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[WebAssembly] Add DBG_VALUE with local operands location in WebAssemblyExplicitLocals pass
Extends DWARF expression larguage to express locals/globals locations. (via target-index operands) The WebAssemblyExplicitLocals can replace virtual registers to target-index() operand type at the time when WebAssembly backend introduces local.{get,set,tee} instead of corresponding virtual registers. Reviewers: aprantl, dschuff Differential Revision: https://reviews.llvm.org/D52634
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15 files changed

+171
-4
lines changed

15 files changed

+171
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lines changed

‎llvm/include/llvm/BinaryFormat/Dwarf.def

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -627,6 +627,8 @@ HANDLE_DW_OP(0xa9, reinterpret, 5, DWARF)
627627
// Vendor extensions:
628628
// Extensions for GNU-style thread-local storage.
629629
HANDLE_DW_OP(0xe0, GNU_push_tls_address, 0, GNU)
630+
// Extensions for WebAssembly.
631+
HANDLE_DW_OP(0xed, WASM_location, 0, WASM)
630632
// Extensions for Fission proposal.
631633
HANDLE_DW_OP(0xfb, GNU_addr_index, 0, GNU)
632634
HANDLE_DW_OP(0xfc, GNU_const_index, 0, GNU)

‎llvm/include/llvm/BinaryFormat/Dwarf.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -59,7 +59,8 @@ enum LLVMConstants : uint32_t {
5959
DWARF_VENDOR_GNU = 3,
6060
DWARF_VENDOR_GOOGLE = 4,
6161
DWARF_VENDOR_LLVM = 5,
62-
DWARF_VENDOR_MIPS = 6
62+
DWARF_VENDOR_MIPS = 6,
63+
DWARF_VENDOR_WASM = 7
6364
};
6465

6566
/// Constants that define the DWARF format as 32 or 64 bit.

‎llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -895,6 +895,10 @@ static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
895895
OS << MI->getOperand(0).getImm();
896896
} else if (MI->getOperand(0).isCImm()) {
897897
MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
898+
} else if (MI->getOperand(0).isTargetIndex()) {
899+
auto Op = MI->getOperand(0);
900+
OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
901+
return true;
898902
} else {
899903
unsigned Reg;
900904
if (MI->getOperand(0).isReg()) {

‎llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h

Lines changed: 34 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,19 @@
2121
namespace llvm {
2222
class AsmPrinter;
2323

24+
struct 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+
2437
/// This struct describes location entries emitted in the .debug_loc
2538
/// section.
2639
class DebugLocEntry {
@@ -47,12 +60,20 @@ class DebugLocEntry {
4760
: Expression(Expr), EntryKind(E_Location), Loc(Loc) {
4861
assert(cast<DIExpression>(Expr)->isValid());
4962
}
63+
Value(const DIExpression *Expr, TargetIndexLocation Loc)
64+
: Expression(Expr), EntryKind(E_TargetIndexLocation), TIL(Loc) {}
5065

5166
/// Any complex address location expression for this Value.
5267
const DIExpression *Expression;
5368

5469
/// Type of entry that this represents.
55-
enum EntryType { E_Location, E_Integer, E_ConstantFP, E_ConstantInt };
70+
enum EntryType {
71+
E_Location,
72+
E_Integer,
73+
E_ConstantFP,
74+
E_ConstantInt,
75+
E_TargetIndexLocation
76+
};
5677
enum EntryType EntryKind;
5778

5879
/// Either a constant,
@@ -62,17 +83,25 @@ class DebugLocEntry {
6283
const ConstantInt *CIP;
6384
} Constant;
6485

65-
// Or a location in the machine frame.
66-
MachineLocation Loc;
86+
union {
87+
// Or a location in the machine frame.
88+
MachineLocation Loc;
89+
// Or a location from target specific location.
90+
TargetIndexLocation TIL;
91+
};
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6893
bool isLocation() const { return EntryKind == E_Location; }
94+
bool isTargetIndexLocation() const {
95+
return EntryKind == E_TargetIndexLocation;
96+
}
6997
bool isInt() const { return EntryKind == E_Integer; }
7098
bool isConstantFP() const { return EntryKind == E_ConstantFP; }
7199
bool isConstantInt() const { return EntryKind == E_ConstantInt; }
72100
int64_t getInt() const { return Constant.Int; }
73101
const ConstantFP *getConstantFP() const { return Constant.CFP; }
74102
const ConstantInt *getConstantInt() const { return Constant.CIP; }
75103
MachineLocation getLoc() const { return Loc; }
104+
TargetIndexLocation getTargetIndexLocation() const { return TIL; }
76105
bool isFragment() const { return getExpression()->isFragment(); }
77106
const DIExpression *getExpression() const { return Expression; }
78107
friend bool operator==(const Value &, const Value &);
@@ -165,6 +194,8 @@ inline bool operator==(const DebugLocEntry::Value &A,
165194
switch (A.EntryKind) {
166195
case DebugLocEntry::Value::E_Location:
167196
return A.Loc == B.Loc;
197+
case DebugLocEntry::Value::E_TargetIndexLocation:
198+
return A.TIL == B.TIL;
168199
case DebugLocEntry::Value::E_Integer:
169200
return A.Constant.Int == B.Constant.Int;
170201
case DebugLocEntry::Value::E_ConstantFP:

‎llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1072,6 +1072,11 @@ static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) {
10721072
MachineLocation MLoc(RegOp.getReg(), Op1.isImm());
10731073
return DebugLocEntry::Value(Expr, MLoc);
10741074
}
1075+
if (MI->getOperand(0).isTargetIndex()) {
1076+
auto Op = MI->getOperand(0);
1077+
return DebugLocEntry::Value(
1078+
Expr, TargetIndexLocation(Op.getIndex(), Op.getOffset()));
1079+
}
10751080
if (MI->getOperand(0).isImm())
10761081
return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm());
10771082
if (MI->getOperand(0).isFPImm())
@@ -1920,6 +1925,9 @@ static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
19201925
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
19211926
return;
19221927
return DwarfExpr.addExpression(std::move(Cursor));
1928+
} else if (Value.isTargetIndexLocation()) {
1929+
TargetIndexLocation Loc = Value.getTargetIndexLocation();
1930+
DwarfExpr.addTargetIndexLocation(Loc.Index, Loc.Offset);
19231931
} else if (Value.isConstantFP()) {
19241932
APInt RawBytes = Value.getConstantFP()->getValueAPF().bitcastToAPInt();
19251933
DwarfExpr.addUnsignedConstant(RawBytes);

‎llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -437,3 +437,11 @@ void DwarfExpression::addFragmentOffset(const DIExpression *Expr) {
437437
addOpPiece(FragmentOffset - OffsetInBits);
438438
OffsetInBits = FragmentOffset;
439439
}
440+
441+
void DwarfExpression::addTargetIndexLocation(unsigned Index, int64_t Offset) {
442+
assert(LocationKind == Implicit || LocationKind == Unknown);
443+
LocationKind = Implicit;
444+
emitOp(dwarf::DW_OP_WASM_location);
445+
emitUnsigned(Index);
446+
emitSigned(Offset);
447+
}

‎llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -248,6 +248,10 @@ class DwarfExpression {
248248
/// If applicable, emit an empty DW_OP_piece / DW_OP_bit_piece to advance to
249249
/// the fragment described by \c Expr.
250250
void addFragmentOffset(const DIExpression *Expr);
251+
252+
/// Emit location information expressed via target's index + offset
253+
/// It is an extension for WebAssembly locals, globals and operand stack.
254+
void addTargetIndexLocation(unsigned Index, int64_t Offset);
251255
};
252256

253257
/// DwarfExpression implementation for .debug_loc entries.

‎llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -93,6 +93,8 @@ static DescVector getDescriptions() {
9393
Descriptions[DW_OP_implicit_value] =
9494
Desc(Op::Dwarf3, Op::SizeLEB, Op::SizeBlock);
9595
Descriptions[DW_OP_stack_value] = Desc(Op::Dwarf3);
96+
Descriptions[DW_OP_WASM_location] =
97+
Desc(Op::Dwarf4, Op::SizeLEB, Op::SignedSizeLEB);
9698
Descriptions[DW_OP_GNU_push_tls_address] = Desc(Op::Dwarf3);
9799
Descriptions[DW_OP_addrx] = Desc(Op::Dwarf4, Op::SizeLEB);
98100
Descriptions[DW_OP_GNU_addr_index] = Desc(Op::Dwarf4, Op::SizeLEB);

‎llvm/lib/Target/WebAssembly/WebAssembly.h

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -82,6 +82,10 @@ void initializeWebAssemblyRegNumberingPass(PassRegistry &);
8282
void initializeWebAssemblyPeepholePass(PassRegistry &);
8383
void initializeWebAssemblyCallIndirectFixupPass(PassRegistry &);
8484

85+
namespace WebAssembly {
86+
enum TargetIndex { TI_LOCAL_START, TI_GLOBAL_START, TI_OPERAND_STACK_START };
87+
} // end namespace WebAssembly
88+
8589
} // end namespace llvm
8690

8791
#endif

‎llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.cpp

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,7 @@
1212
///
1313
//===----------------------------------------------------------------------===//
1414

15+
#include "WebAssembly.h"
1516
#include "WebAssemblyDebugValueManager.h"
1617
#include "WebAssemblyMachineFunctionInfo.h"
1718
#include "llvm/CodeGen/MachineInstr.h"
@@ -44,3 +45,10 @@ void WebAssemblyDebugValueManager::clone(MachineInstr *Insert,
4445
MBB->insert(Insert, Clone);
4546
}
4647
}
48+
49+
void WebAssemblyDebugValueManager::replaceWithLocal(unsigned LocalId) {
50+
for (auto *DBI : DbgValues) {
51+
MachineOperand &Op = DBI->getOperand(0);
52+
Op.ChangeToTargetIndex(llvm::WebAssembly::TI_LOCAL_START, LocalId);
53+
}
54+
}

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