1 //=--- AArch64MCExpr.h - AArch64 specific MC expression classes ---*- C++ -*-=//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file describes AArch64-specific MCExprs, used for modifiers like
10 // ":lo12:" or ":gottprel_g1:".
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_AARCH64_MCTARGETDESC_AARCH64MCEXPR_H
15 #define LLVM_LIB_TARGET_AARCH64_MCTARGETDESC_AARCH64MCEXPR_H
16 
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/Support/ErrorHandling.h"
19 
20 namespace llvm {
21 
22 class AArch64MCExpr : public MCTargetExpr {
23 public:
24   enum VariantKind {
25     // Symbol locations specifying (roughly speaking) what calculation should be
26     // performed to construct the final address for the relocated
27     // symbol. E.g. direct, via the GOT, ...
28     VK_ABS      = 0x001,
29     VK_SABS     = 0x002,
30     VK_PREL     = 0x003,
31     VK_GOT      = 0x004,
32     VK_DTPREL   = 0x005,
33     VK_GOTTPREL = 0x006,
34     VK_TPREL    = 0x007,
35     VK_TLSDESC  = 0x008,
36     VK_SECREL   = 0x009,
37     VK_SymLocBits = 0x00f,
38 
39     // Variants specifying which part of the final address calculation is
40     // used. E.g. the low 12 bits for an ADD/LDR, the middle 16 bits for a
41     // MOVZ/MOVK.
42     VK_PAGE     = 0x010,
43     VK_PAGEOFF  = 0x020,
44     VK_HI12     = 0x030,
45     VK_G0       = 0x040,
46     VK_G1       = 0x050,
47     VK_G2       = 0x060,
48     VK_G3       = 0x070,
49     VK_LO15     = 0x080,
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_PAGE_NC       = VK_ABS      | VK_PAGE    | VK_NC,
66     VK_ABS_G3            = VK_ABS      | VK_G3,
67     VK_ABS_G2            = VK_ABS      | VK_G2,
68     VK_ABS_G2_S          = VK_SABS     | VK_G2,
69     VK_ABS_G2_NC         = VK_ABS      | VK_G2      | VK_NC,
70     VK_ABS_G1            = VK_ABS      | VK_G1,
71     VK_ABS_G1_S          = VK_SABS     | VK_G1,
72     VK_ABS_G1_NC         = VK_ABS      | VK_G1      | VK_NC,
73     VK_ABS_G0            = VK_ABS      | VK_G0,
74     VK_ABS_G0_S          = VK_SABS     | VK_G0,
75     VK_ABS_G0_NC         = VK_ABS      | VK_G0      | VK_NC,
76     VK_LO12              = VK_ABS      | VK_PAGEOFF | VK_NC,
77     VK_PREL_G3           = VK_PREL     | VK_G3,
78     VK_PREL_G2           = VK_PREL     | VK_G2,
79     VK_PREL_G2_NC        = VK_PREL     | VK_G2      | VK_NC,
80     VK_PREL_G1           = VK_PREL     | VK_G1,
81     VK_PREL_G1_NC        = VK_PREL     | VK_G1      | VK_NC,
82     VK_PREL_G0           = VK_PREL     | VK_G0,
83     VK_PREL_G0_NC        = VK_PREL     | VK_G0      | VK_NC,
84     VK_GOT_LO12          = VK_GOT      | VK_PAGEOFF | VK_NC,
85     VK_GOT_PAGE          = VK_GOT      | VK_PAGE,
86     VK_GOT_PAGE_LO15     = VK_GOT      | VK_LO15    | VK_NC,
87     VK_DTPREL_G2         = VK_DTPREL   | VK_G2,
88     VK_DTPREL_G1         = VK_DTPREL   | VK_G1,
89     VK_DTPREL_G1_NC      = VK_DTPREL   | VK_G1      | VK_NC,
90     VK_DTPREL_G0         = VK_DTPREL   | VK_G0,
91     VK_DTPREL_G0_NC      = VK_DTPREL   | VK_G0      | VK_NC,
92     VK_DTPREL_HI12       = VK_DTPREL   | VK_HI12,
93     VK_DTPREL_LO12       = VK_DTPREL   | VK_PAGEOFF,
94     VK_DTPREL_LO12_NC    = VK_DTPREL   | VK_PAGEOFF | VK_NC,
95     VK_GOTTPREL_PAGE     = VK_GOTTPREL | VK_PAGE,
96     VK_GOTTPREL_LO12_NC  = VK_GOTTPREL | VK_PAGEOFF | VK_NC,
97     VK_GOTTPREL_G1       = VK_GOTTPREL | VK_G1,
98     VK_GOTTPREL_G0_NC    = VK_GOTTPREL | VK_G0      | VK_NC,
99     VK_TPREL_G2          = VK_TPREL    | VK_G2,
100     VK_TPREL_G1          = VK_TPREL    | VK_G1,
101     VK_TPREL_G1_NC       = VK_TPREL    | VK_G1      | VK_NC,
102     VK_TPREL_G0          = VK_TPREL    | VK_G0,
103     VK_TPREL_G0_NC       = VK_TPREL    | VK_G0      | VK_NC,
104     VK_TPREL_HI12        = VK_TPREL    | VK_HI12,
105     VK_TPREL_LO12        = VK_TPREL    | VK_PAGEOFF,
106     VK_TPREL_LO12_NC     = VK_TPREL    | VK_PAGEOFF | VK_NC,
107     VK_TLSDESC_LO12      = VK_TLSDESC  | VK_PAGEOFF,
108     VK_TLSDESC_PAGE      = VK_TLSDESC  | VK_PAGE,
109     VK_SECREL_LO12       = VK_SECREL   | VK_PAGEOFF,
110     VK_SECREL_HI12       = VK_SECREL   | VK_HI12,
111 
112     VK_INVALID  = 0xfff
113   };
114 
115 private:
116   const MCExpr *Expr;
117   const VariantKind Kind;
118 
AArch64MCExpr(const MCExpr * Expr,VariantKind Kind)119   explicit AArch64MCExpr(const MCExpr *Expr, VariantKind Kind)
120     : Expr(Expr), Kind(Kind) {}
121 
122 public:
123   /// @name Construction
124   /// @{
125 
126   static const AArch64MCExpr *create(const MCExpr *Expr, VariantKind Kind,
127                                    MCContext &Ctx);
128 
129   /// @}
130   /// @name Accessors
131   /// @{
132 
133   /// Get the kind of this expression.
getKind()134   VariantKind getKind() const { return Kind; }
135 
136   /// Get the expression this modifier applies to.
getSubExpr()137   const MCExpr *getSubExpr() const { return Expr; }
138 
139   /// @}
140   /// @name VariantKind information extractors.
141   /// @{
142 
getSymbolLoc(VariantKind Kind)143   static VariantKind getSymbolLoc(VariantKind Kind) {
144     return static_cast<VariantKind>(Kind & VK_SymLocBits);
145   }
146 
getAddressFrag(VariantKind Kind)147   static VariantKind getAddressFrag(VariantKind Kind) {
148     return static_cast<VariantKind>(Kind & VK_AddressFragBits);
149   }
150 
isNotChecked(VariantKind Kind)151   static bool isNotChecked(VariantKind Kind) { return Kind & VK_NC; }
152 
153   /// @}
154 
155   /// Convert the variant kind into an ELF-appropriate modifier
156   /// (e.g. ":got:", ":lo12:").
157   StringRef getVariantKindName() const;
158 
159   void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override;
160 
161   void visitUsedExpr(MCStreamer &Streamer) const override;
162 
163   MCFragment *findAssociatedFragment() const override;
164 
165   bool evaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout,
166                                  const MCFixup *Fixup) const override;
167 
168   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override;
169 
classof(const MCExpr * E)170   static bool classof(const MCExpr *E) {
171     return E->getKind() == MCExpr::Target;
172   }
173 
classof(const AArch64MCExpr *)174   static bool classof(const AArch64MCExpr *) { return true; }
175 };
176 } // end namespace llvm
177 
178 #endif
179