[DebugInfo] DW_OP_deref_size in PrologEpilogInserter.
The PrologEpilogInserter need to insert a DW_OP_deref_size before
prepending a memory location expression to an already implicit
expression to avoid having the existing expression act on the memory
address instead of the value behind it.
The reason for using DW_OP_deref_size and not plain DW_OP_deref is that
big-endian targets need to read the right size as simply truncating a
larger read would yield the wrong result (LSB bytes are not at the lower
address).
This re-commit fixes issues reported in the first one. Namely deref was
inserted under wrong conditions and additionally the deref_size argument
was incorrectly encoded.
Differential Revision: https://reviews.llvm.org/D59687
llvm-svn: 359535
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index e31b1e5..c3dad62 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -179,6 +179,10 @@
BS.EmitULEB128(Value, Twine(Value));
}
+void DebugLocDwarfExpression::emitData1(uint8_t Value) {
+ BS.EmitInt8(Value, Twine(Value));
+}
+
void DebugLocDwarfExpression::emitBaseTypeRef(uint64_t Idx) {
assert(Idx < (1ULL << (ULEB128PadSize * 7)) && "Idx wont fit");
BS.EmitULEB128(Idx, Twine(Idx), ULEB128PadSize);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 41fa45f..1235c14 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -434,6 +434,10 @@
assert(LocationKind != Register);
emitOp(dwarf::DW_OP_xderef);
break;
+ case dwarf::DW_OP_deref_size:
+ emitOp(dwarf::DW_OP_deref_size);
+ emitData1(Op->getArg(0));
+ break;
default:
llvm_unreachable("unhandled opcode found in expression");
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
index 18bedf0..1455049 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
@@ -139,6 +139,8 @@
/// Emit a raw unsigned value.
virtual void emitUnsigned(uint64_t Value) = 0;
+ virtual void emitData1(uint8_t Value) = 0;
+
virtual void emitBaseTypeRef(uint64_t Idx) = 0;
/// Emit a normalized unsigned constant.
@@ -264,6 +266,7 @@
void emitOp(uint8_t Op, const char *Comment = nullptr) override;
void emitSigned(int64_t Value) override;
void emitUnsigned(uint64_t Value) override;
+ void emitData1(uint8_t Value) override;
void emitBaseTypeRef(uint64_t Idx) override;
bool isFrameRegister(const TargetRegisterInfo &TRI,
unsigned MachineReg) override;
@@ -281,6 +284,7 @@
void emitOp(uint8_t Op, const char *Comment = nullptr) override;
void emitSigned(int64_t Value) override;
void emitUnsigned(uint64_t Value) override;
+ void emitData1(uint8_t Value) override;
void emitBaseTypeRef(uint64_t Idx) override;
bool isFrameRegister(const TargetRegisterInfo &TRI,
unsigned MachineReg) override;
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index cace8f0..6b641ea 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -64,6 +64,10 @@
CU.addUInt(DIE, dwarf::DW_FORM_udata, Value);
}
+void DIEDwarfExpression::emitData1(uint8_t Value) {
+ CU.addUInt(DIE, dwarf::DW_FORM_data1, Value);
+}
+
void DIEDwarfExpression::emitBaseTypeRef(uint64_t Idx) {
CU.addBaseTypeRef(DIE, Idx);
}
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 971944b..d414b6a 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -1854,6 +1854,11 @@
Elements.push_back(Op);
continue;
}
+ if (unsigned Enc = dwarf::getAttributeEncoding(Token.stringValue())) {
+ lex();
+ Elements.push_back(Enc);
+ continue;
+ }
return error(Twine("invalid DWARF op '") + Token.stringValue() + "'");
}
diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index 67834c8..55925c8 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -1172,12 +1172,26 @@
assert(i == 0 && "Frame indices can only appear as the first "
"operand of a DBG_VALUE machine instruction");
unsigned Reg;
+ unsigned FrameIdx = MI.getOperand(0).getIndex();
+ unsigned Size = MF.getFrameInfo().getObjectSize(FrameIdx);
+
int64_t Offset =
- TFI->getFrameIndexReference(MF, MI.getOperand(0).getIndex(), Reg);
+ TFI->getFrameIndexReference(MF, FrameIdx, Reg);
MI.getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
MI.getOperand(0).setIsDebug();
- auto *DIExpr = DIExpression::prepend(MI.getDebugExpression(),
- DIExpression::NoDeref, Offset);
+
+ const DIExpression *DIExpr = MI.getDebugExpression();
+ // If we have DBG_VALUE that is indirect and has a Implicit location
+ // expression need to insert a deref before prepending a Memory
+ // location expression. Also after doing this we change the DBG_VALUE
+ // to be direct.
+ if (MI.isIndirectDebugValue() && DIExpr->isImplicit()) {
+ SmallVector<uint64_t, 2> Ops = {dwarf::DW_OP_deref_size, Size};
+ DIExpr = DIExpression::prependOpcodes(DIExpr, Ops, DIExpression::WithStackValue);
+ // Make the DBG_VALUE direct.
+ MI.getOperand(1).ChangeToRegister(0, false);
+ }
+ DIExpr = DIExpression::prepend(DIExpr, DIExpression::NoDeref, Offset);
MI.getOperand(3).setMetadata(DIExpr);
continue;
}
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 7158e57..4ef38b6 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -833,6 +833,7 @@
case dwarf::DW_OP_LLVM_fragment:
return 3;
case dwarf::DW_OP_constu:
+ case dwarf::DW_OP_deref_size:
case dwarf::DW_OP_plus_uconst:
return 2;
default:
@@ -889,6 +890,7 @@
case dwarf::DW_OP_shr:
case dwarf::DW_OP_shra:
case dwarf::DW_OP_deref:
+ case dwarf::DW_OP_deref_size:
case dwarf::DW_OP_xderef:
case dwarf::DW_OP_lit0:
case dwarf::DW_OP_not:
@@ -899,6 +901,19 @@
return true;
}
+bool DIExpression::isImplicit() const {
+ unsigned N = getNumElements();
+ if (isValid() && N > 0) {
+ switch (getElement(N-1)) {
+ case dwarf::DW_OP_stack_value: return true;
+ case dwarf::DW_OP_LLVM_fragment:
+ return N > 1 && getElement(N-2) == dwarf::DW_OP_stack_value;
+ default: break;
+ }
+ }
+ return false;
+}
+
Optional<DIExpression::FragmentInfo>
DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
for (auto I = Start; I != End; ++I)