1 //===-- MipsMCExpr.cpp - Mips specific MC expression classes --------------===//
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 #define DEBUG_TYPE "mipsmcexpr"
11 #include "MipsMCExpr.h"
12 #include "llvm/MC/MCAsmInfo.h"
13 #include "llvm/MC/MCAssembler.h"
14 #include "llvm/MC/MCContext.h"
15 
16 using namespace llvm;
17 
18 bool MipsMCExpr::isSupportedBinaryExpr(MCSymbolRefExpr::VariantKind VK,
19                                        const MCBinaryExpr *BE) {
20   switch (VK) {
21   case MCSymbolRefExpr::VK_Mips_ABS_LO:
22   case MCSymbolRefExpr::VK_Mips_ABS_HI:
23   case MCSymbolRefExpr::VK_Mips_HIGHER:
24   case MCSymbolRefExpr::VK_Mips_HIGHEST:
25     break;
26   default:
27     return false;
28   }
29 
30   // We support expressions of the form "(sym1 binop1 sym2) binop2 const",
31   // where "binop2 const" is optional.
32   if (isa<MCBinaryExpr>(BE->getLHS())) {
33     if (!isa<MCConstantExpr>(BE->getRHS()))
34       return false;
35     BE = cast<MCBinaryExpr>(BE->getLHS());
36   }
37   return (isa<MCSymbolRefExpr>(BE->getLHS())
38           && isa<MCSymbolRefExpr>(BE->getRHS()));
39 }
40 
41 const MipsMCExpr*
42 MipsMCExpr::Create(MCSymbolRefExpr::VariantKind VK, const MCExpr *Expr,
43                    MCContext &Ctx) {
44   VariantKind Kind;
45   switch (VK) {
46   case MCSymbolRefExpr::VK_Mips_ABS_LO:
47     Kind = VK_Mips_LO;
48     break;
49   case MCSymbolRefExpr::VK_Mips_ABS_HI:
50     Kind = VK_Mips_HI;
51     break;
52   case MCSymbolRefExpr::VK_Mips_HIGHER:
53     Kind = VK_Mips_HIGHER;
54     break;
55   case MCSymbolRefExpr::VK_Mips_HIGHEST:
56     Kind = VK_Mips_HIGHEST;
57     break;
58   default:
59     llvm_unreachable("Invalid kind!");
60   }
61 
62   return new (Ctx) MipsMCExpr(Kind, Expr);
63 }
64 
65 void MipsMCExpr::PrintImpl(raw_ostream &OS) const {
66   switch (Kind) {
67   default: llvm_unreachable("Invalid kind!");
68   case VK_Mips_LO: OS << "%lo"; break;
69   case VK_Mips_HI: OS << "%hi"; break;
70   case VK_Mips_HIGHER: OS << "%higher"; break;
71   case VK_Mips_HIGHEST: OS << "%highest"; break;
72   }
73 
74   OS << '(';
75   Expr->print(OS);
76   OS << ')';
77 }
78 
79 bool
80 MipsMCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
81                                       const MCAsmLayout *Layout) const {
82   return getSubExpr()->EvaluateAsRelocatable(Res, Layout);
83 }
84 
85 // FIXME: This basically copies MCObjectStreamer::AddValueSymbols. Perhaps
86 // that method should be made public?
87 static void AddValueSymbolsImpl(const MCExpr *Value, MCAssembler *Asm) {
88   switch (Value->getKind()) {
89   case MCExpr::Target:
90     llvm_unreachable("Can't handle nested target expr!");
91 
92   case MCExpr::Constant:
93     break;
94 
95   case MCExpr::Binary: {
96     const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
97     AddValueSymbolsImpl(BE->getLHS(), Asm);
98     AddValueSymbolsImpl(BE->getRHS(), Asm);
99     break;
100   }
101 
102   case MCExpr::SymbolRef:
103     Asm->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
104     break;
105 
106   case MCExpr::Unary:
107     AddValueSymbolsImpl(cast<MCUnaryExpr>(Value)->getSubExpr(), Asm);
108     break;
109   }
110 }
111 
112 void MipsMCExpr::AddValueSymbols(MCAssembler *Asm) const {
113   AddValueSymbolsImpl(getSubExpr(), Asm);
114 }
115