[PATCH] D84094: [DebugInfo] Fix misleading using of DWARF forms with DIELabel. NFCI.

[Igor Kudrin via Phabricator via llvm-commits]

ikudrin created this revision.
ikudrin added reviewers: dblaikie, echristo, jhenderson, aprantl, aardappel, yurydelendik.
ikudrin added projects: LLVM, debug-info.
Herald added subscribers: aheejin, hiraditya.

`DIELabel` can emit only 32- or 64-bit values, while it was created in some places with `DW_FORM_udata`, which implies emitting uleb128. Nevertheless, these places also expected to emit U32 or U64, but just used a misleading DWARF form. The patch updates those places to use more appropriate DWARF forms and restricts `DIELabel::SizeOf()` to accept only forms that are actually used in the LLVM codebase.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D84094

Files:
  llvm/lib/CodeGen/AsmPrinter/DIE.cpp
  llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
  llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp


Index: llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -353,7 +353,7 @@
   }
 
   addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);
-  addLabel(Die, dwarf::DW_FORM_udata, Sym);
+  addLabel(Die, dwarf::DW_FORM_addr, Sym);
 }
 
 void DwarfUnit::addLabelDelta(DIE &Die, dwarf::Attribute Attribute,
Index: llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -451,8 +451,8 @@
             true});
         DIELoc *Loc = new (DIEValueAllocator) DIELoc;
         addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_WASM_location);
-        addSInt(*Loc, dwarf::DW_FORM_sdata, FrameBase.Location.WasmLoc.Kind);
-        addLabel(*Loc, dwarf::DW_FORM_udata, SPSym);
+        addSInt(*Loc, dwarf::DW_FORM_sdata, TI_GLOBAL_RELOC);
+        addLabel(*Loc, dwarf::DW_FORM_data4, SPSym);
         DD->addArangeLabel(SymbolCU(this, SPSym));
         addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_stack_value);
         addBlock(*SPDie, dwarf::DW_AT_frame_base, Loc);
Index: llvm/lib/CodeGen/AsmPrinter/DIE.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/DIE.cpp
+++ llvm/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -495,19 +495,25 @@
 /// EmitValue - Emit label value.
 ///
 void DIELabel::emitValue(const AsmPrinter *AP, dwarf::Form Form) const {
-  AP->emitLabelReference(
-      Label, SizeOf(AP, Form),
-      Form == dwarf::DW_FORM_strp || Form == dwarf::DW_FORM_sec_offset ||
-          Form == dwarf::DW_FORM_ref_addr || Form == dwarf::DW_FORM_data4);
+  bool IsSectionRelative = Form != dwarf::DW_FORM_addr;
+  AP->emitLabelReference(Label, SizeOf(AP, Form), IsSectionRelative);
 }
 
 /// SizeOf - Determine size of label value in bytes.
 ///
 unsigned DIELabel::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
-  if (Form == dwarf::DW_FORM_data4) return 4;
-  if (Form == dwarf::DW_FORM_sec_offset) return 4;
-  if (Form == dwarf::DW_FORM_strp) return 4;
-  return AP->MAI->getCodePointerSize();
+  switch (Form) {
+  case dwarf::DW_FORM_data4:
+    return 4;
+  case dwarf::DW_FORM_sec_offset:
+  case dwarf::DW_FORM_strp:
+    // FIXME: add support for DWARF64
+    return 4;
+  case dwarf::DW_FORM_addr:
+    return AP->MAI->getCodePointerSize();
+  default:
+    llvm_unreachable("DIE Value form not supported yet");
+  }
 }
 
 LLVM_DUMP_METHOD


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