[Lldb-commits] [lldb] r258040 - Unconditionally accept symbol sizes from elf

[Tamas Berghammer via lldb-commits]

Author: tberghammer
Date: Mon Jan 18 04:38:34 2016
New Revision: 258040

URL: http://llvm.org/viewvc/llvm-project?rev=258040&view=rev
Log:
Unconditionally accept symbol sizes from elf

The ELF symbol table always contain the size of the symbols so we
don't have to try to guess them based on the address of the next
symbol (it is needed for mach-o).

The change fixes an issue when a symbol is removed after a 0 size
symbol (e.g. because the second one is not public) what previously
caused the symbol lookup algorithm to end up with showing the 0 size
symbol even for the later addresses (what are not part of any symbol).
That symbol lookup error can confuse the user and also confuses the
current stack unwinder.

Differential revision: http://reviews.llvm.org/D16186

Modified:
    lldb/trunk/include/lldb/Symbol/Symbol.h
    lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
    lldb/trunk/source/Symbol/Symbol.cpp
    lldb/trunk/source/Symbol/Symtab.cpp

Modified: lldb/trunk/include/lldb/Symbol/Symbol.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Symbol/Symbol.h?rev=258040&r1=258039&r2=258040&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Symbol/Symbol.h (original)
+++ lldb/trunk/include/lldb/Symbol/Symbol.h Mon Jan 18 04:38:34 2016
@@ -383,6 +383,9 @@ public:
                     bool prefer_file_cache,
                     Stream &strm);
 
+    bool
+    ContainsFileAddress (lldb::addr_t file_addr) const;
+
 protected:
     // This is the internal guts of ResolveReExportedSymbol, it assumes reexport_name is not null, and that module_spec
     // is valid.  We track the modules we've already seen to make sure we don't get caught in a cycle.

Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp?rev=258040&r1=258039&r2=258040&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp Mon Jan 18 04:38:34 2016
@@ -2295,7 +2295,7 @@ ObjectFileELF::ParseSymbols (Symtab *sym
                 symbol_section_sp,  // Section in which this symbol is defined or null.
                 symbol_value,       // Offset in section or symbol value.
                 symbol.st_size),    // Size in bytes of this symbol.
-            symbol.st_size != 0,    // Size is valid if it is not 0
+            true,                   // Symbol size is valid
             has_suffix,             // Contains linker annotations?
             flags);                 // Symbol flags.
         symtab->AddSymbol(dc_symbol);
@@ -2304,7 +2304,9 @@ ObjectFileELF::ParseSymbols (Symtab *sym
 }
 
 unsigned
-ObjectFileELF::ParseSymbolTable(Symtab *symbol_table, user_id_t start_id, lldb_private::Section *symtab)
+ObjectFileELF::ParseSymbolTable(Symtab *symbol_table,
+                                user_id_t start_id,
+                                lldb_private::Section *symtab)
 {
     if (symtab->GetObjectFile() != this)
     {

Modified: lldb/trunk/source/Symbol/Symbol.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/Symbol.cpp?rev=258040&r1=258039&r2=258040&view=diff
==============================================================================
--- lldb/trunk/source/Symbol/Symbol.cpp (original)
+++ lldb/trunk/source/Symbol/Symbol.cpp Mon Jan 18 04:38:34 2016
@@ -737,3 +737,10 @@ Symbol::GetDisassembly (const ExecutionC
     }
     return false;
 }
+
+bool
+Symbol::ContainsFileAddress (lldb::addr_t file_addr) const
+{
+    return m_addr_range.ContainsFileAddress(file_addr);
+}
+

Modified: lldb/trunk/source/Symbol/Symtab.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/Symtab.cpp?rev=258040&r1=258039&r2=258040&view=diff
==============================================================================
--- lldb/trunk/source/Symbol/Symtab.cpp (original)
+++ lldb/trunk/source/Symbol/Symtab.cpp Mon Jan 18 04:38:34 2016
@@ -971,9 +971,11 @@ Symtab::InitAddressIndexes()
                     if (end_section_file_addr > symbol_file_addr)
                     {
                         Symbol &symbol = m_symbols[entry.data];
-
-                        symbol.SetByteSize(end_section_file_addr - symbol_file_addr);
-                        symbol.SetSizeIsSynthesized(true);
+                        if (!symbol.GetByteSizeIsValid())
+                        {
+                            symbol.SetByteSize(end_section_file_addr - symbol_file_addr);
+                            symbol.SetSizeIsSynthesized(true);
+                        }
                     }
                 }
             }
@@ -1039,18 +1041,15 @@ Symtab::FindSymbolContainingFileAddress
             return info.match_symbol;
         }
 
-        const size_t symbol_byte_size = info.match_symbol->GetByteSize();
-        
-        if (symbol_byte_size == 0)
+        if (!info.match_symbol->GetByteSizeIsValid())
         {
-            // We weren't able to find the size of the symbol so lets just go 
-            // with that match we found in our search...
+            // The matched symbol dosn't have a valid byte size so lets just go with that match...
             return info.match_symbol;
         }
 
         // We were able to figure out a symbol size so lets make sure our 
         // offset puts "file_addr" in the symbol's address range.
-        if (info.match_offset < symbol_byte_size)
+        if (info.match_offset < info.match_symbol->GetByteSize())
             return info.match_symbol;
     }
     return nullptr;
@@ -1066,7 +1065,11 @@ Symtab::FindSymbolContainingFileAddress
 
     const FileRangeToIndexMap::Entry *entry = m_file_addr_to_index.FindEntryThatContains(file_addr);
     if (entry)
-        return SymbolAtIndex(entry->data);
+    {
+        Symbol* symbol = SymbolAtIndex(entry->data);
+        if (symbol->ContainsFileAddress(file_addr))
+            return symbol;
+    }
     return nullptr;
 }