1 //===- MCInstPrinter.cpp - Convert an MCInst to target assembly syntax ----===//
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 #include "llvm/MC/MCInstPrinter.h"
10 #include "llvm/ADT/ArrayRef.h"
11 #include "llvm/ADT/StringRef.h"
12 #include "llvm/MC/MCAsmInfo.h"
13 #include "llvm/MC/MCInst.h"
14 #include "llvm/MC/MCInstrInfo.h"
15 #include "llvm/MC/MCSubtargetInfo.h"
16 #include "llvm/Support/ErrorHandling.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/raw_ostream.h"
19 #include <cinttypes>
20 #include <cstdint>
21 
22 using namespace llvm;
23 
24 void llvm::dumpBytes(ArrayRef<uint8_t> bytes, raw_ostream &OS) {
25   static const char hex_rep[] = "0123456789abcdef";
26   bool First = true;
27   for (char i: bytes) {
28     if (First)
29       First = false;
30     else
31       OS << ' ';
32     OS << hex_rep[(i & 0xF0) >> 4];
33     OS << hex_rep[i & 0xF];
34   }
35 }
36 
37 MCInstPrinter::~MCInstPrinter() = default;
38 
39 /// getOpcodeName - Return the name of the specified opcode enum (e.g.
40 /// "MOV32ri") or empty if we can't resolve it.
41 StringRef MCInstPrinter::getOpcodeName(unsigned Opcode) const {
42   return MII.getName(Opcode);
43 }
44 
45 void MCInstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
46   llvm_unreachable("Target should implement this");
47 }
48 
49 void MCInstPrinter::printAnnotation(raw_ostream &OS, StringRef Annot) {
50   if (!Annot.empty()) {
51     if (CommentStream) {
52       (*CommentStream) << Annot;
53       // By definition (see MCInstPrinter.h), CommentStream must end with
54       // a newline after each comment.
55       if (Annot.back() != '\n')
56         (*CommentStream) << '\n';
57     } else
58       OS << " " << MAI.getCommentString() << " " << Annot;
59   }
60 }
61 
62 static bool matchAliasCondition(const MCInst &MI, const MCSubtargetInfo *STI,
63                                 const MCRegisterInfo &MRI, unsigned &OpIdx,
64                                 const AliasMatchingData &M,
65                                 const AliasPatternCond &C) {
66   // Feature tests are special, they don't consume operands.
67   if (C.Kind == AliasPatternCond::K_Feature)
68     return STI->getFeatureBits().test(C.Value);
69   if (C.Kind == AliasPatternCond::K_NegFeature)
70     return !STI->getFeatureBits().test(C.Value);
71 
72   // Get and consume an operand.
73   const MCOperand &Opnd = MI.getOperand(OpIdx);
74   ++OpIdx;
75 
76   // Check the specific condition for the operand.
77   switch (C.Kind) {
78   case AliasPatternCond::K_Imm:
79     // Operand must be a specific immediate.
80     return Opnd.isImm() && Opnd.getImm() == int32_t(C.Value);
81   case AliasPatternCond::K_Reg:
82     // Operand must be a specific register.
83     return Opnd.isReg() && Opnd.getReg() == C.Value;
84   case AliasPatternCond::K_TiedReg:
85     // Operand must match the register of another operand.
86     return Opnd.isReg() && Opnd.getReg() == MI.getOperand(C.Value).getReg();
87   case AliasPatternCond::K_RegClass:
88     // Operand must be a register in this class. Value is a register class id.
89     return Opnd.isReg() && MRI.getRegClass(C.Value).contains(Opnd.getReg());
90   case AliasPatternCond::K_Custom:
91     // Operand must match some custom criteria.
92     return M.ValidateMCOperand(Opnd, *STI, C.Value);
93   case AliasPatternCond::K_Ignore:
94     // Operand can be anything.
95     return true;
96   case AliasPatternCond::K_Feature:
97   case AliasPatternCond::K_NegFeature:
98     llvm_unreachable("handled earlier");
99   }
100   llvm_unreachable("invalid kind");
101 }
102 
103 const char *MCInstPrinter::matchAliasPatterns(const MCInst *MI,
104                                               const MCSubtargetInfo *STI,
105                                               const AliasMatchingData &M) {
106   // Binary search by opcode. Return false if there are no aliases for this
107   // opcode.
108   auto It = lower_bound(M.OpToPatterns, MI->getOpcode(),
109                         [](const PatternsForOpcode &L, unsigned Opcode) {
110                           return L.Opcode < Opcode;
111                         });
112   if (It == M.OpToPatterns.end() || It->Opcode != MI->getOpcode())
113     return nullptr;
114 
115   // Try all patterns for this opcode.
116   uint32_t AsmStrOffset = ~0U;
117   ArrayRef<AliasPattern> Patterns =
118       M.Patterns.slice(It->PatternStart, It->NumPatterns);
119   for (const AliasPattern &P : Patterns) {
120     // Check operand count first.
121     if (MI->getNumOperands() != P.NumOperands)
122       return nullptr;
123 
124     // Test all conditions for this pattern.
125     ArrayRef<AliasPatternCond> Conds =
126         M.PatternConds.slice(P.AliasCondStart, P.NumConds);
127     unsigned OpIdx = 0;
128     if (llvm::all_of(Conds, [&](const AliasPatternCond &C) {
129           return matchAliasCondition(*MI, STI, MRI, OpIdx, M, C);
130         })) {
131       // If all conditions matched, use this asm string.
132       AsmStrOffset = P.AsmStrOffset;
133       break;
134     }
135   }
136 
137   // If no alias matched, don't print an alias.
138   if (AsmStrOffset == ~0U)
139     return nullptr;
140 
141   // Go to offset AsmStrOffset and use the null terminated string there. The
142   // offset should point to the beginning of an alias string, so it should
143   // either be zero or be preceded by a null byte.
144   assert(AsmStrOffset < M.AsmStrings.size() &&
145          (AsmStrOffset == 0 || M.AsmStrings[AsmStrOffset - 1] == '\0') &&
146          "bad asm string offset");
147   return M.AsmStrings.data() + AsmStrOffset;
148 }
149 
150 /// Utility functions to make adding mark ups simpler.
151 StringRef MCInstPrinter::markup(StringRef s) const {
152   if (getUseMarkup())
153     return s;
154   else
155     return "";
156 }
157 
158 // For asm-style hex (e.g. 0ffh) the first digit always has to be a number.
159 static bool needsLeadingZero(uint64_t Value)
160 {
161   while (Value)
162   {
163     uint64_t digit = (Value >> 60) & 0xf;
164     if (digit != 0)
165       return (digit >= 0xa);
166     Value <<= 4;
167   }
168   return false;
169 }
170 
171 format_object<int64_t> MCInstPrinter::formatDec(int64_t Value) const {
172   return format("%" PRId64, Value);
173 }
174 
175 format_object<int64_t> MCInstPrinter::formatHex(int64_t Value) const {
176   switch (PrintHexStyle) {
177   case HexStyle::C:
178     if (Value < 0) {
179       if (Value == std::numeric_limits<int64_t>::min())
180         return format<int64_t>("-0x8000000000000000", Value);
181       return format("-0x%" PRIx64, -Value);
182     }
183     return format("0x%" PRIx64, Value);
184   case HexStyle::Asm:
185     if (Value < 0) {
186       if (Value == std::numeric_limits<int64_t>::min())
187         return format<int64_t>("-8000000000000000h", Value);
188       if (needsLeadingZero(-(uint64_t)(Value)))
189         return format("-0%" PRIx64 "h", -Value);
190       return format("-%" PRIx64 "h", -Value);
191     }
192     if (needsLeadingZero((uint64_t)(Value)))
193       return format("0%" PRIx64 "h", Value);
194     return format("%" PRIx64 "h", Value);
195   }
196   llvm_unreachable("unsupported print style");
197 }
198 
199 format_object<uint64_t> MCInstPrinter::formatHex(uint64_t Value) const {
200   switch(PrintHexStyle) {
201   case HexStyle::C:
202      return format("0x%" PRIx64, Value);
203   case HexStyle::Asm:
204     if (needsLeadingZero(Value))
205       return format("0%" PRIx64 "h", Value);
206     else
207       return format("%" PRIx64 "h", Value);
208   }
209   llvm_unreachable("unsupported print style");
210 }
211