X86AsmPrinter.cpp revision b12c9fa565ca03fdfc40d8d9933561f47bc5f89e 
1//===-- X86AsmPrinter.cpp - Convert X86 LLVM IR to X86 assembly -----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
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.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file the shared super class printer that converts from our internal
11// representation of machine-dependent LLVM code to Intel and AT&T format
12// assembly language.
13// This printer is the output mechanism used by `llc'.
14//
15//===----------------------------------------------------------------------===//
16
17#include "X86ATTAsmPrinter.h"
18#include "X86IntelAsmPrinter.h"
19#include "X86.h"
20#include "llvm/Module.h"
21#include "llvm/Assembly/Writer.h"
22#include "llvm/CodeGen/MachineConstantPool.h"
23#include "llvm/Support/Mangler.h"
24#include "llvm/Support/CommandLine.h"
25using namespace llvm;
26using namespace x86;
27
28Statistic<> llvm::x86::EmittedInsts("asm-printer",
29                                    "Number of machine instrs printed");
30
31enum AsmWriterFlavorTy { att, intel };
32cl::opt<AsmWriterFlavorTy>
33AsmWriterFlavor("x86-asm-syntax",
34                cl::desc("Choose style of code to emit from X86 backend:"),
35                cl::values(
36                           clEnumVal(att,   "  Emit AT&T-style assembly"),
37                           clEnumVal(intel, "  Emit Intel-style assembly"),
38                           clEnumValEnd),
39                cl::init(att));
40
41/// doInitialization
42bool X86SharedAsmPrinter::doInitialization(Module& M) {
43  bool leadingUnderscore = false;
44  forCygwin = false;
45  const std::string& TT = M.getTargetTriple();
46  if (TT.length() > 5) {
47    forCygwin = TT.find("cygwin") != std::string::npos ||
48                TT.find("mingw")  != std::string::npos;
49    forDarwin = TT.find("darwin") != std::string::npos;
50  } else if (TT.empty()) {
51#if defined(__CYGWIN__) || defined(__MINGW32__)
52    forCygwin = true;
53#elif defined(__APPLE__)
54    forDarwin = true;
55#elif defined(_WIN32)
56    leadingUnderscore = true;
57#else
58    leadingUnderscore = false;
59#endif
60  }
61  if (leadingUnderscore || forCygwin || forDarwin)
62    GlobalPrefix = "_";
63
64  if (forDarwin)
65    AlignmentIsInBytes = false;
66
67  return AsmPrinter::doInitialization(M);
68}
69
70/// printConstantPool - Print to the current output stream assembly
71/// representations of the constants in the constant pool MCP. This is
72/// used to print out constants which have been "spilled to memory" by
73/// the code generator.
74///
75void X86SharedAsmPrinter::printConstantPool(MachineConstantPool *MCP) {
76  const std::vector<Constant*> &CP = MCP->getConstants();
77  const TargetData &TD = TM.getTargetData();
78
79  if (CP.empty()) return;
80
81  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
82    if (forDarwin)
83      O << "\t.data\n";
84    else
85      O << "\t.section .rodata\n";
86    emitAlignment(TD.getTypeAlignmentShift(CP[i]->getType()));
87    O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t" << CommentString
88      << *CP[i] << "\n";
89    emitGlobalConstant(CP[i]);
90  }
91}
92
93bool X86SharedAsmPrinter::doFinalization(Module &M) {
94  const TargetData &TD = TM.getTargetData();
95  std::string CurSection;
96
97  // Print out module-level global variables here.
98  for (Module::const_global_iterator I = M.global_begin(),
99         E = M.global_end(); I != E; ++I)
100    if (I->hasInitializer()) {   // External global require no code
101      O << "\n\n";
102      std::string name = Mang->getValueName(I);
103      Constant *C = I->getInitializer();
104      unsigned Size = TD.getTypeSize(C->getType());
105      unsigned Align = TD.getTypeAlignmentShift(C->getType());
106
107      if (C->isNullValue() &&
108          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
109           I->hasWeakLinkage() /* FIXME: Verify correct */)) {
110        SwitchSection(O, CurSection, ".data");
111        if (!forCygwin && !forDarwin && I->hasInternalLinkage())
112          O << "\t.local " << name << "\n";
113        if (forDarwin && I->hasInternalLinkage())
114          O << "\t.lcomm " << name << "," << Size << "," << Align;
115        else
116          O << "\t.comm " << name << "," << Size;
117        if (!forCygwin && !forDarwin)
118          O << "," << (1 << Align);
119        O << "\t\t# ";
120        WriteAsOperand(O, I, true, true, &M);
121        O << "\n";
122      } else {
123        switch (I->getLinkage()) {
124        default: assert(0 && "Unknown linkage type!");
125        case GlobalValue::LinkOnceLinkage:
126        case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
127          // Nonnull linkonce -> weak
128          O << "\t.weak " << name << "\n";
129          SwitchSection(O, CurSection, "");
130          O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
131          break;
132        case GlobalValue::AppendingLinkage:
133          // FIXME: appending linkage variables should go into a section of
134          // their name or something.  For now, just emit them as external.
135        case GlobalValue::ExternalLinkage:
136          // If external or appending, declare as a global symbol
137          O << "\t.globl " << name << "\n";
138          // FALL THROUGH
139        case GlobalValue::InternalLinkage:
140          if (C->isNullValue())
141            SwitchSection(O, CurSection, ".bss");
142          else
143            SwitchSection(O, CurSection, ".data");
144          break;
145        }
146
147        emitAlignment(Align);
148        if (!forCygwin && !forDarwin) {
149          O << "\t.type " << name << ",@object\n";
150          O << "\t.size " << name << "," << Size << "\n";
151        }
152        O << name << ":\t\t\t\t# ";
153        WriteAsOperand(O, I, true, true, &M);
154        O << " = ";
155        WriteAsOperand(O, C, false, false, &M);
156        O << "\n";
157        emitGlobalConstant(C);
158      }
159    }
160
161  if (forDarwin) {
162    // Output stubs for dynamically-linked functions
163    unsigned j = 1;
164    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
165         i != e; ++i, ++j) {
166      O << "\t.symbol_stub\n";
167      O << "L" << *i << "$stub:\n";
168      O << "\t.indirect_symbol " << *i << "\n";
169      O << "\tjmp\t*L" << j << "$lz\n";
170      O << "L" << *i << "$stub_binder:\n";
171      O << "\tpushl\t$L" << j << "$lz\n";
172      O << "\tjmp\tdyld_stub_binding_helper\n";
173      O << "\t.section __DATA, __la_sym_ptr3,lazy_symbol_pointers\n";
174      O << "L" << j << "$lz:\n";
175      O << "\t.indirect_symbol " << *i << "\n";
176      O << "\t.long\tL" << *i << "$stub_binder\n";
177    }
178
179    O << "\n";
180
181    // Output stubs for external global variables
182    if (GVStubs.begin() != GVStubs.end())
183      O << ".data\n.non_lazy_symbol_pointer\n";
184    for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
185         i != e; ++i) {
186      O << "L" << *i << "$non_lazy_ptr:\n";
187      O << "\t.indirect_symbol " << *i << "\n";
188      O << "\t.long\t0\n";
189    }
190
191    // Output stubs for link-once variables
192    if (LinkOnceStubs.begin() != LinkOnceStubs.end())
193      O << ".data\n.align 2\n";
194    for (std::set<std::string>::iterator i = LinkOnceStubs.begin(),
195         e = LinkOnceStubs.end(); i != e; ++i) {
196      O << "L" << *i << "$non_lazy_ptr:\n"
197        << "\t.long\t" << *i << '\n';
198    }
199  }
200
201  AsmPrinter::doFinalization(M);
202  return false; // success
203}
204
205/// createX86CodePrinterPass - Returns a pass that prints the X86 assembly code
206/// for a MachineFunction to the given output stream, using the given target
207/// machine description.
208///
209FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,TargetMachine &tm){
210  switch (AsmWriterFlavor) {
211  default:
212    assert(0 && "Unknown asm flavor!");
213  case intel:
214    return new X86IntelAsmPrinter(o, tm);
215  case att:
216    return new X86ATTAsmPrinter(o, tm);
217  }
218}
219