Get MCSymbol out of the mangling business, and move all the logic

to Mangler.  Now MCSymbol just decides whether to slap quotes around
a symbol when printing it.

This also fixes some weirdness where two MCSymbols could be created
for the same symbol, if one needed to be mangled and got mangled to
the other one.

llvm-svn: 93690

include/llvm/MC/MCSymbol.h

@@ -26,7 +26,8 @@ namespace llvm {
   class raw_ostream;
 
   /// MCSymbol - Instances of this class represent a symbol name in the MC file,
-  /// and MCSymbols are created and unique'd by the MCContext class.
+  /// and MCSymbols are created and unique'd by the MCContext class.  MCSymbols
+  /// should only be constructed with valid names for the object file.
   ///
   /// If the symbol is defined/emitted into the current translation unit, the
   /// Section member is set to indicate what section it lives in.  Otherwise, if
@@ -53,7 +54,7 @@ namespace llvm {
     /// typically does not survive in the .o file's symbol table.  Usually
     /// "Lfoo" or ".foo".
     unsigned IsTemporary : 1;
-
+    
   private:  // MCContext creates and uniques these.
     friend class MCContext;
     MCSymbol(StringRef _Name, bool _IsTemporary)
@@ -136,11 +137,6 @@ namespace llvm {
 
     /// dump - Print the value to stderr.
     void dump() const;
-    
-    /// printMangledName - Print the specified string in mangled form if it uses
-    /// any unusual characters.
-    static void printMangledName(StringRef Str, raw_ostream &OS,
-                                 const MCAsmInfo *MAI);
   };
 
 } // end namespace llvm

include/llvm/Target/Mangler.h

@@ -18,6 +18,7 @@
 #include <string>
 
 namespace llvm {
+class StringRef;
 class Twine;
 class Value;
 class GlobalValue;
@@ -67,6 +68,11 @@ public:
   /// have a name, this fills in a unique name for the global.
   std::string getNameWithPrefix(const GlobalValue *GV,
                                 bool isImplicitlyPrivate = false);
+
+  /// appendMangledName - Add the specified string in mangled form if it uses
+  /// any unusual characters.
+  static void appendMangledName(SmallVectorImpl<char> &OutName, StringRef Str,
+                                const MCAsmInfo *MAI);
 };
 
 } // End llvm namespace

lib/MC/MCSymbol.cpp

@@ -26,14 +26,6 @@ static bool isAcceptableChar(char C) {
   return true;
 }
 
-static char HexDigit(int V) {
-  return V < 10 ? V+'0' : V+'A'-10;
-}
-
-static void MangleLetter(raw_ostream &OS, unsigned char C) {
-  OS << '_' << HexDigit(C >> 4) << HexDigit(C & 15) << '_';
-}
-
 /// NameNeedsEscaping - Return true if the identifier \arg Str needs quotes
 /// for this assembler.
 static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo &MAI) {
@@ -43,7 +35,7 @@ static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo &MAI) {
   // need quotes.
   if (!MAI.doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9')
     return true;
-
+  
   // If any of the characters in the string is an unacceptable character, force
   // quotes.
   for (unsigned i = 0, e = Str.size(); i != e; ++i)
@@ -52,59 +44,14 @@ static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo &MAI) {
   return false;
 }
 
-/// printMangledName - Print the specified string in mangled form if it uses
-/// any unusual characters.
-void MCSymbol::printMangledName(StringRef Str, raw_ostream &OS,
-                                const MCAsmInfo *MAI) {
-  // The first character is not allowed to be a number unless the target
-  // explicitly allows it.
-  if ((MAI == 0 || !MAI->doesAllowNameToStartWithDigit()) &&
-      Str[0] >= '0' && Str[0] <= '9') {
-    MangleLetter(OS, Str[0]);
-    Str = Str.substr(1);
-  }
-  
-  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
-    if (!isAcceptableChar(Str[i]))
-      MangleLetter(OS, Str[i]);
-    else
-      OS << Str[i];
-  }
-}
-
-/// PrintMangledQuotedName - On systems that support quoted symbols, we still
-/// have to escape some (obscure) characters like " and \n which would break the
-/// assembler's lexing.
-static void PrintMangledQuotedName(raw_ostream &OS, StringRef Str) {
-  OS << '"';
-
-  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
-    if (Str[i] == '"')
-      OS << "_QQ_";
-    else if (Str[i] == '\n')
-      OS << "_NL_";
-    else
-      OS << Str[i];
-  }
-  OS << '"';
-}
-
-
 void MCSymbol::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
+  // The name for this MCSymbol is required to be a valid target name.  However,
+  // some targets support quoting names with funny characters.  If the name
+  // contains a funny character, then print it quoted.
   if (MAI == 0 || !NameNeedsEscaping(getName(), *MAI)) {
     OS << getName();
     return;
   }
-
-  // On systems that do not allow quoted names, print with mangling.
-  if (!MAI->doesAllowQuotesInName())
-    return printMangledName(getName(), OS, MAI);
-
-  // If the string contains a double quote or newline, we still have to mangle
-  // it.
-  if (getName().find('"') != std::string::npos ||
-      getName().find('\n') != std::string::npos)
-    return PrintMangledQuotedName(OS, getName());
     
   OS << '"' << getName() << '"';
 }

lib/Target/CBackend/CBackend.cpp

@@ -352,10 +352,9 @@ char CWriter::ID = 0;
 
 
 static std::string Mangle(const std::string &S) {
-  std::string Result;
-  raw_string_ostream OS(Result);
-  MCSymbol::printMangledName(S, OS, 0);
-  return OS.str();
+  SmallString<52> Result;
+  Mangler::appendMangledName(Result, S, 0);
+  return std::string(Result.begin(), Result.end());
 }
 
 
@@ -1452,7 +1451,7 @@ std::string CWriter::GetValueName(const Value *Operand) {
   if (const GlobalValue *GV = dyn_cast<GlobalValue>(Operand)) {
     SmallString<128> Str;
     Mang->getNameWithPrefix(Str, GV, false);
-    return Mangle(Str.str().str());
+    return Str.str().str();
   }
     
   std::string Name = Operand->getName();

lib/Target/Mangler.cpp

@@ -18,6 +18,79 @@
 #include "llvm/ADT/Twine.h"
 using namespace llvm;
 
+static bool isAcceptableChar(char C) {
+  if ((C < 'a' || C > 'z') &&
+      (C < 'A' || C > 'Z') &&
+      (C < '0' || C > '9') &&
+      C != '_' && C != '$' && C != '.' && C != '@')
+    return false;
+  return true;
+}
+
+static char HexDigit(int V) {
+  return V < 10 ? V+'0' : V+'A'-10;
+}
+
+static void MangleLetter(SmallVectorImpl<char> &OutName, unsigned char C) {
+  OutName.push_back('_');
+  OutName.push_back(HexDigit(C >> 4));
+  OutName.push_back(HexDigit(C & 15));
+  OutName.push_back('_');
+}
+
+/// NameNeedsEscaping - Return true if the identifier \arg Str needs quotes
+/// for this assembler.
+static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo &MAI) {
+  assert(!Str.empty() && "Cannot create an empty MCSymbol");
+  
+  // If the first character is a number and the target does not allow this, we
+  // need quotes.
+  if (!MAI.doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9')
+    return true;
+  
+  // If any of the characters in the string is an unacceptable character, force
+  // quotes.
+  for (unsigned i = 0, e = Str.size(); i != e; ++i)
+    if (!isAcceptableChar(Str[i]))
+      return true;
+  return false;
+}
+
+/// appendMangledName - Add the specified string in mangled form if it uses
+/// any unusual characters.
+void Mangler::appendMangledName(SmallVectorImpl<char> &OutName, StringRef Str,
+                                const MCAsmInfo *MAI) {
+  // The first character is not allowed to be a number unless the target
+  // explicitly allows it.
+  if ((MAI == 0 || !MAI->doesAllowNameToStartWithDigit()) &&
+      Str[0] >= '0' && Str[0] <= '9') {
+    MangleLetter(OutName, Str[0]);
+    Str = Str.substr(1);
+  }
+  
+  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
+    if (!isAcceptableChar(Str[i]))
+      MangleLetter(OutName, Str[i]);
+    else
+      OutName.push_back(Str[i]);
+  }
+}
+
+
+/// appendMangledQuotedName - On systems that support quoted symbols, we still
+/// have to escape some (obscure) characters like " and \n which would break the
+/// assembler's lexing.
+static void appendMangledQuotedName(SmallVectorImpl<char> &OutName,
+                                   StringRef Str) {
+  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
+    if (Str[i] == '"' || Str[i] == '\n')
+      MangleLetter(OutName, Str[i]);
+    else
+      OutName.push_back(Str[i]);
+  }
+}
+
+
 /// getNameWithPrefix - Fill OutName with the name of the appropriate prefix
 /// and the specified name as the global variable name.  GVName must not be
 /// empty.
@@ -28,7 +101,9 @@ void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
   assert(!Name.empty() && "getNameWithPrefix requires non-empty name");
   
   // If the global name is not led with \1, add the appropriate prefixes.
-  if (Name[0] != '\1') {
+  if (Name[0] == '\1') {
+    Name = Name.substr(1);
+  } else {
     if (PrefixTy == Mangler::Private) {
       const char *Prefix = MAI.getPrivateGlobalPrefix();
       OutName.append(Prefix, Prefix+strlen(Prefix));
@@ -44,11 +119,27 @@ void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
       OutName.push_back(Prefix[0]);  // Common, one character prefix.
     else
       OutName.append(Prefix, Prefix+strlen(Prefix)); // Arbitrary length prefix.
-  } else {
-    Name = Name.substr(1);
   }
   
-  OutName.append(Name.begin(), Name.end());
+  // If this is a simple string that doesn't need escaping, just append it.
+  if (!NameNeedsEscaping(Name, MAI) ||
+      // If quotes are supported, they can be used unless the string contains
+      // a quote or newline.
+      (MAI.doesAllowQuotesInName() &&
+       Name.find_first_of("\n\"") == StringRef::npos)) {
+    OutName.append(Name.begin(), Name.end());
+    return;
+  }
+  
+  // On systems that do not allow quoted names, we need to mangle most
+  // strange characters.
+  if (!MAI.doesAllowQuotesInName())
+    return appendMangledName(OutName, Name, &MAI);
+  
+  // Okay, the system allows quoted strings.  We can quote most anything, the
+  // only characters that need escaping are " and \n.
+  assert(Name.find_first_of("\n\"") != StringRef::npos);
+  return appendMangledQuotedName(OutName, Name);
 }
 
 

lib/Target/TargetLoweringObjectFile.cpp

@@ -579,18 +579,11 @@ SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
   // into a 'uniqued' section name, create and return the section now.
   if (GV->isWeakForLinker()) {
     const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
-    SmallString<128> Name, MangledName;
+    SmallString<128> Name;
     Name.append(Prefix, Prefix+strlen(Prefix));
     Mang->getNameWithPrefix(Name, GV, false);
-    
-    raw_svector_ostream OS(MangledName);
-    MCSymbol::printMangledName(Name, OS, 0);
-    OS.flush();
-    
-    return getELFSection(MangledName.str(),
-                         getELFSectionType(MangledName.str(), Kind),
-                         getELFSectionFlags(Kind),
-                         Kind);
+    return getELFSection(Name.str(), getELFSectionType(Name.str(), Kind),
+                         getELFSectionFlags(Kind), Kind);
   }
 
   if (Kind.isText()) return TextSection;