[ELF] Implement --strip-all/-s

Differential Revision:	D7489
Reviewed by:	shankarke

llvm-svn: 228533

diff --git a/lld/include/lld/ReaderWriter/ELFLinkingContext.h b/lld/include/lld/ReaderWriter/ELFLinkingContext.h
index b010951..61edb26 100644 (file)
--- a/lld/include/lld/ReaderWriter/ELFLinkingContext.h
+++ b/lld/include/lld/ReaderWriter/ELFLinkingContext.h
@@ -292,6 +292,10 @@ public:
   bool alignSegments() const { return _alignSegments; }
   void setAlignSegments(bool align) { _alignSegments = align; }
 
+  /// \brief Strip symbols.
+  bool stripSymbols() const { return _stripSymbols; }
+  void setStripSymbols(bool strip) { _stripSymbols = strip; }
+
   // We can parse several linker scripts via command line whose ASTs are stored
   // in the current linking context via addLinkerScript().
   void addLinkerScript(std::unique_ptr<script::Parser> script) {
@@ -322,6 +326,7 @@ protected:
   bool _noAllowDynamicLibraries;
   bool _mergeRODataToTextSegment;
   bool _demangle;
+  bool _stripSymbols;
   bool _alignSegments;
   bool _nostdlib;
   llvm::Optional<uint64_t> _maxPageSize;

diff --git a/lld/lib/Driver/GnuLdDriver.cpp b/lld/lib/Driver/GnuLdDriver.cpp
index 2ec4e05..43474a2 100644 (file)
--- a/lld/lib/Driver/GnuLdDriver.cpp
+++ b/lld/lib/Driver/GnuLdDriver.cpp
@@ -685,6 +685,11 @@ bool GnuLdDriver::parse(int argc, const char *argv[],
       break;
     }
 
+    case OPT_strip_all: {
+      ctx->setStripSymbols(true);
+      break;
+    }
+
     case OPT_soname:
       ctx->setSharedObjectName(inputArg->getValue());
       break;

diff --git a/lld/lib/Driver/GnuLdOptions.td b/lld/lib/Driver/GnuLdOptions.td
index ff40ca6..6f22150 100644 (file)
--- a/lld/lib/Driver/GnuLdOptions.td
+++ b/lld/lib/Driver/GnuLdOptions.td
@@ -239,6 +239,11 @@ def demangle : Flag<["--"], "demangle">,
 def no_demangle : Flag<["--"], "no-demangle">,
      HelpText<"Dont demangle C++ symbols">,
      Group<grp_symbolopts>;
+def strip_all : Flag<["--"], "strip-all">,
+     HelpText<"Omit all symbol informations from output">,
+     Group<grp_symbolopts>;
+def alias_strip_all : Flag<["-"], "s">,
+     Alias<strip_all>;
 
 //===----------------------------------------------------------------------===//
 /// Optimization Options

diff --git a/lld/lib/ReaderWriter/ELF/ELFLinkingContext.cpp b/lld/lib/ReaderWriter/ELF/ELFLinkingContext.cpp
index 8983d45..90a7698 100644 (file)
--- a/lld/lib/ReaderWriter/ELF/ELFLinkingContext.cpp
+++ b/lld/lib/ReaderWriter/ELF/ELFLinkingContext.cpp
@@ -60,7 +60,8 @@ ELFLinkingContext::ELFLinkingContext(
       _isStaticExecutable(false), _noInhibitExec(false), _exportDynamic(false),
       _mergeCommonStrings(false), _useShlibUndefines(true),
       _dynamicLinkerArg(false), _noAllowDynamicLibraries(false),
-      _mergeRODataToTextSegment(true), _demangle(true), _alignSegments(true),
+      _mergeRODataToTextSegment(true), _demangle(true),
+      _stripSymbols(false), _alignSegments(true),
       _outputMagic(OutputMagic::DEFAULT), _initFunction("_init"),
       _finiFunction("_fini"), _sysrootPath("") {}
 

diff --git a/lld/lib/ReaderWriter/ELF/OutputELFWriter.h b/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
index 46e3146..a857caa 100644 (file)
--- a/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
+++ b/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
@@ -417,7 +417,9 @@ std::error_code OutputELFWriter<ELFT>::buildOutput(const File &file) {
   buildAtomToAddressMap(file);
 
   // Create symbol table and section string table
-  buildStaticSymbolTable(file);
+  // Do it only if -s is not specified.
+  if (!_context.stripSymbols())
+    buildStaticSymbolTable(file);
 
   // Finalize the layout by calling the finalize() functions
   _layout.finalize();

diff --git a/lld/test/elf/strip-all.test b/lld/test/elf/strip-all.test
new file mode 100644 (file)
index 0000000..e319284
--- /dev/null
+++ b/lld/test/elf/strip-all.test
@@ -0,0 +1,107 @@
+# Tests the --strip-all (-s) flag. We expect the symbol table to not contain
+# any symbol in the output file.
+#
+# The following code was used to generate the object.
+# $ clang -c blah.c -o blah
+#
+# void
+# callMeMaybe(int *v)
+# {
+#      *v += 1;
+# }
+#
+# int
+# main(void)
+# {
+#
+#      int blah = 42;
+#      callMeMaybe(&blah);
+# }
+
+#RUN: yaml2obj -format=elf %s -o=%t.o
+#RUN: lld -flavor gnu -target x86_64 %t.o -e=main --strip-all -o %t1
+#RUN: llvm-readobj -dt %t1 | FileCheck -check-prefix CHECKSYMS %s
+
+#CHECKSYMS: @
+
+---
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+...