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[ELF] Set large section flag for globals with an explicit section #69396

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Merged
merged 1 commit into from
Oct 18, 2023
Merged

[ELF] Set large section flag for globals with an explicit section #69396

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43 changes: 23 additions & 20 deletions llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -763,6 +763,25 @@ calcUniqueIDUpdateFlagsAndSize(const GlobalObject *GO, StringRef SectionName,
return NextUniqueID++;
}

static std::tuple<StringRef, bool, unsigned>
getGlobalObjectInfo(const GlobalObject *GO, const TargetMachine &TM) {
StringRef Group = "";
bool IsComdat = false;
unsigned Flags = 0;
if (const Comdat *C = getELFComdat(GO)) {
Flags |= ELF::SHF_GROUP;
Group = C->getName();
IsComdat = C->getSelectionKind() == Comdat::Any;
}
if (auto *GV = dyn_cast<GlobalVariable>(GO)) {
if (TM.isLargeData(GV)) {
assert(TM.getTargetTriple().getArch() == Triple::x86_64);
Flags |= ELF::SHF_X86_64_LARGE;
}
}
return {Group, IsComdat, Flags};
}

static MCSection *selectExplicitSectionGlobal(
const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM,
MCContext &Ctx, Mangler &Mang, unsigned &NextUniqueID,
Expand Down Expand Up @@ -793,14 +812,9 @@ static MCSection *selectExplicitSectionGlobal(
// Infer section flags from the section name if we can.
Kind = getELFKindForNamedSection(SectionName, Kind);

StringRef Group = "";
bool IsComdat = false;
unsigned Flags = getELFSectionFlags(Kind);
if (const Comdat *C = getELFComdat(GO)) {
Group = C->getName();
IsComdat = C->getSelectionKind() == Comdat::Any;
Flags |= ELF::SHF_GROUP;
}
auto [Group, IsComdat, ExtraFlags] = getGlobalObjectInfo(GO, TM);
Flags |= ExtraFlags;

unsigned EntrySize = getEntrySizeForKind(Kind);
const unsigned UniqueID = calcUniqueIDUpdateFlagsAndSize(
Expand Down Expand Up @@ -848,19 +862,8 @@ static MCSectionELF *selectELFSectionForGlobal(
const TargetMachine &TM, bool EmitUniqueSection, unsigned Flags,
unsigned *NextUniqueID, const MCSymbolELF *AssociatedSymbol) {

StringRef Group = "";
bool IsComdat = false;
if (const Comdat *C = getELFComdat(GO)) {
Flags |= ELF::SHF_GROUP;
Group = C->getName();
IsComdat = C->getSelectionKind() == Comdat::Any;
}
if (auto *GV = dyn_cast<GlobalVariable>(GO)) {
if (TM.isLargeData(GV)) {
assert(TM.getTargetTriple().getArch() == Triple::x86_64);
Flags |= ELF::SHF_X86_64_LARGE;
}
}
auto [Group, IsComdat, ExtraFlags] = getGlobalObjectInfo(GO, TM);
Flags |= ExtraFlags;

// Get the section entry size based on the kind.
unsigned EntrySize = getEntrySizeForKind(Kind);
Expand Down
5 changes: 5 additions & 0 deletions llvm/test/CodeGen/X86/code-model-elf-sections.ll
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Expand Up @@ -17,27 +17,31 @@
; RUN: llvm-readelf -S %t | FileCheck %s --check-prefix=SMALL-DS

; SMALL: .data {{.*}} WA {{.*}}
; SMALL: foo {{.*}} WA {{.*}}
; SMALL: .bss {{.*}} WA {{.*}}
; SMALL: .rodata {{.*}} A {{.*}}
; SMALL: .data.rel.ro {{.*}} WA {{.*}}
; SMALL: .tbss {{.*}} WAT {{.*}}
; SMALL: .tdata {{.*}} WAT {{.*}}

; SMALL-DS: .data.data {{.*}} WA {{.*}}
; SMALL-DS: foo {{.*}} WA {{.*}}
; SMALL-DS: .bss.bss {{.*}} WA {{.*}}
; SMALL-DS: .rodata.rodata {{.*}} A {{.*}}
; SMALL-DS: .data.rel.ro.relro {{.*}} WA {{.*}}
; SMALL-DS: .tbss.tbss {{.*}} WAT {{.*}}
; SMALL-DS: .tdata.tdata {{.*}} WAT {{.*}}

; LARGE: .ldata {{.*}} WAl {{.*}}
; LARGE: foo {{.*}} WAl {{.*}}
; LARGE: .lbss {{.*}} WAl {{.*}}
; LARGE: .lrodata {{.*}} Al {{.*}}
; LARGE: .ldata.rel.ro {{.*}} WAl {{.*}}
; LARGE: .tbss {{.*}} WAT {{.*}}
; LARGE: .tdata {{.*}} WAT {{.*}}

; LARGE-DS: .ldata.data {{.*}} WAl {{.*}}
; LARGE-DS: foo {{.*}} WAl {{.*}}
; LARGE-DS: .lbss.bss {{.*}} WAl {{.*}}
; LARGE-DS: .lrodata.rodata {{.*}} Al {{.*}}
; LARGE-DS: .ldata.rel.ro.relro {{.*}} WAl {{.*}}
Expand All @@ -48,6 +52,7 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64--linux"

@data = internal global [10 x i64] [i64 1, i64 2, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0]
@data_with_explicit_section = internal global [10 x i64] [i64 1, i64 2, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0], section "foo"
@bss = internal global [10 x i64] zeroinitializer
@rodata = internal constant [10 x i64] zeroinitializer
@relro = internal constant [10 x ptr] [ptr @func, ptr @func, ptr @func, ptr @func, ptr @func, ptr @func, ptr @func, ptr @func, ptr @func, ptr @func]
Expand Down