[llvm] [ELF] Set large section flag for globals with an explicit section (PR #69396)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: Arthur Eubanks (aeubanks)

<details>
<summary>Changes</summary>

An oversight in https://reviews.llvm.org/D148836 since this is a different code path.


---
Full diff: https://github.com/llvm/llvm-project/pull/69396.diff


2 Files Affected:

- (modified) llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (+23-20) 
- (modified) llvm/test/CodeGen/X86/code-model-elf-sections.ll (+5) 


``````````diff
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 6210e7fc128a30c..f3ba380818901ca 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -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,
@@ -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(
@@ -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);
diff --git a/llvm/test/CodeGen/X86/code-model-elf-sections.ll b/llvm/test/CodeGen/X86/code-model-elf-sections.ll
index 716bf01bb59361b..fe659fa9a46e727 100644
--- a/llvm/test/CodeGen/X86/code-model-elf-sections.ll
+++ b/llvm/test/CodeGen/X86/code-model-elf-sections.ll
@@ -17,6 +17,7 @@
 ; 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 {{.*}}
@@ -24,6 +25,7 @@
 ; 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 {{.*}}
@@ -31,6 +33,7 @@
 ; SMALL-DS: .tdata.tdata {{.*}} WAT {{.*}}
 
 ; LARGE: .ldata {{.*}} WAl {{.*}}
+; LARGE: foo {{.*}} WAl {{.*}}
 ; LARGE: .lbss {{.*}} WAl {{.*}}
 ; LARGE: .lrodata {{.*}} Al {{.*}}
 ; LARGE: .ldata.rel.ro {{.*}} WAl {{.*}}
@@ -38,6 +41,7 @@
 ; 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 {{.*}}
@@ -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]
+ at 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]

``````````

</details>


https://github.com/llvm/llvm-project/pull/69396