elfcpp/:

* elf_file.h: (class Elf_strtab): New class.
gold/:
	* gold.cc: (queue_initial_tasks): Pass incremental_inputs to
	Incremental_checker.
	* incremental.cc: (INCREMENTAL_LINK_VERSION): Change type to
	unsigned int.
	(class Incremental_inputs_header): New class.
	(Incremental_inputs_header_writer): Edit comment.
	(Incremental_inputs_entry): New class.
	(Incremental_inputs_entry_writer): Edit comment.
	(Sized_incremental_binary::do_find_incremental_inputs_section):
	Add *strtab_shndx parameter, fill it.
	(Sized_incremental_binary::do_check_inputs): New method.
	(Incremental_checker::can_incrementally_link_output_file): Use
	Sized_incremental_binary::check_inputs.
	(Incremental_inputs::report_command_line): Save command line in
	command_line_.
	* incremental.h:
	(Incremental_binary::find_incremental_inputs_section): New
	method.
	(Incremental_binary::do_find_incremental_inputs_section): Add
	strtab_shndx parameter.
	(Incremental_binary::do_check_inputs): New pure virtual method.
	(Sized_incremental_binary::do_check_inputs): Declare.
	(Incremental_checker::Incremental_checker): Add incremental_inputs
	parameter, use it to initialize incremental_inputs_.
	(Incremental_checker::incremental_inputs_): New field.
	(Incremental_checker::command_line): New method.
	(Incremental_checker::inputs): New method.
	(Incremental_checker::command_line_): New field.

elfcpp/elfcpp_file.h

@@ -228,6 +228,33 @@ class Elf_file
   int large_shndx_offset_;
 };
 
+// A small wrapper around SHT_STRTAB data mapped to memory. It checks that the
+// index is not out of bounds and the string is NULL-terminated.
+
+class Elf_strtab
+{
+ public:
+  // Construct an Elf_strtab for a section with contents *P and size SIZE.
+  Elf_strtab(const unsigned char* p, size_t size);
+
+  // Return the file offset to the section headers.
+  bool
+  get_c_string(size_t offset, const char** cstring) const
+  {
+    if (offset >= this->usable_size_)
+      return false;
+    *cstring = this->base_ + offset;
+    return true;
+  }
+
+ private:
+  // Contents of the section mapped to memory.
+  const char* base_;
+  // One larger that the position of the last NULL character in the section.
+  // For valid SHT_STRTAB sections, this is the size of the section.
+  size_t usable_size_;
+};
+
 // Inline function definitions.
 
 // Check for presence of the ELF magic number.
@@ -642,6 +669,18 @@ Elf_file<size, big_endian, File>::section_addralign(unsigned int shndx)
   return shdr.get_sh_addralign();
 }
 
+inline
+Elf_strtab::Elf_strtab(const unsigned char* p, size_t size)
+{
+  // Check if the section is NUL-terminated. If it isn't, we ignore
+  // the last part to make sure we don't return non-NUL-terminated
+  // strings.
+  while (size > 0 && p[size - 1] != 0)
+    size--;
+  this->base_ = reinterpret_cast<const char*>(p);
+  this->usable_size_ = size;
+}
+
 } // End namespace elfcpp.
 
 #endif // !defined(ELFCPP_FILE_H)