[ELF2] Add support for -discard-none.
Differential Revision: http://reviews.llvm.org/D13083
llvm-svn: 248499
diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index ea97ff4..5108a65 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -22,6 +22,7 @@
bool Shared = false;
bool DiscardAll = false;
bool DiscardLocals = false;
+ bool DiscardNone = false;
bool ExportDynamic = false;
};
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 9d487ad..deafb6a 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -88,6 +88,9 @@
if (Args.hasArg(OPT_discard_locals))
Config->DiscardLocals = true;
+ if (Args.hasArg(OPT_discard_none))
+ Config->DiscardNone = true;
+
if (Args.hasArg(OPT_export_dynamic))
Config->ExportDynamic = true;
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
index cf7251a..5ab4301 100644
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -28,6 +28,9 @@
def alias_discard_locals: Flag<["-"], "X">,
Alias<discard_locals>;
+def discard_none : Flag<["-"], "discard-none">,
+ HelpText<"Keep all symbols in the symbol table">;
+
//===----------------------------------------------------------------------===//
/// Ignored options
//===----------------------------------------------------------------------===//
diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index 3e9f815..113f25b 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -272,6 +272,15 @@
return true;
}
+template <class ELFT>
+bool SymbolTableSection<ELFT>::shouldKeepInSymtab(StringRef SymName) {
+ if (Config->DiscardNone)
+ return true;
+
+ // ELF defines dynamic locals as symbols which name starts with ".L".
+ return !(Config->DiscardLocals && SymName.startswith(".L"));
+}
+
bool lld::elf2::includeInDynamicSymtab(const SymbolBody &B) {
if (Config->ExportDynamic || Config->Shared)
return true;
@@ -294,7 +303,7 @@
auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
uint32_t SecIndex = Sym.st_shndx;
ErrorOr<StringRef> SymName = Sym.getName(File.getStringTable());
- if (Config->DiscardLocals && SymName->startswith(".L"))
+ if (SymName && !shouldKeepInSymtab(*SymName))
continue;
ESym->st_name = (SymName) ? StrTabSec.getFileOff(*SymName) : 0;
ESym->st_size = Sym.st_size;
diff --git a/lld/ELF/OutputSections.h b/lld/ELF/OutputSections.h
index 8a53b22..c40ee88 100644
--- a/lld/ELF/OutputSections.h
+++ b/lld/ELF/OutputSections.h
@@ -186,6 +186,8 @@
++NumLocals;
}
+ bool shouldKeepInSymtab(StringRef Name);
+
StringTableSection<ELFT::Is64Bits> &getStrTabSec() const { return StrTabSec; }
unsigned getNumSymbols() const { return NumVisible + 1; }
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 5946958..c9bf60e 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -336,7 +336,7 @@
Elf_Sym_Range Syms = File.getLocalSymbols();
for (const Elf_Sym &Sym : Syms) {
ErrorOr<StringRef> SymName = Sym.getName(File.getStringTable());
- if (SymName && !(Config->DiscardLocals && SymName->startswith(".L")))
+ if (SymName && SymTabSec.shouldKeepInSymtab(*SymName))
SymTabSec.addSymbol(*SymName, true);
}
}
diff --git a/lld/test/elf2/discard-none.s b/lld/test/elf2/discard-none.s
new file mode 100644
index 0000000..2c3d798
--- /dev/null
+++ b/lld/test/elf2/discard-none.s
@@ -0,0 +1,58 @@
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux -save-temp-labels %s -o %t
+// RUN: lld -flavor gnu2 -discard-none -shared %t -o %t2
+// RUN: llvm-readobj -s -sd -t %t2 | FileCheck %s
+// REQUIRES: x86
+
+.text
+.Lmyvar:
+.Lmyothervar:
+
+// CHECK: Section {
+// CHECK: Name: .strtab
+// CHECK-NEXT: Type: SHT_STRTAB
+// CHECK-NEXT: Flags [
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address:
+// CHECK-NEXT: Offset:
+// CHECK-NEXT: Size:
+// CHECK-NEXT: Link:
+// CHECK-NEXT: Info:
+// CHECK-NEXT: AddressAlignment:
+// CHECK-NEXT: EntrySize:
+// CHECK-NEXT: SectionData (
+// CHECK-NEXT: 0000: 002E7465 7874002E 62737300 2E64796E |..text..bss..dyn|
+// CHECK-NEXT: 0010: 73747200 2E4C6D79 76617200 2E4C6D79 |str..Lmyvar..Lmy|
+// CHECK-NEXT: 0020: 6F746865 72766172 002E6479 6E73796D |othervar..dynsym|
+// CHECK-NEXT: 0030: 002E6861 7368002E 64796E61 6D696300 |..hash..dynamic.|
+// CHECK-NEXT: 0040: 2E737472 74616200 2E73796D 74616200 |.strtab..symtab.|
+// CHECK-NEXT: 0050: 2E646174 6100 |.data.|
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+
+// CHECK: Symbol {
+// CHECK-NEXT: Name:
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Local
+// CHECK-NEXT: Type: None
+// CHECK-NEXT: Other: 0
+// CHECK-NEXT: Section: Undefined
+// CHECK-NEXT: }
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: .Lmyothervar
+// CHECK-NEXT: Value: 0x1000
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Local
+// CHECK-NEXT: Type: None
+// CHECK-NEXT: Other: 0
+// CHECK-NEXT: Section: .text
+// CHECK-NEXT: }
+// CHECK-NEXT: Symbol {
+// CHECK-NEXT: Name: .Lmyvar
+// CHECK-NEXT: Value: 0x1000
+// CHECK-NEXT: Size: 0
+// CHECK-NEXT: Binding: Local
+// CHECK-NEXT: Type: None
+// CHECK-NEXT: Other: 0
+// CHECK-NEXT: Section: .text
+// CHECK-NEXT: }