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1 //=--- AArch64MCExpr.h - AArch64 specific MC expression classes ---*- C++ -*-=//
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 // This file describes AArch64-specific MCExprs, used for modifiers like
11 // ":lo12:" or ":gottprel_g1:".
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_TARGET_AARCH64_MCTARGETDESC_AARCH64MCEXPR_H
16 #define LLVM_LIB_TARGET_AARCH64_MCTARGETDESC_AARCH64MCEXPR_H
17 
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/Support/ErrorHandling.h"
20 
21 namespace llvm {
22 
23 class AArch64MCExpr : public MCTargetExpr {
24 public:
25   enum VariantKind {
26     VK_NONE     = 0x000,
27 
28     // Symbol locations specifying (roughly speaking) what calculation should be
29     // performed to construct the final address for the relocated
30     // symbol. E.g. direct, via the GOT, ...
31     VK_ABS      = 0x001,
32     VK_SABS     = 0x002,
33     VK_GOT      = 0x003,
34     VK_DTPREL   = 0x004,
35     VK_GOTTPREL = 0x005,
36     VK_TPREL    = 0x006,
37     VK_TLSDESC  = 0x007,
38     VK_SymLocBits = 0x00f,
39 
40     // Variants specifying which part of the final address calculation is
41     // used. E.g. the low 12 bits for an ADD/LDR, the middle 16 bits for a
42     // MOVZ/MOVK.
43     VK_PAGE     = 0x010,
44     VK_PAGEOFF  = 0x020,
45     VK_HI12     = 0x030,
46     VK_G0       = 0x040,
47     VK_G1       = 0x050,
48     VK_G2       = 0x060,
49     VK_G3       = 0x070,
50     VK_AddressFragBits = 0x0f0,
51 
52     // Whether the final relocation is a checked one (where a linker should
53     // perform a range-check on the final address) or not. Note that this field
54     // is unfortunately sometimes omitted from the assembly syntax. E.g. :lo12:
55     // on its own is a non-checked relocation. We side with ELF on being
56     // explicit about this!
57     VK_NC       = 0x100,
58 
59     // Convenience definitions for referring to specific textual representations
60     // of relocation specifiers. Note that this means the "_NC" is sometimes
61     // omitted in line with assembly syntax here (VK_LO12 rather than VK_LO12_NC
62     // since a user would write ":lo12:").
63     VK_CALL              = VK_ABS,
64     VK_ABS_PAGE          = VK_ABS      | VK_PAGE,
65     VK_ABS_G3            = VK_ABS      | VK_G3,
66     VK_ABS_G2            = VK_ABS      | VK_G2,
67     VK_ABS_G2_S          = VK_SABS     | VK_G2,
68     VK_ABS_G2_NC         = VK_ABS      | VK_G2      | VK_NC,
69     VK_ABS_G1            = VK_ABS      | VK_G1,
70     VK_ABS_G1_S          = VK_SABS     | VK_G1,
71     VK_ABS_G1_NC         = VK_ABS      | VK_G1      | VK_NC,
72     VK_ABS_G0            = VK_ABS      | VK_G0,
73     VK_ABS_G0_S          = VK_SABS     | VK_G0,
74     VK_ABS_G0_NC         = VK_ABS      | VK_G0      | VK_NC,
75     VK_LO12              = VK_ABS      | VK_PAGEOFF | VK_NC,
76     VK_GOT_LO12          = VK_GOT      | VK_PAGEOFF | VK_NC,
77     VK_GOT_PAGE          = VK_GOT      | VK_PAGE,
78     VK_DTPREL_G2         = VK_DTPREL   | VK_G2,
79     VK_DTPREL_G1         = VK_DTPREL   | VK_G1,
80     VK_DTPREL_G1_NC      = VK_DTPREL   | VK_G1      | VK_NC,
81     VK_DTPREL_G0         = VK_DTPREL   | VK_G0,
82     VK_DTPREL_G0_NC      = VK_DTPREL   | VK_G0      | VK_NC,
83     VK_DTPREL_HI12       = VK_DTPREL   | VK_HI12,
84     VK_DTPREL_LO12       = VK_DTPREL   | VK_PAGEOFF,
85     VK_DTPREL_LO12_NC    = VK_DTPREL   | VK_PAGEOFF | VK_NC,
86     VK_GOTTPREL_PAGE     = VK_GOTTPREL | VK_PAGE,
87     VK_GOTTPREL_LO12_NC  = VK_GOTTPREL | VK_PAGEOFF | VK_NC,
88     VK_GOTTPREL_G1       = VK_GOTTPREL | VK_G1,
89     VK_GOTTPREL_G0_NC    = VK_GOTTPREL | VK_G0      | VK_NC,
90     VK_TPREL_G2          = VK_TPREL    | VK_G2,
91     VK_TPREL_G1          = VK_TPREL    | VK_G1,
92     VK_TPREL_G1_NC       = VK_TPREL    | VK_G1      | VK_NC,
93     VK_TPREL_G0          = VK_TPREL    | VK_G0,
94     VK_TPREL_G0_NC       = VK_TPREL    | VK_G0      | VK_NC,
95     VK_TPREL_HI12        = VK_TPREL    | VK_HI12,
96     VK_TPREL_LO12        = VK_TPREL    | VK_PAGEOFF,
97     VK_TPREL_LO12_NC     = VK_TPREL    | VK_PAGEOFF | VK_NC,
98     VK_TLSDESC_LO12      = VK_TLSDESC  | VK_PAGEOFF | VK_NC,
99     VK_TLSDESC_PAGE      = VK_TLSDESC  | VK_PAGE,
100 
101     VK_INVALID  = 0xfff
102   };
103 
104 private:
105   const MCExpr *Expr;
106   const VariantKind Kind;
107 
AArch64MCExpr(const MCExpr * Expr,VariantKind Kind)108   explicit AArch64MCExpr(const MCExpr *Expr, VariantKind Kind)
109     : Expr(Expr), Kind(Kind) {}
110 
111 public:
112   /// @name Construction
113   /// @{
114 
115   static const AArch64MCExpr *create(const MCExpr *Expr, VariantKind Kind,
116                                    MCContext &Ctx);
117 
118   /// @}
119   /// @name Accessors
120   /// @{
121 
122   /// Get the kind of this expression.
getKind()123   VariantKind getKind() const { return Kind; }
124 
125   /// Get the expression this modifier applies to.
getSubExpr()126   const MCExpr *getSubExpr() const { return Expr; }
127 
128   /// @}
129   /// @name VariantKind information extractors.
130   /// @{
131 
getSymbolLoc(VariantKind Kind)132   static VariantKind getSymbolLoc(VariantKind Kind) {
133     return static_cast<VariantKind>(Kind & VK_SymLocBits);
134   }
135 
getAddressFrag(VariantKind Kind)136   static VariantKind getAddressFrag(VariantKind Kind) {
137     return static_cast<VariantKind>(Kind & VK_AddressFragBits);
138   }
139 
isNotChecked(VariantKind Kind)140   static bool isNotChecked(VariantKind Kind) { return Kind & VK_NC; }
141 
142   /// @}
143 
144   /// Convert the variant kind into an ELF-appropriate modifier
145   /// (e.g. ":got:", ":lo12:").
146   StringRef getVariantKindName() const;
147 
148   void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override;
149 
150   void visitUsedExpr(MCStreamer &Streamer) const override;
151 
152   MCFragment *findAssociatedFragment() const override;
153 
154   bool evaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout,
155                                  const MCFixup *Fixup) const override;
156 
157   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override;
158 
classof(const MCExpr * E)159   static bool classof(const MCExpr *E) {
160     return E->getKind() == MCExpr::Target;
161   }
162 
classof(const AArch64MCExpr *)163   static bool classof(const AArch64MCExpr *) { return true; }
164 };
165 } // end namespace llvm
166 
167 #endif
168