caio/clang-p2996
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Unconditionally accept symbol sizes from elf

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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.

Re-commit this CL after fixing the issue with gcc-4.9.2 on i386 Linux.

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

llvm-svn: 258113
This commit is contained in:
Tamas Berghammer
2016-01-19 10:24:51 +00:00
parent 2a3810e8f7
commit 8c6996f737
4 changed files with 33 additions and 12 deletions
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12
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
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@@ -2283,6 +2283,12 @@ ObjectFileELF::ParseSymbols (Symtab *symtab,
mangled.SetDemangledName( ConstString((demangled_name + suffix).str()) );
}
// In ELF all symbol should have a valid size but it is not true for some code symbols
// coming from hand written assembly. As none of the code symbol should have 0 size we try
// to calculate the size for these symbols in the symtab with saying that their original
// size is not valid.
bool symbol_size_valid = symbol.st_size != 0 || symbol_type != eSymbolTypeCode;
Symbol dc_symbol(
i + start_id, // ID is the original symbol table index.
mangled,
@@ -2295,7 +2301,7 @@ ObjectFileELF::ParseSymbols (Symtab *symtab,
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
symbol_size_valid, // Symbol size is valid
has_suffix, // Contains linker annotations?
flags); // Symbol flags.
symtab->AddSymbol(dc_symbol);
@@ -2304,7 +2310,9 @@ ObjectFileELF::ParseSymbols (Symtab *symtab,
}
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)
{