Basic/TargetInfo.cpp

//===--- TargetInfo.cpp - Information about Target machine ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the TargetInfo and TargetInfoImpl interfaces.
//
//===----------------------------------------------------------------------===//

#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/AST/Builtins.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/STLExtras.h"
#include <set>
using namespace clang;

void TargetInfoImpl::ANCHOR() {} // out-of-line virtual method for class.


//===----------------------------------------------------------------------===//
// FIXME: These are temporary hacks, they should revector into the
// TargetInfoImpl.

void TargetInfo::getFloatInfo(uint64_t &Size, unsigned &Align,
                              const llvm::fltSemantics *&Format,
                              SourceLocation Loc) {
  Align = 32;  // FIXME: implement correctly.
  Size = 32;
  Format = &llvm::APFloat::IEEEsingle;
}
void TargetInfo::getDoubleInfo(uint64_t &Size, unsigned &Align,
                               const llvm::fltSemantics *&Format,
                               SourceLocation Loc) {
  Size = Align = 64;  // FIXME: implement correctly.
  Format = &llvm::APFloat::IEEEdouble;
}
void TargetInfo::getLongDoubleInfo(uint64_t &Size, unsigned &Align,
                                   const llvm::fltSemantics *&Format,
                                   SourceLocation Loc) {
  Size = Align = 64;  // FIXME: implement correctly.
  Format = &llvm::APFloat::IEEEdouble;
  //Size = 80; Align = 32;  // FIXME: implement correctly.
  //Format = &llvm::APFloat::x87DoubleExtended;
}


//===----------------------------------------------------------------------===//

/// DiagnoseNonPortability - When a use of a non-portable target feature is
/// used, this method emits the diagnostic and marks the translation unit as
/// non-portable.
void TargetInfo::DiagnoseNonPortability(SourceLocation Loc, unsigned DiagKind) {
  NonPortable = true;
  if (Diag && Loc.isValid()) Diag->Report(Loc, DiagKind);
}

/// GetTargetDefineMap - Get the set of target #defines in an associative
/// collection for easy lookup.
static void GetTargetDefineMap(const TargetInfoImpl *Target,
                               llvm::StringMap<std::string> &Map) {
  std::vector<char> Defines;
  Defines.reserve(4096);
  Target->getTargetDefines(Defines);

  for (const char *DefStr = &Defines[0], *E = DefStr+Defines.size();
       DefStr != E;) {
    // Skip the '#define ' portion.
    assert(memcmp(DefStr, "#define ", strlen("#define ")) == 0 &&
           "#define didn't start with #define!");
    DefStr += strlen("#define ");
    
    // Find the divider between the key and value.
    const char *SpacePos = strchr(DefStr, ' ');

    std::string &Entry = Map.GetOrCreateValue(DefStr, SpacePos).getValue();

    const char *EndPos = strchr(SpacePos+1, '\n');
    Entry = std::string(SpacePos+1, EndPos);
    DefStr = EndPos+1;
  }
}

/// getTargetDefines - Appends the target-specific #define values for this
/// target set to the specified buffer.
void TargetInfo::getTargetDefines(std::vector<char> &Buffer) {
  // If we have no secondary targets, be a bit more efficient.
  if (SecondaryTargets.empty()) {
    PrimaryTarget->getTargetDefines(Buffer);
    return;
  }
  
  // This is tricky in the face of secondary targets.  Specifically, 
  // target-specific #defines that are present and identical across all
  // secondary targets are turned into #defines, #defines that are present in
  // the primary target but are missing or different in the secondary targets
  // are turned into #define_target, and #defines that are not defined in the
  // primary, but are defined in a secondary are turned into
  // #define_other_target.  This allows the preprocessor to correctly track uses
  // of target-specific macros.
  
  // Get the set of primary #defines.
  llvm::StringMap<std::string> PrimaryDefines;
  GetTargetDefineMap(PrimaryTarget, PrimaryDefines);
  
  // Get the sets of secondary #defines.
  llvm::StringMap<std::string> *SecondaryDefines
    = new llvm::StringMap<std::string>[SecondaryTargets.size()];
  for (unsigned i = 0, e = SecondaryTargets.size(); i != e; ++i)
    GetTargetDefineMap(SecondaryTargets[i], SecondaryDefines[i]);

  // Loop over all defines in the primary target, processing them until we run
  // out.
  for (llvm::StringMap<std::string>::iterator PDI = 
         PrimaryDefines.begin(), E = PrimaryDefines.end(); PDI != E; ++PDI) {
    std::string DefineName(PDI->getKeyData(),
                           PDI->getKeyData() + PDI->getKeyLength());
    std::string DefineValue = PDI->getValue();
    
    // Check to see whether all secondary targets have this #define and whether
    // it is to the same value.  Remember if not, but remove the #define from
    // their collection in any case if they have it.
    bool isPortable = true;
    
    for (unsigned i = 0, e = SecondaryTargets.size(); i != e; ++i) {
      llvm::StringMap<std::string>::iterator I = 
        SecondaryDefines[i].find(&DefineName[0],
                                 &DefineName[0]+DefineName.size());
      if (I == SecondaryDefines[i].end()) {
        // Secondary target doesn't have this #define.
        isPortable = false;
      } else {
        // Secondary target has this define, remember if it disagrees.
        if (isPortable)
          isPortable = I->getValue() == DefineValue;
        // Remove it from the secondary target unconditionally.
        SecondaryDefines[i].erase(I);
      }
    }
    
    // If this define is non-portable, turn it into #define_target, otherwise
    // just use #define.
    const char *Command = isPortable ? "#define " : "#define_target ";
    Buffer.insert(Buffer.end(), Command, Command+strlen(Command));

    // Insert "defname defvalue\n".
    Buffer.insert(Buffer.end(), DefineName.begin(), DefineName.end());
    Buffer.push_back(' ');
    Buffer.insert(Buffer.end(), DefineValue.begin(), DefineValue.end());
    Buffer.push_back('\n');
  }
  
  // Now that all of the primary target's defines have been handled and removed
  // from the secondary target's define sets, go through the remaining secondary
  // target's #defines and taint them.
  for (unsigned i = 0, e = SecondaryTargets.size(); i != e; ++i) {
    llvm::StringMap<std::string> &Defs = SecondaryDefines[i];
    while (!Defs.empty()) {
      const char *DefStart = Defs.begin()->getKeyData();
      const char *DefEnd = DefStart + Defs.begin()->getKeyLength();
      
      // Insert "#define_other_target defname".
      const char *Command = "#define_other_target ";
      Buffer.insert(Buffer.end(), Command, Command+strlen(Command));
      Buffer.insert(Buffer.end(), DefStart, DefEnd);
      Buffer.push_back('\n');
      
      // If any other secondary targets have this same define, remove it from
      // them to avoid duplicate #define_other_target directives.
      for (unsigned j = i+1; j != e; ++j) {
        llvm::StringMap<std::string>::iterator I =
          SecondaryDefines[j].find(DefStart, DefEnd);
        if (I != SecondaryDefines[j].end())
          SecondaryDefines[j].erase(I);
      }
      Defs.erase(Defs.begin());
    }
  }
  
  delete[] SecondaryDefines;
}

/// ComputeWCharWidth - Determine the width of the wchar_t type for the primary
/// target, diagnosing whether this is non-portable across the secondary
/// targets.
void TargetInfo::ComputeWCharInfo(SourceLocation Loc) {
  PrimaryTarget->getWCharInfo(WCharWidth, WCharAlign);
  
  // Check whether this is portable across the secondary targets if the T-U is
  // portable so far.
  for (unsigned i = 0, e = SecondaryTargets.size(); i != e; ++i) {
    unsigned Width, Align;
    SecondaryTargets[i]->getWCharInfo(Width, Align);
    if (Width != WCharWidth || Align != WCharAlign)
      return DiagnoseNonPortability(Loc, diag::port_wchar_t);
  }
}


/// getTargetBuiltins - Return information about target-specific builtins for
/// the current primary target, and info about which builtins are non-portable
/// across the current set of primary and secondary targets.
void TargetInfo::getTargetBuiltins(const Builtin::Info *&Records,
                                   unsigned &NumRecords,
                                   std::vector<const char *> &NPortable) const {
  // Get info about what actual builtins we will expose.
  PrimaryTarget->getTargetBuiltins(Records, NumRecords);
  if (SecondaryTargets.empty()) return;
 
  // Compute the set of non-portable builtins.
  
  // Start by computing a mapping from the primary target's builtins to their
  // info records for efficient lookup.
  llvm::StringMap<const Builtin::Info*> PrimaryRecs;
  for (unsigned i = 0, e = NumRecords; i != e; ++i) {
    const char *BIName = Records[i].Name;
    PrimaryRecs.GetOrCreateValue(BIName, BIName+strlen(BIName)).getValue()
      = Records+i;
  }
  
  for (unsigned i = 0, e = SecondaryTargets.size(); i != e; ++i) {
    // Get the builtins for this secondary target.
    const Builtin::Info *Records2nd;
    unsigned NumRecords2nd;
    SecondaryTargets[i]->getTargetBuiltins(Records2nd, NumRecords2nd);
    
    // Remember all of the secondary builtin names.
    std::set<std::string> BuiltinNames2nd;

    for (unsigned j = 0, e = NumRecords2nd; j != e; ++j) {
      BuiltinNames2nd.insert(Records2nd[j].Name);
      
      // Check to see if the primary target has this builtin.
      llvm::StringMap<const Builtin::Info*>::iterator I =
        PrimaryRecs.find(Records2nd[j].Name,
                         Records2nd[j].Name+strlen(Records2nd[j].Name));
      if (I != PrimaryRecs.end()) {
        const Builtin::Info *PrimBI = I->getValue();
        // If does.  If they are not identical, mark the builtin as being
        // non-portable.
        if (Records2nd[j] != *PrimBI)
          NPortable.push_back(PrimBI->Name);
      } else {
        // The primary target doesn't have this, it is non-portable.
        NPortable.push_back(Records2nd[j].Name);
      }
    }
    
    // Now that we checked all the secondary builtins, check to see if the
    // primary target has any builtins that the secondary one doesn't.  If so,
    // then those are non-portable.
    for (unsigned j = 0, e = NumRecords; j != e; ++j) {
      if (!BuiltinNames2nd.count(Records[j].Name))
        NPortable.push_back(Records[j].Name);
    }
  }
}

/// getVAListDeclaration - Return the declaration to use for
/// __builtin_va_list, which is target-specific.
const char *TargetInfo::getVAListDeclaration() const {
  return PrimaryTarget->getVAListDeclaration();
}

/// isValidGCCRegisterName - Returns whether the passed in string
/// is a valid register name according to GCC. This is used by Sema for
/// inline asm statements.
bool TargetInfo::isValidGCCRegisterName(const char *Name) const {
  const char * const *Names;
  unsigned NumNames;
  
  // Get rid of any register prefix.
  if (Name[0] == '%' || Name[0] == '#')
    Name++;
  
  if (strcmp(Name, "memory") == 0 ||
      strcmp(Name, "cc") == 0)
    return true;
  
  PrimaryTarget->getGCCRegNames(Names, NumNames);
  
  // If we have a number it maps to an entry in the register name array.
  if (isdigit(Name[0])) {
    char *End;
    int n = (int)strtol(Name, &End, 0);
    if (*End == 0)
      return n >= 0 && (unsigned)n < NumNames;
  }

  // Check register names.
  for (unsigned i = 0; i < NumNames; i++) {
    if (strcmp(Name, Names[i]) == 0)
      return true;
  }
  
  // Now check aliases.
  const TargetInfoImpl::GCCRegAlias *Aliases;
  unsigned NumAliases;
  
  PrimaryTarget->getGCCRegAliases(Aliases, NumAliases);
  for (unsigned i = 0; i < NumAliases; i++) {
    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
      if (!Aliases[i].Aliases[j])
        break;
      if (strcmp(Aliases[i].Aliases[j], Name) == 0)
        return true;
    }
  }
  
  return false;
}

const char *TargetInfo::getNormalizedGCCRegisterName(const char *Name) const
{
  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
  
  const char * const *Names;
  unsigned NumNames;

  PrimaryTarget->getGCCRegNames(Names, NumNames);

  // First, check if we have a number.
  if (isdigit(Name[0])) {
    char *End;
    int n = (int)strtol(Name, &End, 0);
    if (*End == 0) {
      assert(n >= 0 && (unsigned)n < NumNames && 
             "Out of bounds register number!");
      return Names[n];
    }
  }
  
  // Now check aliases.
  const TargetInfoImpl::GCCRegAlias *Aliases;
  unsigned NumAliases;
  
  PrimaryTarget->getGCCRegAliases(Aliases, NumAliases);
  for (unsigned i = 0; i < NumAliases; i++) {
    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
      if (!Aliases[i].Aliases[j])
        break;
      if (strcmp(Aliases[i].Aliases[j], Name) == 0)
        return Aliases[i].Register;
    }
  }
  
  return Name;
}

bool TargetInfo::validateOutputConstraint(const char *Name, 
                                          ConstraintInfo &info) const
{
  // An output constraint must start with '=' or '+'
  if (*Name != '=' && *Name != '+')
    return false;

  if (*Name == '+')
    info = CI_ReadWrite;
  else
    info = CI_None;

  Name++;
  while (*Name) {
    switch (*Name) {
    default:
      if (!PrimaryTarget->validateAsmConstraint(*Name, info)) {
        // FIXME: This assert is in place temporarily 
        // so we can add more constraints as we hit it.
        // Eventually, an unknown constraint should just be treated as 'g'.
        assert(0 && "Unknown output constraint type!");
      }
    case '&': // early clobber.
      break;
    case 'r': // general register.
      info = (ConstraintInfo)(info|CI_AllowsRegister);
      break;
    case 'm': // memory operand.
      info = (ConstraintInfo)(info|CI_AllowsMemory);
      break;
    case 'g': // general register, memory operand or immediate integer.
      info = (ConstraintInfo)(info|CI_AllowsMemory|CI_AllowsRegister);
      break;
    }
    
    Name++;
  }
  
  return true;
}

bool TargetInfo::validateInputConstraint(const char *Name,
                                         unsigned NumOutputs,
                                         ConstraintInfo &info) const
{
  while (*Name) {
    switch (*Name) {
    default:
      // Check if we have a matching constraint
      if (*Name >= '0' && *Name <= '9') {
        unsigned i = *Name - '0';
        
        // Check if matching constraint is out of bounds.
        if (i >= NumOutputs)
          return false;
      } else if (!PrimaryTarget->validateAsmConstraint(*Name, info)) {
        // FIXME: This assert is in place temporarily 
        // so we can add more constraints as we hit it.
        // Eventually, an unknown constraint should just be treated as 'g'.
        assert(0 && "Unknown input constraint type!");
      }        
    case 'i': // immediate integer.
      break;
    case 'r': // general register.
      info = (ConstraintInfo)(info|CI_AllowsRegister);
      break;
    case 'm': // memory operand.
      info = (ConstraintInfo)(info|CI_AllowsMemory);
      break;
    case 'g': // general register, memory operand or immediate integer.
      info = (ConstraintInfo)(info|CI_AllowsMemory|CI_AllowsRegister);
      break;
    }
    
    Name++;
  }
  
  return true;
}

const char *TargetInfo::getClobbers() const
{
  return PrimaryTarget->getClobbers();
}