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Diffstat (limited to 'gcc/config/aarch64/aarch64-elf-metadata.h')
| -rw-r--r-- | gcc/config/aarch64/aarch64-elf-metadata.h | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/gcc/config/aarch64/aarch64-elf-metadata.h b/gcc/config/aarch64/aarch64-elf-metadata.h new file mode 100644 index 0000000..e99f6df --- /dev/null +++ b/gcc/config/aarch64/aarch64-elf-metadata.h @@ -0,0 +1,253 @@ +/* ELF metadata for AArch64 architecture. + Copyright (C) 2024-2025 Free Software Foundation, Inc. + Contributed by ARM Ltd. + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + GCC is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING3. If not see + <http://www.gnu.org/licenses/>. */ + +#ifndef GCC_AARCH64_ELF_METADATA_H +#define GCC_AARCH64_ELF_METADATA_H + +#include "vec.h" + +namespace aarch64 { + +class section_note_gnu_property +{ + public: + section_note_gnu_property (); + + /* Add BTI flag to GNU properties. */ + void bti_enabled (); + /* Add GCS flag to GNU properties. */ + void gcs_enabled (); + /* Add PAC flag to GNU properties. */ + void pac_enabled (); + + /* Write the data to the assembly file. */ + void write () const; + + private: + unsigned m_feature_1_and; +}; + +enum subsection_optionality : uint8_t +{ + required = 0x0, + optional = 0x1, +}; + +enum subsection_val_type : uint8_t +{ + uleb128 = 0x0, + ntbs = 0x1, +}; + +enum BA_TagFeature_t : uint8_t +{ + Tag_Feature_BTI = 0, + Tag_Feature_PAC = 1, + Tag_Feature_GCS = 2, +}; + +template <typename T_tag, typename T_val> +struct aeabi_attribute +{ + T_tag tag; + T_val value; +}; + +template <typename T_tag, typename T_val> +aeabi_attribute<T_tag, T_val> +make_aeabi_attribute (T_tag tag, T_val val) +{ + return aeabi_attribute<T_tag, T_val>{tag, val}; +} + +namespace details { + +constexpr const char * +to_c_str (bool b) +{ + return b ? "true" : "false"; +} + +constexpr const char * +to_c_str (const char *s) +{ + return s; +} + +constexpr const char * +to_c_str (subsection_optionality v) +{ + return (v == optional ? "optional" + : v == required ? "required" + : nullptr); +} + +constexpr const char * +to_c_str (subsection_val_type v) +{ + return (v == uleb128 ? "ULEB128" + : v == ntbs ? "NTBS" + : nullptr); +} + +constexpr const char * +to_c_str (BA_TagFeature_t feature) +{ + return (feature == Tag_Feature_BTI ? "Tag_Feature_BTI" + : feature == Tag_Feature_PAC ? "Tag_Feature_PAC" + : feature == Tag_Feature_GCS ? "Tag_Feature_GCS" + : nullptr); +} + +template < + typename T, + typename = typename std::enable_if<std::is_unsigned<T>::value, T>::type +> +constexpr const char * +aeabi_attr_str_fmt (T) +{ + return "\t.aeabi_attribute %s, %u"; +} + +constexpr const char * +aeabi_attr_str_fmt (const char *) +{ + return "\t.aeabi_attribute %s, \"%s\""; +} + +template < + typename T, + typename = typename std::enable_if<std::is_unsigned<T>::value, T>::type +> +constexpr uint8_t +aeabi_attr_val_for_fmt (T value) +{ + return static_cast<uint8_t>(value); +} + +constexpr const char * +aeabi_attr_val_for_fmt (const char *s) +{ + return s; +} + +template <typename T_tag, typename T_val> +void +write (FILE *out_file, aeabi_attribute<T_tag, T_val> const &attr) +{ + asm_fprintf (out_file, aeabi_attr_str_fmt (T_val{}), + to_c_str (attr.tag), aeabi_attr_val_for_fmt (attr.value)); + if (flag_debug_asm) + asm_fprintf (out_file, "\t%s %s: %s", ASM_COMMENT_START, + to_c_str (attr.tag), to_c_str (attr.value)); + asm_fprintf (out_file, "\n"); +} + +template < + typename T, + typename = typename std::enable_if<std::is_unsigned<T>::value, T>::type +> +constexpr subsection_val_type +deduce_attr_av_type (T) +{ + return subsection_val_type::uleb128; +} + +constexpr subsection_val_type +deduce_attr_av_type (const char *) +{ + return subsection_val_type::ntbs; +} + +} // namespace details + +/* AEABI subsections can be public or private. A subsection is public if it is + prefixed with "aeabi", private otherwise. The header of an AEABI subsection + is composed of a name (usually a vendor name), an optionality status (optional + or required), and the expected type of its associated attributes (ULEB128 or + NTBS). Note: The attributes in the same subsection have all the same type. + An attribute is composed of a tag identifier (ULEB128), and its value (ULEB128 + or NTBS). + + Syntax: + .aeabi_subsection NameOfTheSubsection: string (=NTBS), + Optional: boolean (=ULEB128), + AttributeValueType: enum{ULEB128, NTBS} (=ULEB128) + [ + .aeabi_attribute TagIdentifier: ULEB128, + TagValue: Variant[ULEB128|NTBS] + ]* + + Example: + .aeabi_subsection .aeabi-feature-and-bits, optional, ULEB128 + .aeabi_attribute Tag_Feature_GCS, 1 // Tag_Feature_GCS: true + + Note: The textual representations of the tag and its value are emitted as a + comment along their numerical representations to annotate the assembler + output when the developer flag '-dA' is provided. */ +template < + typename T_tag, /* The type of a tag. */ + typename T_val, /* The type of a value. */ + size_t N = 0 /* The number of expected attributes if we know it. */ +> +class aeabi_subsection +{ + public: + aeabi_subsection (const char *name, bool optional) + : m_name (name), + m_optionality (optional + ? subsection_optionality::optional + : subsection_optionality::required), + m_avtype (details::deduce_attr_av_type (T_val{})) + {} + + /* Append an attribute to the subsection. */ + void append (aeabi_attribute<T_tag, T_val> &&attr) + { + m_attributes.quick_push (std::move (attr)); + } + + /* Write the data to the assembly file. */ + void write (FILE *out_file) const + { + asm_fprintf (out_file, "\n\t.aeabi_subsection %s, %s, %s\n", + m_name, details::to_c_str (m_optionality), + details::to_c_str (m_avtype)); + + for (auto const &attr : m_attributes) + details::write (out_file, attr); + } + + /* Indicate if the subsection is empty. */ + bool empty () const + { + return m_attributes.is_empty (); + } + + private: + const char *m_name; + subsection_optionality m_optionality; + subsection_val_type m_avtype; + auto_vec<aeabi_attribute<T_tag, T_val>, N> m_attributes; +}; + +} // namespace aarch64 + +#endif /* GCC_AARCH64_ELF_METADATA_H */ |