ARMSubtarget.cpp revision d4022c3fbb0705abdc8eddc3ee4a5059f5ef8094 
1//===-- ARMSubtarget.cpp - ARM Subtarget Information ------------*- 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 implements the ARM specific subclass of TargetSubtarget.
11//
12//===----------------------------------------------------------------------===//
13
14#include "ARMSubtarget.h"
15#include "ARMGenSubtarget.inc"
16#include "llvm/Module.h"
17using namespace llvm;
18
19ARMSubtarget::ARMSubtarget(const Module &M, const std::string &FS,
20                           bool isThumb)
21  : ARMArchVersion(V4T)
22  , ARMFPUType(None)
23  , ThumbMode((isThumb ? Thumb1 : ThumbNone))
24  , UseThumbBacktraces(false)
25  , IsR9Reserved(false)
26  , stackAlignment(4)
27  , CPUString("generic")
28  , TargetType(isELF) // Default to ELF unless otherwise specified.
29  , TargetABI(ARM_ABI_APCS) {
30  // Determine default and user specified characteristics
31
32  // Parse features string.
33  CPUString = ParseSubtargetFeatures(FS, CPUString);
34
35  // Set the boolean corresponding to the current target triple, or the default
36  // if one cannot be determined, to true.
37  const std::string& TT = M.getTargetTriple();
38  unsigned Len = TT.length();
39  unsigned Idx = 0;
40
41  if (Len >= 5 && TT.substr(0, 4) == "armv")
42    Idx = 4;
43  else if (Len >= 6 && TT.substr(0, 6) == "thumb") {
44    isThumb = true;
45    if (Len >= 7 && TT[5] == 'v')
46      Idx = 6;
47  }
48  if (Idx) {
49    unsigned SubVer = TT[Idx];
50    if (SubVer > '4' && SubVer <= '9') {
51      if (SubVer >= '7') {
52        ARMArchVersion = V7A;
53        if (isThumb)
54          ThumbMode = Thumb2;
55      } else if (SubVer == '6') {
56        ARMArchVersion = V6;
57        if (isThumb && Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
58          ThumbMode = Thumb2;
59      } else if (SubVer == '5') {
60        ARMArchVersion = V5T;
61        if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
62          ARMArchVersion = V5TE;
63      }
64    }
65  }
66
67  if (Len >= 10) {
68    if (TT.find("-darwin") != std::string::npos)
69      // arm-darwin
70      TargetType = isDarwin;
71  } else if (TT.empty()) {
72#if defined(__APPLE__)
73    TargetType = isDarwin;
74#endif
75  }
76
77  if (TT.find("eabi") != std::string::npos)
78    TargetABI = ARM_ABI_AAPCS;
79
80  if (isAAPCS_ABI())
81    stackAlignment = 8;
82
83  if (isTargetDarwin()) {
84    UseThumbBacktraces = true;
85    IsR9Reserved = true;
86  }
87}
88