teak-llvm/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h
Jeremy Morse 045c67769d [DebugInfo] Emit undef DBG_VALUEs when SDNodes are optimised out
This is a fix for PR39896, where dbg.value's of SDNodes that have been
optimised out do not lead to "DBG_VALUE undef" instructions being created.
Such undef instructions are necessary to terminate earlier variable
ranges, otherwise variable values leak past the point where they're valid.

The "invalidated" flag of SDDbgValue is currently being abused to mean two
things:
 * The corresponding SDNode is now invalid
 * This SDDbgValue should not be emitted
Of which there are several legitimate combinations of meaning:
 * The SDNode has been invalidated and we should emit "DBG_VALUE undef"
 * The SDNode has been invalidated but the debug data was salvaged, don't
   emit anything for this SDDbgValue
 * This SDDbgValue has been emitted

This patch introduces distinct "Emitted" and "Invalidated" fields to the
SDDbgValue class, updates users accordingly, and generates "undef"
DBG_VALUEs for invalidated records. Awkwardly, there are circumstances
where we emit SDDbgValue's twice, specifically DebugInfo/X86/dbg-addr-dse.ll
which I've preserved.

Differential Revision: https://reviews.llvm.org/D55372

llvm-svn: 348751
2018-12-10 11:20:47 +00:00

167 lines
5.2 KiB
C++

//===-- llvm/CodeGen/SDNodeDbgValue.h - SelectionDAG dbg_value --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the SDDbgValue class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_SELECTIONDAG_SDNODEDBGVALUE_H
#define LLVM_LIB_CODEGEN_SELECTIONDAG_SDNODEDBGVALUE_H
#include "llvm/IR/DebugLoc.h"
#include "llvm/Support/DataTypes.h"
#include <utility>
namespace llvm {
class DIVariable;
class DIExpression;
class SDNode;
class Value;
class raw_ostream;
/// Holds the information from a dbg_value node through SDISel.
/// We do not use SDValue here to avoid including its header.
class SDDbgValue {
public:
enum DbgValueKind {
SDNODE = 0, ///< Value is the result of an expression.
CONST = 1, ///< Value is a constant.
FRAMEIX = 2, ///< Value is contents of a stack location.
VREG = 3 ///< Value is a virtual register.
};
private:
union {
struct {
SDNode *Node; ///< Valid for expressions.
unsigned ResNo; ///< Valid for expressions.
} s;
const Value *Const; ///< Valid for constants.
unsigned FrameIx; ///< Valid for stack objects.
unsigned VReg; ///< Valid for registers.
} u;
DIVariable *Var;
DIExpression *Expr;
DebugLoc DL;
unsigned Order;
enum DbgValueKind kind;
bool IsIndirect;
bool Invalid = false;
bool Emitted = false;
public:
/// Constructor for non-constants.
SDDbgValue(DIVariable *Var, DIExpression *Expr, SDNode *N, unsigned R,
bool indir, DebugLoc dl, unsigned O)
: Var(Var), Expr(Expr), DL(std::move(dl)), Order(O), IsIndirect(indir) {
kind = SDNODE;
u.s.Node = N;
u.s.ResNo = R;
}
/// Constructor for constants.
SDDbgValue(DIVariable *Var, DIExpression *Expr, const Value *C, DebugLoc dl,
unsigned O)
: Var(Var), Expr(Expr), DL(std::move(dl)), Order(O), IsIndirect(false) {
kind = CONST;
u.Const = C;
}
/// Constructor for virtual registers and frame indices.
SDDbgValue(DIVariable *Var, DIExpression *Expr, unsigned VRegOrFrameIdx,
bool IsIndirect, DebugLoc DL, unsigned Order,
enum DbgValueKind Kind)
: Var(Var), Expr(Expr), DL(DL), Order(Order), IsIndirect(IsIndirect) {
assert((Kind == VREG || Kind == FRAMEIX) &&
"Invalid SDDbgValue constructor");
kind = Kind;
if (kind == VREG)
u.VReg = VRegOrFrameIdx;
else
u.FrameIx = VRegOrFrameIdx;
}
/// Returns the kind.
DbgValueKind getKind() const { return kind; }
/// Returns the DIVariable pointer for the variable.
DIVariable *getVariable() const { return Var; }
/// Returns the DIExpression pointer for the expression.
DIExpression *getExpression() const { return Expr; }
/// Returns the SDNode* for a register ref
SDNode *getSDNode() const { assert (kind==SDNODE); return u.s.Node; }
/// Returns the ResNo for a register ref
unsigned getResNo() const { assert (kind==SDNODE); return u.s.ResNo; }
/// Returns the Value* for a constant
const Value *getConst() const { assert (kind==CONST); return u.Const; }
/// Returns the FrameIx for a stack object
unsigned getFrameIx() const { assert (kind==FRAMEIX); return u.FrameIx; }
/// Returns the Virtual Register for a VReg
unsigned getVReg() const { assert (kind==VREG); return u.VReg; }
/// Returns whether this is an indirect value.
bool isIndirect() const { return IsIndirect; }
/// Returns the DebugLoc.
DebugLoc getDebugLoc() const { return DL; }
/// Returns the SDNodeOrder. This is the order of the preceding node in the
/// input.
unsigned getOrder() const { return Order; }
/// setIsInvalidated / isInvalidated - Setter / getter of the "Invalidated"
/// property. A SDDbgValue is invalid if the SDNode that produces the value is
/// deleted.
void setIsInvalidated() { Invalid = true; }
bool isInvalidated() const { return Invalid; }
/// setIsEmitted / isEmitted - Getter/Setter for flag indicating that this
/// SDDbgValue has been emitted to an MBB.
void setIsEmitted() { Emitted = true; }
bool isEmitted() const { return Emitted; }
/// clearIsEmitted - Reset Emitted flag, for certain special cases where
/// dbg.addr is emitted twice.
void clearIsEmitted() { Emitted = false; }
LLVM_DUMP_METHOD void dump(raw_ostream &OS) const;
};
/// Holds the information from a dbg_label node through SDISel.
/// We do not use SDValue here to avoid including its header.
class SDDbgLabel {
MDNode *Label;
DebugLoc DL;
unsigned Order;
public:
SDDbgLabel(MDNode *Label, DebugLoc dl, unsigned O)
: Label(Label), DL(std::move(dl)), Order(O) {}
/// Returns the MDNode pointer for the label.
MDNode *getLabel() const { return Label; }
/// Returns the DebugLoc.
DebugLoc getDebugLoc() const { return DL; }
/// Returns the SDNodeOrder. This is the order of the preceding node in the
/// input.
unsigned getOrder() const { return Order; }
};
} // end llvm namespace
#endif