summaryrefslogtreecommitdiff
path: root/tools/gold/gold-plugin.cpp
diff options
context:
space:
mode:
authorRafael Espindola <rafael.espindola@gmail.com>2013-10-31 20:51:58 +0000
committerRafael Espindola <rafael.espindola@gmail.com>2013-10-31 20:51:58 +0000
commit7e667c56cf7e27ff521ceb86518beab32bfb630d (patch)
tree70a76ad0c4af2d93a15e630ebd9864665253a72f /tools/gold/gold-plugin.cpp
parentf7ba4897302bf930f7ec4682a296ff4cd736a0e3 (diff)
downloadllvm-7e667c56cf7e27ff521ceb86518beab32bfb630d.tar.gz
llvm-7e667c56cf7e27ff521ceb86518beab32bfb630d.tar.bz2
llvm-7e667c56cf7e27ff521ceb86518beab32bfb630d.tar.xz
Use LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN instead of the "dso list".
There are two ways one could implement hiding of linkonce_odr symbols in LTO: * LLVM tells the linker which symbols can be hidden if not used from native files. * The linker tells LLVM which symbols are not used from other object files, but will be put in the dso symbol table if present. GOLD's API is the second option. It was implemented almost 1:1 in llvm by passing the list down to internalize. LLVM already had partial support for the first option. It is also very similar to how ld64 handles hiding these symbols when *not* doing LTO. This patch then * removes the APIs for the DSO list. * marks LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN all linkonce_odr unnamed_addr global values and other linkonce_odr whose address is not used. * makes the gold plugin responsible for handling the API mismatch. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193800 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'tools/gold/gold-plugin.cpp')
-rw-r--r--tools/gold/gold-plugin.cpp21
1 files changed, 15 insertions, 6 deletions
diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index 360ec07e79..0e3bad2599 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -15,6 +15,7 @@
#include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
#include "plugin-api.h"
#include "llvm-c/lto.h"
+#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Support/Errno.h"
#include "llvm/Support/FileSystem.h"
@@ -67,6 +68,7 @@ namespace {
std::list<claimed_file> Modules;
std::vector<std::string> Cleanup;
lto_code_gen_t code_gen = NULL;
+ StringSet<> CannotBeHidden;
}
namespace options {
@@ -297,6 +299,9 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
sym.version = NULL;
int scope = attrs & LTO_SYMBOL_SCOPE_MASK;
+ bool CanBeHidden = scope == LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN;
+ if (!CanBeHidden)
+ CannotBeHidden.insert(sym.name);
switch (scope) {
case LTO_SYMBOL_SCOPE_HIDDEN:
sym.visibility = LDPV_HIDDEN;
@@ -306,6 +311,7 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
break;
case 0: // extern
case LTO_SYMBOL_SCOPE_DEFAULT:
+ case LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN:
sym.visibility = LDPV_DEFAULT;
break;
default:
@@ -364,6 +370,14 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
return LDPS_OK;
}
+static bool mustPreserve(const claimed_file &F, int i) {
+ if (F.syms[i].resolution == LDPR_PREVAILING_DEF)
+ return true;
+ if (F.syms[i].resolution == LDPR_PREVAILING_DEF_IRONLY_EXP)
+ return CannotBeHidden.count(F.syms[i].name);
+ return false;
+}
+
/// all_symbols_read_hook - gold informs us that all symbols have been read.
/// At this point, we use get_symbols to see if any of our definitions have
/// been overridden by a native object file. Then, perform optimization and
@@ -386,16 +400,11 @@ static ld_plugin_status all_symbols_read_hook(void) {
continue;
(*get_symbols)(I->handle, I->syms.size(), &I->syms[0]);
for (unsigned i = 0, e = I->syms.size(); i != e; i++) {
- if (I->syms[i].resolution == LDPR_PREVAILING_DEF) {
+ if (mustPreserve(*I, i)) {
lto_codegen_add_must_preserve_symbol(code_gen, I->syms[i].name);
if (options::generate_api_file)
api_file << I->syms[i].name << "\n";
- } else if (I->syms[i].resolution == LDPR_PREVAILING_DEF_IRONLY_EXP) {
- lto_codegen_add_dso_symbol(code_gen, I->syms[i].name);
-
- if (options::generate_api_file)
- api_file << I->syms[i].name << " dso only\n";
}
}
}