FuncUnwinders.h revision 81a96aa6242f7b559770f5dc62316253cb8cb0d4 
1#ifndef liblldb_FuncUnwinders_h
2#define liblldb_FuncUnwinders_h
3
4#include "lldb/Core/AddressRange.h"
5#include "lldb/Core/ArchSpec.h"
6#include "lldb/Core/AddressRange.h"
7#include "lldb/Host/Mutex.h"
8
9namespace lldb_private {
10
11class UnwindTable;
12
13class FuncUnwinders
14{
15public:
16    // FuncUnwinders objects are used to track UnwindPlans for a function
17    // (named or not - really just an address range)
18
19    // We'll record three different UnwindPlans for each address range:
20    //   1. Unwinding from a call site (a valid exception throw location)
21    //      This is often sourced from the eh_frame exception handling info
22    //   2. Unwinding from a non-call site (any location in the function)
23    //      This is often done by analyzing the function prologue assembly
24    //      langauge instructions
25    //   3. A fast unwind method for this function which only retrieves a
26    //      limited set of registers necessary to walk the stack
27    //   4. An architectural default unwind plan when none of the above are
28    //      available for some reason.
29
30    // Additionally, FuncUnwinds object can be asked where the prologue
31    // instructions are finished for migrating breakpoints past the
32    // stack frame setup instructions when we don't have line table information.
33
34    FuncUnwinders (lldb_private::UnwindTable& unwind_table, lldb_private::UnwindAssembly *assembly_profiler, AddressRange range);
35
36    ~FuncUnwinders ();
37
38    // current_offset is the byte offset into the function.
39    // 0 means no instructions have executed yet.  -1 means the offset is unknown.
40    // On architectures where the pc points to the next instruction that will execute, this
41    // offset value will have already been decremented by 1 to stay within the bounds of the
42    // correct function body.
43    lldb::UnwindPlanSP
44    GetUnwindPlanAtCallSite (int current_offset);
45
46    lldb::UnwindPlanSP
47    GetUnwindPlanAtNonCallSite (lldb_private::Thread& thread);
48
49    lldb::UnwindPlanSP
50    GetUnwindPlanFastUnwind (lldb_private::Thread& Thread);
51
52    lldb::UnwindPlanSP
53    GetUnwindPlanArchitectureDefault (lldb_private::Thread& thread);
54
55    lldb::UnwindPlanSP
56    GetUnwindPlanArchitectureDefaultAtFunctionEntry (lldb_private::Thread& thread);
57
58    Address&
59    GetFirstNonPrologueInsn (Target& target);
60
61    const Address&
62    GetFunctionStartAddress () const;
63
64    bool
65    ContainsAddress (const Address& addr) const
66    {
67        return m_range.ContainsFileAddress (addr);
68    }
69
70    // When we're doing an unwind using the UnwindPlanAtNonCallSite and we find an
71    // impossible unwind condition, we know that the UnwindPlan is invalid.  Calling
72    // this method on the FuncUnwinder will tell it to replace that UnwindPlan with
73    // the architectural default UnwindPlan so hopefully our stack walk will get past
74    // this frame.
75    void
76    InvalidateNonCallSiteUnwindPlan (lldb_private::Thread& Thread);
77
78private:
79    UnwindTable& m_unwind_table;
80    UnwindAssembly *m_assembly_profiler;
81    AddressRange m_range;
82
83    Mutex m_mutex;
84    lldb::UnwindPlanSP m_unwind_plan_call_site_sp;
85    lldb::UnwindPlanSP m_unwind_plan_non_call_site_sp;
86    lldb::UnwindPlanSP m_unwind_plan_fast_sp;
87    lldb::UnwindPlanSP m_unwind_plan_arch_default_sp;
88    lldb::UnwindPlanSP m_unwind_plan_arch_default_at_func_entry_sp;
89
90    bool m_tried_unwind_at_call_site:1,
91         m_tried_unwind_at_non_call_site:1,
92         m_tried_unwind_fast:1,
93         m_tried_unwind_arch_default:1,
94         m_tried_unwind_arch_default_at_func_entry:1;
95
96
97    Address m_first_non_prologue_insn;
98
99    DISALLOW_COPY_AND_ASSIGN (FuncUnwinders);
100
101}; // class FuncUnwinders
102
103} // namespace lldb_private
104
105
106#endif //liblldb_FuncUnwinders_h
107