llvm-mirror/lib/CodeGen/AsmPrinter/DebugLocEntry.h
Adrian Prantl 0ff6a1fc33 Remove unreachable code. (NFC)
MachineLocation::getOffset() always returns 0.

rdar://problem/33580047

llvm-svn: 309823
2017-08-02 15:22:17 +00:00

187 lines
6.1 KiB
C++

//===-- llvm/CodeGen/DebugLocEntry.h - Entry in debug_loc list -*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
#include "DebugLocStream.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;
/// \brief 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;
public:
/// \brief A single location or constant.
struct Value {
Value(const DIExpression *Expr, int64_t i)
: Expression(Expr), EntryKind(E_Integer) {
Constant.Int = i;
}
Value(const DIExpression *Expr, const ConstantFP *CFP)
: Expression(Expr), EntryKind(E_ConstantFP) {
Constant.CFP = CFP;
}
Value(const DIExpression *Expr, const ConstantInt *CIP)
: Expression(Expr), EntryKind(E_ConstantInt) {
Constant.CIP = CIP;
}
Value(const DIExpression *Expr, MachineLocation Loc)
: Expression(Expr), EntryKind(E_Location), Loc(Loc) {
assert(cast<DIExpression>(Expr)->isValid());
}
/// Any complex address location expression for this Value.
const DIExpression *Expression;
/// Type of entry that this represents.
enum EntryType { E_Location, E_Integer, E_ConstantFP, E_ConstantInt };
enum EntryType EntryKind;
/// Either a constant,
union {
int64_t Int;
const ConstantFP *CFP;
const ConstantInt *CIP;
} Constant;
// Or a location in the machine frame.
MachineLocation Loc;
bool isLocation() const { return EntryKind == E_Location; }
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; }
bool isFragment() const { return getExpression()->isFragment(); }
const DIExpression *getExpression() const { return Expression; }
friend bool operator==(const Value &, const Value &);
friend bool operator<(const Value &, const Value &);
#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();
if (Expression)
Expression->dump();
}
#endif
};
private:
/// A nonempty list of locations/constants belonging to this entry,
/// sorted by offset.
SmallVector<Value, 1> Values;
public:
DebugLocEntry(const MCSymbol *B, const MCSymbol *E, Value Val)
: Begin(B), End(E) {
Values.push_back(std::move(Val));
}
/// \brief If this and Next are describing different pieces of the same
/// variable, merge them by appending Next's values to the current
/// list of values.
/// Return true if the merge was successful.
bool MergeValues(const DebugLocEntry &Next);
/// \brief 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<Value> getValues() const { return Values; }
void addValues(ArrayRef<DebugLocEntry::Value> Vals) {
Values.append(Vals.begin(), Vals.end());
sortUniqueValues();
assert(all_of(Values, [](DebugLocEntry::Value V) {
return V.isFragment();
}) && "value must be a piece");
}
// \brief Sort the pieces by offset.
// Remove any duplicate entries by dropping all but the first.
void sortUniqueValues() {
std::sort(Values.begin(), Values.end());
Values.erase(
std::unique(
Values.begin(), Values.end(), [](const Value &A, const Value &B) {
return A.getExpression() == B.getExpression();
}),
Values.end());
}
/// \brief Lower this entry into a DWARF expression.
void finalize(const AsmPrinter &AP, DebugLocStream::ListBuilder &List,
const DIBasicType *BT);
};
/// \brief Compare two Values for equality.
inline bool operator==(const DebugLocEntry::Value &A,
const DebugLocEntry::Value &B) {
if (A.EntryKind != B.EntryKind)
return false;
if (A.Expression != B.Expression)
return false;
switch (A.EntryKind) {
case DebugLocEntry::Value::E_Location:
return A.Loc == B.Loc;
case DebugLocEntry::Value::E_Integer:
return A.Constant.Int == B.Constant.Int;
case DebugLocEntry::Value::E_ConstantFP:
return A.Constant.CFP == B.Constant.CFP;
case DebugLocEntry::Value::E_ConstantInt:
return A.Constant.CIP == B.Constant.CIP;
}
llvm_unreachable("unhandled EntryKind");
}
/// Compare two fragments based on their offset.
inline bool operator<(const DebugLocEntry::Value &A,
const DebugLocEntry::Value &B) {
return A.getExpression()->getFragmentInfo()->OffsetInBits <
B.getExpression()->getFragmentInfo()->OffsetInBits;
}
}
#endif