1//===-- llvm/CodeGen/DebugLocEntry.h - Entry in debug_loc list -*- C++ -*--===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
10#define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
11
12#include "DebugLocStream.h"
13#include "llvm/Config/llvm-config.h"
14#include "llvm/IR/Constants.h"
15#include "llvm/IR/DebugInfo.h"
16#include "llvm/MC/MCSymbol.h"
17#include "llvm/MC/MachineLocation.h"
18#include "llvm/Support/Debug.h"
19
20namespace llvm {
21class AsmPrinter;
22
23/// This struct describes target specific location.
24struct TargetIndexLocation {
25 int Index;
26 int Offset;
27
28 TargetIndexLocation() = default;
29 TargetIndexLocation(unsigned Idx, int64_t Offset)
30 : Index(Idx), Offset(Offset) {}
31
32 bool operator==(const TargetIndexLocation &Other) const {
33 return Index == Other.Index && Offset == Other.Offset;
34 }
35};
36
37/// A single location or constant within a variable location description, with
38/// either a single entry (with an optional DIExpression) used for a DBG_VALUE,
39/// or a list of entries used for a DBG_VALUE_LIST.
40class DbgValueLocEntry {
41
42 /// Type of entry that this represents.
43 enum EntryType {
44 E_Location,
45 E_Integer,
46 E_ConstantFP,
47 E_ConstantInt,
48 E_TargetIndexLocation
49 };
50 enum EntryType EntryKind;
51
52 /// Either a constant,
53 union {
54 int64_t Int;
55 const ConstantFP *CFP;
56 const ConstantInt *CIP;
57 } Constant;
58
59 union {
60 /// Or a location in the machine frame.
61 MachineLocation Loc;
62 /// Or a location from target specific location.
63 TargetIndexLocation TIL;
64 };
65
66public:
67 DbgValueLocEntry(int64_t i) : EntryKind(E_Integer) { Constant.Int = i; }
68 DbgValueLocEntry(const ConstantFP *CFP) : EntryKind(E_ConstantFP) {
69 Constant.CFP = CFP;
70 }
71 DbgValueLocEntry(const ConstantInt *CIP) : EntryKind(E_ConstantInt) {
72 Constant.CIP = CIP;
73 }
74 DbgValueLocEntry(MachineLocation Loc) : EntryKind(E_Location), Loc(Loc) {}
75 DbgValueLocEntry(TargetIndexLocation Loc)
76 : EntryKind(E_TargetIndexLocation), TIL(Loc) {}
77
78 bool isLocation() const { return EntryKind == E_Location; }
79 bool isIndirectLocation() const {
80 return EntryKind == E_Location && Loc.isIndirect();
81 }
82 bool isTargetIndexLocation() const {
83 return EntryKind == E_TargetIndexLocation;
84 }
85 bool isInt() const { return EntryKind == E_Integer; }
86 bool isConstantFP() const { return EntryKind == E_ConstantFP; }
87 bool isConstantInt() const { return EntryKind == E_ConstantInt; }
88 int64_t getInt() const { return Constant.Int; }
89 const ConstantFP *getConstantFP() const { return Constant.CFP; }
90 const ConstantInt *getConstantInt() const { return Constant.CIP; }
91 MachineLocation getLoc() const { return Loc; }
92 TargetIndexLocation getTargetIndexLocation() const { return TIL; }
93 friend bool operator==(const DbgValueLocEntry &, const DbgValueLocEntry &);
94#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
95 LLVM_DUMP_METHOD void dump() const {
96 if (isLocation()) {
97 llvm::dbgs() << "Loc = { reg=" << Loc.getReg() << " ";
98 if (Loc.isIndirect())
99 llvm::dbgs() << "+0";
100 llvm::dbgs() << "} ";
101 } else if (isConstantInt())
102 Constant.CIP->dump();
103 else if (isConstantFP())
104 Constant.CFP->dump();
105 }
106#endif
107};
108
109/// The location of a single variable, composed of an expression and 0 or more
110/// DbgValueLocEntries.
111class DbgValueLoc {
112 /// Any complex address location expression for this DbgValueLoc.
113 const DIExpression *Expression;
114
115 SmallVector<DbgValueLocEntry, 2> ValueLocEntries;
116
117 bool IsVariadic;
118
119public:
120 DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs)
121 : Expression(Expr), ValueLocEntries(Locs), IsVariadic(true) {}
122
123 DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs,
124 bool IsVariadic)
125 : Expression(Expr), ValueLocEntries(Locs), IsVariadic(IsVariadic) {
126#ifndef NDEBUG
127 assert(Expr->isValid() ||
128 !any_of(Locs, [](auto LE) { return LE.isLocation(); }));
129 if (!IsVariadic) {
130 assert(ValueLocEntries.size() == 1);
131 }
132#endif
133 }
134
135 DbgValueLoc(const DIExpression *Expr, DbgValueLocEntry Loc)
136 : Expression(Expr), ValueLocEntries(1, Loc), IsVariadic(false) {
137 assert(((Expr && Expr->isValid()) || !Loc.isLocation()) &&
138 "DBG_VALUE with a machine location must have a valid expression.");
139 }
140
141 bool isFragment() const { return getExpression()->isFragment(); }
142 bool isEntryVal() const { return getExpression()->isEntryValue(); }
143 bool isVariadic() const { return IsVariadic; }
144 bool isEquivalent(const DbgValueLoc &Other) const {
145 // Cannot be equivalent with different numbers of entries.
146 if (ValueLocEntries.size() != Other.ValueLocEntries.size())
147 return false;
148 bool ThisIsIndirect =
149 !IsVariadic && ValueLocEntries[0].isIndirectLocation();
150 bool OtherIsIndirect =
151 !Other.IsVariadic && Other.ValueLocEntries[0].isIndirectLocation();
152 // Check equivalence of DIExpressions + Directness together.
153 if (!DIExpression::isEqualExpression(FirstExpr: Expression, FirstIndirect: ThisIsIndirect,
154 SecondExpr: Other.Expression, SecondIndirect: OtherIsIndirect))
155 return false;
156 // Indirectness should have been accounted for in the above check, so just
157 // compare register values directly here.
158 if (ThisIsIndirect || OtherIsIndirect) {
159 DbgValueLocEntry ThisOp = ValueLocEntries[0];
160 DbgValueLocEntry OtherOp = Other.ValueLocEntries[0];
161 return ThisOp.isLocation() && OtherOp.isLocation() &&
162 ThisOp.getLoc().getReg() == OtherOp.getLoc().getReg();
163 }
164 // If neither are indirect, then just compare the loc entries directly.
165 return ValueLocEntries == Other.ValueLocEntries;
166 }
167 const DIExpression *getExpression() const { return Expression; }
168 ArrayRef<DbgValueLocEntry> getLocEntries() const { return ValueLocEntries; }
169 friend bool operator==(const DbgValueLoc &, const DbgValueLoc &);
170 friend bool operator<(const DbgValueLoc &, const DbgValueLoc &);
171#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
172 LLVM_DUMP_METHOD void dump() const {
173 for (const DbgValueLocEntry &DV : ValueLocEntries)
174 DV.dump();
175 if (Expression)
176 Expression->dump();
177 }
178#endif
179};
180
181/// This struct describes location entries emitted in the .debug_loc
182/// section.
183class DebugLocEntry {
184 /// Begin and end symbols for the address range that this location is valid.
185 const MCSymbol *Begin;
186 const MCSymbol *End;
187
188 /// A nonempty list of locations/constants belonging to this entry,
189 /// sorted by offset.
190 SmallVector<DbgValueLoc, 1> Values;
191
192public:
193 /// Create a location list entry for the range [\p Begin, \p End).
194 ///
195 /// \param Vals One or more values describing (parts of) the variable.
196 DebugLocEntry(const MCSymbol *Begin, const MCSymbol *End,
197 ArrayRef<DbgValueLoc> Vals)
198 : Begin(Begin), End(End) {
199 addValues(Vals);
200 }
201
202 /// Attempt to merge this DebugLocEntry with Next and return
203 /// true if the merge was successful. Entries can be merged if they
204 /// share the same Loc/Constant and if Next immediately follows this
205 /// Entry.
206 bool MergeRanges(const DebugLocEntry &Next) {
207 // If this and Next are describing the same variable, merge them.
208 if (End != Next.Begin)
209 return false;
210 if (Values.size() != Next.Values.size())
211 return false;
212 for (unsigned EntryIdx = 0; EntryIdx < Values.size(); ++EntryIdx)
213 if (!Values[EntryIdx].isEquivalent(Other: Next.Values[EntryIdx]))
214 return false;
215 End = Next.End;
216 return true;
217 }
218
219 const MCSymbol *getBeginSym() const { return Begin; }
220 const MCSymbol *getEndSym() const { return End; }
221 ArrayRef<DbgValueLoc> getValues() const { return Values; }
222 void addValues(ArrayRef<DbgValueLoc> Vals) {
223 Values.append(in_start: Vals.begin(), in_end: Vals.end());
224 sortUniqueValues();
225 assert((Values.size() == 1 || all_of(Values, [](DbgValueLoc V) {
226 return V.isFragment();
227 })) && "must either have a single value or multiple pieces");
228 }
229
230 // Sort the pieces by offset.
231 // Remove any duplicate entries by dropping all but the first.
232 void sortUniqueValues() {
233 // Values is either 1 item that does not have a fragment, or many items
234 // that all do. No need to sort if the former and also prevents operator<
235 // being called on a non fragment item when _GLIBCXX_DEBUG is defined.
236 if (Values.size() == 1)
237 return;
238 llvm::sort(C&: Values);
239 Values.erase(CS: llvm::unique(R&: Values,
240 P: [](const DbgValueLoc &A, const DbgValueLoc &B) {
241 return A.getExpression() == B.getExpression();
242 }),
243 CE: Values.end());
244 }
245
246 /// Lower this entry into a DWARF expression.
247 void finalize(const AsmPrinter &AP,
248 DebugLocStream::ListBuilder &List,
249 const DIBasicType *BT,
250 DwarfCompileUnit &TheCU);
251};
252
253/// Compare two DbgValueLocEntries for equality.
254inline bool operator==(const DbgValueLocEntry &A, const DbgValueLocEntry &B) {
255 if (A.EntryKind != B.EntryKind)
256 return false;
257
258 switch (A.EntryKind) {
259 case DbgValueLocEntry::E_Location:
260 return A.Loc == B.Loc;
261 case DbgValueLocEntry::E_TargetIndexLocation:
262 return A.TIL == B.TIL;
263 case DbgValueLocEntry::E_Integer:
264 return A.Constant.Int == B.Constant.Int;
265 case DbgValueLocEntry::E_ConstantFP:
266 return A.Constant.CFP == B.Constant.CFP;
267 case DbgValueLocEntry::E_ConstantInt:
268 return A.Constant.CIP == B.Constant.CIP;
269 }
270 llvm_unreachable("unhandled EntryKind");
271}
272
273/// Compare two DbgValueLocs for equality.
274inline bool operator==(const DbgValueLoc &A, const DbgValueLoc &B) {
275 return A.ValueLocEntries == B.ValueLocEntries &&
276 A.Expression == B.Expression && A.IsVariadic == B.IsVariadic;
277}
278
279/// Compare two fragments based on their offset.
280inline bool operator<(const DbgValueLoc &A,
281 const DbgValueLoc &B) {
282 return A.getExpression()->getFragmentInfo()->OffsetInBits <
283 B.getExpression()->getFragmentInfo()->OffsetInBits;
284}
285
286}
287
288#endif
289