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Amirhossein Pashaeehir
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Separate UnwindTable from DWARF Debug Frame
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llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h

Lines changed: 1 addition & 379 deletions
Original file line numberDiff line numberDiff line change
@@ -9,15 +9,13 @@
99
#ifndef LLVM_DEBUGINFO_DWARF_DWARFDEBUGFRAME_H
1010
#define LLVM_DEBUGINFO_DWARF_DWARFDEBUGFRAME_H
1111

12-
#include "llvm/ADT/ArrayRef.h"
1312
#include "llvm/ADT/SmallString.h"
1413
#include "llvm/ADT/iterator.h"
1514
#include "llvm/DebugInfo/DWARF/DWARFCFIProgram.h"
1615
#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
17-
#include "llvm/Support/Compiler.h"
16+
#include "llvm/DebugInfo/DWARF/DWARFUnwindTable.h"
1817
#include "llvm/Support/Error.h"
1918
#include "llvm/TargetParser/Triple.h"
20-
#include <map>
2119
#include <memory>
2220
#include <vector>
2321

@@ -30,382 +28,6 @@ struct DIDumpOptions;
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3129
namespace dwarf {
3230

33-
constexpr uint32_t InvalidRegisterNumber = UINT32_MAX;
34-
35-
/// A class that represents a location for the Call Frame Address (CFA) or a
36-
/// register. This is decoded from the DWARF Call Frame Information
37-
/// instructions and put into an UnwindRow.
38-
class UnwindLocation {
39-
public:
40-
enum Location {
41-
/// Not specified.
42-
Unspecified,
43-
/// Register is not available and can't be recovered.
44-
Undefined,
45-
/// Register value is in the register, nothing needs to be done to unwind
46-
/// it:
47-
/// reg = reg
48-
Same,
49-
/// Register is in or at the CFA plus an offset:
50-
/// reg = CFA + offset
51-
/// reg = defef(CFA + offset)
52-
CFAPlusOffset,
53-
/// Register or CFA is in or at a register plus offset, optionally in
54-
/// an address space:
55-
/// reg = reg + offset [in addrspace]
56-
/// reg = deref(reg + offset [in addrspace])
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RegPlusOffset,
58-
/// Register or CFA value is in or at a value found by evaluating a DWARF
59-
/// expression:
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/// reg = eval(dwarf_expr)
61-
/// reg = deref(eval(dwarf_expr))
62-
DWARFExpr,
63-
/// Value is a constant value contained in "Offset":
64-
/// reg = Offset
65-
Constant,
66-
};
67-
68-
private:
69-
Location Kind; /// The type of the location that describes how to unwind it.
70-
uint32_t RegNum; /// The register number for Kind == RegPlusOffset.
71-
int32_t Offset; /// The offset for Kind == CFAPlusOffset or RegPlusOffset.
72-
std::optional<uint32_t> AddrSpace; /// The address space for Kind ==
73-
/// RegPlusOffset for CFA.
74-
std::optional<DWARFExpression> Expr; /// The DWARF expression for Kind ==
75-
/// DWARFExpression.
76-
bool Dereference; /// If true, the resulting location must be dereferenced
77-
/// after the location value is computed.
78-
79-
// Constructors are private to force people to use the create static
80-
// functions.
81-
UnwindLocation(Location K)
82-
: Kind(K), RegNum(InvalidRegisterNumber), Offset(0),
83-
AddrSpace(std::nullopt), Dereference(false) {}
84-
85-
UnwindLocation(Location K, uint32_t Reg, int32_t Off,
86-
std::optional<uint32_t> AS, bool Deref)
87-
: Kind(K), RegNum(Reg), Offset(Off), AddrSpace(AS), Dereference(Deref) {}
88-
89-
UnwindLocation(DWARFExpression E, bool Deref)
90-
: Kind(DWARFExpr), RegNum(InvalidRegisterNumber), Offset(0), Expr(E),
91-
Dereference(Deref) {}
92-
93-
public:
94-
/// Create a location whose rule is set to Unspecified. This means the
95-
/// register value might be in the same register but it wasn't specified in
96-
/// the unwind opcodes.
97-
LLVM_ABI static UnwindLocation createUnspecified();
98-
/// Create a location where the value is undefined and not available. This can
99-
/// happen when a register is volatile and can't be recovered.
100-
LLVM_ABI static UnwindLocation createUndefined();
101-
/// Create a location where the value is known to be in the register itself.
102-
LLVM_ABI static UnwindLocation createSame();
103-
/// Create a location that is in (Deref == false) or at (Deref == true) the
104-
/// CFA plus an offset. Most registers that are spilled onto the stack use
105-
/// this rule. The rule for the register will use this rule and specify a
106-
/// unique offset from the CFA with \a Deref set to true. This value will be
107-
/// relative to a CFA value which is typically defined using the register
108-
/// plus offset location. \see createRegisterPlusOffset(...) for more
109-
/// information.
110-
LLVM_ABI static UnwindLocation createIsCFAPlusOffset(int32_t Off);
111-
LLVM_ABI static UnwindLocation createAtCFAPlusOffset(int32_t Off);
112-
/// Create a location where the saved value is in (Deref == false) or at
113-
/// (Deref == true) a regiser plus an offset and, optionally, in the specified
114-
/// address space (used mostly for the CFA).
115-
///
116-
/// The CFA is usually defined using this rule by using the stack pointer or
117-
/// frame pointer as the register, with an offset that accounts for all
118-
/// spilled registers and all local variables in a function, and Deref ==
119-
/// false.
120-
LLVM_ABI static UnwindLocation
121-
createIsRegisterPlusOffset(uint32_t Reg, int32_t Off,
122-
std::optional<uint32_t> AddrSpace = std::nullopt);
123-
LLVM_ABI static UnwindLocation
124-
createAtRegisterPlusOffset(uint32_t Reg, int32_t Off,
125-
std::optional<uint32_t> AddrSpace = std::nullopt);
126-
/// Create a location whose value is the result of evaluating a DWARF
127-
/// expression. This allows complex expressions to be evaluated in order to
128-
/// unwind a register or CFA value.
129-
LLVM_ABI static UnwindLocation createIsDWARFExpression(DWARFExpression Expr);
130-
LLVM_ABI static UnwindLocation createAtDWARFExpression(DWARFExpression Expr);
131-
LLVM_ABI static UnwindLocation createIsConstant(int32_t Value);
132-
133-
Location getLocation() const { return Kind; }
134-
uint32_t getRegister() const { return RegNum; }
135-
int32_t getOffset() const { return Offset; }
136-
uint32_t getAddressSpace() const {
137-
assert(Kind == RegPlusOffset && AddrSpace);
138-
return *AddrSpace;
139-
}
140-
int32_t getConstant() const { return Offset; }
141-
/// Some opcodes will modify the CFA location's register only, so we need
142-
/// to be able to modify the CFA register when evaluating DWARF Call Frame
143-
/// Information opcodes.
144-
void setRegister(uint32_t NewRegNum) { RegNum = NewRegNum; }
145-
/// Some opcodes will modify the CFA location's offset only, so we need
146-
/// to be able to modify the CFA offset when evaluating DWARF Call Frame
147-
/// Information opcodes.
148-
void setOffset(int32_t NewOffset) { Offset = NewOffset; }
149-
/// Some opcodes modify a constant value and we need to be able to update
150-
/// the constant value (DW_CFA_GNU_window_save which is also known as
151-
// DW_CFA_AARCH64_negate_ra_state).
152-
void setConstant(int32_t Value) { Offset = Value; }
153-
154-
std::optional<DWARFExpression> getDWARFExpressionBytes() const {
155-
return Expr;
156-
}
157-
/// Dump a location expression as text and use the register information if
158-
/// some is provided.
159-
///
160-
/// \param OS the stream to use for output.
161-
///
162-
/// \param MRI register information that helps emit register names insteead
163-
/// of raw register numbers.
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///
165-
/// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
166-
/// instead of from .debug_frame. This is needed for register number
167-
/// conversion because some register numbers differ between the two sections
168-
/// for certain architectures like x86.
169-
LLVM_ABI void dump(raw_ostream &OS, DIDumpOptions DumpOpts) const;
170-
171-
LLVM_ABI bool operator==(const UnwindLocation &RHS) const;
172-
};
173-
174-
LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const UnwindLocation &R);
175-
176-
/// A class that can track all registers with locations in a UnwindRow object.
177-
///
178-
/// Register locations use a map where the key is the register number and the
179-
/// the value is a UnwindLocation.
180-
///
181-
/// The register maps are put into a class so that all register locations can
182-
/// be copied when parsing the unwind opcodes DW_CFA_remember_state and
183-
/// DW_CFA_restore_state.
184-
class RegisterLocations {
185-
std::map<uint32_t, UnwindLocation> Locations;
186-
187-
public:
188-
/// Return the location for the register in \a RegNum if there is a location.
189-
///
190-
/// \param RegNum the register number to find a location for.
191-
///
192-
/// \returns A location if one is available for \a RegNum, or std::nullopt
193-
/// otherwise.
194-
std::optional<UnwindLocation> getRegisterLocation(uint32_t RegNum) const {
195-
auto Pos = Locations.find(RegNum);
196-
if (Pos == Locations.end())
197-
return std::nullopt;
198-
return Pos->second;
199-
}
200-
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/// Set the location for the register in \a RegNum to \a Location.
202-
///
203-
/// \param RegNum the register number to set the location for.
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///
205-
/// \param Location the UnwindLocation that describes how to unwind the value.
206-
void setRegisterLocation(uint32_t RegNum, const UnwindLocation &Location) {
207-
Locations.erase(RegNum);
208-
Locations.insert(std::make_pair(RegNum, Location));
209-
}
210-
211-
/// Removes any rule for the register in \a RegNum.
212-
///
213-
/// \param RegNum the register number to remove the location for.
214-
void removeRegisterLocation(uint32_t RegNum) { Locations.erase(RegNum); }
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/// Dump all registers + locations that are currently defined in this object.
217-
///
218-
/// \param OS the stream to use for output.
219-
///
220-
/// \param MRI register information that helps emit register names insteead
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/// of raw register numbers.
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///
223-
/// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
224-
/// instead of from .debug_frame. This is needed for register number
225-
/// conversion because some register numbers differ between the two sections
226-
/// for certain architectures like x86.
227-
LLVM_ABI void dump(raw_ostream &OS, DIDumpOptions DumpOpts) const;
228-
229-
/// Returns true if we have any register locations in this object.
230-
bool hasLocations() const { return !Locations.empty(); }
231-
232-
size_t size() const { return Locations.size(); }
233-
234-
bool operator==(const RegisterLocations &RHS) const {
235-
return Locations == RHS.Locations;
236-
}
237-
};
238-
239-
LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const RegisterLocations &RL);
240-
241-
/// A class that represents a single row in the unwind table that is decoded by
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/// parsing the DWARF Call Frame Information opcodes.
243-
///
244-
/// The row consists of an optional address, the rule to unwind the CFA and all
245-
/// rules to unwind any registers. If the address doesn't have a value, this
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/// row represents the initial instructions for a CIE. If the address has a
247-
/// value the UnwindRow represents a row in the UnwindTable for a FDE. The
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/// address is the first address for which the CFA location and register rules
249-
/// are valid within a function.
250-
///
251-
/// UnwindRow objects are created by parsing opcodes in the DWARF Call Frame
252-
/// Information and UnwindRow objects are lazily populated and pushed onto a
253-
/// stack in the UnwindTable when evaluating this state machine. Accessors are
254-
/// needed for the address, CFA value, and register locations as the opcodes
255-
/// encode a state machine that produces a sorted array of UnwindRow objects
256-
/// \see UnwindTable.
257-
class UnwindRow {
258-
/// The address will be valid when parsing the instructions in a FDE. If
259-
/// invalid, this object represents the initial instructions of a CIE.
260-
std::optional<uint64_t> Address; ///< Address for row in FDE, invalid for CIE.
261-
UnwindLocation CFAValue; ///< How to unwind the Call Frame Address (CFA).
262-
RegisterLocations RegLocs; ///< How to unwind all registers in this list.
263-
264-
public:
265-
UnwindRow() : CFAValue(UnwindLocation::createUnspecified()) {}
266-
267-
/// Returns true if the address is valid in this object.
268-
bool hasAddress() const { return Address.has_value(); }
269-
270-
/// Get the address for this row.
271-
///
272-
/// Clients should only call this function after verifying it has a valid
273-
/// address with a call to \see hasAddress().
274-
uint64_t getAddress() const { return *Address; }
275-
276-
/// Set the address for this UnwindRow.
277-
///
278-
/// The address represents the first address for which the CFAValue and
279-
/// RegLocs are valid within a function.
280-
void setAddress(uint64_t Addr) { Address = Addr; }
281-
282-
/// Offset the address for this UnwindRow.
283-
///
284-
/// The address represents the first address for which the CFAValue and
285-
/// RegLocs are valid within a function. Clients must ensure that this object
286-
/// already has an address (\see hasAddress()) prior to calling this
287-
/// function.
288-
void slideAddress(uint64_t Offset) { *Address += Offset; }
289-
UnwindLocation &getCFAValue() { return CFAValue; }
290-
const UnwindLocation &getCFAValue() const { return CFAValue; }
291-
RegisterLocations &getRegisterLocations() { return RegLocs; }
292-
const RegisterLocations &getRegisterLocations() const { return RegLocs; }
293-
294-
/// Dump the UnwindRow to the stream.
295-
///
296-
/// \param OS the stream to use for output.
297-
///
298-
/// \param MRI register information that helps emit register names insteead
299-
/// of raw register numbers.
300-
///
301-
/// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
302-
/// instead of from .debug_frame. This is needed for register number
303-
/// conversion because some register numbers differ between the two sections
304-
/// for certain architectures like x86.
305-
///
306-
/// \param IndentLevel specify the indent level as an integer. The UnwindRow
307-
/// will be output to the stream preceded by 2 * IndentLevel number of spaces.
308-
LLVM_ABI void dump(raw_ostream &OS, DIDumpOptions DumpOpts,
309-
unsigned IndentLevel = 0) const;
310-
};
311-
312-
LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const UnwindRow &Row);
313-
314-
/// A class that contains all UnwindRow objects for an FDE or a single unwind
315-
/// row for a CIE. To unwind an address the rows, which are sorted by start
316-
/// address, can be searched to find the UnwindRow with the lowest starting
317-
/// address that is greater than or equal to the address that is being looked
318-
/// up.
319-
class UnwindTable {
320-
public:
321-
using RowContainer = std::vector<UnwindRow>;
322-
using iterator = RowContainer::iterator;
323-
using const_iterator = RowContainer::const_iterator;
324-
325-
size_t size() const { return Rows.size(); }
326-
iterator begin() { return Rows.begin(); }
327-
const_iterator begin() const { return Rows.begin(); }
328-
iterator end() { return Rows.end(); }
329-
const_iterator end() const { return Rows.end(); }
330-
const UnwindRow &operator[](size_t Index) const {
331-
assert(Index < size());
332-
return Rows[Index];
333-
}
334-
void insertRow(const UnwindRow &Row) { Rows.push_back(Row); }
335-
336-
/// Set the last address that this unwinding table refers to.
337-
///
338-
/// This is used when this table is created based on a FDE.
339-
void setEndAddress(uint64_t Addr) { EndAddress = Addr; }
340-
341-
/// Dump the UnwindTable to the stream.
342-
///
343-
/// \param OS the stream to use for output.
344-
///
345-
/// \param MRI register information that helps emit register names insteead
346-
/// of raw register numbers.
347-
///
348-
/// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
349-
/// instead of from .debug_frame. This is needed for register number
350-
/// conversion because some register numbers differ between the two sections
351-
/// for certain architectures like x86.
352-
///
353-
/// \param IndentLevel specify the indent level as an integer. The UnwindRow
354-
/// will be output to the stream preceded by 2 * IndentLevel number of spaces.
355-
LLVM_ABI void dump(raw_ostream &OS, DIDumpOptions DumpOpts,
356-
unsigned IndentLevel = 0) const;
357-
358-
/// Parse the information in the CFIProgram and update the CurrRow object
359-
/// that the state machine describes.
360-
///
361-
/// This is an internal implementation that emulates the state machine
362-
/// described in the DWARF Call Frame Information opcodes and will push
363-
/// CurrRow onto the Rows container when needed.
364-
///
365-
/// \param CFIP the CFI program that contains the opcodes from a CIE or FDE.
366-
///
367-
/// \param CurrRow the current row to modify while parsing the state machine.
368-
///
369-
/// \param InitialLocs If non-NULL, we are parsing a FDE and this contains
370-
/// the initial register locations from the CIE. If NULL, then a CIE's
371-
/// opcodes are being parsed and this is not needed. This is used for the
372-
/// DW_CFA_restore and DW_CFA_restore_extended opcodes.
373-
Error parseRows(const CFIProgram &CFIP, UnwindRow &CurrRow,
374-
const RegisterLocations *InitialLocs);
375-
376-
private:
377-
RowContainer Rows;
378-
/// The end address when data is extracted from a FDE. This value will be
379-
/// invalid when a UnwindTable is extracted from a CIE.
380-
std::optional<uint64_t> EndAddress;
381-
};
382-
383-
LLVM_ABI raw_ostream &operator<<(raw_ostream &OS, const UnwindTable &Rows);
384-
385-
class CIE;
386-
387-
/// Create an UnwindTable from a Common Information Entry (CIE).
388-
///
389-
/// \param Cie The Common Information Entry to extract the table from. The
390-
/// CFIProgram is retrieved from the \a Cie object and used to create the
391-
/// UnwindTable.
392-
///
393-
/// \returns An error if the DWARF Call Frame Information opcodes have state
394-
/// machine errors, or a valid UnwindTable otherwise.
395-
LLVM_ABI Expected<UnwindTable> createUnwindTable(const CIE *Cie);
396-
397-
class FDE;
398-
399-
/// Create an UnwindTable from a Frame Descriptor Entry (FDE).
400-
///
401-
/// \param Fde The Frame Descriptor Entry to extract the table from. The
402-
/// CFIProgram is retrieved from the \a Fde object and used to create the
403-
/// UnwindTable.
404-
///
405-
/// \returns An error if the DWARF Call Frame Information opcodes have state
406-
/// machine errors, or a valid UnwindTable otherwise.
407-
LLVM_ABI Expected<UnwindTable> createUnwindTable(const FDE *Fde);
408-
40931
class CIE;
41032

41133
/// Create an UnwindTable from a Common Information Entry (CIE).

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