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//===-- llvm/MC/SectionKind.h - Classification of sections ------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_SECTIONKIND_H
#define LLVM_MC_SECTIONKIND_H
namespace llvm {
/// SectionKind - This is a simple POD value that classifies the properties of
/// a section. A section is classified into the deepest possible
/// classification, and then the target maps them onto their sections based on
/// what capabilities they have.
///
/// The comments below describe these as if they were an inheritance hierarchy
/// in order to explain the predicates below.
///
class SectionKind {
enum Kind {
/// Metadata - Debug info sections or other metadata.
Metadata,
/// Exclude - This section will be excluded from the final executable or
/// shared library. Only valid for ELF / COFF targets.
Exclude,
/// Text - Text section, used for functions and other executable code.
Text,
/// ExecuteOnly, Text section that is not readable.
ExecuteOnly,
/// ReadOnly - Data that is never written to at program runtime by the
/// program or the dynamic linker. Things in the top-level readonly
/// SectionKind are not mergeable.
ReadOnly,
/// MergableCString - Any null-terminated string which allows merging.
/// These values are known to end in a nul value of the specified size,
/// not otherwise contain a nul value, and be mergable. This allows the
/// linker to unique the strings if it so desires.
/// Mergeable1ByteCString - 1 byte mergable, null terminated, string.
Mergeable1ByteCString,
/// Mergeable2ByteCString - 2 byte mergable, null terminated, string.
Mergeable2ByteCString,
/// Mergeable4ByteCString - 4 byte mergable, null terminated, string.
Mergeable4ByteCString,
/// MergeableConst - These are sections for merging fixed-length
/// constants together. For example, this can be used to unique
/// constant pool entries etc.
/// MergeableConst4 - This is a section used by 4-byte constants,
/// for example, floats.
MergeableConst4,
/// MergeableConst8 - This is a section used by 8-byte constants,
/// for example, doubles.
MergeableConst8,
/// MergeableConst16 - This is a section used by 16-byte constants,
/// for example, vectors.
MergeableConst16,
/// MergeableConst32 - This is a section used by 32-byte constants,
/// for example, vectors.
MergeableConst32,
/// Writeable - This is the base of all segments that need to be written
/// to during program runtime.
/// ThreadLocal - This is the base of all TLS segments. All TLS
/// objects must be writeable, otherwise there is no reason for them to
/// be thread local!
/// ThreadBSS - Zero-initialized TLS data objects.
ThreadBSS,
/// ThreadData - Initialized TLS data objects.
ThreadData,
/// ThreadBSSLocal - Zero-initialized TLS data objects with local linkage.
ThreadBSSLocal,
/// GlobalWriteableData - Writeable data that is global (not thread
/// local).
/// BSS - Zero initialized writeable data.
BSS,
/// BSSLocal - This is BSS (zero initialized and writable) data
/// which has local linkage.
BSSLocal,
/// BSSExtern - This is BSS data with normal external linkage.
BSSExtern,
/// Common - Data with common linkage. These represent tentative
/// definitions, which always have a zero initializer and are never
/// marked 'constant'.
Common,
/// This is writeable data that has a non-zero initializer.
Data,
/// ReadOnlyWithRel - These are global variables that are never
/// written to by the program, but that have relocations, so they
/// must be stuck in a writeable section so that the dynamic linker
/// can write to them. If it chooses to, the dynamic linker can
/// mark the pages these globals end up on as read-only after it is
/// done with its relocation phase.
ReadOnlyWithRel
} K : 8;
public:
bool isMetadata() const { return K == Metadata; }
bool isExclude() const { return K == Exclude; }
bool isText() const { return K == Text || K == ExecuteOnly; }
bool isExecuteOnly() const { return K == ExecuteOnly; }
bool isReadOnly() const {
return K == ReadOnly || isMergeableCString() ||
isMergeableConst();
}
bool isMergeableCString() const {
return K == Mergeable1ByteCString || K == Mergeable2ByteCString ||
K == Mergeable4ByteCString;
}
bool isMergeable1ByteCString() const { return K == Mergeable1ByteCString; }
bool isMergeable2ByteCString() const { return K == Mergeable2ByteCString; }
bool isMergeable4ByteCString() const { return K == Mergeable4ByteCString; }
bool isMergeableConst() const {
return K == MergeableConst4 || K == MergeableConst8 ||
K == MergeableConst16 || K == MergeableConst32;
}
bool isMergeableConst4() const { return K == MergeableConst4; }
bool isMergeableConst8() const { return K == MergeableConst8; }
bool isMergeableConst16() const { return K == MergeableConst16; }
bool isMergeableConst32() const { return K == MergeableConst32; }
bool isWriteable() const {
return isThreadLocal() || isGlobalWriteableData();
}
bool isThreadLocal() const {
return K == ThreadData || K == ThreadBSS || K == ThreadBSSLocal;
}
bool isThreadBSS() const { return K == ThreadBSS || K == ThreadBSSLocal; }
bool isThreadData() const { return K == ThreadData; }
bool isThreadBSSLocal() const { return K == ThreadBSSLocal; }
bool isGlobalWriteableData() const {
return isBSS() || isCommon() || isData() || isReadOnlyWithRel();
}
bool isBSS() const { return K == BSS || K == BSSLocal || K == BSSExtern; }
bool isBSSLocal() const { return K == BSSLocal; }
bool isBSSExtern() const { return K == BSSExtern; }
bool isCommon() const { return K == Common; }
bool isData() const { return K == Data; }
bool isReadOnlyWithRel() const {
return K == ReadOnlyWithRel;
}
private:
static SectionKind get(Kind K) {
SectionKind Res;
Res.K = K;
return Res;
}
public:
static SectionKind getMetadata() { return get(Metadata); }
static SectionKind getExclude() { return get(Exclude); }
static SectionKind getText() { return get(Text); }
static SectionKind getExecuteOnly() { return get(ExecuteOnly); }
static SectionKind getReadOnly() { return get(ReadOnly); }
static SectionKind getMergeable1ByteCString() {
return get(Mergeable1ByteCString);
}
static SectionKind getMergeable2ByteCString() {
return get(Mergeable2ByteCString);
}
static SectionKind getMergeable4ByteCString() {
return get(Mergeable4ByteCString);
}
static SectionKind getMergeableConst4() { return get(MergeableConst4); }
static SectionKind getMergeableConst8() { return get(MergeableConst8); }
static SectionKind getMergeableConst16() { return get(MergeableConst16); }
static SectionKind getMergeableConst32() { return get(MergeableConst32); }
static SectionKind getThreadBSS() { return get(ThreadBSS); }
static SectionKind getThreadData() { return get(ThreadData); }
static SectionKind getThreadBSSLocal() { return get(ThreadBSSLocal); }
static SectionKind getBSS() { return get(BSS); }
static SectionKind getBSSLocal() { return get(BSSLocal); }
static SectionKind getBSSExtern() { return get(BSSExtern); }
static SectionKind getCommon() { return get(Common); }
static SectionKind getData() { return get(Data); }
static SectionKind getReadOnlyWithRel() { return get(ReadOnlyWithRel); }
};
} // end namespace llvm
#endif
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