gold/ 2013-08-26 Roland McGrath * output.cc (Output_segment::set_section_addresses): Take new Target* argument. If target->isolate_execinstr() and the segment is executable and starts at a target->abi_pagesize() boundary, pad its end out to a target->abi_pagesize() boundary with code fill. * output.h (Output_segment::set_section_addresses): Update decl. * layout.h (Layout::check_output_data_for_reset_values): Take new argument RELAX_OUTPUTS. (Layout): New member relax_output_list_. (Layout::add_relax_output): New method. * layout.cc (Layout::Layout): Update constructor. (Layout::reset_relax_output): New method. (Layout::clean_up_after_relaxation): Call it. (Layout::prepare_for_relaxation): Update caller. (Layout::set_segment_offsets): Update callers of set_section_addresses. Call reset_relax_output before re-processing segments for isolate_execinstr case. (Layout::write_data): Handle relax_output_list_. (Layout::Relaxation_debug_check::check_output_data_for_reset_values): Take new argument RELAX_OUTPUTS. Assert it's an empty collection. --- a/gold/layout.cc +++ b/gold/layout.cc @@ -293,7 +293,8 @@ Hash_task::is_runnable() void Layout::Relaxation_debug_check::check_output_data_for_reset_values( const Layout::Section_list& sections, - const Layout::Data_list& special_outputs) + const Layout::Data_list& special_outputs, + const Layout::Data_list& relax_outputs) { for(Layout::Section_list::const_iterator p = sections.begin(); p != sections.end(); @@ -304,6 +305,8 @@ Layout::Relaxation_debug_check::check_output_data_for_reset_values( p != special_outputs.end(); ++p) gold_assert((*p)->address_and_file_offset_have_reset_values()); + + gold_assert(relax_outputs.empty()); } // Save information of SECTIONS for checking later. @@ -428,6 +431,7 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) section_list_(), unattached_section_list_(), special_output_list_(), + relax_output_list_(), section_headers_(NULL), tls_segment_(NULL), relro_segment_(NULL), @@ -2341,6 +2345,20 @@ Layout::clean_up_after_relaxation() ++p) delete *p; this->script_output_section_data_list_.clear(); + + // Special-case fill output objects are recreated each time through + // the relaxation loop. + this->reset_relax_output(); +} + +void +Layout::reset_relax_output() +{ + for (Data_list::const_iterator p = this->relax_output_list_.begin(); + p != this->relax_output_list_.end(); + ++p) + delete *p; + this->relax_output_list_.clear(); } // Prepare for relaxation. @@ -2363,7 +2381,8 @@ Layout::prepare_for_relaxation() if (is_debugging_enabled(DEBUG_RELAXATION)) this->relaxation_debug_check_->check_output_data_for_reset_values( - this->section_list_, this->special_output_list_); + this->section_list_, this->special_output_list_, + this->relax_output_list_); // Also enable recording of output section data from scripts. this->record_output_section_data_from_script_ = true; @@ -3540,7 +3559,8 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, unsigned int shndx_hold = *pshndx; bool has_relro = false; - uint64_t new_addr = (*p)->set_section_addresses(this, false, addr, + uint64_t new_addr = (*p)->set_section_addresses(target, this, + false, addr, &increase_relro, &has_relro, &off, pshndx); @@ -3581,7 +3601,8 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, increase_relro = 0; has_relro = false; - new_addr = (*p)->set_section_addresses(this, true, addr, + new_addr = (*p)->set_section_addresses(target, this, + true, addr, &increase_relro, &has_relro, &off, pshndx); @@ -3617,6 +3638,8 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, // so they land after the segments starting at LOAD_SEG. off = align_file_offset(off, 0, target->abi_pagesize()); + this->reset_relax_output(); + for (Segment_list::iterator p = this->segment_list_.begin(); *p != load_seg; ++p) @@ -3630,8 +3653,8 @@ Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, bool has_relro = false; const uint64_t old_addr = (*p)->vaddr(); const uint64_t old_end = old_addr + (*p)->memsz(); - uint64_t new_addr = (*p)->set_section_addresses(this, true, - old_addr, + uint64_t new_addr = (*p)->set_section_addresses(target, this, + true, old_addr, &increase_relro, &has_relro, &off, @@ -5268,6 +5291,13 @@ Layout::write_data(const Symbol_table* symtab, Output_file* of) const p != this->special_output_list_.end(); ++p) (*p)->write(of); + + // Write out the Output_data which are not in an Output_section + // and are regenerated in each iteration of relaxation. + for (Data_list::const_iterator p = this->relax_output_list_.begin(); + p != this->relax_output_list_.end(); + ++p) + (*p)->write(of); } // Write out the Output_sections which can only be written after the --- a/gold/layout.h +++ b/gold/layout.h @@ -1,6 +1,6 @@ // layout.h -- lay out output file sections for gold -*- C++ -*- -// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012 +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 // Free Software Foundation, Inc. // Written by Ian Lance Taylor . @@ -977,6 +977,16 @@ class Layout bool keep_input_section(const Relobj*, const char*); + // Add a special output object that will be recreated afresh + // if there is another relaxation iteration. + void + add_relax_output(Output_data* data) + { this->relax_output_list_.push_back(data); } + + // Clear out (and free) everything added by add_relax_output. + void + reset_relax_output(); + private: Layout(const Layout&); Layout& operator=(const Layout&); @@ -1272,7 +1282,8 @@ class Layout // Check that sections and special data are in reset states. void check_output_data_for_reset_values(const Layout::Section_list&, - const Layout::Data_list&); + const Layout::Data_list& special_outputs, + const Layout::Data_list& relax_outputs); // Record information of a section list. void @@ -1324,6 +1335,9 @@ class Layout // The list of unattached Output_data objects which require special // handling because they are not Output_sections. Data_list special_output_list_; + // Like special_output_list_, but cleared and recreated on each + // iteration of relaxation. + Data_list relax_output_list_; // The section headers. Output_section_headers* section_headers_; // A pointer to the PT_TLS segment if there is one. --- a/gold/output.cc +++ b/gold/output.cc @@ -1,6 +1,6 @@ // output.cc -- manage the output file for gold -// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012 +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 // Free Software Foundation, Inc. // Written by Ian Lance Taylor . @@ -4299,7 +4299,8 @@ Output_segment::has_dynamic_reloc_list(const Output_data_list* pdl) const // and *PSHNDX. uint64_t -Output_segment::set_section_addresses(Layout* layout, bool reset, +Output_segment::set_section_addresses(const Target* target, + Layout* layout, bool reset, uint64_t addr, unsigned int* increase_relro, bool* has_relro, @@ -4439,6 +4440,41 @@ Output_segment::set_section_addresses(Layout* layout, bool reset, // objects. *poff = off; + // If code segments must contain only code, and this code segment is + // page-aligned in the file, then fill it out to a whole page with + // code fill (the tail of the segment will not be within any section). + // Thus the entire code segment can be mapped from the file as whole + // pages and that mapping will contain only valid instructions. + if (target->isolate_execinstr() && (this->flags() & elfcpp::PF_X) != 0) + { + uint64_t abi_pagesize = target->abi_pagesize(); + if (orig_off % abi_pagesize == 0 && off % abi_pagesize != 0) + { + size_t fill_size = abi_pagesize - (off % abi_pagesize); + + std::string fill_data; + if (target->has_code_fill()) + fill_data = target->code_fill(fill_size); + else + fill_data.resize(fill_size); // Zero fill. + + Output_data_const* fill = new Output_data_const(fill_data, 0); + fill->set_address(this->vaddr_ + this->memsz_); + fill->set_file_offset(off); + layout->add_relax_output(fill); + + off += fill_size; + gold_assert(off % abi_pagesize == 0); + ret += fill_size; + gold_assert(ret % abi_pagesize == 0); + + gold_assert((uint64_t) this->filesz_ == this->memsz_); + this->memsz_ = this->filesz_ += fill_size; + + *poff = off; + } + } + return ret; } --- a/gold/output.h +++ b/gold/output.h @@ -1,6 +1,7 @@ // output.h -- manage the output file for gold -*- C++ -*- -// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2013 +// Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -4596,7 +4597,7 @@ class Output_segment // address of the immediately following segment. Update *POFF and // *PSHNDX. This should only be called for a PT_LOAD segment. uint64_t - set_section_addresses(Layout*, bool reset, uint64_t addr, + set_section_addresses(const Target*, Layout*, bool reset, uint64_t addr, unsigned int* increase_relro, bool* has_relro, off_t* poff, unsigned int* pshndx);