseDirectiveEndr(SMLoc DirectiveLoc); // ".endr"
 
-  // "_emit"
-  bool ParseDirectiveEmit(SMLoc DirectiveLoc, ParseStatementInfo &Info,
-                          size_t len);
+  // "_emit" or "__emit"
+  bool ParseDirectiveMSEmit(SMLoc DirectiveLoc, ParseStatementInfo &Info,
+                            size_t Len);
+
+  // "align"
+  bool ParseDirectiveMSAlign(SMLoc DirectiveLoc, ParseStatementInfo &Info);
 
   void initializeDirectiveKindMap();
 };
@@ -1447,9 +1450,14 @@ bool AsmParser::ParseStatement(ParseStatementInfo &Info) {
     return Error(IDLoc, "unknown directive");
   }
 
-  // _emit or __emit
-  if (ParsingInlineAsm && (IDVal == "_emit" || IDVal == "__emit"))
-    return ParseDirectiveEmit(IDLoc, Info, IDVal.size());
+  // __asm _emit or __asm __emit
+  if (ParsingInlineAsm && (IDVal == "_emit" || IDVal == "__emit" ||
+                           IDVal == "_EMIT" || IDVal == "__EMIT"))
+    return ParseDirectiveMSEmit(IDLoc, Info, IDVal.size());
+
+  // __asm align
+  if (ParsingInlineAsm && (IDVal == "align" || IDVal == "ALIGN"))
+    return ParseDirectiveMSAlign(IDLoc, Info);
 
   CheckForValidSection();
 
@@ -3989,7 +3997,7 @@ bool AsmParser::ParseDirectiveEndr(SMLoc DirectiveLoc) {
   return false;
 }
 
-bool AsmParser::ParseDirectiveEmit(SMLoc IDLoc, ParseStatementInfo &Info, size_t len) {
+bool AsmParser::ParseDirectiveMSEmit(SMLoc IDLoc, ParseStatementInfo &Info, size_t Len) {
   const MCExpr *Value;
   SMLoc ExprLoc = getLexer().getLoc();
   if (ParseExpression(Value))
@@ -4001,7 +4009,23 @@ bool AsmParser::ParseDirectiveEmit(SMLoc IDLoc, ParseStatementInfo &Info, size_t
   if (!isUIntN(8, IntValue) && !isIntN(8, IntValue))
     return Error(ExprLoc, "literal value out of range for directive");
 
-  Info.AsmRewrites->push_back(AsmRewrite(AOK_Emit, IDLoc, len));
+  Info.AsmRewrites->push_back(AsmRewrite(AOK_Emit, IDLoc, Len));
+  return false;
+}
+
+bool AsmParser::ParseDirectiveMSAlign(SMLoc IDLoc, ParseStatementInfo &Info) {
+  const MCExpr *Value;
+  SMLoc ExprLoc = getLexer().getLoc();
+  if (ParseExpression(Value))
+    return true;
+  const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value);
+  if (!MCE)
+    return Error(ExprLoc, "unexpected expression in align");
+  uint64_t IntValue = MCE->getValue();
+  if (!isPowerOf2_64(IntValue))
+    return Error(ExprLoc, "literal value not a power of two greater then zero");
+
+  Info.AsmRewrites->push_back(AsmRewrite(AOK_Align, IDLoc, 5, Log2_64(IntValue)));
   return false;
 }
 
@@ -4133,6 +4157,7 @@ bool AsmParser::ParseMSInlineAsm(void *AsmLoc, std::string &AsmString,
          I = AsmStrRewrites.begin(), E = AsmStrRewrites.end(); I != E; ++I) {
     const char *Loc = (*I).Loc.getPointer();
 
+    unsigned AdditionalSkip = 0;
     AsmRewriteKind Kind = (*I).Kind;
 
     // Emit everything up to the immediate/expression.  If the previous rewrite
@@ -4180,6 +4205,15 @@ bool AsmParser::ParseMSInlineAsm(void *AsmLoc, std::string &AsmString,
     case AOK_Emit:
       OS << ".byte";
       break;
+    case AOK_Align: {
+      unsigned Val = (*I).Val;
+      OS << ".align " << Val;
+
+      // Skip the original immediate.
+      assert (Val < 10 && "Expected alignment less then 2^10.");
+      AdditionalSkip = (Val < 4) ? 2 : Val < 7 ? 3 : 4;
+      break;
+    }
     case AOK_DotOperator:
       OS << (*I).Val;
       break;
@@ -4187,7 +4221,7 @@ bool AsmParser::ParseMSInlineAsm(void *AsmLoc, std::string &AsmString,
 
     // Skip the original expression.
     if (Kind != AOK_SizeDirective)
-      Start = Loc + (*I).Len;
+      Start = Loc + (*I).Len + AdditionalSkip;
   }
 
   // Emit the remainder of the asm string.
-- 
2.7.4