TargetInfo.cpp revision 2b16165d8ee6a02ede96ae74a46075a1801e68d7 
1//===--- TargetInfo.cpp - Information about Target machine ----------------===//
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 implements the TargetInfo and TargetInfoImpl interfaces.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Basic/TargetInfo.h"
15#include "llvm/ADT/APFloat.h"
16#include "llvm/ADT/STLExtras.h"
17#include <cstdlib>
18using namespace clang;
19
20// TargetInfo Constructor.
21TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
22  // Set defaults.  Defaults are set for a 32-bit RISC platform,
23  // like PPC or SPARC.
24  // These should be overridden by concrete targets as needed.
25  CharIsSigned = true;
26  PointerWidth = PointerAlign = 32;
27  WCharWidth = WCharAlign = 32;
28  IntWidth = IntAlign = 32;
29  LongWidth = LongAlign = 32;
30  LongLongWidth = LongLongAlign = 64;
31  FloatWidth = 32;
32  FloatAlign = 32;
33  DoubleWidth = 64;
34  DoubleAlign = 64;
35  LongDoubleWidth = 64;
36  LongDoubleAlign = 64;
37  FloatFormat = &llvm::APFloat::IEEEsingle;
38  DoubleFormat = &llvm::APFloat::IEEEdouble;
39  LongDoubleFormat = &llvm::APFloat::IEEEdouble;
40  DescriptionString = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
41                      "i64:64:64-f32:32:32-f64:64:64";
42}
43
44// Out of line virtual dtor for TargetInfo.
45TargetInfo::~TargetInfo() {}
46
47//===----------------------------------------------------------------------===//
48
49
50static void removeGCCRegisterPrefix(const char *&Name) {
51  if (Name[0] == '%' || Name[0] == '#')
52    Name++;
53}
54
55/// isValidGCCRegisterName - Returns whether the passed in string
56/// is a valid register name according to GCC. This is used by Sema for
57/// inline asm statements.
58bool TargetInfo::isValidGCCRegisterName(const char *Name) const {
59  const char * const *Names;
60  unsigned NumNames;
61
62  // Get rid of any register prefix.
63  removeGCCRegisterPrefix(Name);
64
65
66  if (strcmp(Name, "memory") == 0 ||
67      strcmp(Name, "cc") == 0)
68    return true;
69
70  getGCCRegNames(Names, NumNames);
71
72  // If we have a number it maps to an entry in the register name array.
73  if (isdigit(Name[0])) {
74    char *End;
75    int n = (int)strtol(Name, &End, 0);
76    if (*End == 0)
77      return n >= 0 && (unsigned)n < NumNames;
78  }
79
80  // Check register names.
81  for (unsigned i = 0; i < NumNames; i++) {
82    if (strcmp(Name, Names[i]) == 0)
83      return true;
84  }
85
86  // Now check aliases.
87  const GCCRegAlias *Aliases;
88  unsigned NumAliases;
89
90  getGCCRegAliases(Aliases, NumAliases);
91  for (unsigned i = 0; i < NumAliases; i++) {
92    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
93      if (!Aliases[i].Aliases[j])
94        break;
95      if (strcmp(Aliases[i].Aliases[j], Name) == 0)
96        return true;
97    }
98  }
99
100  return false;
101}
102
103const char *TargetInfo::getNormalizedGCCRegisterName(const char *Name) const {
104  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
105
106  removeGCCRegisterPrefix(Name);
107
108  const char * const *Names;
109  unsigned NumNames;
110
111  getGCCRegNames(Names, NumNames);
112
113  // First, check if we have a number.
114  if (isdigit(Name[0])) {
115    char *End;
116    int n = (int)strtol(Name, &End, 0);
117    if (*End == 0) {
118      assert(n >= 0 && (unsigned)n < NumNames &&
119             "Out of bounds register number!");
120      return Names[n];
121    }
122  }
123
124  // Now check aliases.
125  const GCCRegAlias *Aliases;
126  unsigned NumAliases;
127
128  getGCCRegAliases(Aliases, NumAliases);
129  for (unsigned i = 0; i < NumAliases; i++) {
130    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
131      if (!Aliases[i].Aliases[j])
132        break;
133      if (strcmp(Aliases[i].Aliases[j], Name) == 0)
134        return Aliases[i].Register;
135    }
136  }
137
138  return Name;
139}
140
141bool TargetInfo::validateOutputConstraint(const char *Name,
142                                          ConstraintInfo &info) const
143{
144  // An output constraint must start with '=' or '+'
145  if (*Name != '=' && *Name != '+')
146    return false;
147
148  if (*Name == '+')
149    info = CI_ReadWrite;
150  else
151    info = CI_None;
152
153  Name++;
154  while (*Name) {
155    switch (*Name) {
156    default:
157      if (!validateAsmConstraint(*Name, info)) {
158        // FIXME: We temporarily return false
159        // so we can add more constraints as we hit it.
160        // Eventually, an unknown constraint should just be treated as 'g'.
161        return false;
162      }
163    case '&': // early clobber.
164      break;
165    case 'r': // general register.
166      info = (ConstraintInfo)(info|CI_AllowsRegister);
167      break;
168    case 'm': // memory operand.
169      info = (ConstraintInfo)(info|CI_AllowsMemory);
170      break;
171    case 'g': // general register, memory operand or immediate integer.
172      info = (ConstraintInfo)(info|CI_AllowsMemory|CI_AllowsRegister);
173      break;
174    }
175
176    Name++;
177  }
178
179  return true;
180}
181
182bool TargetInfo::validateInputConstraint(const char *Name,
183                                         unsigned NumOutputs,
184                                         ConstraintInfo &info) const {
185  while (*Name) {
186    switch (*Name) {
187    default:
188      // Check if we have a matching constraint
189      if (*Name >= '0' && *Name <= '9') {
190        unsigned i = *Name - '0';
191
192        // Check if matching constraint is out of bounds.
193        if (i >= NumOutputs)
194          return false;
195      } else if (!validateAsmConstraint(*Name, info)) {
196        // FIXME: This assert is in place temporarily
197        // so we can add more constraints as we hit it.
198        // Eventually, an unknown constraint should just be treated as 'g'.
199        assert(0 && "Unknown input constraint type!");
200      }
201    case '%': // commutative
202      // FIXME: Fail if % is used with the last operand.
203      break;
204    case 'i': // immediate integer.
205    case 'I':
206    case 'n': // immediate integer with a known value.
207      break;
208    case 'r': // general register.
209      info = (ConstraintInfo)(info|CI_AllowsRegister);
210      break;
211    case 'm': // memory operand.
212      info = (ConstraintInfo)(info|CI_AllowsMemory);
213      break;
214    case 'g': // general register, memory operand or immediate integer.
215      info = (ConstraintInfo)(info|CI_AllowsMemory|CI_AllowsRegister);
216      break;
217    }
218
219    Name++;
220  }
221
222  return true;
223}
224