X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Fehframe.h;h=3fe96002dc94dd3ab57a853081f2976d364565bf;hb=456e800a63def18484f69a51f59c2338a5cc4568;hp=cf3b738567e5ce941571cdb2c1173e40b663fe3a;hpb=935e887746227322222835cd002ec486f9f31402;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/ehframe.h b/gold/ehframe.h index cf3b738567..3fe96002dc 100644 --- a/gold/ehframe.h +++ b/gold/ehframe.h @@ -1,6 +1,6 @@ // ehframe.h -- handle exception frame sections for gold -*- C++ -*- -// Copyright 2006, 2007 Free Software Foundation, Inc. +// Copyright (C) 2006-2020 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -45,10 +45,6 @@ class Eh_frame; // time and when a shared object is loaded, and the time required to // deregister the exception handlers when a shared object is unloaded. -// FIXME: gcc supports using storing a sorted lookup table for the -// FDEs in the PT_GNU_EH_FRAME segment, but we do not yet generate -// that. - class Eh_frame_hdr : public Output_section_data { public: @@ -67,6 +63,7 @@ class Eh_frame_hdr : public Output_section_data this->fde_offsets_.push_back(std::make_pair(fde_offset, fde_encoding)); } + protected: // Set the final data size. void set_final_data_size(); @@ -75,6 +72,11 @@ class Eh_frame_hdr : public Output_section_data void do_write(Output_file*); + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** eh_frame_hdr")); } + private: // Write the data to the file with the right endianness. template @@ -164,9 +166,22 @@ class Fde public: Fde(Relobj* object, unsigned int shndx, section_offset_type input_offset, const unsigned char* contents, size_t length) - : object_(object), shndx_(shndx), input_offset_(input_offset), + : object_(object), contents_(reinterpret_cast(contents), length) - { } + { + this->u_.from_object.shndx = shndx; + this->u_.from_object.input_offset = input_offset; + } + + // Create an FDE associated with a PLT. + Fde(Output_data* plt, const unsigned char* contents, size_t length, + bool post_map) + : object_(NULL), + contents_(reinterpret_cast(contents), length) + { + this->u_.from_linker.plt = plt; + this->u_.from_linker.post_map = post_map; + } // Return the length of this FDE. Add 4 for the length and 4 for // the offset to the CIE. @@ -174,36 +189,84 @@ class Fde length() const { return this->contents_.length() + 8; } - // Add a mapping for this FDE to MERGE_MAP. + // Add a mapping for this FDE to MERGE_MAP, so that relocations + // against the FDE are applied to right part of the output file. void - add_mapping(section_offset_type output_offset, Merge_map* merge_map) const + add_mapping(section_offset_type output_offset, + Output_section_data* output_data) const { - merge_map->add_mapping(this->object_, this->shndx_, - this->input_offset_, this->length(), - output_offset); + if (this->object_ != NULL) + this->object_->add_merge_mapping(output_data, this->u_.from_object.shndx, + this->u_.from_object.input_offset, this->length(), + output_offset); } + // Return whether this FDE was added after merge mapping. + bool + post_map() const + { return this->object_ == NULL && this->u_.from_linker.post_map; } + + // Return whether this FDE was added for the PLT after merge mapping. + bool + post_map(const Output_data* plt) const + { return this->post_map() && this->u_.from_linker.plt == plt; } + // Write the FDE to OVIEW starting at OFFSET. FDE_ENCODING is the // encoding, from the CIE. Round up the bytes to ADDRALIGN if - // necessary. Record the FDE in EH_FRAME_HDR. Return the new - // offset. + // necessary. ADDRESS is the virtual address of OVIEW. Record the + // FDE in EH_FRAME_HDR. Return the new offset. template section_offset_type - write(unsigned char* oview, section_offset_type offset, - unsigned int addralign, section_offset_type cie_offset, - unsigned char fde_encoding, Eh_frame_hdr* eh_frame_hdr); + write(unsigned char* oview, section_offset_type output_section_offset, + section_offset_type offset, uint64_t address, unsigned int addralign, + section_offset_type cie_offset, unsigned char fde_encoding, + Eh_frame_hdr* eh_frame_hdr); private: - // The object in which this FDE was seen. + // The object in which this FDE was seen. This will be NULL for a + // linker generated FDE. Relobj* object_; - // Input section index for this FDE. - unsigned int shndx_; - // Offset within the input section for this FDE. - section_offset_type input_offset_; + union + { + // These fields are used if the FDE is from an input object (the + // object_ field is not NULL). + struct + { + // Input section index for this FDE. + unsigned int shndx; + // Offset within the input section for this FDE. + section_offset_type input_offset; + } from_object; + // This field is used if the FDE is generated by the linker (the + // object_ field is NULL). + struct + { + // The only linker generated FDEs are for PLT sections, and this + // points to the PLT section. + Output_data* plt; + // Set if the FDE was added after merge mapping. + bool post_map; + } from_linker; + } u_; // FDE data. std::string contents_; }; +// A FDE plus some info from a CIE to allow later writing of the FDE. + +struct Post_fde +{ + Post_fde(Fde* f, section_offset_type cie_off, unsigned char encoding) + : fde(f), cie_offset(cie_off), fde_encoding(encoding) + { } + + Fde* fde; + section_offset_type cie_offset; + unsigned char fde_encoding; +}; + +typedef std::vector Post_fdes; + // This class holds a CIE. class Cie @@ -240,6 +303,16 @@ class Cie add_fde(Fde* fde) { this->fdes_.push_back(fde); } + // Remove the last FDE associated with this CIE. + void + remove_fde() + { this->fdes_.pop_back(); } + + // Access the last FDE associated with this CIE. + const Fde* + last_fde() const + { return this->fdes_.back(); } + // Return the number of FDEs. unsigned int fde_count() const @@ -251,15 +324,24 @@ class Cie // mapping. It returns the new output offset. section_offset_type set_output_offset(section_offset_type output_offset, unsigned int addralign, - Merge_map*); + Output_section_data*); - // Write the CIE to OVIEW starting at OFFSET. EH_FRAME_HDR is the - // exception frame header for FDE recording. Round up the bytes to - // ADDRALIGN. Return the new offset. + // Write the CIE to OVIEW starting at OFFSET. Round up the bytes to + // ADDRALIGN. ADDRESS is the virtual address of OVIEW. + // EH_FRAME_HDR is the exception frame header for FDE recording. + // POST_FDES stashes FDEs created after mappings were done, for later + // writing. Return the new offset. template section_offset_type - write(unsigned char* oview, section_offset_type offset, - unsigned int addralign, Eh_frame_hdr* eh_frame_hdr); + write(unsigned char* oview, section_offset_type output_section_offset, + section_offset_type offset, uint64_t address, + unsigned int addralign, Eh_frame_hdr* eh_frame_hdr, + Post_fdes* post_fdes); + + // Return the FDE encoding. + unsigned char + fde_encoding() const + { return this->fde_encoding_; } friend bool operator<(const Cie&, const Cie&); friend bool operator==(const Cie&, const Cie&); @@ -268,11 +350,14 @@ class Cie // The class is not assignable. Cie& operator=(const Cie&); - // The object in which this CIE was first seen. + // The object in which this CIE was first seen. This will be NULL + // for a linker generated CIE. Relobj* object_; - // Input section index for this CIE. + // Input section index for this CIE. This will be 0 for a linker + // generated CIE. unsigned int shndx_; - // Offset within the input section for this CIE. + // Offset within the input section for this CIE. This will be 0 for + // a linker generated CIE. section_offset_type input_offset_; // The encoding of the FDE. This is a DW_EH_PE code. unsigned char fde_encoding_; @@ -294,6 +379,14 @@ extern bool operator==(const Cie&, const Cie&); class Eh_frame : public Output_section_data { public: + enum Eh_frame_section_disposition + { + EH_EMPTY_SECTION, + EH_UNRECOGNIZED_SECTION, + EH_OPTIMIZABLE_SECTION, + EH_END_MARKER_SECTION + }; + Eh_frame(); // Record the associated Eh_frame_hdr, if any. @@ -309,8 +402,8 @@ class Eh_frame : public Output_section_data // returns whether the section was incorporated into the .eh_frame // data. template - bool - add_ehframe_input_section(Sized_relobj* object, + Eh_frame_section_disposition + add_ehframe_input_section(Sized_relobj_file* object, const unsigned char* symbols, section_size_type symbols_size, const unsigned char* symbol_names, @@ -318,10 +411,25 @@ class Eh_frame : public Output_section_data unsigned int shndx, unsigned int reloc_shndx, unsigned int reloc_type); + // Add a CIE and an FDE for a PLT section, to permit unwinding + // through a PLT. The FDE data should start with 8 bytes of zero, + // which will be replaced by a 4 byte PC relative reference to the + // address of PLT and a 4 byte size of PLT. + void + add_ehframe_for_plt(Output_data* plt, const unsigned char* cie_data, + size_t cie_length, const unsigned char* fde_data, + size_t fde_length); + + // Remove all post-map unwind information for a PLT. + void + remove_ehframe_for_plt(Output_data* plt, const unsigned char* cie_data, + size_t cie_length); + // Return the number of FDEs. unsigned int fde_count() const; + protected: // Set the final data size. void set_final_data_size(); @@ -332,14 +440,15 @@ class Eh_frame : public Output_section_data section_offset_type offset, section_offset_type* poutput) const; - // Return whether this is the merge section for an input section. - bool - do_is_merge_section_for(const Relobj*, unsigned int shndx) const; - // Write the data to the file. void do_write(Output_file*); + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** eh_frame")); } + private: // The comparison routine for the CIE map. struct Cie_less @@ -370,7 +479,7 @@ class Eh_frame : public Output_section_data // The implementation of add_ehframe_input_section. template bool - do_add_ehframe_input_section(Sized_relobj* object, + do_add_ehframe_input_section(Sized_relobj_file* object, const unsigned char* symbols, section_size_type symbols_size, const unsigned char* symbol_names, @@ -385,7 +494,7 @@ class Eh_frame : public Output_section_data // Read a CIE. template bool - read_cie(Sized_relobj* object, + read_cie(Sized_relobj_file* object, unsigned int shndx, const unsigned char* symbols, section_size_type symbols_size, @@ -393,7 +502,7 @@ class Eh_frame : public Output_section_data section_size_type symbol_names_size, const unsigned char* pcontents, const unsigned char* pcie, - const unsigned char *pcieend, + const unsigned char* pcieend, Track_relocs* relocs, Offsets_to_cie* cies, New_cies* new_cies); @@ -401,14 +510,14 @@ class Eh_frame : public Output_section_data // Read an FDE. template bool - read_fde(Sized_relobj* object, + read_fde(Sized_relobj_file* object, unsigned int shndx, const unsigned char* symbols, section_size_type symbols_size, const unsigned char* pcontents, unsigned int offset, const unsigned char* pfde, - const unsigned char *pfdeend, + const unsigned char* pfdeend, Track_relocs* relocs, Offsets_to_cie* cies); @@ -425,8 +534,11 @@ class Eh_frame : public Output_section_data // A mapping from unmergeable CIEs to their offset in the output // file. Unmergeable_cie_offsets unmergeable_cie_offsets_; - // A mapping from input sections to the output section. - Merge_map merge_map_; + // Whether we have created the mappings to the output section. + bool mappings_are_done_; + // The final data size. This is only set if mappings_are_done_ is + // true. + section_size_type final_data_size_; }; } // End namespace gold.