[ELF] Linkerscript: support hidden symbols assignments

This add support for HIDDEN command which can be used to define
a symbol that will be hidden and won't be exported.

Differential Revision: https://reviews.llvm.org/D23534

llvm-svn: 278770

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index d5748f85e2883da05c2f4b86b007bd1384d4a6db..dd9ef6a7f9a92156243dea199a70199b3de30e93 100644 (file)
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -602,7 +602,7 @@ private:
   InputSectionDescription *readInputSectionRules();
   unsigned readPhdrType();
   SortKind readSortKind();
-  SymbolAssignment *readProvide(bool Hidden);
+  SymbolAssignment *readProvideHidden(bool Provide, bool Hidden);
   SymbolAssignment *readProvideOrAssignment(StringRef Tok);
   Expr readAlign();
   void readSort();
@@ -969,10 +969,10 @@ std::vector<uint8_t> ScriptParser::readOutputSectionFiller() {
   return { uint8_t(V >> 24), uint8_t(V >> 16), uint8_t(V >> 8), uint8_t(V) };
 }
 
-SymbolAssignment *ScriptParser::readProvide(bool Hidden) {
+SymbolAssignment *ScriptParser::readProvideHidden(bool Provide, bool Hidden) {
   expect("(");
   SymbolAssignment *Cmd = readAssignment(next());
-  Cmd->Provide = true;
+  Cmd->Provide = Provide;
   Cmd->Hidden = Hidden;
   expect(")");
   expect(";");
@@ -985,9 +985,11 @@ SymbolAssignment *ScriptParser::readProvideOrAssignment(StringRef Tok) {
     Cmd = readAssignment(Tok);
     expect(";");
   } else if (Tok == "PROVIDE") {
-    Cmd = readProvide(false);
+    Cmd = readProvideHidden(true, false);
+  } else if (Tok == "HIDDEN") {
+    Cmd = readProvideHidden(false, true);
   } else if (Tok == "PROVIDE_HIDDEN") {
-    Cmd = readProvide(true);
+    Cmd = readProvideHidden(true, true);
   }
   return Cmd;
 }

diff --git a/lld/test/ELF/linkerscript/linkerscript-symbols.s b/lld/test/ELF/linkerscript/linkerscript-symbols.s
index 7d8685bcaa9b331f28d26a448b9c5fb0d7783cce..4cd1a27c89267839b88d467f357c3a6cfd43eef9 100644 (file)
--- a/lld/test/ELF/linkerscript/linkerscript-symbols.s
+++ b/lld/test/ELF/linkerscript/linkerscript-symbols.s
@@ -35,6 +35,12 @@
 # RUN: llvm-objdump -t %t1 | FileCheck --check-prefix=HIDDEN2 %s
 # HIDDEN2: 0000000000000000         *ABS*    00000000 somesym
 
+# Hidden symbol assignment.
+# RUN: echo "SECTIONS { HIDDEN(newsym = 1);}" > %t.script
+# RUN: ld.lld -o %t1 --script %t.script %t
+# RUN: llvm-objdump -t %t1 | FileCheck --check-prefix=HIDDEN3 %s
+# HIDDEN3: 0000000000000001         *ABS*    00000000 .hidden newsym
+
 .global _start
 _start:
  nop