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llvm-mirror/lib/CodeGen/AsmPrinter/DebugLocEntry.h
Stephen Tozer 782c047ef4 Partial Reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands"
This is a partial reapply of the original commit and the followup commit
that were previously reverted; this reapply also includes a small fix
for a potential source of non-determinism, but also has a small change
to turn off variadic debug value salvaging, to ensure that any future
revert/reapply steps to disable and renable this feature do not risk
causing conflicts.

Differential Revision: https://reviews.llvm.org/D91722

This reverts commit 386b66b2fc297cda121a3cc8a36887a6ecbcfc68.
2021-06-24 09:46:38 +01:00

268 lines
8.9 KiB
C++

//===-- llvm/CodeGen/DebugLocEntry.h - Entry in debug_loc list -*- C++ -*--===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
#include "DebugLocStream.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/Debug.h"
namespace llvm {
class AsmPrinter;
/// This struct describes target specific location.
struct TargetIndexLocation {
int Index;
int Offset;
TargetIndexLocation() = default;
TargetIndexLocation(unsigned Idx, int64_t Offset)
: Index(Idx), Offset(Offset) {}
bool operator==(const TargetIndexLocation &Other) const {
return Index == Other.Index && Offset == Other.Offset;
}
};
/// A single location or constant within a variable location description, with
/// either a single entry (with an optional DIExpression) used for a DBG_VALUE,
/// or a list of entries used for a DBG_VALUE_LIST.
class DbgValueLocEntry {
/// Type of entry that this represents.
enum EntryType {
E_Location,
E_Integer,
E_ConstantFP,
E_ConstantInt,
E_TargetIndexLocation
};
enum EntryType EntryKind;
/// Either a constant,
union {
int64_t Int;
const ConstantFP *CFP;
const ConstantInt *CIP;
} Constant;
union {
/// Or a location in the machine frame.
MachineLocation Loc;
/// Or a location from target specific location.
TargetIndexLocation TIL;
};
public:
DbgValueLocEntry(int64_t i) : EntryKind(E_Integer) { Constant.Int = i; }
DbgValueLocEntry(const ConstantFP *CFP) : EntryKind(E_ConstantFP) {
Constant.CFP = CFP;
}
DbgValueLocEntry(const ConstantInt *CIP) : EntryKind(E_ConstantInt) {
Constant.CIP = CIP;
}
DbgValueLocEntry(MachineLocation Loc) : EntryKind(E_Location), Loc(Loc) {}
DbgValueLocEntry(TargetIndexLocation Loc)
: EntryKind(E_TargetIndexLocation), TIL(Loc) {}
bool isLocation() const { return EntryKind == E_Location; }
bool isTargetIndexLocation() const {
return EntryKind == E_TargetIndexLocation;
}
bool isInt() const { return EntryKind == E_Integer; }
bool isConstantFP() const { return EntryKind == E_ConstantFP; }
bool isConstantInt() const { return EntryKind == E_ConstantInt; }
int64_t getInt() const { return Constant.Int; }
const ConstantFP *getConstantFP() const { return Constant.CFP; }
const ConstantInt *getConstantInt() const { return Constant.CIP; }
MachineLocation getLoc() const { return Loc; }
TargetIndexLocation getTargetIndexLocation() const { return TIL; }
friend bool operator==(const DbgValueLocEntry &, const DbgValueLocEntry &);
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void dump() const {
if (isLocation()) {
llvm::dbgs() << "Loc = { reg=" << Loc.getReg() << " ";
if (Loc.isIndirect())
llvm::dbgs() << "+0";
llvm::dbgs() << "} ";
} else if (isConstantInt())
Constant.CIP->dump();
else if (isConstantFP())
Constant.CFP->dump();
}
#endif
};
/// The location of a single variable, composed of an expression and 0 or more
/// DbgValueLocEntries.
class DbgValueLoc {
/// Any complex address location expression for this DbgValueLoc.
const DIExpression *Expression;
SmallVector<DbgValueLocEntry, 2> ValueLocEntries;
bool IsVariadic;
public:
DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs)
: Expression(Expr), ValueLocEntries(Locs.begin(), Locs.end()),
IsVariadic(true) {
#ifndef NDEBUG
// Currently, DBG_VALUE_VAR expressions must use stack_value.
assert(Expr && Expr->isValid() &&
is_contained(Locs, dwarf::DW_OP_stack_value));
#endif
}
DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs,
bool IsVariadic)
: Expression(Expr), ValueLocEntries(Locs.begin(), Locs.end()),
IsVariadic(IsVariadic) {
#ifndef NDEBUG
assert(cast<DIExpression>(Expr)->isValid() ||
!any_of(Locs, [](auto LE) { return LE.isLocation(); }));
if (!IsVariadic) {
assert(ValueLocEntries.size() == 1);
} else {
// Currently, DBG_VALUE_VAR expressions must use stack_value.
assert(Expr && Expr->isValid() &&
is_contained(Expr->getElements(), dwarf::DW_OP_stack_value));
}
#endif
}
DbgValueLoc(const DIExpression *Expr, DbgValueLocEntry Loc)
: Expression(Expr), ValueLocEntries(1, Loc), IsVariadic(false) {
assert(((Expr && Expr->isValid()) || !Loc.isLocation()) &&
"DBG_VALUE with a machine location must have a valid expression.");
}
bool isFragment() const { return getExpression()->isFragment(); }
bool isEntryVal() const { return getExpression()->isEntryValue(); }
bool isVariadic() const { return IsVariadic; }
const DIExpression *getExpression() const { return Expression; }
const ArrayRef<DbgValueLocEntry> getLocEntries() const {
return ValueLocEntries;
}
friend bool operator==(const DbgValueLoc &, const DbgValueLoc &);
friend bool operator<(const DbgValueLoc &, const DbgValueLoc &);
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void dump() const {
for (DbgValueLocEntry DV : ValueLocEntries)
DV.dump();
if (Expression)
Expression->dump();
}
#endif
};
/// This struct describes location entries emitted in the .debug_loc
/// section.
class DebugLocEntry {
/// Begin and end symbols for the address range that this location is valid.
const MCSymbol *Begin;
const MCSymbol *End;
/// A nonempty list of locations/constants belonging to this entry,
/// sorted by offset.
SmallVector<DbgValueLoc, 1> Values;
public:
/// Create a location list entry for the range [\p Begin, \p End).
///
/// \param Vals One or more values describing (parts of) the variable.
DebugLocEntry(const MCSymbol *Begin, const MCSymbol *End,
ArrayRef<DbgValueLoc> Vals)
: Begin(Begin), End(End) {
addValues(Vals);
}
/// Attempt to merge this DebugLocEntry with Next and return
/// true if the merge was successful. Entries can be merged if they
/// share the same Loc/Constant and if Next immediately follows this
/// Entry.
bool MergeRanges(const DebugLocEntry &Next) {
// If this and Next are describing the same variable, merge them.
if ((End == Next.Begin && Values == Next.Values)) {
End = Next.End;
return true;
}
return false;
}
const MCSymbol *getBeginSym() const { return Begin; }
const MCSymbol *getEndSym() const { return End; }
ArrayRef<DbgValueLoc> getValues() const { return Values; }
void addValues(ArrayRef<DbgValueLoc> Vals) {
Values.append(Vals.begin(), Vals.end());
sortUniqueValues();
assert((Values.size() == 1 || all_of(Values, [](DbgValueLoc V) {
return V.isFragment();
})) && "must either have a single value or multiple pieces");
}
// Sort the pieces by offset.
// Remove any duplicate entries by dropping all but the first.
void sortUniqueValues() {
llvm::sort(Values);
Values.erase(std::unique(Values.begin(), Values.end(),
[](const DbgValueLoc &A, const DbgValueLoc &B) {
return A.getExpression() == B.getExpression();
}),
Values.end());
}
/// Lower this entry into a DWARF expression.
void finalize(const AsmPrinter &AP,
DebugLocStream::ListBuilder &List,
const DIBasicType *BT,
DwarfCompileUnit &TheCU);
};
/// Compare two DbgValueLocEntries for equality.
inline bool operator==(const DbgValueLocEntry &A, const DbgValueLocEntry &B) {
if (A.EntryKind != B.EntryKind)
return false;
switch (A.EntryKind) {
case DbgValueLocEntry::E_Location:
return A.Loc == B.Loc;
case DbgValueLocEntry::E_TargetIndexLocation:
return A.TIL == B.TIL;
case DbgValueLocEntry::E_Integer:
return A.Constant.Int == B.Constant.Int;
case DbgValueLocEntry::E_ConstantFP:
return A.Constant.CFP == B.Constant.CFP;
case DbgValueLocEntry::E_ConstantInt:
return A.Constant.CIP == B.Constant.CIP;
}
llvm_unreachable("unhandled EntryKind");
}
/// Compare two DbgValueLocs for equality.
inline bool operator==(const DbgValueLoc &A, const DbgValueLoc &B) {
return A.ValueLocEntries == B.ValueLocEntries &&
A.Expression == B.Expression && A.IsVariadic == B.IsVariadic;
}
/// Compare two fragments based on their offset.
inline bool operator<(const DbgValueLoc &A,
const DbgValueLoc &B) {
return A.getExpression()->getFragmentInfo()->OffsetInBits <
B.getExpression()->getFragmentInfo()->OffsetInBits;
}
}
#endif