[Lldb-commits] [lldb] [LLDB][DWARF] Add an option to silence unsupported DW_FORM warnings (PR #106609)

[Walter Erquinigo via lldb-commits]

https://github.com/walter-erquinigo created https://github.com/llvm/llvm-project/pull/106609

My build of LLDB is all the time loading targets with a version of libc++ that was built with gcc that uses the DW_FORM 0x1e that is not implemented by LLVM, and I doubt it'll ever implement it. It's used for some 128 bit encoding of numbers, which is just very weird. Because of this, LLDB is showing some warnings all the time for my users, so I'm adding a flag to control the enablement of this warning.

>From 6e0b743f9f6b676b6f2237fa8b5d680d10525e0d Mon Sep 17 00:00:00 2001
From: Walter Erquinigo <walter at modular.com>
Date: Thu, 29 Aug 2024 18:41:01 +0000
Subject: [PATCH] [LLDB][DWARF] Add an option to silence unsupported DW_FORM
 warnings

My build of LLDB is all the time loading targets with a version of
libc++ that was built with gcc that uses the DW_FORM 0x1e that is not
implemented by LLVM, and I doubt it'll ever implement it. It's used for
some 128 bit encoding of numbers, which is just very weird.
Because of this, LLDB is showing some warnings all the time for my
users, so I'm adding a flag to control the enablement of this warning.
---
 .../SymbolFile/DWARF/SymbolFileDWARF.cpp      | 30 ++++++++++++-------
 .../DWARF/SymbolFileDWARFProperties.td        |  4 +++
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 7e0cf36d0de1b8..cb2625a2928701 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -87,7 +87,7 @@
 #include <cctype>
 #include <cstring>
 
-//#define ENABLE_DEBUG_PRINTF // COMMENT OUT THIS LINE PRIOR TO CHECKIN
+// #define ENABLE_DEBUG_PRINTF // COMMENT OUT THIS LINE PRIOR TO CHECKIN
 
 #ifdef ENABLE_DEBUG_PRINTF
 #include <cstdio>
@@ -129,6 +129,11 @@ class PluginProperties : public Properties {
   bool IgnoreFileIndexes() const {
     return GetPropertyAtIndexAs<bool>(ePropertyIgnoreIndexes, false);
   }
+
+  bool EmitUnsupportedDWFormValueWarning() const {
+    return GetPropertyAtIndexAs<bool>(
+        ePropertyEmitUnsupportedDWFormValueWarning, true);
+  }
 };
 
 } // namespace
@@ -624,12 +629,14 @@ uint32_t SymbolFileDWARF::CalculateAbilities() {
       llvm::DWARFDebugAbbrev *abbrev = DebugAbbrev();
       std::set<dw_form_t> unsupported_forms = GetUnsupportedForms(abbrev);
       if (!unsupported_forms.empty()) {
-        StreamString error;
-        error.Printf("unsupported DW_FORM value%s:",
-                     unsupported_forms.size() > 1 ? "s" : "");
-        for (auto form : unsupported_forms)
-          error.Printf(" %#x", form);
-        m_objfile_sp->GetModule()->ReportWarning("{0}", error.GetString());
+        if (GetGlobalPluginProperties().EmitUnsupportedDWFormValueWarning()) {
+          StreamString error;
+          error.Printf("unsupported DW_FORM value%s:",
+                       unsupported_forms.size() > 1 ? "s" : "");
+          for (auto form : unsupported_forms)
+            error.Printf(" %#x", form);
+          m_objfile_sp->GetModule()->ReportWarning("{0}", error.GetString());
+        }
         return 0;
       }
 
@@ -1770,16 +1777,17 @@ SymbolFileDWARF *SymbolFileDWARF::GetDIERefSymbolFile(const DIERef &die_ref) {
     return this;
 
   if (file_index) {
-      // We have a SymbolFileDWARFDebugMap, so let it find the right file
+    // We have a SymbolFileDWARFDebugMap, so let it find the right file
     if (SymbolFileDWARFDebugMap *debug_map = GetDebugMapSymfile())
       return debug_map->GetSymbolFileByOSOIndex(*file_index);
-    
+
     // Handle the .dwp file case correctly
     if (*file_index == DIERef::k_file_index_mask)
       return GetDwpSymbolFile().get(); // DWP case
 
     // Handle the .dwo file case correctly
-    return DebugInfo().GetUnitAtIndex(*die_ref.file_index())
+    return DebugInfo()
+        .GetUnitAtIndex(*die_ref.file_index())
         ->GetDwoSymbolFile(); // DWO case
   }
   return this;
@@ -3594,7 +3602,7 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
     lldb::addr_t location_DW_OP_addr = LLDB_INVALID_ADDRESS;
     if (!location_is_const_value_data) {
       bool op_error = false;
-      const DWARFExpression* location = location_list.GetAlwaysValidExpr();
+      const DWARFExpression *location = location_list.GetAlwaysValidExpr();
       if (location)
         location_DW_OP_addr =
             location->GetLocation_DW_OP_addr(location_form.GetUnit(), op_error);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFProperties.td b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFProperties.td
index 2f1ce88808b763..0f980a514b6720 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFProperties.td
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFProperties.td
@@ -5,4 +5,8 @@ let Definition = "symbolfiledwarf" in {
     Global,
     DefaultFalse,
     Desc<"Ignore indexes present in the object files and always index DWARF manually.">;
+  def EmitUnsupportedDWFormValueWarning: Property<"emit-unsupported-dwform-value", "Boolean">,
+    Global,
+    DefaultTrue,
+    Desc<"Emit warnings about unsupported DW_Form values.">;
 }