Honour relocation behaviour stuff for ro objects

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68005 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2009-03-29 17:13:49 +00:00
parent ab267a2823
commit db2323148b
3 changed files with 29 additions and 3 deletions

View File

@ -20,6 +20,7 @@ namespace llvm {
template<typename T> class SmallVectorImpl;
namespace Reloc {
const unsigned None = 0;
const unsigned Local = 1 << 0; ///< Local relocations are required
const unsigned Global = 1 << 1; ///< Global relocations are required
const unsigned LocalOrGlobal = Local | Global;

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@ -577,6 +577,12 @@ namespace llvm {
virtual SectionKind::Kind
SectionKindForGlobal(const GlobalValue *GV) const;
/// RelocBehaviour - Describes how relocations should be treated when
/// selecting sections. Reloc::Global bit should be set if global
/// relocations should force object to be placed in read-write
/// sections. Reloc::Local bit should be set if local relocations should
/// force object to be placed in read-write sections.
virtual unsigned RelocBehaviour() const;
/// SectionFlagsForGlobal - This hook allows the target to select proper
/// section flags either for given global or for section.

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@ -19,6 +19,7 @@
#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/Dwarf.h"
#include <cctype>
@ -189,6 +190,12 @@ static bool isConstantString(const Constant *C) {
return false;
}
unsigned TargetAsmInfo::RelocBehaviour() const {
// By default - all relocations in PIC mode would force symbol to be
// placed in r/w section.
return (TM.getRelocationModel() != Reloc::Static ?
Reloc::LocalOrGlobal : Reloc::None);
}
SectionKind::Kind
TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
@ -208,9 +215,21 @@ TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
// check its initializer to decide, which section to output it into. Also
// note, there is no thread-local r/o section.
Constant *C = GVar->getInitializer();
if (C->ContainsRelocations())
return SectionKind::ROData;
else {
if (C->ContainsRelocations(Reloc::LocalOrGlobal)) {
// Decide, whether it is still possible to put symbol into r/o section.
unsigned Reloc = RelocBehaviour();
// We already did a query for 'all' relocs, thus - early exits.
if (Reloc == Reloc::LocalOrGlobal)
return SectionKind::Data;
else if (Reloc == Reloc::None)
return SectionKind::ROData;
else {
// Ok, target wants something funny. Honour it.
return (C->ContainsRelocations(Reloc) ?
SectionKind::Data : SectionKind::ROData);
}
} else {
// Check, if initializer is a null-terminated string
if (isConstantString(C))
return SectionKind::RODataMergeStr;