1 //===-- Writer.cpp - Library for converting LLVM code to C ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This library converts LLVM code to C code, compilable by GCC and other C
13 //===----------------------------------------------------------------------===//
15 #include "CTargetMachine.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Module.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Pass.h"
21 #include "llvm/PassManager.h"
22 #include "llvm/SymbolTable.h"
23 #include "llvm/Intrinsics.h"
24 #include "llvm/Analysis/ConstantsScanner.h"
25 #include "llvm/Analysis/FindUsedTypes.h"
26 #include "llvm/Analysis/LoopInfo.h"
27 #include "llvm/CodeGen/IntrinsicLowering.h"
28 #include "llvm/Transforms/Scalar.h"
29 #include "llvm/Target/TargetMachineRegistry.h"
30 #include "llvm/Support/CallSite.h"
31 #include "llvm/Support/CFG.h"
32 #include "llvm/Support/GetElementPtrTypeIterator.h"
33 #include "llvm/Support/InstVisitor.h"
34 #include "llvm/Support/Mangler.h"
35 #include "llvm/ADT/StringExtras.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Config/config.h"
44 // Register the target.
45 RegisterTarget<CTargetMachine> X("c", " C backend");
47 /// NameAllUsedStructs - This pass inserts names for any unnamed structure
48 /// types that are used by the program.
50 class CBackendNameAllUsedStructs : public ModulePass {
51 void getAnalysisUsage(AnalysisUsage &AU) const {
52 AU.addRequired<FindUsedTypes>();
55 virtual const char *getPassName() const {
56 return "C backend type canonicalizer";
59 virtual bool runOnModule(Module &M);
62 /// CWriter - This class is the main chunk of code that converts an LLVM
63 /// module to a C translation unit.
64 class CWriter : public FunctionPass, public InstVisitor<CWriter> {
66 IntrinsicLowering &IL;
69 const Module *TheModule;
70 std::map<const Type *, std::string> TypeNames;
72 std::map<const ConstantFP *, unsigned> FPConstantMap;
74 CWriter(std::ostream &o, IntrinsicLowering &il) : Out(o), IL(il) {}
76 virtual const char *getPassName() const { return "C backend"; }
78 void getAnalysisUsage(AnalysisUsage &AU) const {
79 AU.addRequired<LoopInfo>();
83 virtual bool doInitialization(Module &M);
85 bool runOnFunction(Function &F) {
86 LI = &getAnalysis<LoopInfo>();
88 // Get rid of intrinsics we can't handle.
91 // Output all floating point constants that cannot be printed accurately.
92 printFloatingPointConstants(F);
94 // Ensure that no local symbols conflict with global symbols.
95 F.renameLocalSymbols();
98 FPConstantMap.clear();
102 virtual bool doFinalization(Module &M) {
109 std::ostream &printType(std::ostream &Out, const Type *Ty,
110 const std::string &VariableName = "",
111 bool IgnoreName = false);
113 void writeOperand(Value *Operand);
114 void writeOperandInternal(Value *Operand);
117 void lowerIntrinsics(Function &F);
119 bool nameAllUsedStructureTypes(Module &M);
120 void printModule(Module *M);
121 void printModuleTypes(const SymbolTable &ST);
122 void printContainedStructs(const Type *Ty, std::set<const StructType *> &);
123 void printFloatingPointConstants(Function &F);
124 void printFunctionSignature(const Function *F, bool Prototype);
126 void printFunction(Function &);
127 void printBasicBlock(BasicBlock *BB);
128 void printLoop(Loop *L);
130 void printConstant(Constant *CPV);
131 void printConstantArray(ConstantArray *CPA);
133 // isInlinableInst - Attempt to inline instructions into their uses to build
134 // trees as much as possible. To do this, we have to consistently decide
135 // what is acceptable to inline, so that variable declarations don't get
136 // printed and an extra copy of the expr is not emitted.
138 static bool isInlinableInst(const Instruction &I) {
139 // Always inline setcc instructions, even if they are shared by multiple
140 // expressions. GCC generates horrible code if we don't.
141 if (isa<SetCondInst>(I)) return true;
143 // Must be an expression, must be used exactly once. If it is dead, we
144 // emit it inline where it would go.
145 if (I.getType() == Type::VoidTy || !I.hasOneUse() ||
146 isa<TerminatorInst>(I) || isa<CallInst>(I) || isa<PHINode>(I) ||
147 isa<LoadInst>(I) || isa<VAArgInst>(I) || isa<VANextInst>(I))
148 // Don't inline a load across a store or other bad things!
151 // Only inline instruction it it's use is in the same BB as the inst.
152 return I.getParent() == cast<Instruction>(I.use_back())->getParent();
155 // isDirectAlloca - Define fixed sized allocas in the entry block as direct
156 // variables which are accessed with the & operator. This causes GCC to
157 // generate significantly better code than to emit alloca calls directly.
159 static const AllocaInst *isDirectAlloca(const Value *V) {
160 const AllocaInst *AI = dyn_cast<AllocaInst>(V);
161 if (!AI) return false;
162 if (AI->isArrayAllocation())
163 return 0; // FIXME: we can also inline fixed size array allocas!
164 if (AI->getParent() != &AI->getParent()->getParent()->getEntryBlock())
169 // Instruction visitation functions
170 friend class InstVisitor<CWriter>;
172 void visitReturnInst(ReturnInst &I);
173 void visitBranchInst(BranchInst &I);
174 void visitSwitchInst(SwitchInst &I);
175 void visitInvokeInst(InvokeInst &I) {
176 assert(0 && "Lowerinvoke pass didn't work!");
179 void visitUnwindInst(UnwindInst &I) {
180 assert(0 && "Lowerinvoke pass didn't work!");
182 void visitUnreachableInst(UnreachableInst &I);
184 void visitPHINode(PHINode &I);
185 void visitBinaryOperator(Instruction &I);
187 void visitCastInst (CastInst &I);
188 void visitSelectInst(SelectInst &I);
189 void visitCallInst (CallInst &I);
190 void visitShiftInst(ShiftInst &I) { visitBinaryOperator(I); }
192 void visitMallocInst(MallocInst &I);
193 void visitAllocaInst(AllocaInst &I);
194 void visitFreeInst (FreeInst &I);
195 void visitLoadInst (LoadInst &I);
196 void visitStoreInst (StoreInst &I);
197 void visitGetElementPtrInst(GetElementPtrInst &I);
198 void visitVANextInst(VANextInst &I);
199 void visitVAArgInst (VAArgInst &I);
201 void visitInstruction(Instruction &I) {
202 std::cerr << "C Writer does not know about " << I;
206 void outputLValue(Instruction *I) {
207 Out << " " << Mang->getValueName(I) << " = ";
210 bool isGotoCodeNecessary(BasicBlock *From, BasicBlock *To);
211 void printPHICopiesForSuccessor(BasicBlock *CurBlock,
212 BasicBlock *Successor, unsigned Indent);
213 void printBranchToBlock(BasicBlock *CurBlock, BasicBlock *SuccBlock,
215 void printIndexingExpression(Value *Ptr, gep_type_iterator I,
216 gep_type_iterator E);
217 void printCodeForMain();
221 /// This method inserts names for any unnamed structure types that are used by
222 /// the program, and removes names from structure types that are not used by the
225 bool CBackendNameAllUsedStructs::runOnModule(Module &M) {
226 // Get a set of types that are used by the program...
227 std::set<const Type *> UT = getAnalysis<FindUsedTypes>().getTypes();
229 // Loop over the module symbol table, removing types from UT that are
230 // already named, and removing names for types that are not used.
232 SymbolTable &MST = M.getSymbolTable();
233 for (SymbolTable::type_iterator TI = MST.type_begin(), TE = MST.type_end();
235 SymbolTable::type_iterator I = TI++;
237 // If this is not used, remove it from the symbol table.
238 std::set<const Type *>::iterator UTI = UT.find(I->second);
242 UT.erase(UTI); // Only keep one name for this type.
245 // UT now contains types that are not named. Loop over it, naming
248 bool Changed = false;
249 unsigned RenameCounter = 0;
250 for (std::set<const Type *>::const_iterator I = UT.begin(), E = UT.end();
252 if (const StructType *ST = dyn_cast<StructType>(*I)) {
253 while (M.addTypeName("unnamed"+utostr(RenameCounter), ST))
261 // Pass the Type* and the variable name and this prints out the variable
264 std::ostream &CWriter::printType(std::ostream &Out, const Type *Ty,
265 const std::string &NameSoFar,
267 if (Ty->isPrimitiveType())
268 switch (Ty->getTypeID()) {
269 case Type::VoidTyID: return Out << "void " << NameSoFar;
270 case Type::BoolTyID: return Out << "bool " << NameSoFar;
271 case Type::UByteTyID: return Out << "unsigned char " << NameSoFar;
272 case Type::SByteTyID: return Out << "signed char " << NameSoFar;
273 case Type::UShortTyID: return Out << "unsigned short " << NameSoFar;
274 case Type::ShortTyID: return Out << "short " << NameSoFar;
275 case Type::UIntTyID: return Out << "unsigned " << NameSoFar;
276 case Type::IntTyID: return Out << "int " << NameSoFar;
277 case Type::ULongTyID: return Out << "unsigned long long " << NameSoFar;
278 case Type::LongTyID: return Out << "signed long long " << NameSoFar;
279 case Type::FloatTyID: return Out << "float " << NameSoFar;
280 case Type::DoubleTyID: return Out << "double " << NameSoFar;
282 std::cerr << "Unknown primitive type: " << *Ty << "\n";
286 // Check to see if the type is named.
287 if (!IgnoreName || isa<OpaqueType>(Ty)) {
288 std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
289 if (I != TypeNames.end()) return Out << I->second << ' ' << NameSoFar;
292 switch (Ty->getTypeID()) {
293 case Type::FunctionTyID: {
294 const FunctionType *MTy = cast<FunctionType>(Ty);
295 std::stringstream FunctionInnards;
296 FunctionInnards << " (" << NameSoFar << ") (";
297 for (FunctionType::param_iterator I = MTy->param_begin(),
298 E = MTy->param_end(); I != E; ++I) {
299 if (I != MTy->param_begin())
300 FunctionInnards << ", ";
301 printType(FunctionInnards, *I, "");
303 if (MTy->isVarArg()) {
304 if (MTy->getNumParams())
305 FunctionInnards << ", ...";
306 } else if (!MTy->getNumParams()) {
307 FunctionInnards << "void";
309 FunctionInnards << ')';
310 std::string tstr = FunctionInnards.str();
311 printType(Out, MTy->getReturnType(), tstr);
314 case Type::StructTyID: {
315 const StructType *STy = cast<StructType>(Ty);
316 Out << NameSoFar + " {\n";
318 for (StructType::element_iterator I = STy->element_begin(),
319 E = STy->element_end(); I != E; ++I) {
321 printType(Out, *I, "field" + utostr(Idx++));
327 case Type::PointerTyID: {
328 const PointerType *PTy = cast<PointerType>(Ty);
329 std::string ptrName = "*" + NameSoFar;
331 if (isa<ArrayType>(PTy->getElementType()))
332 ptrName = "(" + ptrName + ")";
334 return printType(Out, PTy->getElementType(), ptrName);
337 case Type::ArrayTyID: {
338 const ArrayType *ATy = cast<ArrayType>(Ty);
339 unsigned NumElements = ATy->getNumElements();
340 if (NumElements == 0) NumElements = 1;
341 return printType(Out, ATy->getElementType(),
342 NameSoFar + "[" + utostr(NumElements) + "]");
345 case Type::OpaqueTyID: {
346 static int Count = 0;
347 std::string TyName = "struct opaque_" + itostr(Count++);
348 assert(TypeNames.find(Ty) == TypeNames.end());
349 TypeNames[Ty] = TyName;
350 return Out << TyName << ' ' << NameSoFar;
353 assert(0 && "Unhandled case in getTypeProps!");
360 void CWriter::printConstantArray(ConstantArray *CPA) {
362 // As a special case, print the array as a string if it is an array of
363 // ubytes or an array of sbytes with positive values.
365 const Type *ETy = CPA->getType()->getElementType();
366 bool isString = (ETy == Type::SByteTy || ETy == Type::UByteTy);
368 // Make sure the last character is a null char, as automatically added by C
369 if (isString && (CPA->getNumOperands() == 0 ||
370 !cast<Constant>(*(CPA->op_end()-1))->isNullValue()))
375 // Keep track of whether the last number was a hexadecimal escape
376 bool LastWasHex = false;
378 // Do not include the last character, which we know is null
379 for (unsigned i = 0, e = CPA->getNumOperands()-1; i != e; ++i) {
380 unsigned char C = cast<ConstantInt>(CPA->getOperand(i))->getRawValue();
382 // Print it out literally if it is a printable character. The only thing
383 // to be careful about is when the last letter output was a hex escape
384 // code, in which case we have to be careful not to print out hex digits
385 // explicitly (the C compiler thinks it is a continuation of the previous
386 // character, sheesh...)
388 if (isprint(C) && (!LastWasHex || !isxdigit(C))) {
390 if (C == '"' || C == '\\')
397 case '\n': Out << "\\n"; break;
398 case '\t': Out << "\\t"; break;
399 case '\r': Out << "\\r"; break;
400 case '\v': Out << "\\v"; break;
401 case '\a': Out << "\\a"; break;
402 case '\"': Out << "\\\""; break;
403 case '\'': Out << "\\\'"; break;
406 Out << (char)(( C/16 < 10) ? ( C/16 +'0') : ( C/16 -10+'A'));
407 Out << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
416 if (CPA->getNumOperands()) {
418 printConstant(cast<Constant>(CPA->getOperand(0)));
419 for (unsigned i = 1, e = CPA->getNumOperands(); i != e; ++i) {
421 printConstant(cast<Constant>(CPA->getOperand(i)));
428 // isFPCSafeToPrint - Returns true if we may assume that CFP may be written out
429 // textually as a double (rather than as a reference to a stack-allocated
430 // variable). We decide this by converting CFP to a string and back into a
431 // double, and then checking whether the conversion results in a bit-equal
432 // double to the original value of CFP. This depends on us and the target C
433 // compiler agreeing on the conversion process (which is pretty likely since we
434 // only deal in IEEE FP).
436 static bool isFPCSafeToPrint(const ConstantFP *CFP) {
439 sprintf(Buffer, "%a", CFP->getValue());
441 if (!strncmp(Buffer, "0x", 2) ||
442 !strncmp(Buffer, "-0x", 3) ||
443 !strncmp(Buffer, "+0x", 3))
444 return atof(Buffer) == CFP->getValue();
447 std::string StrVal = ftostr(CFP->getValue());
449 while (StrVal[0] == ' ')
450 StrVal.erase(StrVal.begin());
452 // Check to make sure that the stringized number is not some string like "Inf"
453 // or NaN. Check that the string matches the "[-+]?[0-9]" regex.
454 if ((StrVal[0] >= '0' && StrVal[0] <= '9') ||
455 ((StrVal[0] == '-' || StrVal[0] == '+') &&
456 (StrVal[1] >= '0' && StrVal[1] <= '9')))
457 // Reparse stringized version!
458 return atof(StrVal.c_str()) == CFP->getValue();
463 // printConstant - The LLVM Constant to C Constant converter.
464 void CWriter::printConstant(Constant *CPV) {
465 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
466 switch (CE->getOpcode()) {
467 case Instruction::Cast:
469 printType(Out, CPV->getType());
471 printConstant(CE->getOperand(0));
475 case Instruction::GetElementPtr:
477 printIndexingExpression(CE->getOperand(0), gep_type_begin(CPV),
481 case Instruction::Select:
483 printConstant(CE->getOperand(0));
485 printConstant(CE->getOperand(1));
487 printConstant(CE->getOperand(2));
490 case Instruction::Add:
491 case Instruction::Sub:
492 case Instruction::Mul:
493 case Instruction::Div:
494 case Instruction::Rem:
495 case Instruction::And:
496 case Instruction::Or:
497 case Instruction::Xor:
498 case Instruction::SetEQ:
499 case Instruction::SetNE:
500 case Instruction::SetLT:
501 case Instruction::SetLE:
502 case Instruction::SetGT:
503 case Instruction::SetGE:
504 case Instruction::Shl:
505 case Instruction::Shr:
507 printConstant(CE->getOperand(0));
508 switch (CE->getOpcode()) {
509 case Instruction::Add: Out << " + "; break;
510 case Instruction::Sub: Out << " - "; break;
511 case Instruction::Mul: Out << " * "; break;
512 case Instruction::Div: Out << " / "; break;
513 case Instruction::Rem: Out << " % "; break;
514 case Instruction::And: Out << " & "; break;
515 case Instruction::Or: Out << " | "; break;
516 case Instruction::Xor: Out << " ^ "; break;
517 case Instruction::SetEQ: Out << " == "; break;
518 case Instruction::SetNE: Out << " != "; break;
519 case Instruction::SetLT: Out << " < "; break;
520 case Instruction::SetLE: Out << " <= "; break;
521 case Instruction::SetGT: Out << " > "; break;
522 case Instruction::SetGE: Out << " >= "; break;
523 case Instruction::Shl: Out << " << "; break;
524 case Instruction::Shr: Out << " >> "; break;
525 default: assert(0 && "Illegal opcode here!");
527 printConstant(CE->getOperand(1));
532 std::cerr << "CWriter Error: Unhandled constant expression: "
536 } else if (isa<UndefValue>(CPV) && CPV->getType()->isFirstClassType()) {
538 printType(Out, CPV->getType());
539 Out << ")/*UNDEF*/0)";
543 switch (CPV->getType()->getTypeID()) {
545 Out << (CPV == ConstantBool::False ? '0' : '1'); break;
546 case Type::SByteTyID:
547 case Type::ShortTyID:
548 Out << cast<ConstantSInt>(CPV)->getValue(); break;
550 if ((int)cast<ConstantSInt>(CPV)->getValue() == (int)0x80000000)
551 Out << "((int)0x80000000U)"; // Handle MININT specially to avoid warning
553 Out << cast<ConstantSInt>(CPV)->getValue();
557 if (cast<ConstantSInt>(CPV)->isMinValue())
558 Out << "(/*INT64_MIN*/(-9223372036854775807LL)-1)";
560 Out << cast<ConstantSInt>(CPV)->getValue() << "ll"; break;
562 case Type::UByteTyID:
563 case Type::UShortTyID:
564 Out << cast<ConstantUInt>(CPV)->getValue(); break;
566 Out << cast<ConstantUInt>(CPV)->getValue() << 'u'; break;
567 case Type::ULongTyID:
568 Out << cast<ConstantUInt>(CPV)->getValue() << "ull"; break;
570 case Type::FloatTyID:
571 case Type::DoubleTyID: {
572 ConstantFP *FPC = cast<ConstantFP>(CPV);
573 std::map<const ConstantFP*, unsigned>::iterator I = FPConstantMap.find(FPC);
574 if (I != FPConstantMap.end()) {
575 // Because of FP precision problems we must load from a stack allocated
576 // value that holds the value in hex.
577 Out << "(*(" << (FPC->getType() == Type::FloatTy ? "float" : "double")
578 << "*)&FPConstant" << I->second << ')';
580 if (IsNAN(FPC->getValue())) {
583 // The prefix for a quiet NaN is 0x7FF8. For a signalling NaN,
585 const unsigned long QuietNaN = 0x7ff8UL;
586 const unsigned long SignalNaN = 0x7ff4UL;
588 // We need to grab the first part of the FP #
595 DHex.d = FPC->getValue();
596 sprintf(Buffer, "0x%llx", (unsigned long long)DHex.ll);
598 std::string Num(&Buffer[0], &Buffer[6]);
599 unsigned long Val = strtoul(Num.c_str(), 0, 16);
601 if (FPC->getType() == Type::FloatTy)
602 Out << "LLVM_NAN" << (Val == QuietNaN ? "" : "S") << "F(\""
603 << Buffer << "\") /*nan*/ ";
605 Out << "LLVM_NAN" << (Val == QuietNaN ? "" : "S") << "(\""
606 << Buffer << "\") /*nan*/ ";
607 } else if (IsInf(FPC->getValue())) {
609 if (FPC->getValue() < 0) Out << '-';
610 Out << "LLVM_INF" << (FPC->getType() == Type::FloatTy ? "F" : "")
615 // Print out the constant as a floating point number.
617 sprintf(Buffer, "%a", FPC->getValue());
620 Num = ftostr(FPC->getValue());
628 case Type::ArrayTyID:
629 if (isa<ConstantAggregateZero>(CPV) || isa<UndefValue>(CPV)) {
630 const ArrayType *AT = cast<ArrayType>(CPV->getType());
632 if (AT->getNumElements()) {
634 Constant *CZ = Constant::getNullValue(AT->getElementType());
636 for (unsigned i = 1, e = AT->getNumElements(); i != e; ++i) {
643 printConstantArray(cast<ConstantArray>(CPV));
647 case Type::StructTyID:
648 if (isa<ConstantAggregateZero>(CPV) || isa<UndefValue>(CPV)) {
649 const StructType *ST = cast<StructType>(CPV->getType());
651 if (ST->getNumElements()) {
653 printConstant(Constant::getNullValue(ST->getElementType(0)));
654 for (unsigned i = 1, e = ST->getNumElements(); i != e; ++i) {
656 printConstant(Constant::getNullValue(ST->getElementType(i)));
662 if (CPV->getNumOperands()) {
664 printConstant(cast<Constant>(CPV->getOperand(0)));
665 for (unsigned i = 1, e = CPV->getNumOperands(); i != e; ++i) {
667 printConstant(cast<Constant>(CPV->getOperand(i)));
674 case Type::PointerTyID:
675 if (isa<ConstantPointerNull>(CPV)) {
677 printType(Out, CPV->getType());
678 Out << ")/*NULL*/0)";
680 } else if (GlobalValue *GV = dyn_cast<GlobalValue>(CPV)) {
686 std::cerr << "Unknown constant type: " << *CPV << "\n";
691 void CWriter::writeOperandInternal(Value *Operand) {
692 if (Instruction *I = dyn_cast<Instruction>(Operand))
693 if (isInlinableInst(*I) && !isDirectAlloca(I)) {
694 // Should we inline this instruction to build a tree?
701 Constant* CPV = dyn_cast<Constant>(Operand);
702 if (CPV && !isa<GlobalValue>(CPV)) {
705 Out << Mang->getValueName(Operand);
709 void CWriter::writeOperand(Value *Operand) {
710 if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
711 Out << "(&"; // Global variables are references as their addresses by llvm
713 writeOperandInternal(Operand);
715 if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
719 // generateCompilerSpecificCode - This is where we add conditional compilation
720 // directives to cater to specific compilers as need be.
722 static void generateCompilerSpecificCode(std::ostream& Out) {
723 // Alloca is hard to get, and we don't want to include stdlib.h here...
724 Out << "/* get a declaration for alloca */\n"
725 << "#if defined(__CYGWIN__)\n"
726 << "extern void *_alloca(unsigned long);\n"
727 << "#define alloca(x) _alloca(x)\n"
728 << "#elif defined(__APPLE__)\n"
729 << "extern void *__builtin_alloca(unsigned long);\n"
730 << "#define alloca(x) __builtin_alloca(x)\n"
731 << "#elif defined(__sun__)\n"
732 << "#if defined(__sparcv9)\n"
733 << "extern void *__builtin_alloca(unsigned long);\n"
735 << "extern void *__builtin_alloca(unsigned int);\n"
737 << "#define alloca(x) __builtin_alloca(x)\n"
738 << "#elif defined(__FreeBSD__)\n"
739 << "#define alloca(x) __builtin_alloca(x)\n"
740 << "#elif !defined(_MSC_VER)\n"
741 << "#include <alloca.h>\n"
744 // We output GCC specific attributes to preserve 'linkonce'ness on globals.
745 // If we aren't being compiled with GCC, just drop these attributes.
746 Out << "#ifndef __GNUC__ /* Can only support \"linkonce\" vars with GCC */\n"
747 << "#define __attribute__(X)\n"
751 // At some point, we should support "external weak" vs. "weak" linkages.
752 // On Mac OS X, "external weak" is spelled "__attribute__((weak_import))".
753 Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
754 << "#define __EXTERNAL_WEAK__ __attribute__((weak_import))\n"
755 << "#elif defined(__GNUC__)\n"
756 << "#define __EXTERNAL_WEAK__ __attribute__((weak))\n"
758 << "#define __EXTERNAL_WEAK__\n"
762 // For now, turn off the weak linkage attribute on Mac OS X. (See above.)
763 Out << "#if defined(__GNUC__) && defined(__APPLE_CC__)\n"
764 << "#define __ATTRIBUTE_WEAK__\n"
765 << "#elif defined(__GNUC__)\n"
766 << "#define __ATTRIBUTE_WEAK__ __attribute__((weak))\n"
768 << "#define __ATTRIBUTE_WEAK__\n"
771 // Define NaN and Inf as GCC builtins if using GCC, as 0 otherwise
772 // From the GCC documentation:
774 // double __builtin_nan (const char *str)
776 // This is an implementation of the ISO C99 function nan.
778 // Since ISO C99 defines this function in terms of strtod, which we do
779 // not implement, a description of the parsing is in order. The string is
780 // parsed as by strtol; that is, the base is recognized by leading 0 or
781 // 0x prefixes. The number parsed is placed in the significand such that
782 // the least significant bit of the number is at the least significant
783 // bit of the significand. The number is truncated to fit the significand
784 // field provided. The significand is forced to be a quiet NaN.
786 // This function, if given a string literal, is evaluated early enough
787 // that it is considered a compile-time constant.
789 // float __builtin_nanf (const char *str)
791 // Similar to __builtin_nan, except the return type is float.
793 // double __builtin_inf (void)
795 // Similar to __builtin_huge_val, except a warning is generated if the
796 // target floating-point format does not support infinities. This
797 // function is suitable for implementing the ISO C99 macro INFINITY.
799 // float __builtin_inff (void)
801 // Similar to __builtin_inf, except the return type is float.
802 Out << "#ifdef __GNUC__\n"
803 << "#define LLVM_NAN(NanStr) __builtin_nan(NanStr) /* Double */\n"
804 << "#define LLVM_NANF(NanStr) __builtin_nanf(NanStr) /* Float */\n"
805 << "#define LLVM_NANS(NanStr) __builtin_nans(NanStr) /* Double */\n"
806 << "#define LLVM_NANSF(NanStr) __builtin_nansf(NanStr) /* Float */\n"
807 << "#define LLVM_INF __builtin_inf() /* Double */\n"
808 << "#define LLVM_INFF __builtin_inff() /* Float */\n"
809 << "#define LLVM_PREFETCH(addr,rw,locality) __builtin_prefetch(addr,rw,locality)\n"
811 << "#define LLVM_NAN(NanStr) ((double)0.0) /* Double */\n"
812 << "#define LLVM_NANF(NanStr) 0.0F /* Float */\n"
813 << "#define LLVM_NANS(NanStr) ((double)0.0) /* Double */\n"
814 << "#define LLVM_NANSF(NanStr) 0.0F /* Float */\n"
815 << "#define LLVM_INF ((double)0.0) /* Double */\n"
816 << "#define LLVM_INFF 0.0F /* Float */\n"
817 << "#define LLVM_PREFETCH(addr,rw,locality) \n"
821 bool CWriter::doInitialization(Module &M) {
827 // Ensure that all structure types have names...
828 Mang = new Mangler(M);
830 // get declaration for alloca
831 Out << "/* Provide Declarations */\n";
832 Out << "#include <stdarg.h>\n"; // Varargs support
833 Out << "#include <setjmp.h>\n"; // Unwind support
834 generateCompilerSpecificCode(Out);
836 // Provide a definition for `bool' if not compiling with a C++ compiler.
838 << "#ifndef __cplusplus\ntypedef unsigned char bool;\n#endif\n"
840 << "\n\n/* Support for floating point constants */\n"
841 << "typedef unsigned long long ConstantDoubleTy;\n"
842 << "typedef unsigned int ConstantFloatTy;\n"
844 << "\n\n/* Global Declarations */\n";
846 // First output all the declarations for the program, because C requires
847 // Functions & globals to be declared before they are used.
850 // Loop over the symbol table, emitting all named constants...
851 printModuleTypes(M.getSymbolTable());
853 // Global variable declarations...
855 Out << "\n/* External Global Variable Declarations */\n";
856 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I) {
857 if (I->hasExternalLinkage()) {
859 printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
865 // Function declarations
867 Out << "\n/* Function Declarations */\n";
868 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
869 // Don't print declarations for intrinsic functions.
870 if (!I->getIntrinsicID() &&
871 I->getName() != "setjmp" && I->getName() != "longjmp") {
872 printFunctionSignature(I, true);
873 if (I->hasWeakLinkage()) Out << " __ATTRIBUTE_WEAK__";
874 if (I->hasLinkOnceLinkage()) Out << " __ATTRIBUTE_WEAK__";
880 // Output the global variable declarations
882 Out << "\n\n/* Global Variable Declarations */\n";
883 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
884 if (!I->isExternal()) {
885 if (I->hasInternalLinkage())
889 printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
891 if (I->hasLinkOnceLinkage())
892 Out << " __attribute__((common))";
893 else if (I->hasWeakLinkage())
894 Out << " __ATTRIBUTE_WEAK__";
899 // Output the global variable definitions and contents...
901 Out << "\n\n/* Global Variable Definitions and Initialization */\n";
902 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
903 if (!I->isExternal()) {
904 if (I->hasInternalLinkage())
906 printType(Out, I->getType()->getElementType(), Mang->getValueName(I));
907 if (I->hasLinkOnceLinkage())
908 Out << " __attribute__((common))";
909 else if (I->hasWeakLinkage())
910 Out << " __ATTRIBUTE_WEAK__";
912 // If the initializer is not null, emit the initializer. If it is null,
913 // we try to avoid emitting large amounts of zeros. The problem with
914 // this, however, occurs when the variable has weak linkage. In this
915 // case, the assembler will complain about the variable being both weak
916 // and common, so we disable this optimization.
917 if (!I->getInitializer()->isNullValue()) {
919 writeOperand(I->getInitializer());
920 } else if (I->hasWeakLinkage()) {
921 // We have to specify an initializer, but it doesn't have to be
922 // complete. If the value is an aggregate, print out { 0 }, and let
923 // the compiler figure out the rest of the zeros.
925 if (isa<StructType>(I->getInitializer()->getType()) ||
926 isa<ArrayType>(I->getInitializer()->getType())) {
929 // Just print it out normally.
930 writeOperand(I->getInitializer());
938 Out << "\n\n/* Function Bodies */\n";
943 /// Output all floating point constants that cannot be printed accurately...
944 void CWriter::printFloatingPointConstants(Function &F) {
955 // Scan the module for floating point constants. If any FP constant is used
956 // in the function, we want to redirect it here so that we do not depend on
957 // the precision of the printed form, unless the printed form preserves
960 static unsigned FPCounter = 0;
961 for (constant_iterator I = constant_begin(&F), E = constant_end(&F);
963 if (const ConstantFP *FPC = dyn_cast<ConstantFP>(*I))
964 if (!isFPCSafeToPrint(FPC) && // Do not put in FPConstantMap if safe.
965 !FPConstantMap.count(FPC)) {
966 double Val = FPC->getValue();
968 FPConstantMap[FPC] = FPCounter; // Number the FP constants
970 if (FPC->getType() == Type::DoubleTy) {
972 Out << "static const ConstantDoubleTy FPConstant" << FPCounter++
973 << " = 0x" << std::hex << DBLUnion.U << std::dec
974 << "ULL; /* " << Val << " */\n";
975 } else if (FPC->getType() == Type::FloatTy) {
977 Out << "static const ConstantFloatTy FPConstant" << FPCounter++
978 << " = 0x" << std::hex << FLTUnion.U << std::dec
979 << "U; /* " << Val << " */\n";
981 assert(0 && "Unknown float type!");
988 /// printSymbolTable - Run through symbol table looking for type names. If a
989 /// type name is found, emit it's declaration...
991 void CWriter::printModuleTypes(const SymbolTable &ST) {
992 // We are only interested in the type plane of the symbol table.
993 SymbolTable::type_const_iterator I = ST.type_begin();
994 SymbolTable::type_const_iterator End = ST.type_end();
996 // If there are no type names, exit early.
997 if (I == End) return;
999 // Print out forward declarations for structure types before anything else!
1000 Out << "/* Structure forward decls */\n";
1001 for (; I != End; ++I)
1002 if (const Type *STy = dyn_cast<StructType>(I->second)) {
1003 std::string Name = "struct l_" + Mangler::makeNameProper(I->first);
1004 Out << Name << ";\n";
1005 TypeNames.insert(std::make_pair(STy, Name));
1010 // Now we can print out typedefs...
1011 Out << "/* Typedefs */\n";
1012 for (I = ST.type_begin(); I != End; ++I) {
1013 const Type *Ty = cast<Type>(I->second);
1014 std::string Name = "l_" + Mangler::makeNameProper(I->first);
1016 printType(Out, Ty, Name);
1022 // Keep track of which structures have been printed so far...
1023 std::set<const StructType *> StructPrinted;
1025 // Loop over all structures then push them into the stack so they are
1026 // printed in the correct order.
1028 Out << "/* Structure contents */\n";
1029 for (I = ST.type_begin(); I != End; ++I)
1030 if (const StructType *STy = dyn_cast<StructType>(I->second))
1031 // Only print out used types!
1032 printContainedStructs(STy, StructPrinted);
1035 // Push the struct onto the stack and recursively push all structs
1036 // this one depends on.
1037 void CWriter::printContainedStructs(const Type *Ty,
1038 std::set<const StructType*> &StructPrinted){
1039 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
1040 //Check to see if we have already printed this struct
1041 if (StructPrinted.count(STy) == 0) {
1042 // Print all contained types first...
1043 for (StructType::element_iterator I = STy->element_begin(),
1044 E = STy->element_end(); I != E; ++I) {
1045 const Type *Ty1 = I->get();
1046 if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
1047 printContainedStructs(*I, StructPrinted);
1050 //Print structure type out..
1051 StructPrinted.insert(STy);
1052 std::string Name = TypeNames[STy];
1053 printType(Out, STy, Name, true);
1057 // If it is an array, check contained types and continue
1058 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)){
1059 const Type *Ty1 = ATy->getElementType();
1060 if (isa<StructType>(Ty1) || isa<ArrayType>(Ty1))
1061 printContainedStructs(Ty1, StructPrinted);
1066 void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
1067 if (F->hasInternalLinkage()) Out << "static ";
1069 // Loop over the arguments, printing them...
1070 const FunctionType *FT = cast<FunctionType>(F->getFunctionType());
1072 std::stringstream FunctionInnards;
1074 // Print out the name...
1075 FunctionInnards << Mang->getValueName(F) << '(';
1077 if (!F->isExternal()) {
1079 std::string ArgName;
1080 if (F->abegin()->hasName() || !Prototype)
1081 ArgName = Mang->getValueName(F->abegin());
1082 printType(FunctionInnards, F->afront().getType(), ArgName);
1083 for (Function::const_aiterator I = ++F->abegin(), E = F->aend();
1085 FunctionInnards << ", ";
1086 if (I->hasName() || !Prototype)
1087 ArgName = Mang->getValueName(I);
1090 printType(FunctionInnards, I->getType(), ArgName);
1094 // Loop over the arguments, printing them...
1095 for (FunctionType::param_iterator I = FT->param_begin(),
1096 E = FT->param_end(); I != E; ++I) {
1097 if (I != FT->param_begin()) FunctionInnards << ", ";
1098 printType(FunctionInnards, *I);
1102 // Finish printing arguments... if this is a vararg function, print the ...,
1103 // unless there are no known types, in which case, we just emit ().
1105 if (FT->isVarArg() && FT->getNumParams()) {
1106 if (FT->getNumParams()) FunctionInnards << ", ";
1107 FunctionInnards << "..."; // Output varargs portion of signature!
1108 } else if (!FT->isVarArg() && FT->getNumParams() == 0) {
1109 FunctionInnards << "void"; // ret() -> ret(void) in C.
1111 FunctionInnards << ')';
1112 // Print out the return type and the entire signature for that matter
1113 printType(Out, F->getReturnType(), FunctionInnards.str());
1116 void CWriter::printFunction(Function &F) {
1117 printFunctionSignature(&F, false);
1120 // print local variable information for the function
1121 for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I)
1122 if (const AllocaInst *AI = isDirectAlloca(&*I)) {
1124 printType(Out, AI->getAllocatedType(), Mang->getValueName(AI));
1125 Out << "; /* Address-exposed local */\n";
1126 } else if (I->getType() != Type::VoidTy && !isInlinableInst(*I)) {
1128 printType(Out, I->getType(), Mang->getValueName(&*I));
1131 if (isa<PHINode>(*I)) { // Print out PHI node temporaries as well...
1133 printType(Out, I->getType(),
1134 Mang->getValueName(&*I)+"__PHI_TEMPORARY");
1141 if (F.hasExternalLinkage() && F.getName() == "main")
1144 // print the basic blocks
1145 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
1146 if (Loop *L = LI->getLoopFor(BB)) {
1147 if (L->getHeader() == BB && L->getParentLoop() == 0)
1150 printBasicBlock(BB);
1157 void CWriter::printCodeForMain() {
1158 // On X86, set the FP control word to 64-bits of precision instead of 80 bits.
1159 Out << "#if defined(__GNUC__) && !defined(__llvm__)\n"
1160 << "#if defined(i386) || defined(__i386__) || defined(__i386)\n"
1161 << "{short FPCW;__asm__ (\"fnstcw %0\" : \"=m\" (*&FPCW));\n"
1162 << "FPCW=(FPCW&~0x300)|0x200;__asm__(\"fldcw %0\" :: \"m\" (*&FPCW));}\n"
1163 << "#endif\n#endif\n";
1166 void CWriter::printLoop(Loop *L) {
1167 Out << " do { /* Syntactic loop '" << L->getHeader()->getName()
1168 << "' to make GCC happy */\n";
1169 for (unsigned i = 0, e = L->getBlocks().size(); i != e; ++i) {
1170 BasicBlock *BB = L->getBlocks()[i];
1171 Loop *BBLoop = LI->getLoopFor(BB);
1173 printBasicBlock(BB);
1174 else if (BB == BBLoop->getHeader() && BBLoop->getParentLoop() == L)
1177 Out << " } while (1); /* end of syntactic loop '"
1178 << L->getHeader()->getName() << "' */\n";
1181 void CWriter::printBasicBlock(BasicBlock *BB) {
1183 // Don't print the label for the basic block if there are no uses, or if
1184 // the only terminator use is the predecessor basic block's terminator.
1185 // We have to scan the use list because PHI nodes use basic blocks too but
1186 // do not require a label to be generated.
1188 bool NeedsLabel = false;
1189 for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
1190 if (isGotoCodeNecessary(*PI, BB)) {
1195 if (NeedsLabel) Out << Mang->getValueName(BB) << ":\n";
1197 // Output all of the instructions in the basic block...
1198 for (BasicBlock::iterator II = BB->begin(), E = --BB->end(); II != E;
1200 if (!isInlinableInst(*II) && !isDirectAlloca(II)) {
1201 if (II->getType() != Type::VoidTy)
1210 // Don't emit prefix or suffix for the terminator...
1211 visit(*BB->getTerminator());
1215 // Specific Instruction type classes... note that all of the casts are
1216 // necessary because we use the instruction classes as opaque types...
1218 void CWriter::visitReturnInst(ReturnInst &I) {
1219 // Don't output a void return if this is the last basic block in the function
1220 if (I.getNumOperands() == 0 &&
1221 &*--I.getParent()->getParent()->end() == I.getParent() &&
1222 !I.getParent()->size() == 1) {
1227 if (I.getNumOperands()) {
1229 writeOperand(I.getOperand(0));
1234 void CWriter::visitSwitchInst(SwitchInst &SI) {
1237 writeOperand(SI.getOperand(0));
1238 Out << ") {\n default:\n";
1239 printPHICopiesForSuccessor (SI.getParent(), SI.getDefaultDest(), 2);
1240 printBranchToBlock(SI.getParent(), SI.getDefaultDest(), 2);
1242 for (unsigned i = 2, e = SI.getNumOperands(); i != e; i += 2) {
1244 writeOperand(SI.getOperand(i));
1246 BasicBlock *Succ = cast<BasicBlock>(SI.getOperand(i+1));
1247 printPHICopiesForSuccessor (SI.getParent(), Succ, 2);
1248 printBranchToBlock(SI.getParent(), Succ, 2);
1249 if (Succ == SI.getParent()->getNext())
1255 void CWriter::visitUnreachableInst(UnreachableInst &I) {
1256 Out << " /*UNREACHABLE*/;\n";
1259 bool CWriter::isGotoCodeNecessary(BasicBlock *From, BasicBlock *To) {
1260 /// FIXME: This should be reenabled, but loop reordering safe!!
1263 if (From->getNext() != To) // Not the direct successor, we need a goto
1266 //isa<SwitchInst>(From->getTerminator())
1269 if (LI->getLoopFor(From) != LI->getLoopFor(To))
1274 void CWriter::printPHICopiesForSuccessor (BasicBlock *CurBlock,
1275 BasicBlock *Successor,
1277 for (BasicBlock::iterator I = Successor->begin(); isa<PHINode>(I); ++I) {
1278 PHINode *PN = cast<PHINode>(I);
1279 // Now we have to do the printing.
1280 Value *IV = PN->getIncomingValueForBlock(CurBlock);
1281 if (!isa<UndefValue>(IV)) {
1282 Out << std::string(Indent, ' ');
1283 Out << " " << Mang->getValueName(I) << "__PHI_TEMPORARY = ";
1285 Out << "; /* for PHI node */\n";
1290 void CWriter::printBranchToBlock(BasicBlock *CurBB, BasicBlock *Succ,
1292 if (isGotoCodeNecessary(CurBB, Succ)) {
1293 Out << std::string(Indent, ' ') << " goto ";
1299 // Branch instruction printing - Avoid printing out a branch to a basic block
1300 // that immediately succeeds the current one.
1302 void CWriter::visitBranchInst(BranchInst &I) {
1304 if (I.isConditional()) {
1305 if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(0))) {
1307 writeOperand(I.getCondition());
1310 printPHICopiesForSuccessor (I.getParent(), I.getSuccessor(0), 2);
1311 printBranchToBlock(I.getParent(), I.getSuccessor(0), 2);
1313 if (isGotoCodeNecessary(I.getParent(), I.getSuccessor(1))) {
1314 Out << " } else {\n";
1315 printPHICopiesForSuccessor (I.getParent(), I.getSuccessor(1), 2);
1316 printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
1319 // First goto not necessary, assume second one is...
1321 writeOperand(I.getCondition());
1324 printPHICopiesForSuccessor (I.getParent(), I.getSuccessor(1), 2);
1325 printBranchToBlock(I.getParent(), I.getSuccessor(1), 2);
1330 printPHICopiesForSuccessor (I.getParent(), I.getSuccessor(0), 0);
1331 printBranchToBlock(I.getParent(), I.getSuccessor(0), 0);
1336 // PHI nodes get copied into temporary values at the end of predecessor basic
1337 // blocks. We now need to copy these temporary values into the REAL value for
1339 void CWriter::visitPHINode(PHINode &I) {
1341 Out << "__PHI_TEMPORARY";
1345 void CWriter::visitBinaryOperator(Instruction &I) {
1346 // binary instructions, shift instructions, setCond instructions.
1347 assert(!isa<PointerType>(I.getType()));
1349 // We must cast the results of binary operations which might be promoted.
1350 bool needsCast = false;
1351 if ((I.getType() == Type::UByteTy) || (I.getType() == Type::SByteTy)
1352 || (I.getType() == Type::UShortTy) || (I.getType() == Type::ShortTy)
1353 || (I.getType() == Type::FloatTy)) {
1356 printType(Out, I.getType());
1360 // If this is a negation operation, print it out as such. For FP, we don't
1361 // want to print "-0.0 - X".
1362 if (BinaryOperator::isNeg(&I)) {
1364 writeOperand(BinaryOperator::getNegArgument(cast<BinaryOperator>(&I)));
1367 writeOperand(I.getOperand(0));
1369 switch (I.getOpcode()) {
1370 case Instruction::Add: Out << " + "; break;
1371 case Instruction::Sub: Out << " - "; break;
1372 case Instruction::Mul: Out << '*'; break;
1373 case Instruction::Div: Out << '/'; break;
1374 case Instruction::Rem: Out << '%'; break;
1375 case Instruction::And: Out << " & "; break;
1376 case Instruction::Or: Out << " | "; break;
1377 case Instruction::Xor: Out << " ^ "; break;
1378 case Instruction::SetEQ: Out << " == "; break;
1379 case Instruction::SetNE: Out << " != "; break;
1380 case Instruction::SetLE: Out << " <= "; break;
1381 case Instruction::SetGE: Out << " >= "; break;
1382 case Instruction::SetLT: Out << " < "; break;
1383 case Instruction::SetGT: Out << " > "; break;
1384 case Instruction::Shl : Out << " << "; break;
1385 case Instruction::Shr : Out << " >> "; break;
1386 default: std::cerr << "Invalid operator type!" << I; abort();
1389 writeOperand(I.getOperand(1));
1397 void CWriter::visitCastInst(CastInst &I) {
1398 if (I.getType() == Type::BoolTy) {
1400 writeOperand(I.getOperand(0));
1405 printType(Out, I.getType());
1407 if (isa<PointerType>(I.getType())&&I.getOperand(0)->getType()->isIntegral() ||
1408 isa<PointerType>(I.getOperand(0)->getType())&&I.getType()->isIntegral()) {
1409 // Avoid "cast to pointer from integer of different size" warnings
1413 writeOperand(I.getOperand(0));
1416 void CWriter::visitSelectInst(SelectInst &I) {
1418 writeOperand(I.getCondition());
1420 writeOperand(I.getTrueValue());
1422 writeOperand(I.getFalseValue());
1427 void CWriter::lowerIntrinsics(Function &F) {
1428 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1429 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
1430 if (CallInst *CI = dyn_cast<CallInst>(I++))
1431 if (Function *F = CI->getCalledFunction())
1432 switch (F->getIntrinsicID()) {
1433 case Intrinsic::not_intrinsic:
1434 case Intrinsic::vastart:
1435 case Intrinsic::vacopy:
1436 case Intrinsic::vaend:
1437 case Intrinsic::returnaddress:
1438 case Intrinsic::frameaddress:
1439 case Intrinsic::setjmp:
1440 case Intrinsic::longjmp:
1441 case Intrinsic::prefetch:
1442 // We directly implement these intrinsics
1445 // All other intrinsic calls we must lower.
1446 Instruction *Before = CI->getPrev();
1447 IL.LowerIntrinsicCall(CI);
1448 if (Before) { // Move iterator to instruction after call
1458 void CWriter::visitCallInst(CallInst &I) {
1459 // Handle intrinsic function calls first...
1460 if (Function *F = I.getCalledFunction())
1461 if (Intrinsic::ID ID = (Intrinsic::ID)F->getIntrinsicID()) {
1463 default: assert(0 && "Unknown LLVM intrinsic!");
1464 case Intrinsic::vastart:
1467 Out << "va_start(*(va_list*)&" << Mang->getValueName(&I) << ", ";
1468 // Output the last argument to the enclosing function...
1469 if (I.getParent()->getParent()->aempty()) {
1470 std::cerr << "The C backend does not currently support zero "
1471 << "argument varargs functions, such as '"
1472 << I.getParent()->getParent()->getName() << "'!\n";
1475 writeOperand(&I.getParent()->getParent()->aback());
1478 case Intrinsic::vaend:
1479 if (!isa<ConstantPointerNull>(I.getOperand(1))) {
1480 Out << "va_end(*(va_list*)&";
1481 writeOperand(I.getOperand(1));
1484 Out << "va_end(*(va_list*)0)";
1487 case Intrinsic::vacopy:
1489 Out << "va_copy(*(va_list*)&" << Mang->getValueName(&I) << ", ";
1490 Out << "*(va_list*)&";
1491 writeOperand(I.getOperand(1));
1494 case Intrinsic::returnaddress:
1495 Out << "__builtin_return_address(";
1496 writeOperand(I.getOperand(1));
1499 case Intrinsic::frameaddress:
1500 Out << "__builtin_frame_address(";
1501 writeOperand(I.getOperand(1));
1504 case Intrinsic::setjmp:
1505 Out << "setjmp(*(jmp_buf*)";
1506 writeOperand(I.getOperand(1));
1509 case Intrinsic::longjmp:
1510 Out << "longjmp(*(jmp_buf*)";
1511 writeOperand(I.getOperand(1));
1513 writeOperand(I.getOperand(2));
1516 case Intrinsic::prefetch:
1517 Out << "LLVM_PREFETCH((const void *)";
1518 writeOperand(I.getOperand(1));
1520 writeOperand(I.getOperand(2));
1522 writeOperand(I.getOperand(3));
1528 Value *Callee = I.getCalledValue();
1530 // GCC is really a PITA. It does not permit codegening casts of functions to
1531 // function pointers if they are in a call (it generates a trap instruction
1532 // instead!). We work around this by inserting a cast to void* in between the
1533 // function and the function pointer cast. Unfortunately, we can't just form
1534 // the constant expression here, because the folder will immediately nuke it.
1536 // Note finally, that this is completely unsafe. ANSI C does not guarantee
1537 // that void* and function pointers have the same size. :( To deal with this
1538 // in the common case, we handle casts where the number of arguments passed
1541 bool WroteCallee = false;
1542 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Callee))
1543 if (CE->getOpcode() == Instruction::Cast)
1544 if (Function *RF = dyn_cast<Function>(CE->getOperand(0))) {
1545 const FunctionType *RFTy = RF->getFunctionType();
1546 if (RFTy->getNumParams() == I.getNumOperands()-1) {
1547 // If the call site expects a value, and the actual callee doesn't
1548 // provide one, return 0.
1549 if (I.getType() != Type::VoidTy &&
1550 RFTy->getReturnType() == Type::VoidTy)
1551 Out << "0 /*actual callee doesn't return value*/; ";
1554 // Ok, just cast the pointer type.
1556 printType(Out, CE->getType());
1564 const PointerType *PTy = cast<PointerType>(Callee->getType());
1565 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1566 const Type *RetTy = FTy->getReturnType();
1568 if (!WroteCallee) writeOperand(Callee);
1571 unsigned NumDeclaredParams = FTy->getNumParams();
1573 if (I.getNumOperands() != 1) {
1574 CallSite::arg_iterator AI = I.op_begin()+1, AE = I.op_end();
1575 if (NumDeclaredParams && (*AI)->getType() != FTy->getParamType(0)) {
1577 printType(Out, FTy->getParamType(0));
1584 for (ArgNo = 1, ++AI; AI != AE; ++AI, ++ArgNo) {
1586 if (ArgNo < NumDeclaredParams &&
1587 (*AI)->getType() != FTy->getParamType(ArgNo)) {
1589 printType(Out, FTy->getParamType(ArgNo));
1598 void CWriter::visitMallocInst(MallocInst &I) {
1599 assert(0 && "lowerallocations pass didn't work!");
1602 void CWriter::visitAllocaInst(AllocaInst &I) {
1604 printType(Out, I.getType());
1605 Out << ") alloca(sizeof(";
1606 printType(Out, I.getType()->getElementType());
1608 if (I.isArrayAllocation()) {
1610 writeOperand(I.getOperand(0));
1615 void CWriter::visitFreeInst(FreeInst &I) {
1616 assert(0 && "lowerallocations pass didn't work!");
1619 void CWriter::printIndexingExpression(Value *Ptr, gep_type_iterator I,
1620 gep_type_iterator E) {
1621 bool HasImplicitAddress = false;
1622 // If accessing a global value with no indexing, avoid *(&GV) syndrome
1623 if (GlobalValue *V = dyn_cast<GlobalValue>(Ptr)) {
1624 HasImplicitAddress = true;
1625 } else if (isDirectAlloca(Ptr)) {
1626 HasImplicitAddress = true;
1630 if (!HasImplicitAddress)
1631 Out << '*'; // Implicit zero first argument: '*x' is equivalent to 'x[0]'
1633 writeOperandInternal(Ptr);
1637 const Constant *CI = dyn_cast<Constant>(I.getOperand());
1638 if (HasImplicitAddress && (!CI || !CI->isNullValue()))
1641 writeOperandInternal(Ptr);
1643 if (HasImplicitAddress && (!CI || !CI->isNullValue())) {
1645 HasImplicitAddress = false; // HIA is only true if we haven't addressed yet
1648 assert(!HasImplicitAddress || (CI && CI->isNullValue()) &&
1649 "Can only have implicit address with direct accessing");
1651 if (HasImplicitAddress) {
1653 } else if (CI && CI->isNullValue()) {
1654 gep_type_iterator TmpI = I; ++TmpI;
1656 // Print out the -> operator if possible...
1657 if (TmpI != E && isa<StructType>(*TmpI)) {
1658 Out << (HasImplicitAddress ? "." : "->");
1659 Out << "field" << cast<ConstantUInt>(TmpI.getOperand())->getValue();
1665 if (isa<StructType>(*I)) {
1666 Out << ".field" << cast<ConstantUInt>(I.getOperand())->getValue();
1669 writeOperand(I.getOperand());
1674 void CWriter::visitLoadInst(LoadInst &I) {
1676 if (I.isVolatile()) {
1678 printType(Out, I.getType());
1679 Out << " volatile*)";
1682 writeOperand(I.getOperand(0));
1688 void CWriter::visitStoreInst(StoreInst &I) {
1690 if (I.isVolatile()) {
1692 printType(Out, I.getOperand(0)->getType());
1693 Out << " volatile*)";
1695 writeOperand(I.getPointerOperand());
1696 if (I.isVolatile()) Out << ')';
1698 writeOperand(I.getOperand(0));
1701 void CWriter::visitGetElementPtrInst(GetElementPtrInst &I) {
1703 printIndexingExpression(I.getPointerOperand(), gep_type_begin(I),
1707 void CWriter::visitVANextInst(VANextInst &I) {
1708 Out << Mang->getValueName(I.getOperand(0));
1709 Out << "; va_arg(*(va_list*)&" << Mang->getValueName(&I) << ", ";
1710 printType(Out, I.getArgType());
1714 void CWriter::visitVAArgInst(VAArgInst &I) {
1716 Out << "{ va_list Tmp; va_copy(Tmp, *(va_list*)&";
1717 writeOperand(I.getOperand(0));
1718 Out << ");\n " << Mang->getValueName(&I) << " = va_arg(Tmp, ";
1719 printType(Out, I.getType());
1720 Out << ");\n va_end(Tmp); }";
1723 //===----------------------------------------------------------------------===//
1724 // External Interface declaration
1725 //===----------------------------------------------------------------------===//
1727 bool CTargetMachine::addPassesToEmitAssembly(PassManager &PM, std::ostream &o) {
1728 PM.add(createLowerGCPass());
1729 PM.add(createLowerAllocationsPass(true));
1730 PM.add(createLowerInvokePass());
1731 PM.add(new CBackendNameAllUsedStructs());
1732 PM.add(new CWriter(o, getIntrinsicLowering()));