llvm-6502/include/llvm/MC/SectionKind.h
Chris Lattner a3839bc371 introduce a section kind for common linkage. Use this to slightly
simplify and commonize some of the asmprinter logic for globals.

This also avoids printing the MCSection for .zerofill, which broke
the llvm-gcc build.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93843 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-19 02:48:26 +00:00

229 lines
8.3 KiB
C++

//===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements classes used to handle lowerings specific to common
// object file formats.
//
//===----------------------------------------------------------------------===//
#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,
/// Text - Text section, used for functions and other executable code.
Text,
/// 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.
MergeableConst,
/// 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,
/// 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,
/// GlobalWriteableData - Writeable data that is global (not thread
/// local).
/// BSS - Zero initialized writeable data.
BSS,
/// Common - Data with common linkage. These represent tentative
/// definitions, which always have a zero initializer and are never
/// marked 'constant'.
Common,
/// DataRel - This is the most general form of data that is written
/// to by the program, it can have random relocations to arbitrary
/// globals.
DataRel,
/// DataRelLocal - This is writeable data that has a non-zero
/// initializer and has relocations in it, but all of the
/// relocations are known to be within the final linked image
/// the global is linked into.
DataRelLocal,
/// DataNoRel - This is writeable data that has a non-zero
/// initializer, but whose initializer is known to have no
/// relocations.
DataNoRel,
/// 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,
/// ReadOnlyWithRelLocal - This is data that is readonly by the
/// program, but must be writeable so that the dynamic linker
/// can perform relocations in it. This is used when we know
/// that all the relocations are to globals in this final
/// linked image.
ReadOnlyWithRelLocal
} K : 8;
public:
bool isMetadata() const { return K == Metadata; }
bool isText() const { return K == Text; }
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 == MergeableConst || K == MergeableConst4 ||
K == MergeableConst8 || K == MergeableConst16;
}
bool isMergeableConst4() const { return K == MergeableConst4; }
bool isMergeableConst8() const { return K == MergeableConst8; }
bool isMergeableConst16() const { return K == MergeableConst16; }
bool isWriteable() const {
return isThreadLocal() || isGlobalWriteableData();
}
bool isThreadLocal() const {
return K == ThreadData || K == ThreadBSS;
}
bool isThreadBSS() const { return K == ThreadBSS; }
bool isThreadData() const { return K == ThreadData; }
bool isGlobalWriteableData() const {
return isBSS() || isCommon() || isDataRel() || isReadOnlyWithRel();
}
bool isBSS() const { return K == BSS; }
bool isCommon() const { return K == Common; }
bool isDataRel() const {
return K == DataRel || K == DataRelLocal || K == DataNoRel;
}
bool isDataRelLocal() const {
return K == DataRelLocal || K == DataNoRel;
}
bool isDataNoRel() const { return K == DataNoRel; }
bool isReadOnlyWithRel() const {
return K == ReadOnlyWithRel || K == ReadOnlyWithRelLocal;
}
bool isReadOnlyWithRelLocal() const {
return K == ReadOnlyWithRelLocal;
}
private:
static SectionKind get(Kind K) {
SectionKind Res;
Res.K = K;
return Res;
}
public:
static SectionKind getMetadata() { return get(Metadata); }
static SectionKind getText() { return get(Text); }
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 getMergeableConst() { return get(MergeableConst); }
static SectionKind getMergeableConst4() { return get(MergeableConst4); }
static SectionKind getMergeableConst8() { return get(MergeableConst8); }
static SectionKind getMergeableConst16() { return get(MergeableConst16); }
static SectionKind getThreadBSS() { return get(ThreadBSS); }
static SectionKind getThreadData() { return get(ThreadData); }
static SectionKind getBSS() { return get(BSS); }
static SectionKind getCommon() { return get(Common); }
static SectionKind getDataRel() { return get(DataRel); }
static SectionKind getDataRelLocal() { return get(DataRelLocal); }
static SectionKind getDataNoRel() { return get(DataNoRel); }
static SectionKind getReadOnlyWithRel() { return get(ReadOnlyWithRel); }
static SectionKind getReadOnlyWithRelLocal(){
return get(ReadOnlyWithRelLocal);
}
};
} // end namespace llvm
#endif