1 //===- llvm/CodeGen/AddressPool.cpp - Dwarf Debug Framework ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "AddressPool.h"
11 #include "llvm/ADT/SmallVector.h"
12 #include "llvm/CodeGen/AsmPrinter.h"
13 #include "llvm/IR/DataLayout.h"
14 #include "llvm/MC/MCStreamer.h"
15 #include "llvm/Target/TargetLoweringObjectFile.h"
16 #include <utility>
17
18 using namespace llvm;
19
getIndex(const MCSymbol * Sym,bool TLS)20 unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) {
21 HasBeenUsed = true;
22 auto IterBool =
23 Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS)));
24 return IterBool.first->second.Number;
25 }
26
27
emitHeader(AsmPrinter & Asm,MCSection * Section)28 void AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) {
29 static const uint8_t AddrSize = Asm.getDataLayout().getPointerSize();
30 Asm.OutStreamer->SwitchSection(Section);
31
32 uint64_t Length = sizeof(uint16_t) // version
33 + sizeof(uint8_t) // address_size
34 + sizeof(uint8_t) // segment_selector_size
35 + AddrSize * Pool.size(); // entries
36 Asm.emitInt32(Length); // TODO: Support DWARF64 format.
37 Asm.emitInt16(Asm.getDwarfVersion());
38 Asm.emitInt8(AddrSize);
39 Asm.emitInt8(0); // TODO: Support non-zero segment_selector_size.
40 }
41
42 // Emit addresses into the section given.
emit(AsmPrinter & Asm,MCSection * AddrSection)43 void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) {
44 if (Asm.getDwarfVersion() >= 5)
45 emitHeader(Asm, AddrSection);
46
47 if (Pool.empty())
48 return;
49
50 // Start the dwarf addr section.
51 Asm.OutStreamer->SwitchSection(AddrSection);
52
53 // Order the address pool entries by ID
54 SmallVector<const MCExpr *, 64> Entries(Pool.size());
55
56 for (const auto &I : Pool)
57 Entries[I.second.Number] =
58 I.second.TLS
59 ? Asm.getObjFileLowering().getDebugThreadLocalSymbol(I.first)
60 : MCSymbolRefExpr::create(I.first, Asm.OutContext);
61
62 for (const MCExpr *Entry : Entries)
63 Asm.OutStreamer->EmitValue(Entry, Asm.getDataLayout().getPointerSize());
64 }
65