1 //=--- X86MCExpr.h - X86 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 X86-specific MCExprs, i.e, registers used for
10 // extended variable assignments.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_X86_MCTARGETDESC_X86MCEXPR_H
15 #define LLVM_LIB_TARGET_X86_MCTARGETDESC_X86MCEXPR_H
16 
17 #include "X86ATTInstPrinter.h"
18 #include "llvm/MC/MCAsmInfo.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCExpr.h"
21 #include "llvm/Support/Casting.h"
22 #include "llvm/Support/ErrorHandling.h"
23 
24 namespace llvm {
25 
26 class X86MCExpr : public MCTargetExpr {
27 
28 private:
29   const int64_t RegNo; // All
30 
31   explicit X86MCExpr(int64_t R) : RegNo(R) {}
32 
33 public:
34   /// @name Construction
35   /// @{
36 
37   static const X86MCExpr *create(int64_t RegNo, MCContext &Ctx) {
38     return new (Ctx) X86MCExpr(RegNo);
39   }
40 
41   /// @}
42   /// @name Accessors
43   /// @{
44 
45   /// getSubExpr - Get the child of this expression.
46   int64_t getRegNo() const { return RegNo; }
47 
48   /// @}
49 
50   void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override {
51     if (!MAI || MAI->getAssemblerDialect() == 0)
52       OS << '%';
53     OS << X86ATTInstPrinter::getRegisterName(RegNo);
54   }
55 
56   bool evaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout,
57                                  const MCFixup *Fixup) const override {
58     return false;
59   }
60   // Register values should be inlined as they are not valid .set expressions.
61   bool inlineAssignedExpr() const override { return true; }
62   bool isEqualTo(const MCExpr *X) const override {
63     if (auto *E = dyn_cast<X86MCExpr>(X))
64       return getRegNo() == E->getRegNo();
65     return false;
66   }
67   void visitUsedExpr(MCStreamer &Streamer) const override{};
68   MCFragment *findAssociatedFragment() const override { return nullptr; }
69 
70   // There are no TLS X86MCExprs at the moment.
71   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override {}
72 
73   static bool classof(const MCExpr *E) {
74     return E->getKind() == MCExpr::Target;
75   }
76 };
77 
78 } // end namespace llvm
79 
80 #endif
81