[CodeGen] Don't treat thread local globals as large data

[aeubanks]

Otherwise they may mistakenly get the large section flag.

[llvmbot]

@llvm/pr-subscribers-backend-x86

Changes

Otherwise they may mistakenly get the large section flag.

---

Full diff: https://github.com/llvm/llvm-project/pull/67764.diff

2 Files Affected:

• (modified) llvm/lib/Target/TargetMachine.cpp (+1-1)
• (modified) llvm/test/CodeGen/X86/code-model-elf-sections.ll (+10)

diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp
index a20c6847c6c590b..45fb612cb91da19 100644
--- a/llvm/lib/Target/TargetMachine.cpp
+++ b/llvm/lib/Target/TargetMachine.cpp
@@ -40,7 +40,7 @@ TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
 TargetMachine::~TargetMachine() = default;
 
 bool TargetMachine::isLargeData(const GlobalVariable *GV) const {
-  if (getTargetTriple().getArch() != Triple::x86_64)
+  if (getTargetTriple().getArch() != Triple::x86_64 || GV->isThreadLocal())
     return false;
   // Large data under the large code model still needs to be thought about, so
   // restrict this to medium.
diff --git a/llvm/test/CodeGen/X86/code-model-elf-sections.ll b/llvm/test/CodeGen/X86/code-model-elf-sections.ll
index 941c4dd1f8c9851..716bf01bb59361b 100644
--- a/llvm/test/CodeGen/X86/code-model-elf-sections.ll
+++ b/llvm/test/CodeGen/X86/code-model-elf-sections.ll
@@ -20,21 +20,29 @@
 ; SMALL: .bss {{.*}} WA {{.*}}
 ; SMALL: .rodata {{.*}} A {{.*}}
 ; SMALL: .data.rel.ro {{.*}} WA {{.*}}
+; SMALL: .tbss {{.*}} WAT {{.*}}
+; SMALL: .tdata {{.*}} WAT {{.*}}
 
 ; SMALL-DS: .data.data {{.*}} 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: .lbss {{.*}} WAl {{.*}}
 ; LARGE: .lrodata {{.*}} Al {{.*}}
 ; LARGE: .ldata.rel.ro {{.*}} WAl {{.*}}
+; LARGE: .tbss {{.*}} WAT {{.*}}
+; LARGE: .tdata {{.*}} WAT {{.*}}
 
 ; LARGE-DS: .ldata.data {{.*}} WAl {{.*}}
 ; LARGE-DS: .lbss.bss {{.*}} WAl {{.*}}
 ; LARGE-DS: .lrodata.rodata {{.*}} Al {{.*}}
 ; LARGE-DS: .ldata.rel.ro.relro {{.*}} WAl {{.*}}
+; LARGE-DS: .tbss.tbss {{.*}} WAT {{.*}}
+; LARGE-DS: .tdata.tdata {{.*}} WAT {{.*}}
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64--linux"
@@ -43,5 +51,7 @@ target triple = "x86_64--linux"
 @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]
+@tbss = internal thread_local global [10 x i64] zeroinitializer
+@tdata = internal thread_local global [10 x i64] [i64 1, i64 2, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0, i64 0]
 
 declare void @func()

[aeubanks]

We could move the check for thread local globals into the callers and assert that we don't call isLargeData on thread local globals, but the callers are a mix of code that should only deal with non-thread local globals and code that handles all globals, so I went down the route of less code.