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"
17 #include "llvm/Target/TargetMachine.h"
18 #include "llvm/Target/TargetOptions.h"
19 using namespace llvm;
20 
21 ARMSubtarget::ARMSubtarget(const Module &M, const std::string &FS,
22                            bool isThumb)
23   : ARMArchVersion(V4T)
24   , ARMFPUType(None)
25   , IsThumb(isThumb)
26   , ThumbMode(Thumb1)
27   , UseThumbBacktraces(false)
28   , IsR9Reserved(false)
29   , stackAlignment(4)
30   , CPUString("generic")
31   , TargetType(isELF) // Default to ELF unless otherwise specified.
32   , TargetABI(ARM_ABI_APCS) {
33   // default to soft float ABI
34   if (FloatABIType == FloatABI::Default)
35     FloatABIType = FloatABI::Soft;
36 
37   // Determine default and user specified characteristics
38 
39   // Parse features string.
40   CPUString = ParseSubtargetFeatures(FS, CPUString);
41 
42   // Set the boolean corresponding to the current target triple, or the default
43   // if one cannot be determined, to true.
44   const std::string& TT = M.getTargetTriple();
45   unsigned Len = TT.length();
46   unsigned Idx = 0;
47 
48   if (Len >= 5 && TT.substr(0, 4) == "armv")
49     Idx = 4;
50   else if (Len >= 6 && TT.substr(0, 6) == "thumb") {
51     IsThumb = true;
52     if (Len >= 7 && TT[5] == 'v')
53       Idx = 6;
54   }
55   if (Idx) {
56     unsigned SubVer = TT[Idx];
57     if (SubVer > '4' && SubVer <= '9') {
58       if (SubVer >= '7')
59         ARMArchVersion = V7A;
60       else if (SubVer == '6')
61         ARMArchVersion = V6;
62       else if (SubVer == '5') {
63         ARMArchVersion = V5T;
64         if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
65           ARMArchVersion = V5TE;
66       }
67     }
68   }
69 
70   if (Len >= 10) {
71     if (TT.find("-darwin") != std::string::npos)
72       // arm-darwin
73       TargetType = isDarwin;
74   } else if (TT.empty()) {
75 #if defined(__APPLE__)
76     TargetType = isDarwin;
77 #endif
78   }
79 
80   if (TT.find("eabi") != std::string::npos)
81     TargetABI = ARM_ABI_AAPCS;
82 
83   if (isAAPCS_ABI())
84     stackAlignment = 8;
85 
86   if (isTargetDarwin()) {
87     UseThumbBacktraces = true;
88     IsR9Reserved = true;
89   }
90 }
91