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llvm-mirror/lib/Target/CBackend/Writer.cpp
John Criswell 0b01bff060 Fixes for PR258 and PR259. 
Functions with linkonce linkage are declared with weak linkage.
Global floating point constants used to represent unprintable values
(such as NaN and infinity) are declared static so that they don't interfere
with other CBE generated translation units.

llvm-svn: 11884
2004-02-26 22:20:58 +00:00

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//===-- 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);
}
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