//===-- Writer.cpp - Library for converting LLVM code to C ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This library converts LLVM code to C code, compilable by GCC and other C
// compilers.
//
//===----------------------------------------------------------------------===//
#include "CTargetMachine.h"
#include "llvm/Target/TargetMachineImpls.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/SymbolTable.h"
#include "llvm/Intrinsics.h"
#include "llvm/IntrinsicLowering.h"
#include "llvm/Analysis/FindUsedTypes.h"
#include "llvm/Analysis/ConstantsScanner.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/Mangler.h"
#include "Support/StringExtras.h"
#include "Config/config.h"
#include <algorithm>
#include <sstream>
using namespace llvm;
namespace {
class CWriter : public Pass, public InstVisitor<CWriter> {
std::ostream &Out;
IntrinsicLowering &IL;
Mangler *Mang;
const Module *TheModule;
FindUsedTypes *FUT;
std::map<const Type *, std::string> TypeNames;
std::map<const ConstantFP *, unsigned> FPConstantMap;
public:
CWriter(std::ostream &o, IntrinsicLowering &il) : Out(o), IL(il) {}
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<FindUsedTypes>();
}
virtual const char *getPassName() const { return "C backend"; }
bool doInitialization(Module &M);
bool run(Module &M) {
// First pass, lower all unhandled intrinsics.
lowerIntrinsics(M);
doInitialization(M);
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal())
printFunction(*I);
// Free memory...
delete Mang;
TypeNames.clear();
return true;
}
std::ostream &printType(std::ostream &Out, const Type *Ty,
const std::string &VariableName = "",
bool IgnoreName = false);
void writeOperand(Value *Operand);
void writeOperandInternal(Value *Operand);
private :
void lowerIntrinsics(Module &M);
bool nameAllUsedStructureTypes(Module &M);
void printModule(Module *M);
void printFloatingPointConstants(Module &M);
void printSymbolTable(const SymbolTable &ST);
void printContainedStructs(const Type *Ty, std::set<const StructType *> &);
void printFunctionSignature(const Function *F, bool Prototype);
void printFunction(Function &);
void printConstant(Constant *CPV);
void printConstantArray(ConstantArray *CPA);
// isInlinableInst - Attempt to inline instructions into their uses to build
// trees as much as possible. To do this, we have to consistently decide
// what is acceptable to inline, so that variable declarations don't get
// printed and an extra copy of the expr is not emitted.
//
static bool isInlinableInst(const Instruction &I) {
// Must be an expression, must be used exactly once. If it is dead, we
// emit it inline where it would go.
if (I.getType() == Type::VoidTy || !I.hasOneUse() ||
isa<TerminatorInst>(I) || isa<CallInst>(I) || isa<PHINode>(I) ||
isa<LoadInst>(I) || isa<VAArgInst>(I) || isa<VANextInst>(I))
// Don't inline a load across a store or other bad things!
return false;
// Only inline instruction it it's use is in the same BB as the inst.
return I.getParent() == cast<Instruction>(I.use_back())->getParent();
}
// isDirectAlloca - Define fixed sized allocas in the entry block as direct
// variables which are accessed with the & operator. This causes GCC to
// generate significantly better code than to emit alloca calls directly.
//
static const AllocaInst *isDirectAlloca(const Value *V) {
const AllocaInst *AI = dyn_cast<AllocaInst>(V);
if (!AI) return false;
if (AI->isArrayAllocation())
return 0; // FIXME: we can also inline fixed size array allocas!
if (AI->getParent() != &AI->getParent()->getParent()->getEntryBlock())
return 0;
return AI;
}
// Instruction visitation functions
friend class InstVisitor<CWriter>;
void visitReturnInst(ReturnInst &I);
void visitBranchInst(BranchInst &I);
void visitSwitchInst(SwitchInst &I);
void visitInvokeInst(InvokeInst &I);
void visitUnwindInst(UnwindInst &I);
void visitPHINode(PHINode &I);
void visitBinaryOperator(Instruction &I);
void visitCastInst (CastInst &I);
void visitCallInst (CallInst &I);
void visitCallSite (CallSite CS);
void visitShiftInst(ShiftInst &I) { visitBinaryOperator(I); }
void visitMallocInst(MallocInst &I);
void visitAllocaInst(AllocaInst &I);
void visitFreeInst (FreeInst &I);
void visitLoadInst (LoadInst &I);
void visitStoreInst (StoreInst &I);
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitVANextInst(VANextInst &I);
void visitVAArgInst (VAArgInst &I);
void visitInstruction(Instruction &I) {
std::cerr << "C Writer does not know about " << I;
abort();
}
void outputLValue(Instruction *I) {
Out << " " << Mang->getValueName(I) << " = ";
}
void printBranchToBlock(BasicBlock *CurBlock, BasicBlock *SuccBlock,
unsigned Indent);
void printIndexingExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E);
};
}
// Pass the Type* and the variable name and this prints out the variable
// declaration.
//
std::ostream &CWriter::printType(std::ostream &Out, const Type *Ty,
const std::string &NameSoFar,
bool IgnoreName) {
if (Ty->isPrimitiveType())
switch (Ty->getPrimitiveID()) {
case Type::VoidTyID: return Out << "void " << NameSoFar;
case Type::BoolTyID: return Out << "bool " << NameSoFar;
case Type::UByteTyID: return Out << "unsigned char " << NameSoFar;
case Type::SByteTyID: return Out << "signed char " << NameSoFar;
case Type::UShortTyID: return Out << "unsigned short " << NameSoFar;
case Type::ShortTyID: return Out << "short " << NameSoFar;
case Type::UIntTyID: return Out << "unsigned " << NameSoFar;
case Type::IntTyID: return Out << "int " << NameSoFar;
case Type::ULongTyID: return Out << "unsigned long long " << NameSoFar;
case Type::LongTyID: return Out << "signed long long " << NameSoFar;
case Type::FloatTyID: return Out << "float " << NameSoFar;
case Type::DoubleTyID: return Out << "double " << NameSoFar;
default :
std::cerr << "Unknown primitive type: " << Ty << "\n";
abort();
}
// Check to see if the type is named.
if (!IgnoreName || isa<OpaqueType>(Ty)) {
std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
if (I != TypeNames.end()) return Out << I->second << " " << NameSoFar;
}
switch (Ty->getPrimitiveID()) {
case Type::FunctionTyID: {
const FunctionType *MTy = cast<FunctionType>(Ty);
std::stringstream FunctionInnards;
FunctionInnards << " (" << NameSoFar << ") (";
for (FunctionType::param_iterator I = MTy->param_begin(),
E = MTy->param_end(); I != E; ++I) {
if (I != MTy->param_begin())
FunctionInnards << ", ";
printType(FunctionInnards, *I, "");
}
if (MTy->isVarArg()) {
if (MTy->getNumParams())
FunctionInnards << ", ...";
} else if (!MTy->getNumParams()) {
FunctionInnards << "void";
}
FunctionInnards << ")";
std::string tstr = FunctionInnards.str();
printType(Out, MTy->getReturnType(), tstr);
return Out;
}
case Type::StructTyID: {
const StructType *STy = cast<StructType>(Ty);
Out << NameSoFar + " {\n";
unsigned Idx = 0;
for (StructType::element_iterator I = STy->element_begin(),
E = STy->element_end(); I != E; ++I) {
Out << " ";
printType(Out, *I, "field" + utostr(Idx++));
Out << ";\n";
}
return Out << "}";
}
case Type::PointerTyID: {
const PointerType *PTy = cast<PointerType>(Ty);
std::string ptrName = "*" + NameSoFar;
if (isa<ArrayType>(PTy->getElementType()))
ptrName = "(" + ptrName + ")";
return printType(Out, PTy->getElementType(), ptrName);
}
case Type::ArrayTyID: {
const ArrayType *ATy = cast<ArrayType>(Ty);
unsigned NumElements = ATy->getNumElements();
return printType(Out, ATy->getElementType(),
NameSoFar + "[" + utostr(NumElements) + "]");
}
case Type::OpaqueTyID: {
static int Count = 0;
std::string TyName = "struct opaque_" + itostr(Count++);
assert(TypeNames.find(Ty) == TypeNames.end());
TypeNames[Ty] = TyName;
return Out << TyName << " " << NameSoFar;
}
default:
assert(0 && "Unhandled case in getTypeProps!");
abort();
}
return Out;
}
void CWriter::printConstantArray(ConstantArray *CPA) {
// As a special case, print the array as a string if it is an array of
// ubytes or an array of sbytes with positive values.
//
const Type *ETy = CPA->getType()->getElementType();
bool isString = (ETy == Type::SByteTy || ETy == Type::UByteTy);
// Make sure the last character is a null char, as automatically added by C
if (isString && (CPA->getNumOperands() == 0 ||
!cast<Constant>(*(CPA->op_end()-1))->isNullValue()))
isString = false;
if (isString) {
Out << "\"";
// Keep track of whether the last number was a hexadecimal escape
bool LastWasHex = false;
// Do not include the last character, which we know is null
for (unsigned i = 0, e = CPA->getNumOperands()-1; i != e; ++i) {
unsigned char C = cast<ConstantInt>(CPA->getOperand(i))->getRawValue();
// Print it out literally if it is a printable character. The only thing
// to be careful about is when the last letter output was a hex escape
// code, in which case we have to be careful not to print out hex digits
// explicitly (the C compiler thinks it is a continuation of the previous
// character, sheesh...)
//
if (isprint(C) && (!LastWasHex || !isxdigit(C))) {
LastWasHex = false;
if (C == '"' || C == '\\')
Out << "\\" << C;
else
Out << C;
} else {
LastWasHex = false;
switch (C) {
case '\n': Out << "\\n"; break;
case '\t': Out << "\\t"; break;
case '\r': Out << "\\r"; break;
case '\v': Out << "\\v"; break;
case '\a': Out << "\\a"; break;
case '\"': Out << "\\\""; break;
case '\'': Out << "\\\'"; break;
default:
Out << "\\x";
Out << (char)(( C/16 < 10) ? ( C/16 +'0') : ( C/16 -10+'A'));
Out << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
LastWasHex = true;
break;
}
}
}
Out << "\"";
} else {
Out << "{";
if (CPA->getNumOperands()) {
Out << " ";
printConstant(cast<Constant>(CPA->getOperand(0)));
for (unsigned i = 1, e = CPA->getNumOperands(); i != e; ++i) {
Out << ", ";
printConstant(cast<Constant>(CPA->getOperand(i)));
}
}
Out << " }";
}
}
// isFPCSafeToPrint - Returns true if we may assume that CFP may be written out
// textually as a double (rather than as a reference to a stack-allocated
// variable). We decide this by converting CFP to a string and back into a
// double, and then checking whether the conversion results in a bit-equal
// double to the original value of CFP. This depends on us and the target C
// compiler agreeing on the conversion process (which is pretty likely since we
// only deal in IEEE FP).
//
bool isFPCSafeToPrint(const ConstantFP *CFP) {
#if HAVE_PRINTF_A
char Buffer[100];
sprintf(Buffer, "%a", CFP->getValue());
if (!strncmp(Buffer, "0x", 2) ||
!strncmp(Buffer, "-0x", 3) ||
!strncmp(Buffer, "+0x", 3))
return atof(Buffer) == CFP->getValue();
return false;
#else
std::string StrVal = ftostr(CFP->getValue());
while (StrVal[0] == ' ')
StrVal.erase(StrVal.begin());
// Check to make sure that the stringized number is not some string like "Inf"
// or NaN. Check that the string matches the "[-+]?[0-9]" regex.
if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
((StrVal[0] == '-' || StrVal[0] == '+') &&
(StrVal[1] >= '0' && StrVal[1] <= '9')))
// Reparse stringized version!
return atof(StrVal.c_str()) == CFP->getValue();
return false;
#endif
}
// printConstant - The LLVM Constant to C Constant converter.
void CWriter::printConstant(Constant *CPV) {
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
switch (CE->getOpcode()) {
case Instruction::Cast:
Out << "((";
printType(Out, CPV->getType());
Out << ")";
printConstant(CE->getOperand(0));
Out << ")";
return;
case Instruction::GetElementPtr:
Out << "(&(";
printIndexingExpression(CE->getOperand(0), gep_type_begin(CPV),
gep_type_end(CPV));
Out << "))";
return;
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::Div:
case Instruction::Rem:
case Instruction::SetEQ:
case Instruction::SetNE:
case Instruction::SetLT:
case Instruction::SetLE:
case Instruction::SetGT:
case Instruction::SetGE:
case Instruction::Shl:
case Instruction::Shr:
Out << "(";
printConstant(CE->getOperand(0));
switch (CE->getOpcode()) {
case Instruction::Add: Out << " + "; break;
case Instruction::Sub: Out << " - "; break;
case Instruction::Mul: Out << " * "; break;
case Instruction::Div: Out << " / "; break;
case Instruction::Rem: Out << " % "; break;
case Instruction::SetEQ: Out << " == "; break;
case Instruction::SetNE: Out << " != "; break;
case Instruction::SetLT: Out << " < "; break;
case Instruction::SetLE: Out << " <= "; break;
case Instruction::SetGT: Out << " > "; break;
case Instruction::SetGE: Out << " >= "; break;
case Instruction::Shl: Out << " << "; break;
case Instruction::Shr: Out << " >> "; break;
default: assert(0 && "Illegal opcode here!");
}
printConstant(CE->getOperand(1));
Out << ")";
return;
default:
std::cerr << "CWriter Error: Unhandled constant expression: "
<< CE << "\n";
abort();
}
}
switch (CPV->getType()->getPrimitiveID()) {
case Type::BoolTyID:
Out << (CPV == ConstantBool::False ? "0" : "1"); break;
case Type::SByteTyID:
case Type::ShortTyID:
Out << cast<ConstantSInt>(CPV)->getValue(); break;
case Type::IntTyID:
if ((int)cast<ConstantSInt>(CPV)->getValue() == (int)0x80000000)
Out << "((int)0x80000000)"; // Handle MININT specially to avoid warning
else
Out << cast<ConstantSInt>(CPV)->getValue();
break;
case Type::LongTyID:
Out << cast<ConstantSInt>(CPV)->getValue() << "ll"; break;
case Type::UByteTyID:
case Type::UShortTyID:
Out << cast<ConstantUInt>(CPV)->getValue(); break;
case Type::UIntTyID:
Out << cast<ConstantUInt>(CPV)->getValue() << "u"; break;
case Type::ULongTyID:
Out << cast<ConstantUInt>(CPV)->getValue() << "ull"; break;
case Type::FloatTyID:
case Type::DoubleTyID: {
ConstantFP *FPC = cast<ConstantFP>(CPV);
std::map<const ConstantFP*, unsigned>::iterator I = FPConstantMap.find(FPC);
if (I != FPConstantMap.end()) {
// Because of FP precision problems we must load from a stack allocated
// value that holds the value in hex.
Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
<< "*)&FPConstant" << I->second << ")";
} else {
#if HAVE_PRINTF_A
// Print out the constant as a floating point number.
char Buffer[100];
sprintf(Buffer, "%a", FPC->getValue());
Out << Buffer << " /*" << FPC->getValue() << "*/ ";
#else
Out << ftostr(FPC->getValue());
#endif
}
break;
}
case Type::ArrayTyID:
if (isa<ConstantAggregateZero>(CPV)) {
const ArrayType *AT = cast<ArrayType>(CPV->getType());
Out << "{";
if (AT->getNumElements()) {
Out << " ";
Constant *CZ = Constant::getNullValue(AT->getElementType());
printConstant(CZ);
for (unsigned i = 1, e = AT->getNumElements(); i != e; ++i) {
Out << ", ";
printConstant(CZ);
}
}
Out << " }";
} else {
printConstantArray(cast<ConstantArray>(CPV));
}
break;
case Type::StructTyID:
if (isa<ConstantAggregateZero>(CPV)) {
const StructType *ST = cast<StructType>(CPV->getType());
Out << "{";
if (ST->getNumElements()) {
Out << " ";
printConstant(Constant::getNullValue(ST->getElementType(0)));
for (unsigned i = 1, e = ST->getNumElements(); i != e; ++i) {
Out << ", ";
printConstant(Constant::getNullValue(ST->getElementType(i)));
}
}
Out << " }";
} else {
Out << "{";
if (CPV->getNumOperands()) {
Out << " ";
printConstant(cast<Constant>(CPV->getOperand(0)));
for (unsigned i = 1, e = CPV->getNumOperands(); i != e; ++i) {
Out << ", ";
printConstant(cast<Constant>(CPV->getOperand(i)));
}
}
Out << " }";
}
break;
case Type::PointerTyID:
if (isa<ConstantPointerNull>(CPV)) {
Out << "((";
printType(Out, CPV->getType());
Out << ")/*NULL*/0)";
break;
} else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CPV)) {
writeOperand(CPR->getValue());
break;
}
// FALL THROUGH
default:
std::cerr << "Unknown constant type: " << CPV << "\n";
abort();
}
}
void CWriter::writeOperandInternal(Value *Operand) {
if (Instruction *I = dyn_cast<Instruction>(Operand))
if (isInlinableInst(*I) && !isDirectAlloca(I)) {
// Should we inline this instruction to build a tree?
Out << "(";
visit(*I);
Out << ")";
return;
}
if (Constant *CPV = dyn_cast<Constant>(Operand)) {
printConstant(CPV);
} else {
Out << Mang->getValueName(Operand);
}
}
void CWriter::writeOperand(Value *Operand) {
if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
Out << "(&"; // Global variables are references as their addresses by llvm
writeOperandInternal(Operand);
if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
Out << ")";
}
// nameAllUsedStructureTypes - If there are structure types in the module that
// are used but do not have names assigned to them in the symbol table yet then
// we assign them names now.
//
bool CWriter::nameAllUsedStructureTypes(Module &M) {
// Get a set of types that are used by the program...
std::set<const Type *> UT = FUT->getTypes();
// Loop over the module symbol table, removing types from UT that are already
// named.
//
SymbolTable &MST = M.getSymbolTable();
if (MST.find(Type::TypeTy) != MST.end())
for (SymbolTable::type_iterator I = MST.type_begin(Type::TypeTy),
E = MST.type_end(Type::TypeTy); I != E; ++I)
UT.erase(cast<Type>(I->second));
// UT now contains types that are not named. Loop over it, naming structure
// types.
//
bool Changed = false;
for (std::set<const Type *>::const_iterator I = UT.begin(), E = UT.end();
I != E; ++I)
if (const StructType *ST = dyn_cast<StructType>(*I)) {
((Value*)ST)->setName("unnamed", &MST);
Changed = true;
}
return Changed;
}
// generateCompilerSpecificCode - This is where we add conditional compilation
// directives to cater to specific compilers as need be.
//
static void generateCompilerSpecificCode(std::ostream& Out) {
// Alloca is hard to get, and we don't want to include stdlib.h here...
Out << "/* get a declaration for alloca */\n"
<< "#ifdef sun\n"
<< "extern void *__builtin_alloca(unsigned long);\n"
<< "#define alloca(x) __builtin_alloca(x)\n"
<< "#else\n"
<< "#ifndef __FreeBSD__\n"
<< "#include <alloca.h>\n"
<< "#endif\n"
<< "#endif\n\n";
// We output GCC specific attributes to preserve 'linkonce'ness on globals.
// If we aren't being compiled with GCC, just drop these attributes.
Out << "#ifndef __GNUC__ /* Can only support \"linkonce\" vars with GCC */\n"
<< "#define __attribute__(X)\n"
<< "#endif\n\n";
#if 0
// At some point, we should support "external weak" vs. "weak" linkages.
// On Mac OS X, "external weak" is spelled "__attribute__((weak_import))".
Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
<< "#define __EXTERNAL_WEAK__ __attribute__((weak_import))\n"
<< "#elif defined(__GNUC__)\n"
<< "#define __EXTERNAL_WEAK__ __attribute__((weak))\n"
<< "#else\n"
<< "#define __EXTERNAL_WEAK__\n"
<< "#endif\n\n";
#endif
// For now, turn off the weak linkage attribute on Mac OS X. (See above.)
Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
<< "#define __ATTRIBUTE_WEAK__\n"
<< "#elif defined(__GNUC__)\n"
<< "#define __ATTRIBUTE_WEAK__ __attribute__((weak))\n"
<< "#else\n"
<< "#define __ATTRIBUTE_WEAK__\n"
<< "#endif\n\n";
}
bool CWriter::doInitialization(Module &M) {
// Initialize
TheModule = &M;
FUT = &getAnalysis<FindUsedTypes>();
// Ensure that all structure types have names...
bool Changed = nameAllUsedStructureTypes(M);
Mang = new Mangler(M);
// get declaration for alloca
Out << "/* Provide Declarations */\n";
Out << "#include <stdarg.h>\n"; // Varargs support
Out << "#include <setjmp.h>\n"; // Unwind support
generateCompilerSpecificCode(Out);
// Provide a definition for `bool' if not compiling with a C++ compiler.
Out << "\n"
<< "#ifndef __cplusplus\ntypedef unsigned char bool;\n#endif\n"
<< "\n\n/* Support for floating point constants */\n"
<< "typedef unsigned long long ConstantDoubleTy;\n"
<< "typedef unsigned int ConstantFloatTy;\n"
<< "\n\n/* Global Declarations */\n";
// First output all the declarations for the program, because C requires
// Functions & globals to be declared before they are used.
//
// Loop over the symbol table, emitting all named constants...
printSymbolTable(M.getSymbolTable());
// Global variable declarations...
if (!M.gempty()) {
Out << "\n/* External Global Variable Declarations */\n";
for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
if (I->hasExternalLinkage()) {
Out << "extern ";
printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
Out << ";\n";
}
}
}
// Function declarations
if (!M.empty()) {
Out << "\n/* Function Declarations */\n";
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
// Don't print declarations for intrinsic functions.
if (!I->getIntrinsicID()) {
printFunctionSignature(I, true);
if (I->hasWeakLinkage()) Out << " __ATTRIBUTE_WEAK__";
if (I->hasLinkOnceLinkage()) Out << " __ATTRIBUTE_WEAK__";
Out << ";\n";
}
}
}
// Output the global variable declarations
if (!M.gempty()) {
Out << "\n\n/* Global Variable Declarations */\n";
for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
if (!I->isExternal()) {
Out << "extern ";
printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
if (I->hasLinkOnceLinkage())
Out << " __attribute__((common))";
else if (I->hasWeakLinkage())
Out << " __ATTRIBUTE_WEAK__";
Out << ";\n";
}
}
// Output the global variable definitions and contents...
if (!M.gempty()) {
Out << "\n\n/* Global Variable Definitions and Initialization */\n";
for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
if (!I->isExternal()) {
if (I->hasInternalLinkage())
Out << "static ";
printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
if (I->hasLinkOnceLinkage())
Out << " __attribute__((common))";
else if (I->hasWeakLinkage())
Out << " __ATTRIBUTE_WEAK__";
// If the initializer is not null, emit the initializer. If it is null,
// we try to avoid emitting large amounts of zeros. The problem with
// this, however, occurs when the variable has weak linkage. In this
// case, the assembler will complain about the variable being both weak
// and common, so we disable this optimization.
if (!I->getInitializer()->isNullValue()) {
Out << " = " ;
writeOperand(I->getInitializer());
} else if (I->hasWeakLinkage()) {
// We have to specify an initializer, but it doesn't have to be
// complete. If the value is an aggregate, print out { 0 }, and let
// the compiler figure out the rest of the zeros.
Out << " = " ;
if (isa<StructType>(I->getInitializer()->getType()) ||
isa<ArrayType>(I->getInitializer()->getType())) {
Out << "{ 0 }";
} else {
// Just print it out normally.
writeOperand(I->getInitializer());
}
}
Out << ";\n";
}
}
// Output all floating point constants that cannot be printed accurately...
printFloatingPointConstants(M);
if (!M.empty())
Out << "\n\n/* Function Bodies */\n";
return false;
}
/// Output all floating point constants that cannot be printed accurately...
void CWriter::printFloatingPointConstants(Module &M) {
union {
double D;
unsigned long long U;
} DBLUnion;
union {
float F;
unsigned U;
} FLTUnion;
// Scan the module for floating point constants. If any FP constant is used
// in the function, we want to redirect it here so that we do not depend on
// the precision of the printed form, unless the printed form preserves
// precision.
//
unsigned FPCounter = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (constant_iterator I = constant_begin(F), E = constant_end(F);
I != E; ++I)
if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
if (!isFPCSafeToPrint(FPC) && // Do not put in FPConstantMap if safe.
!FPConstantMap.count(FPC)) {
double Val = FPC->getValue();
FPConstantMap[FPC] = FPCounter; // Number the FP constants
if (FPC->getType() == Type::DoubleTy) {
DBLUnion.D = Val;
Out << "static const ConstantDoubleTy FPConstant" << FPCounter++
<< " = 0x" << std::hex << DBLUnion.U << std::dec
<< "ULL; /* " << Val << " */\n";
} else if (FPC->getType() == Type::FloatTy) {
FLTUnion.F = Val;
Out << "static const ConstantFloatTy FPConstant" << FPCounter++
<< " = 0x" << std::hex << FLTUnion.U << std::dec
<< "U; /* " << Val << " */\n";
} else
assert(0 && "Unknown float type!");
}
Out << "\n";
}
/// printSymbolTable - Run through symbol table looking for type names. If a
/// type name is found, emit it's declaration...
///
void CWriter::printSymbolTable(const SymbolTable &ST) {
// If there are no type names, exit early.
if (ST.find(Type::TypeTy) == ST.end())
return;
// We are only interested in the type plane of the symbol table...
SymbolTable::type_const_iterator I = ST.type_begin(Type::TypeTy);
SymbolTable::type_const_iterator End = ST.type_end(Type::TypeTy);
// Print out forward declarations for structure types before anything else!
Out << "/* Structure forward decls */\n";
for (; I != End; ++I)
if (const Type *STy = dyn_cast<StructType>(I->second))
// Only print out used types!
if (FUT->getTypes().count(STy)) {
std::string Name = "struct l_" + Mangler::makeNameProper(I->first);
Out << Name << ";\n";
TypeNames.insert(std::make_pair(STy, Name));
}
Out << "\n";
// Now we can print out typedefs...
Out << "/* Typedefs */\n";
for (I = ST.type_begin(Type::TypeTy); I != End; ++I)
// Only print out used types!
if (FUT->getTypes().count(cast<Type>(I->second))) {
const Type *Ty = cast<Type>(I->second);
std::string Name = "l_" + Mangler::makeNameProper(I->first);
Out << "typedef ";
printType(Out, Ty, Name);
Out << ";\n";
}
Out << "\n";
// Keep track of which structures have been printed so far...
std::set<const StructType *> StructPrinted;
// Loop over all structures then push them into the stack so they are
// printed in the correct order.
//
Out << "/* Structure contents */\n";
for (I = ST.type_begin(Type::TypeTy); I != End; ++I)
if (const StructType *STy = dyn_cast<StructType>(I->second))
// Only print out used types!
if (FUT->getTypes().count(STy))
printContainedStructs(STy, StructPrinted);
}
// Push the struct onto the stack and recursively push all structs
// this one depends on.
void CWriter::printContainedStructs(const Type *Ty,
std::set<const StructType*> &StructPrinted){
if (const StructType *STy = dyn_cast<StructType>(Ty)) {
//Check to see if we have already printed this struct
if (StructPrinted.count(STy) == 0) {
// Print all contained types first...
for (StructType::element_iterator I = STy->element_begin(),
E = STy->element_end(); I != E; ++I) {
const Type *Ty1 = I->get();
if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
printContainedStructs(*I, StructPrinted);
}
//Print structure type out..
StructPrinted.insert(STy);
std::string Name = TypeNames[STy];
printType(Out, STy, Name, true);
Out << ";\n\n";
}
// If it is an array, check contained types and continue
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)){
const Type *Ty1 = ATy->getElementType();
if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
printContainedStructs(Ty1, StructPrinted);
}
}
void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
if (F->hasInternalLinkage()) Out << "static ";
// Loop over the arguments, printing them...
const FunctionType *FT = cast<FunctionType>(F->getFunctionType());
std::stringstream FunctionInnards;
// Print out the name...
FunctionInnards << Mang->getValueName(F) << "(";
if (!F->isExternal()) {
if (!F->aempty()) {
std::string ArgName;
if (F->abegin()->hasName() || !Prototype)
ArgName = Mang->getValueName(F->abegin());
printType(FunctionInnards, F->afront().getType(), ArgName);
for (Function::const_aiterator I = ++F->abegin(), E = F->aend();
I != E; ++I) {
FunctionInnards << ", ";
if (I->hasName() || !Prototype)
ArgName = Mang->getValueName(I);
else
ArgName = "";
printType(FunctionInnards, I->getType(), ArgName);
}
}
} else {
// Loop over the arguments, printing them...
for (FunctionType::param_iterator I = FT->param_begin(),
E = FT->param_end(); I != E; ++I) {
if (I != FT->param_begin()) FunctionInnards << ", ";
printType(FunctionInnards, *I);
}
}
// Finish printing arguments... if this is a vararg function, print the ...,
// unless there are no known types, in which case, we just emit ().
//
if (FT->isVarArg() && FT->getNumParams()) {
if (FT->getNumParams()) FunctionInnards << ", ";
FunctionInnards << "..."; // Output varargs portion of signature!
} else if (!FT->isVarArg() && FT->getNumParams() == 0) {
FunctionInnards << "void"; // ret() -> ret(void) in C.
}
FunctionInnards << ")";
// Print out the return type and the entire signature for that matter
printType(Out, F->getReturnType(), FunctionInnards.str());
}
void CWriter::printFunction(Function &F) {
printFunctionSignature(&F, false);
Out << " {\n";
// print local variable information for the function
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I)
if (const AllocaInst *AI = isDirectAlloca(*I)) {
Out << " ";
printType(Out, AI->getAllocatedType(), Mang->getValueName(AI));
Out << "; /* Address exposed local */\n";
} else if ((*I)->getType() != Type::VoidTy && !isInlinableInst(**I)) {
Out << " ";
printType(Out, (*I)->getType(), Mang->getValueName(*I));
Out << ";\n";
if (isa<PHINode>(*I)) { // Print out PHI node temporaries as well...
Out << " ";
printType(Out, (*I)->getType(),
Mang->getValueName(*I)+"__PHI_TEMPORARY");
Out << ";\n";
}
}
Out << "\n";
// print the basic blocks
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
BasicBlock *Prev = BB->getPrev();
// Don't print the label for the basic block if there are no uses, or if the
// only terminator use is the predecessor basic block's terminator. We have
// to scan the use list because PHI nodes use basic blocks too but do not
// require a label to be generated.
//
bool NeedsLabel = false;
for (Value::use_iterator UI = BB->use_begin(), UE = BB->use_end();
UI != UE; ++UI)
if (TerminatorInst *TI = dyn_cast<TerminatorInst>(*UI))
if (TI != Prev->getTerminator() ||
isa<SwitchInst>(Prev->getTerminator()) ||
isa<InvokeInst>(Prev->getTerminator())) {
NeedsLabel = true;
break;
}
if (NeedsLabel) Out << Mang->getValueName(BB) << ":\n";
// Output all of the instructions in the basic block...
for (BasicBlock::iterator II = BB->begin(), E = --BB->end(); II != E; ++II){
if (!isInlinableInst(*II) && !isDirectAlloca(II)) {
if (II->getType() != Type::VoidTy)
outputLValue(II);
else
Out << " ";
visit(*II);
Out << ";\n";
}
}
// Don't emit prefix or suffix for the terminator...
visit(*BB->getTerminator());
}
Out << "}\n\n";
}
// Specific Instruction type classes... note that all of the casts are
// necessary because we use the instruction classes as opaque types...
//
void CWriter::visitReturnInst(ReturnInst &I) {
// Don't output a void return if this is the last basic block in the function
if (I.getNumOperands() == 0 &&
&*--I.getParent()->getParent()->end() == I.getParent() &&
!I.getParent()->size() == 1) {
return;
}
Out << " return";
if (I.getNumOperands()) {
Out << " ";
writeOperand(I.getOperand(0));
}
Out << ";\n";
}
void CWriter::visitSwitchInst(SwitchInst &SI) {
Out << " switch (";
writeOperand(SI.getOperand(0));
Out << ") {\n default:\n";
printBranchToBlock(SI.getParent(), SI.getDefaultDest(), 2);
Out << ";\n";
for (unsigned i = 2, e = SI.getNumOperands(); i != e; i += 2) {
Out << " case ";
writeOperand(SI.getOperand(i));
Out << ":\n";
BasicBlock *Succ = cast<BasicBlock>(SI.getOperand(i+1));
printBranchToBlock(SI.getParent(), Succ, 2);
if (Succ == SI.getParent()->getNext())
Out << " break;\n";
}
Out << " }\n";
}
void CWriter::visitInvokeInst(InvokeInst &II) {
assert(0 && "Lowerinvoke pass didn't work!");
}
void CWriter::visitUnwindInst(UnwindInst &I) {
assert(0 && "Lowerinvoke pass didn't work!");
}
bool isGotoCodeNecessary(BasicBlock *From, BasicBlock *To) {
// If PHI nodes need copies, we need the copy code...
if (isa<PHINode>(To->front()) ||
From->getNext() != To) // Not directly successor, need goto
return true;
// Otherwise we don't need the code.
return false;
}
void CWriter::printBranchToBlock(BasicBlock *CurBB, BasicBlock *Succ,
unsigned Indent) {
for (BasicBlock::iterator I = Succ->begin();
PHINode *PN = dyn_cast<PHINode>(I); ++I) {
// now we have to do the printing
Out << std::string(Indent, ' ');
Out << " " << Mang->getValueName(I) << "__PHI_TEMPORARY = ";
writeOperand(PN->getIncomingValue(PN->getBasicBlockIndex(CurBB)));
Out << "; /* for PHI node */\n";
}
if (CurBB->getNext() != Succ ||
isa<InvokeInst>(CurBB->getTerminator()) ||
isa<SwitchInst>(CurBB->getTerminator())) {
Out << std::string(Indent, ' ') << " goto ";
writeOperand(Succ);
Out << ";\n";
}
}
// Branch instruction printing - Avoid printing out a branch to a basic block
// that immediately succeeds the current one.
//
void CWriter::visitBranchInst(BranchInst &I) {
if (I.isConditional()) {
if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(0))) {
Out << " if (";
writeOperand(I.getCondition());
Out << ") {\n";
printBranchToBlock(I.getParent(), I.getSuccessor(0), 2);
if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(1))) {
Out << " } else {\n";
printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
}
} else {
// First goto not necessary, assume second one is...
Out << " if (!";
writeOperand(I.getCondition());
Out << ") {\n";
printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
}
Out << " }\n";
} else {
printBranchToBlock(I.getParent(), I.getSuccessor(0), 0);
}
Out << "\n";
}
// PHI nodes get copied into temporary values at the end of predecessor basic
// blocks. We now need to copy these temporary values into the REAL value for
// the PHI.
void CWriter::visitPHINode(PHINode &I) {
writeOperand(&I);
Out << "__PHI_TEMPORARY";
}
void CWriter::visitBinaryOperator(Instruction &I) {
// binary instructions, shift instructions, setCond instructions.
assert(!isa<PointerType>(I.getType()));
// We must cast the results of binary operations which might be promoted.
bool needsCast = false;
if ((I.getType() == Type::UByteTy) || (I.getType() == Type::SByteTy)
|| (I.getType() == Type::UShortTy) || (I.getType() == Type::ShortTy)
|| (I.getType() == Type::FloatTy)) {
needsCast = true;
Out << "((";
printType(Out, I.getType());
Out << ")(";
}
writeOperand(I.getOperand(0));
switch (I.getOpcode()) {
case Instruction::Add: Out << " + "; break;
case Instruction::Sub: Out << " - "; break;
case Instruction::Mul: Out << "*"; break;
case Instruction::Div: Out << "/"; break;
case Instruction::Rem: Out << "%"; break;
case Instruction::And: Out << " & "; break;
case Instruction::Or: Out << " | "; break;
case Instruction::Xor: Out << " ^ "; break;
case Instruction::SetEQ: Out << " == "; break;
case Instruction::SetNE: Out << " != "; break;
case Instruction::SetLE: Out << " <= "; break;
case Instruction::SetGE: Out << " >= "; break;
case Instruction::SetLT: Out << " < "; break;
case Instruction::SetGT: Out << " > "; break;
case Instruction::Shl : Out << " << "; break;
case Instruction::Shr : Out << " >> "; break;
default: std::cerr << "Invalid operator type!" << I; abort();
}
writeOperand(I.getOperand(1));
if (needsCast) {
Out << "))";
}
}
void CWriter::visitCastInst(CastInst &I) {
if (I.getType() == Type::BoolTy) {
Out << "(";
writeOperand(I.getOperand(0));
Out << " != 0)";
return;
}
Out << "(";
printType(Out, I.getType());
Out << ")";
if (isa<PointerType>(I.getType())&&I.getOperand(0)->getType()->isIntegral() ||
isa<PointerType>(I.getOperand(0)->getType())&&I.getType()->isIntegral()) {
// Avoid "cast to pointer from integer of different size" warnings
Out << "(long)";
}
writeOperand(I.getOperand(0));
}
void CWriter::lowerIntrinsics(Module &M) {
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
if (CallInst *CI = dyn_cast<CallInst>(I++))
if (Function *F = CI->getCalledFunction())
switch (F->getIntrinsicID()) {
case Intrinsic::not_intrinsic:
case Intrinsic::va_start:
case Intrinsic::va_copy:
case Intrinsic::va_end:
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
case Intrinsic::setjmp:
case Intrinsic::longjmp:
// We directly implement these intrinsics
break;
default:
// All other intrinsic calls we must lower.
Instruction *Before = CI->getPrev();
IL.LowerIntrinsicCall(CI);
if (Before) { // Move iterator to instruction after call
I = Before; ++I;
} else {
I = BB->begin();
}
}
}
void CWriter::visitCallInst(CallInst &I) {
// Handle intrinsic function calls first...
if (Function *F = I.getCalledFunction())
if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID()) {
switch (ID) {
default: assert(0 && "Unknown LLVM intrinsic!");
case Intrinsic::va_start:
Out << "0; ";
Out << "va_start(*(va_list*)&" << Mang->getValueName(&I) << ", ";
// Output the last argument to the enclosing function...
if (I.getParent()->getParent()->aempty()) {
std::cerr << "The C backend does not currently support zero "
<< "argument varargs functions, such as '"
<< I.getParent()->getParent()->getName() << "'!\n";
abort();
}
writeOperand(&I.getParent()->getParent()->aback());
Out << ")";
return;
case Intrinsic::va_end:
Out << "va_end(*(va_list*)&";
writeOperand(I.getOperand(1));
Out << ")";
return;
case Intrinsic::va_copy:
Out << "0;";
Out << "va_copy(*(va_list*)&" << Mang->getValueName(&I) << ", ";
Out << "*(va_list*)&";
writeOperand(I.getOperand(1));
Out << ")";
return;
case Intrinsic::returnaddress:
Out << "__builtin_return_address(";
writeOperand(I.getOperand(1));
Out << ")";
return;
case Intrinsic::frameaddress:
Out << "__builtin_frame_address(";
writeOperand(I.getOperand(1));
Out << ")";
return;
case Intrinsic::setjmp:
Out << "setjmp(*(jmp_buf*)";
writeOperand(I.getOperand(1));
Out << ")";
return;
case Intrinsic::longjmp:
Out << "longjmp(*(jmp_buf*)";
writeOperand(I.getOperand(1));
Out << ", ";
writeOperand(I.getOperand(2));
Out << ")";
return;
}
}
visitCallSite(&I);
}
void CWriter::visitCallSite(CallSite CS) {
const PointerType *PTy = cast<PointerType>(CS.getCalledValue()->getType());
const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
const Type *RetTy = FTy->getReturnType();
writeOperand(CS.getCalledValue());
Out << "(";
if (CS.arg_begin() != CS.arg_end()) {
CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
writeOperand(*AI);
for (++AI; AI != AE; ++AI) {
Out << ", ";
writeOperand(*AI);
}
}
Out << ")";
}
void CWriter::visitMallocInst(MallocInst &I) {
assert(0 && "lowerallocations pass didn't work!");
}
void CWriter::visitAllocaInst(AllocaInst &I) {
Out << "(";
printType(Out, I.getType());
Out << ") alloca(sizeof(";
printType(Out, I.getType()->getElementType());
Out << ")";
if (I.isArrayAllocation()) {
Out << " * " ;
writeOperand(I.getOperand(0));
}
Out << ")";
}
void CWriter::visitFreeInst(FreeInst &I) {
assert(0 && "lowerallocations pass didn't work!");
}
void CWriter::printIndexingExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E) {
bool HasImplicitAddress = false;
// If accessing a global value with no indexing, avoid *(&GV) syndrome
if (GlobalValue *V = dyn_cast<GlobalValue>(Ptr)) {
HasImplicitAddress = true;
} else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Ptr)) {
HasImplicitAddress = true;
Ptr = CPR->getValue(); // Get to the global...
} else if (isDirectAlloca(Ptr)) {
HasImplicitAddress = true;
}
if (I == E) {
if (!HasImplicitAddress)
Out << "*"; // Implicit zero first argument: '*x' is equivalent to 'x[0]'
writeOperandInternal(Ptr);
return;
}
const Constant *CI = dyn_cast<Constant>(I.getOperand());
if (HasImplicitAddress && (!CI || !CI->isNullValue()))
Out << "(&";
writeOperandInternal(Ptr);
if (HasImplicitAddress && (!CI || !CI->isNullValue())) {
Out << ")";
HasImplicitAddress = false; // HIA is only true if we haven't addressed yet
}
assert(!HasImplicitAddress || (CI && CI->isNullValue()) &&
"Can only have implicit address with direct accessing");
if (HasImplicitAddress) {
++I;
} else if (CI && CI->isNullValue()) {
gep_type_iterator TmpI = I; ++TmpI;
// Print out the -> operator if possible...
if (TmpI != E && isa<StructType>(*TmpI)) {
Out << (HasImplicitAddress ? "." : "->");
Out << "field" << cast<ConstantUInt>(TmpI.getOperand())->getValue();
I = ++TmpI;
}
}
for (; I != E; ++I)
if (isa<StructType>(*I)) {
Out << ".field" << cast<ConstantUInt>(I.getOperand())->getValue();
} else {
Out << "[";
writeOperand(I.getOperand());
Out << "]";
}
}
void CWriter::visitLoadInst(LoadInst &I) {
Out << "*";
writeOperand(I.getOperand(0));
}
void CWriter::visitStoreInst(StoreInst &I) {
Out << "*";
writeOperand(I.getPointerOperand());
Out << " = ";
writeOperand(I.getOperand(0));
}
void CWriter::visitGetElementPtrInst(GetElementPtrInst &I) {
Out << "&";
printIndexingExpression(I.getPointerOperand(), gep_type_begin(I),
gep_type_end(I));
}
void CWriter::visitVANextInst(VANextInst &I) {
Out << Mang->getValueName(I.getOperand(0));
Out << "; va_arg(*(va_list*)&" << Mang->getValueName(&I) << ", ";
printType(Out, I.getArgType());
Out << ")";
}
void CWriter::visitVAArgInst(VAArgInst &I) {
Out << "0;\n";
Out << "{ va_list Tmp; va_copy(Tmp, *(va_list*)&";
writeOperand(I.getOperand(0));
Out << ");\n " << Mang->getValueName(&I) << " = va_arg(Tmp, ";
printType(Out, I.getType());
Out << ");\n va_end(Tmp); }";
}
//===----------------------------------------------------------------------===//
// External Interface declaration
//===----------------------------------------------------------------------===//
bool CTargetMachine::addPassesToEmitAssembly(PassManager &PM, std::ostream &o) {
PM.add(createLowerAllocationsPass());
PM.add(createLowerInvokePass());
PM.add(new CWriter(o, getIntrinsicLowering()));
return false;
}
TargetMachine *llvm::allocateCTargetMachine(const Module &M,
IntrinsicLowering *IL) {
return new CTargetMachine(M, IL);
}