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.begin(), Locs.end()),
122 IsVariadic(true) {}
123
124 DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs,
125 bool IsVariadic)
126 : Expression(Expr), ValueLocEntries(Locs.begin(), Locs.end()),
127 IsVariadic(IsVariadic) {
128#ifndef NDEBUG
129 assert(Expr->isValid() ||
130 !any_of(Locs, [](auto LE) { return LE.isLocation(); }));
131 if (!IsVariadic) {
132 assert(ValueLocEntries.size() == 1);
133 }
134#endif
135 }
136
137 DbgValueLoc(const DIExpression *Expr, DbgValueLocEntry Loc)
138 : Expression(Expr), ValueLocEntries(1, Loc), IsVariadic(false) {
139 assert(((Expr && Expr->isValid()) || !Loc.isLocation()) &&
140 "DBG_VALUE with a machine location must have a valid expression.");
141 }
142
143 bool isFragment() const { return getExpression()->isFragment(); }
144 bool isEntryVal() const { return getExpression()->isEntryValue(); }
145 bool isVariadic() const { return IsVariadic; }
146 bool isEquivalent(const DbgValueLoc &Other) const {
147 // Cannot be equivalent with different numbers of entries.
148 if (ValueLocEntries.size() != Other.ValueLocEntries.size())
149 return false;
150 bool ThisIsIndirect =
151 !IsVariadic && ValueLocEntries[0].isIndirectLocation();
152 bool OtherIsIndirect =
153 !Other.IsVariadic && Other.ValueLocEntries[0].isIndirectLocation();
154 // Check equivalence of DIExpressions + Directness together.
155 if (!DIExpression::isEqualExpression(FirstExpr: Expression, FirstIndirect: ThisIsIndirect,
156 SecondExpr: Other.Expression, SecondIndirect: OtherIsIndirect))
157 return false;
158 // Indirectness should have been accounted for in the above check, so just
159 // compare register values directly here.
160 if (ThisIsIndirect || OtherIsIndirect) {
161 DbgValueLocEntry ThisOp = ValueLocEntries[0];
162 DbgValueLocEntry OtherOp = Other.ValueLocEntries[0];
163 return ThisOp.isLocation() && OtherOp.isLocation() &&
164 ThisOp.getLoc().getReg() == OtherOp.getLoc().getReg();
165 }
166 // If neither are indirect, then just compare the loc entries directly.
167 return ValueLocEntries == Other.ValueLocEntries;
168 }
169 const DIExpression *getExpression() const { return Expression; }
170 ArrayRef<DbgValueLocEntry> getLocEntries() const { return ValueLocEntries; }
171 friend bool operator==(const DbgValueLoc &, const DbgValueLoc &);
172 friend bool operator<(const DbgValueLoc &, const DbgValueLoc &);
173#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
174 LLVM_DUMP_METHOD void dump() const {
175 for (const DbgValueLocEntry &DV : ValueLocEntries)
176 DV.dump();
177 if (Expression)
178 Expression->dump();
179 }
180#endif
181};
182
183/// This struct describes location entries emitted in the .debug_loc
184/// section.
185class DebugLocEntry {
186 /// Begin and end symbols for the address range that this location is valid.
187 const MCSymbol *Begin;
188 const MCSymbol *End;
189
190 /// A nonempty list of locations/constants belonging to this entry,
191 /// sorted by offset.
192 SmallVector<DbgValueLoc, 1> Values;
193
194public:
195 /// Create a location list entry for the range [\p Begin, \p End).
196 ///
197 /// \param Vals One or more values describing (parts of) the variable.
198 DebugLocEntry(const MCSymbol *Begin, const MCSymbol *End,
199 ArrayRef<DbgValueLoc> Vals)
200 : Begin(Begin), End(End) {
201 addValues(Vals);
202 }
203
204 /// Attempt to merge this DebugLocEntry with Next and return
205 /// true if the merge was successful. Entries can be merged if they
206 /// share the same Loc/Constant and if Next immediately follows this
207 /// Entry.
208 bool MergeRanges(const DebugLocEntry &Next) {
209 // If this and Next are describing the same variable, merge them.
210 if (End != Next.Begin)
211 return false;
212 if (Values.size() != Next.Values.size())
213 return false;
214 for (unsigned EntryIdx = 0; EntryIdx < Values.size(); ++EntryIdx)
215 if (!Values[EntryIdx].isEquivalent(Other: Next.Values[EntryIdx]))
216 return false;
217 End = Next.End;
218 return true;
219 }
220
221 const MCSymbol *getBeginSym() const { return Begin; }
222 const MCSymbol *getEndSym() const { return End; }
223 ArrayRef<DbgValueLoc> getValues() const { return Values; }
224 void addValues(ArrayRef<DbgValueLoc> Vals) {
225 Values.append(in_start: Vals.begin(), in_end: Vals.end());
226 sortUniqueValues();
227 assert((Values.size() == 1 || all_of(Values, [](DbgValueLoc V) {
228 return V.isFragment();
229 })) && "must either have a single value or multiple pieces");
230 }
231
232 // Sort the pieces by offset.
233 // Remove any duplicate entries by dropping all but the first.
234 void sortUniqueValues() {
235 // Values is either 1 item that does not have a fragment, or many items
236 // that all do. No need to sort if the former and also prevents operator<
237 // being called on a non fragment item when _GLIBCXX_DEBUG is defined.
238 if (Values.size() == 1)
239 return;
240 llvm::sort(C&: Values);
241 Values.erase(CS: llvm::unique(R&: Values,
242 P: [](const DbgValueLoc &A, const DbgValueLoc &B) {
243 return A.getExpression() == B.getExpression();
244 }),
245 CE: Values.end());
246 }
247
248 /// Lower this entry into a DWARF expression.
249 void finalize(const AsmPrinter &AP,
250 DebugLocStream::ListBuilder &List,
251 const DIBasicType *BT,
252 DwarfCompileUnit &TheCU);
253};
254
255/// Compare two DbgValueLocEntries for equality.
256inline bool operator==(const DbgValueLocEntry &A, const DbgValueLocEntry &B) {
257 if (A.EntryKind != B.EntryKind)
258 return false;
259
260 switch (A.EntryKind) {
261 case DbgValueLocEntry::E_Location:
262 return A.Loc == B.Loc;
263 case DbgValueLocEntry::E_TargetIndexLocation:
264 return A.TIL == B.TIL;
265 case DbgValueLocEntry::E_Integer:
266 return A.Constant.Int == B.Constant.Int;
267 case DbgValueLocEntry::E_ConstantFP:
268 return A.Constant.CFP == B.Constant.CFP;
269 case DbgValueLocEntry::E_ConstantInt:
270 return A.Constant.CIP == B.Constant.CIP;
271 }
272 llvm_unreachable("unhandled EntryKind");
273}
274
275/// Compare two DbgValueLocs for equality.
276inline bool operator==(const DbgValueLoc &A, const DbgValueLoc &B) {
277 return A.ValueLocEntries == B.ValueLocEntries &&
278 A.Expression == B.Expression && A.IsVariadic == B.IsVariadic;
279}
280
281/// Compare two fragments based on their offset.
282inline bool operator<(const DbgValueLoc &A,
283 const DbgValueLoc &B) {
284 return A.getExpression()->getFragmentInfo()->OffsetInBits <
285 B.getExpression()->getFragmentInfo()->OffsetInBits;
286}
287
288}
289
290#endif
291