1 //===-- llvm/Support/Win64EH.h ---Win64 EH Constants-------------*- 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 contains constants and structures used for implementing
11 // exception handling on Win64 platforms. For more information, see
12 // http://msdn.microsoft.com/en-us/library/1eyas8tf.aspx
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_SUPPORT_WIN64EH_H
17 #define LLVM_SUPPORT_WIN64EH_H
18 
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/Support/Endian.h"
21 
22 namespace llvm {
23 namespace Win64EH {
24 
25 /// UnwindOpcodes - Enumeration whose values specify a single operation in
26 /// the prolog of a function.
27 enum UnwindOpcodes {
28   UOP_PushNonVol = 0,
29   UOP_AllocLarge,
30   UOP_AllocSmall,
31   UOP_SetFPReg,
32   UOP_SaveNonVol,
33   UOP_SaveNonVolBig,
34   UOP_SaveXMM128 = 8,
35   UOP_SaveXMM128Big,
36   UOP_PushMachFrame
37 };
38 
39 /// UnwindCode - This union describes a single operation in a function prolog,
40 /// or part thereof.
41 union UnwindCode {
42   struct {
43     uint8_t CodeOffset;
44     uint8_t UnwindOpAndOpInfo;
45   } u;
46   support::ulittle16_t FrameOffset;
47 
getUnwindOp()48   uint8_t getUnwindOp() const {
49     return u.UnwindOpAndOpInfo & 0x0F;
50   }
getOpInfo()51   uint8_t getOpInfo() const {
52     return (u.UnwindOpAndOpInfo >> 4) & 0x0F;
53   }
54 };
55 
56 enum {
57   /// UNW_ExceptionHandler - Specifies that this function has an exception
58   /// handler.
59   UNW_ExceptionHandler = 0x01,
60   /// UNW_TerminateHandler - Specifies that this function has a termination
61   /// handler.
62   UNW_TerminateHandler = 0x02,
63   /// UNW_ChainInfo - Specifies that this UnwindInfo structure is chained to
64   /// another one.
65   UNW_ChainInfo = 0x04
66 };
67 
68 /// RuntimeFunction - An entry in the table of functions with unwind info.
69 struct RuntimeFunction {
70   support::ulittle32_t StartAddress;
71   support::ulittle32_t EndAddress;
72   support::ulittle32_t UnwindInfoOffset;
73 };
74 
75 /// UnwindInfo - An entry in the exception table.
76 struct UnwindInfo {
77   uint8_t VersionAndFlags;
78   uint8_t PrologSize;
79   uint8_t NumCodes;
80   uint8_t FrameRegisterAndOffset;
81   UnwindCode UnwindCodes[1];
82 
getVersionUnwindInfo83   uint8_t getVersion() const {
84     return VersionAndFlags & 0x07;
85   }
getFlagsUnwindInfo86   uint8_t getFlags() const {
87     return (VersionAndFlags >> 3) & 0x1f;
88   }
getFrameRegisterUnwindInfo89   uint8_t getFrameRegister() const {
90     return FrameRegisterAndOffset & 0x0f;
91   }
getFrameOffsetUnwindInfo92   uint8_t getFrameOffset() const {
93     return (FrameRegisterAndOffset >> 4) & 0x0f;
94   }
95 
96   // The data after unwindCodes depends on flags.
97   // If UNW_ExceptionHandler or UNW_TerminateHandler is set then follows
98   // the address of the language-specific exception handler.
99   // If UNW_ChainInfo is set then follows a RuntimeFunction which defines
100   // the chained unwind info.
101   // For more information please see MSDN at:
102   // http://msdn.microsoft.com/en-us/library/ddssxxy8.aspx
103 
104   /// \brief Return pointer to language specific data part of UnwindInfo.
getLanguageSpecificDataUnwindInfo105   void *getLanguageSpecificData() {
106     return reinterpret_cast<void *>(&UnwindCodes[(NumCodes+1) & ~1]);
107   }
108 
109   /// \brief Return pointer to language specific data part of UnwindInfo.
getLanguageSpecificDataUnwindInfo110   const void *getLanguageSpecificData() const {
111     return reinterpret_cast<const void *>(&UnwindCodes[(NumCodes + 1) & ~1]);
112   }
113 
114   /// \brief Return image-relative offset of language-specific exception handler.
getLanguageSpecificHandlerOffsetUnwindInfo115   uint32_t getLanguageSpecificHandlerOffset() const {
116     return *reinterpret_cast<const support::ulittle32_t *>(
117                getLanguageSpecificData());
118   }
119 
120   /// \brief Set image-relative offset of language-specific exception handler.
setLanguageSpecificHandlerOffsetUnwindInfo121   void setLanguageSpecificHandlerOffset(uint32_t offset) {
122     *reinterpret_cast<support::ulittle32_t *>(getLanguageSpecificData()) =
123         offset;
124   }
125 
126   /// \brief Return pointer to exception-specific data.
getExceptionDataUnwindInfo127   void *getExceptionData() {
128     return reinterpret_cast<void *>(reinterpret_cast<uint32_t *>(
129                                                   getLanguageSpecificData())+1);
130   }
131 
132   /// \brief Return pointer to chained unwind info.
getChainedFunctionEntryUnwindInfo133   RuntimeFunction *getChainedFunctionEntry() {
134     return reinterpret_cast<RuntimeFunction *>(getLanguageSpecificData());
135   }
136 
137   /// \brief Return pointer to chained unwind info.
getChainedFunctionEntryUnwindInfo138   const RuntimeFunction *getChainedFunctionEntry() const {
139     return reinterpret_cast<const RuntimeFunction *>(getLanguageSpecificData());
140   }
141 };
142 
143 
144 } // End of namespace Win64EH
145 } // End of namespace llvm
146 
147 #endif
148