// 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 <iant@google.com>.
// This file is part of gold.
// 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:
this->fde_offsets_.push_back(std::make_pair(fde_offset, fde_encoding));
}
+ protected:
// Set the final data size.
void
set_final_data_size();
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<int size, bool big_endian>
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<const char*>(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<const char*>(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.
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. Record the FDE in EH_FRAME_HDR. Return
- // the new offset.
+ // encoding, from the CIE. Round up the bytes to ADDRALIGN if
+ // necessary. ADDRESS is the virtual address of OVIEW. Record the
+ // FDE in EH_FRAME_HDR. Return the new offset.
template<int size, bool big_endian>
section_offset_type
- write(unsigned char* oview, section_offset_type offset,
+ 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_fde> Post_fdes;
+
// This class holds a CIE.
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
// 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. 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<int size, bool big_endian>
section_offset_type
- write(unsigned char* oview, section_offset_type offset,
- 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&);
// 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_;
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.
// returns whether the section was incorporated into the .eh_frame
// data.
template<int size, bool big_endian>
- bool
- add_ehframe_input_section(Sized_relobj<size, big_endian>* object,
+ Eh_frame_section_disposition
+ add_ehframe_input_section(Sized_relobj_file<size, big_endian>* object,
const unsigned char* symbols,
section_size_type symbols_size,
const unsigned char* symbol_names,
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();
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
// The implementation of add_ehframe_input_section.
template<int size, bool big_endian>
bool
- do_add_ehframe_input_section(Sized_relobj<size, big_endian>* object,
+ do_add_ehframe_input_section(Sized_relobj_file<size, big_endian>* object,
const unsigned char* symbols,
section_size_type symbols_size,
const unsigned char* symbol_names,
// Read a CIE.
template<int size, bool big_endian>
bool
- read_cie(Sized_relobj<size, big_endian>* object,
+ read_cie(Sized_relobj_file<size, big_endian>* object,
unsigned int shndx,
const unsigned char* symbols,
section_size_type symbols_size,
section_size_type symbol_names_size,
const unsigned char* pcontents,
const unsigned char* pcie,
- const unsigned char *pcieend,
+ const unsigned char* pcieend,
Track_relocs<size, big_endian>* relocs,
Offsets_to_cie* cies,
New_cies* new_cies);
// Read an FDE.
template<int size, bool big_endian>
bool
- read_fde(Sized_relobj<size, big_endian>* object,
+ read_fde(Sized_relobj_file<size, big_endian>* 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<size, big_endian>* relocs,
Offsets_to_cie* cies);
// 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.
projects / deliverable / binutils-gdb.git / blobdiff