[GOLD] Symbol target_flag for PowerPC64 localentry:0 tracking
Alan Modra
amodra@gmail.com
Mon Jul 31 10:15:00 GMT 2017
This patch provides a flag for target use in class Symbol, and
modifies Sized_target::resolve to return whether the symbol has been
resolved. If not, normal processing continues. I use this for
PowerPC64 ELFv2 to keep track of whether a symbol has any definition
with non-zero localentry, in order to disable --plt-localentry for
that symbol.
I know the right way to add target specific symbol fields is via a
derived class and Sized_target::make_symbol, which would be easy to do
for powerpc, but there are lots of holes in Symbol available. So I
thought I'd test the reaction to this patch before wasting another
word per symbol.
OK?
* powerpc.cc (Target_powerpc::is_elfv2_localentry0): Test target_flag.
(Target_powerpc::resolve): New function.
(powerpc_info): Set has_resolve for 64-bit.
* target.h (Sized_target::resolve): Return bool.
* resolve.cc (Symbol_table::resolve): Continue with normal
processing when target resolve returns false.
* symtab.h (Symbol::target_flag, set_target_flag): New accessors.
(Symbol::target_flag_): New flag bit.
* symtab.cc (Symbol::init_fields): Init target_flag_.
diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 14e56d8..142dee2 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -1026,7 +1026,8 @@ class Target_powerpc : public Sized_target<size, big_endian>
&& this->plt_localentry0()
&& gsym->type() == elfcpp::STT_FUNC
&& gsym->is_defined()
- && gsym->nonvis() >> 3 == 0);
+ && gsym->nonvis() >> 3 == 0
+ && !gsym->target_flag());
}
bool
@@ -1051,6 +1052,22 @@ class Target_powerpc : public Sized_target<size, big_endian>
return false;
}
+ // Remember any symbols seen with non-zero localentry, even those
+ // not providing a definition
+ bool
+ resolve(Symbol* to, const elfcpp::Sym<size, big_endian>& sym, Object*,
+ const char*)
+ {
+ if (size == 64)
+ {
+ unsigned char st_other = sym.get_st_other();
+ if ((st_other & elfcpp::STO_PPC64_LOCAL_MASK) != 0)
+ to->set_target_flag();
+ }
+ // We haven't resolved anything, continue normal processing.
+ return false;
+ }
+
int
abiversion () const
{ return this->processor_specific_flags() & elfcpp::EF_PPC64_ABI; }
@@ -1599,7 +1616,7 @@ Target::Target_info Target_powerpc<64, true>::powerpc_info =
true, // is_big_endian
elfcpp::EM_PPC64, // machine_code
false, // has_make_symbol
- false, // has_resolve
+ true, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
@@ -1627,7 +1644,7 @@ Target::Target_info Target_powerpc<64, false>::powerpc_info =
false, // is_big_endian
elfcpp::EM_PPC64, // machine_code
false, // has_make_symbol
- false, // has_resolve
+ true, // has_resolve
false, // has_code_fill
true, // is_default_stack_executable
false, // can_icf_inline_merge_sections
diff --git a/gold/resolve.cc b/gold/resolve.cc
index 8f4d2e3..7c22606 100644
--- a/gold/resolve.cc
+++ b/gold/resolve.cc
@@ -266,8 +266,8 @@ Symbol_table::resolve(Sized_symbol<size>* to,
{
Sized_target<size, big_endian>* sized_target;
sized_target = parameters->sized_target<size, big_endian>();
- sized_target->resolve(to, sym, object, version);
- return;
+ if (sized_target->resolve(to, sym, object, version))
+ return;
}
if (!object->is_dynamic())
diff --git a/gold/symtab.cc b/gold/symtab.cc
index 43909ff..c3538be 100644
--- a/gold/symtab.cc
+++ b/gold/symtab.cc
@@ -81,6 +81,7 @@ Symbol::init_fields(const char* name, const char* version,
this->undef_binding_weak_ = false;
this->is_predefined_ = false;
this->is_protected_ = false;
+ this->target_flag_ = false;
}
// Return the demangled version of the symbol's name, but only
diff --git a/gold/symtab.h b/gold/symtab.h
index 77552ae..cefedda 100644
--- a/gold/symtab.h
+++ b/gold/symtab.h
@@ -883,6 +883,16 @@ class Symbol
set_is_protected()
{ this->is_protected_ = true; }
+ // Return state of target specific flag.
+ bool
+ target_flag() const
+ { return this->target_flag_; }
+
+ // Set target use flag.
+ void
+ set_target_flag(bool val = true)
+ { this->target_flag_ = val; }
+
protected:
// Instances of this class should always be created at a specific
// size.
@@ -1084,6 +1094,8 @@ class Symbol
// The visibility_ field will be STV_DEFAULT in this case because we
// must treat it as such from outside the shared object.
bool is_protected_ : 1;
+ // For target specific use (bit 36).
+ bool target_flag_ : 1;
};
// The parts of a symbol which are size specific. Using a template
diff --git a/gold/target.h b/gold/target.h
index 5ca8435..cf6d902 100644
--- a/gold/target.h
+++ b/gold/target.h
@@ -852,7 +852,7 @@ class Sized_target : public Target
// pre-existing symbol. SYM is the new symbol, seen in OBJECT.
// VERSION is the version of SYM. This will only be called if
// has_resolve() returns true.
- virtual void
+ virtual bool
resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*,
const char*)
{ gold_unreachable(); }
--
Alan Modra
Australia Development Lab, IBM
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