diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAbbreviationDeclaration.cpp
@@ -58,7 +58,7 @@
     DWARFFormValue::ValueType val;
 
     if (form == DW_FORM_implicit_const)
-      val.value.sval = data.GetULEB128(offset_ptr);
+      val.value.sval = data.GetSLEB128(offset_ptr);
 
     m_attributes.push_back(DWARFAttribute(attr, form, val));
   }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.h
@@ -24,6 +24,7 @@
 
   dw_attr_t get_attr() const { return m_attr; }
   dw_form_t get_form() const { return m_form; }
+  DWARFFormValue::ValueType get_value() const { return m_value; }
   void get(dw_attr_t &attr, dw_form_t &form,
            DWARFFormValue::ValueType &val) const {
     attr = m_attr;
@@ -45,8 +46,8 @@
   DWARFAttributes();
   ~DWARFAttributes();
 
-  void Append(DWARFUnit *cu, dw_offset_t attr_die_offset, dw_attr_t attr,
-              dw_form_t form);
+  void Append(const DWARFFormValue &form_value, dw_offset_t attr_die_offset,
+              dw_attr_t attr);
   DWARFUnit *CompileUnitAtIndex(uint32_t i) const { return m_infos[i].cu; }
   dw_offset_t DIEOffsetAtIndex(uint32_t i) const {
     return m_infos[i].die_offset;
@@ -55,6 +56,9 @@
     return m_infos[i].attr.get_attr();
   }
   dw_attr_t FormAtIndex(uint32_t i) const { return m_infos[i].attr.get_form(); }
+  DWARFFormValue::ValueType ValueAtIndex(uint32_t i) const {
+    return m_infos[i].attr.get_value();
+  }
   bool ExtractFormValueAtIndex(uint32_t i, DWARFFormValue &form_value) const;
   DWARFDIE FormValueAsReferenceAtIndex(uint32_t i) const;
   DWARFDIE FormValueAsReference(dw_attr_t attr) const;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFAttribute.cpp
@@ -25,10 +25,11 @@
   return UINT32_MAX;
 }
 
-void DWARFAttributes::Append(DWARFUnit *cu, dw_offset_t attr_die_offset,
-                             dw_attr_t attr, dw_form_t form) {
-  AttributeValue attr_value = {
-      cu, attr_die_offset, {attr, form, DWARFFormValue::ValueType()}};
+void DWARFAttributes::Append(const DWARFFormValue &form_value,
+                             dw_offset_t attr_die_offset, dw_attr_t attr) {
+  AttributeValue attr_value = {const_cast<DWARFUnit *>(form_value.GetUnit()),
+                               attr_die_offset,
+                               {attr, form_value.Form(), form_value.Value()}};
   m_infos.push_back(attr_value);
 }
 
@@ -37,6 +38,10 @@
   const DWARFUnit *cu = CompileUnitAtIndex(i);
   form_value.SetUnit(cu);
   form_value.SetForm(FormAtIndex(i));
+  if (form_value.Form() == DW_FORM_implicit_const) {
+    form_value.SetValue(ValueAtIndex(i));
+    return true;
+  }
   lldb::offset_t offset = DIEOffsetAtIndex(i);
   return form_value.ExtractValue(cu->GetData(), &offset);
 }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
@@ -432,7 +432,7 @@
         }
         LLVM_FALLTHROUGH;
       default:
-        attributes.Append(cu, offset, attr, form);
+        attributes.Append(form_value, offset, attr);
         break;
       }
 
diff --git a/lldb/test/Shell/SymbolFile/DWARF/dwarf5-implicit-const.s b/lldb/test/Shell/SymbolFile/DWARF/dwarf5-implicit-const.s
new file mode 100755
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/dwarf5-implicit-const.s
@@ -0,0 +1,87 @@
+# Test handling of DWARF5 DW_FORM_implicit_const as used by GCC.
+
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-pc-linux %s
+# RUN: %lldb %t -o "expression -T -- variable_implicit_const" \
+# RUN:   -o exit | FileCheck %s
+
+# Failing case was:
+# error: need to add support for DW_TAG_base_type 'int' encoded with DW_ATE = 0x5, bit_size = 0
+# CHECK: (int) $0 = 0
+
+	.bss
+	.globl	variable_implicit_const
+	.type	variable_implicit_const, @object
+	.size	variable_implicit_const, 4
+variable_implicit_const:
+	.long	0
+.Lvariable_implicit_const_end:
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	.Ldebug_info0_end - .Ldebug_info0_start	# Length of Compilation Unit Info
+.Ldebug_info0_start:
+	.value	0x5	# DWARF version number
+	.byte	0x1	# DW_UT_compile
+	.byte	0x8	# Pointer Size (in bytes)
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.uleb128 0x1	# (DIE DW_TAG_compile_unit)
+			# DW_AT_producer
+	.string	"GNU C17 11.0.0 20210210 (Red Hat 11.0.0-0) -mtune=generic -march=x86-64 -g"
+	.byte	0x1d	# DW_AT_language
+			# DW_AT_name
+	.string	"var4.c"
+	.uleb128 0x2	# (DIE DW_TAG_variable)
+			# DW_AT_name
+	.string	"variable_implicit_const"
+	.long	.Ltype_int - .Ldebug_info0	# DW_AT_type
+			# DW_AT_external
+	.uleb128 0x9	# DW_AT_location
+	.byte	0x3	# DW_OP_addr
+	.quad	variable_implicit_const
+.Ltype_int:
+	.uleb128 0x3	# (DIE DW_TAG_base_type)
+			# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.byte	0	# end of children of DIE DW_TAG_compile_unit
+.Ldebug_info0_end:
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0x8	# (DW_FORM_string)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x34	# (TAG: DW_TAG_variable)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x2	# (DW_AT_location)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0x21	# (DW_FORM_implicit_const)
+	.sleb128 .Lvariable_implicit_const_end - variable_implicit_const
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.byte	0