[DebugInfo] Introduce DW_OP_LLVM_convert

Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.

The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.

For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.

Differential Revision: https://reviews.llvm.org/D56587

llvm-svn: 356442

3 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
index 366b4df6657..6bac12f765d 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
@@ -225,6 +225,7 @@ void DWARFDebugLoclists::LocationList::dump(raw_ostream &OS, uint64_t BaseAddr,
                                             bool IsLittleEndian,
                                             unsigned AddressSize,
                                             const MCRegisterInfo *MRI,
+                                            DWARFUnit *U,
                                             unsigned Indent) const {
   for (const Entry &E : Entries) {
     switch (E.Kind) {
@@ -254,7 +255,7 @@ void DWARFDebugLoclists::LocationList::dump(raw_ostream &OS, uint64_t BaseAddr,
       llvm_unreachable("unreachable locations list kind");
     }
 
-    dumpExpression(OS, E.Loc, IsLittleEndian, AddressSize, MRI, nullptr);
+    dumpExpression(OS, E.Loc, IsLittleEndian, AddressSize, MRI, U);
   }
 }
 
@@ -263,7 +264,7 @@ void DWARFDebugLoclists::dump(raw_ostream &OS, uint64_t BaseAddr,
                               Optional<uint64_t> Offset) const {
   auto DumpLocationList = [&](const LocationList &L) {
     OS << format("0x%8.8x: ", L.Offset);
-    L.dump(OS, BaseAddr, IsLittleEndian, AddressSize, MRI, /*Indent=*/12);
+    L.dump(OS, BaseAddr, IsLittleEndian, AddressSize, MRI, nullptr, /*Indent=*/12);
     OS << "\n\n";
   };
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index 4cd69bc8017..4a837cd3526 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -130,7 +130,7 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
 
       if (LL)
         LL->dump(OS, BaseAddr, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI,
-                 Indent);
+                 U, Indent);
       else
         OS << "error extracting location list.";
     }
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp b/llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp
index 24400ff89c6..133b85a0969 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp
@@ -188,6 +188,8 @@ bool DWARFExpression::Operation::extract(DataExtractor Data, uint16_t Version,
     default:
       llvm_unreachable("Unknown DWARFExpression Op size");
     }
+
+    OperandEndOffsets[Operand] = Offset;
   }
 
   EndOffset = Offset;