[llvm] r225851 - Debug Info: Move the complex expression handling (=the remainder) of
Adrian Prantl
aprantl at apple.com
Tue Jan 13 15:39:11 PST 2015
Author: adrian
Date: Tue Jan 13 17:39:11 2015
New Revision: 225851
URL: http://llvm.org/viewvc/llvm-project?rev=225851&view=rev
Log:
Debug Info: Move the complex expression handling (=the remainder) of
emitDebugLocValue() into DwarfExpression.
Ought to be NFC, but it actually uncovered a bug in the debug-loc-asan.ll
testcase. The testcase checks that the address of variable "y" is stored
at [RSP+16], which also lines up with the comment.
It also check(ed) that the *value* of "y" is stored in RDI before that,
but that is actually incorrect, since RDI is the very value that is
stored in [RSP+16]. Here's the assembler output:
movb 2147450880(%rcx), %r8b
#DEBUG_VALUE: bar:y <- RDI
cmpb $0, %r8b
movq %rax, 32(%rsp) # 8-byte Spill
movq %rsi, 24(%rsp) # 8-byte Spill
movq %rdi, 16(%rsp) # 8-byte Spill
.Ltmp3:
#DEBUG_VALUE: bar:y <- [RSP+16]
Fixed the comment to spell out the correct register and the check to
expect an address rather than a value.
Note that the range that is emitted for the RDI location was and is still
wrong, it claims to begin at the function prologue, but really it should
start where RDI is first assigned.
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h
llvm/trunk/test/DebugInfo/X86/debug-loc-asan.ll
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=225851&r1=225850&r2=225851&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Jan 13 17:39:11 2015
@@ -1691,14 +1691,8 @@ void DwarfDebug::emitLocPieces(ByteStrea
assert(PieceSize*SizeOfByte != VarSize
&& "piece covers entire variable");
#endif
- if (Piece.isLocation() && Piece.getLoc().isReg())
- Asm->EmitDwarfRegOpPiece(Streamer,
- Piece.getLoc(),
- PieceSize*SizeOfByte);
- else {
- emitDebugLocValue(Streamer, Piece);
- Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
- }
+
+ emitDebugLocValue(Streamer, Piece, PieceOffset*SizeOfByte);
}
}
@@ -1715,60 +1709,35 @@ void DwarfDebug::emitDebugLocEntry(ByteS
}
void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
- const DebugLocEntry::Value &Value) {
+ const DebugLocEntry::Value &Value,
+ unsigned PieceOffsetInBits) {
DIVariable DV = Value.getVariable();
- DebugLocDwarfExpression Expr(*Asm, Streamer);
+ DebugLocDwarfExpression DwarfExpr(*Asm, Streamer);
+
// Regular entry.
if (Value.isInt()) {
DIBasicType BTy(resolve(DV.getType()));
if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
BTy.getEncoding() == dwarf::DW_ATE_signed_char))
- Expr.AddSignedConstant(Value.getInt());
+ DwarfExpr.AddSignedConstant(Value.getInt());
else
- Expr.AddUnsignedConstant(Value.getInt());
+ DwarfExpr.AddUnsignedConstant(Value.getInt());
} else if (Value.isLocation()) {
MachineLocation Loc = Value.getLoc();
DIExpression Expr = Value.getExpression();
- if (!Expr)
+ if (!Expr || (Expr.getNumElements() == 0))
// Regular entry.
Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
else {
// Complex address entry.
- unsigned N = Expr.getNumElements();
- unsigned i = 0;
- if (N >= 2 && Expr.getElement(0) == dwarf::DW_OP_plus) {
- if (Loc.getOffset()) {
- i = 2;
- Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
- Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
- Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
- Streamer.EmitSLEB128(Expr.getElement(1));
- } else {
- // If first address element is OpPlus then emit
- // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
- MachineLocation TLoc(Loc.getReg(), Expr.getElement(1));
- Asm->EmitDwarfRegOp(Streamer, TLoc, DV.isIndirect());
- i = 2;
- }
- } else {
- Asm->EmitDwarfRegOp(Streamer, Loc, DV.isIndirect());
- }
-
- // Emit remaining complex address elements.
- for (; i < N; ++i) {
- uint64_t Element = Expr.getElement(i);
- if (Element == dwarf::DW_OP_plus) {
- Streamer.EmitInt8(dwarf::DW_OP_plus_uconst, "DW_OP_plus_uconst");
- Streamer.EmitULEB128(Expr.getElement(++i));
- } else if (Element == dwarf::DW_OP_deref) {
- if (!Loc.isReg())
- Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
- } else if (Element == dwarf::DW_OP_piece) {
- i += 3;
- // handled in emitDebugLocEntry.
- } else
- llvm_unreachable("unknown Opcode found in complex address");
- }
+ if (Loc.getOffset()) {
+ DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset());
+ DwarfExpr.AddExpression(Expr, PieceOffsetInBits);
+ } else
+ DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(),
+ PieceOffsetInBits);
+ if (DV.isIndirect())
+ DwarfExpr.EmitOp(dwarf::DW_OP_deref);
}
}
// else ... ignore constant fp. There is not any good way to
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=225851&r1=225850&r2=225851&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Tue Jan 13 17:39:11 2015
@@ -565,7 +565,8 @@ public:
void emitDebugLocEntry(ByteStreamer &Streamer, const DebugLocEntry &Entry);
/// \brief emit a single value for the debug loc section.
void emitDebugLocValue(ByteStreamer &Streamer,
- const DebugLocEntry::Value &Value);
+ const DebugLocEntry::Value &Value,
+ unsigned PieceOffsetInBits = 0);
/// Emits an optimal (=sorted) sequence of DW_OP_pieces.
void emitLocPieces(ByteStreamer &Streamer,
const DITypeIdentifierMap &Map,
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=225851&r1=225850&r2=225851&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Tue Jan 13 17:39:11 2015
@@ -191,3 +191,67 @@ void DwarfExpression::AddUnsignedConstan
if (getDwarfVersion() >= 4)
EmitOp(dwarf::DW_OP_stack_value);
}
+
+static unsigned getOffsetOrZero(unsigned OffsetInBits,
+ unsigned PieceOffsetInBits) {
+ if (OffsetInBits == PieceOffsetInBits)
+ return 0;
+ assert(OffsetInBits >= PieceOffsetInBits && "overlapping pieces");
+ return OffsetInBits;
+}
+
+void DwarfExpression::AddMachineRegExpression(DIExpression Expr,
+ unsigned MachineReg,
+ unsigned PieceOffsetInBits) {
+ unsigned N = Expr.getNumElements();
+ unsigned I = 0;
+ // Pattern-match combinations for which more efficient representations exist
+ // first.
+ if (N >= 3 && Expr.getElement(0) == dwarf::DW_OP_piece) {
+ unsigned SizeOfByte = 8;
+ unsigned OffsetInBits = Expr.getElement(1) * SizeOfByte;
+ unsigned SizeInBits = Expr.getElement(2) * SizeOfByte;
+ AddMachineRegPiece(MachineReg, SizeInBits,
+ getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
+ I = 3;
+ } else if (N >= 3 && Expr.getElement(0) == dwarf::DW_OP_plus &&
+ Expr.getElement(2) == dwarf::DW_OP_deref) {
+ // [DW_OP_reg,Offset,DW_OP_plus,DW_OP_deref] --> [DW_OP_breg,Offset].
+ unsigned Offset = Expr.getElement(1);
+ AddMachineRegIndirect(MachineReg, Offset);
+ I = 3;
+ } else if (N >= 1 && Expr.getElement(0) == dwarf::DW_OP_deref) {
+ // [DW_OP_reg,DW_OP_deref] --> [DW_OP_breg].
+ AddMachineRegIndirect(MachineReg);
+ I = 1;
+ } else
+ AddMachineRegPiece(MachineReg);
+
+ // Emit remaining elements of the expression.
+ AddExpression(Expr, I);
+}
+
+void DwarfExpression::AddExpression(DIExpression Expr, unsigned I,
+ unsigned PieceOffsetInBits) {
+ unsigned N = Expr.getNumElements();
+ for (; I < N; ++I) {
+ switch (Expr.getElement(I)) {
+ case dwarf::DW_OP_piece: {
+ unsigned SizeOfByte = 8;
+ unsigned OffsetInBits = Expr.getElement(++I) * SizeOfByte;
+ unsigned SizeInBits = Expr.getElement(++I) * SizeOfByte;
+ AddOpPiece(SizeInBits, getOffsetOrZero(OffsetInBits, PieceOffsetInBits));
+ break;
+ }
+ case dwarf::DW_OP_plus:
+ EmitOp(dwarf::DW_OP_plus_uconst);
+ EmitUnsigned(Expr.getElement(++I));
+ break;
+ case dwarf::DW_OP_deref:
+ EmitOp(dwarf::DW_OP_deref);
+ break;
+ default:
+ llvm_unreachable("unhandled opcode found in DIExpression");
+ }
+ }
+}
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h?rev=225851&r1=225850&r2=225851&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.h Tue Jan 13 17:39:11 2015
@@ -15,6 +15,7 @@
#define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFEXPRESSION_H
#include "llvm/Support/DataTypes.h"
+#include "llvm/IR/DebugInfo.h"
namespace llvm {
@@ -81,8 +82,18 @@ public:
void AddSignedConstant(int Value);
/// Emit an unsigned constant.
void AddUnsignedConstant(unsigned Value);
-};
+ /// Emit an entire DIExpression on top of a machine register location.
+ /// \param PieceOffsetInBits If this is one piece out of a fragmented
+ /// location, this is the offset of the piece inside the entire variable.
+ void AddMachineRegExpression(DIExpression Expr, unsigned MachineReg,
+ unsigned PieceOffsetInBits = 0);
+ /// Emit a the operations in a DIExpression, starting from element I.
+ /// \param PieceOffsetInBits If this is one piece out of a fragmented
+ /// location, this is the offset of the piece inside the entire variable.
+ void AddExpression(DIExpression Expr, unsigned PieceOffsetInBits = 0,
+ unsigned I = 0);
+};
/// DwarfExpression implementation for .debug_loc entries.
class DebugLocDwarfExpression : public DwarfExpression {
Modified: llvm/trunk/test/DebugInfo/X86/debug-loc-asan.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/debug-loc-asan.ll?rev=225851&r1=225850&r2=225851&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/debug-loc-asan.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/debug-loc-asan.ll Tue Jan 13 17:39:11 2015
@@ -21,10 +21,10 @@
; CHECK: .Ldebug_loc{{[0-9]+}}:
; We expect two location ranges for the variable.
-; First, it is stored in %rdx:
+; First, its address is stored in %rdi:
; CHECK: .quad .Lfunc_begin0-.Lfunc_begin0
; CHECK-NEXT: .quad [[START_LABEL]]-.Lfunc_begin0
-; CHECK: DW_OP_reg5
+; CHECK: DW_OP_breg5
; Then it's addressed via %rsp:
; CHECK: .quad [[START_LABEL]]-.Lfunc_begin0
More information about the llvm-commits
mailing list