From 9ec85a27138aefcd3fc35ddbd7727f384fe299b1 Mon Sep 17 00:00:00 2001 From: Cary Coutant Date: Tue, 25 Nov 2014 13:55:42 -0800 Subject: [PATCH] Fix corrupted .eh_frame section with LTO and --gc-sections. Backport from trunk: When --gc-sections is turned on during an LTO link, the .eh_frame sections from deferred files are processed before those from the replacement files. As a result, the section end-cap from crtendS.o is placed ahead of the .eh_frame data from the replacement files. This patch fixes the bug by skipping the layout of the deferred sections during GC pass 2. gold/ PR gold/17639 * object.cc (Sized_relobj_file): Initialize is_deferred_layout_. (Sized_relobj_file::do_layout): Handle deferred sections properly during GC pass 1. Don't add reloc sections to deferred list twice. * object.h (Sized_relobj_file::is_deferred_layout): New function. (Sized_relobj_file::is_deferred_layout_): New data member. --- gold/ChangeLog | 9 +++++++++ gold/object.cc | 20 ++++++++++++++------ gold/object.h | 7 +++++++ 3 files changed, 30 insertions(+), 6 deletions(-) diff --git a/gold/ChangeLog b/gold/ChangeLog index ff5d5af..141a465 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,12 @@ +2014-11-25 Cary Coutant + + PR gold/17639 + * object.cc (Sized_relobj_file): Initialize is_deferred_layout_. + (Sized_relobj_file::do_layout): Handle deferred sections properly + during GC pass 1. Don't add reloc sections to deferred list twice. + * object.h (Sized_relobj_file::is_deferred_layout): New function. + (Sized_relobj_file::is_deferred_layout_): New data member. + 2014-11-21 Alan Modra * powerpc.cc (Target_powerpc::Relocate::relocate): Correct test diff --git a/gold/object.cc b/gold/object.cc index 6ab84ce..e357ddf 100644 --- a/gold/object.cc +++ b/gold/object.cc @@ -430,6 +430,7 @@ Sized_relobj_file::Sized_relobj_file( kept_comdat_sections_(), has_eh_frame_(false), discarded_eh_frame_shndx_(-1U), + is_deferred_layout_(false), deferred_layout_(), deferred_layout_relocs_(), compressed_sections_() @@ -1430,6 +1431,7 @@ Sized_relobj_file::do_layout(Symbol_table* symtab, { parameters->options().plugins()->add_deferred_layout_object(this); this->deferred_layout_.reserve(num_sections_to_defer); + this->is_deferred_layout_ = true; } // Whether we've seen a .note.GNU-stack section. @@ -1590,10 +1592,13 @@ Sized_relobj_file::do_layout(Symbol_table* symtab, { if (is_pass_one) { - out_sections[i] = reinterpret_cast(1); + if (this->is_deferred_layout()) + out_sections[i] = reinterpret_cast(2); + else + out_sections[i] = reinterpret_cast(1); out_section_offsets[i] = invalid_address; } - else if (should_defer_layout) + else if (this->is_deferred_layout()) this->deferred_layout_.push_back(Deferred_layout(i, name, pshdrs, reloc_shndx[i], @@ -1658,11 +1663,12 @@ Sized_relobj_file::do_layout(Symbol_table* symtab, } // Defer layout here if input files are claimed by plugins. When gc - // is turned on this function is called twice. For the second call - // should_defer_layout should be false. - if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC)) + // is turned on this function is called twice; we only want to do this + // on the first pass. + if (!is_pass_two + && this->is_deferred_layout() + && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC)) { - gold_assert(!is_pass_two); this->deferred_layout_.push_back(Deferred_layout(i, name, pshdrs, reloc_shndx[i], @@ -1764,6 +1770,8 @@ Sized_relobj_file::do_layout(Symbol_table* symtab, Output_section* data_section = out_sections[data_shndx]; if (data_section == reinterpret_cast(2)) { + if (is_pass_two) + continue; // The layout for the data section was deferred, so we need // to defer the relocation section, too. const char* name = pnames + shdr.get_sh_name(); diff --git a/gold/object.h b/gold/object.h index 754b1d2..cf45ec5 100644 --- a/gold/object.h +++ b/gold/object.h @@ -2202,6 +2202,10 @@ class Sized_relobj_file : public Sized_relobj Symbol_value* lv_out, const Symbol_table* symtab); + // Return true if the layout for this object was deferred. + bool is_deferred_layout() const + { return this->is_deferred_layout_; } + protected: typedef typename Sized_relobj::Output_sections Output_sections; @@ -2740,6 +2744,9 @@ class Sized_relobj_file : public Sized_relobj // If this object has a GNU style .eh_frame section that is discarded in // output, record the index here. Otherwise it is -1U. unsigned int discarded_eh_frame_shndx_; + // True if the layout of this object was deferred, waiting for plugin + // replacement files. + bool is_deferred_layout_; // The list of sections whose layout was deferred. std::vector deferred_layout_; // The list of relocation sections whose layout was deferred. -- 2.7.4