[PATCH] D148836: [X86] Use "l" prefix for data sections under medium/large code model

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

For what we want to do with `-mcmodel=large`, I have https://groups.google.com/g/x86-64-abi/c/jnQdJeabxiU and CCed some gcc/binutils folks



================
Comment at: llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp:653
   } else {
-    Name = getSectionPrefixForGlobal(Kind);
+    bool IsLarge = false;
+    if (isa<GlobalVariable>(GO))
----------------
Use `bool IsLarge = ... && ...` or avoid the used-once variable.


================
Comment at: llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp:858
   }
+  if (isa<GlobalVariable>(GO)) {
+    if (TM.isLargeData()) {
----------------
Use `&&`


================
Comment at: llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp:2177
   bool UniqueSectionNames = TM.getUniqueSectionNames();
-  SmallString<128> Name = getSectionPrefixForGlobal(Kind);
+  SmallString<128> Name = getSectionPrefixForGlobal(Kind, /*IsLarge*/ false);
 
----------------
The canonical spelling liked by both clang-format and clang-tidy is `/*IsLarge=*/false` (no space).


================
Comment at: llvm/lib/Target/TargetMachine.cpp:47
+  // restrict this to medium.
+  if (getCodeModel() != CodeModel::Medium)
+    return false;
----------------
`return getCodeModel() == CodeModel::Medium`


================
Comment at: llvm/test/CodeGen/X86/code-model-elf-sections.ll:3
+; RUN: llvm-readobj -S %t | FileCheck %s --check-prefix=SMALL
+; RUN: llc < %s -relocation-model=pic -filetype=obj -code-model=medium -o %t
+; RUN: llvm-readobj -S %t | FileCheck %s --check-prefix=LARGE
----------------
It will be useful to test fdata-sections


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D148836/new/

https://reviews.llvm.org/D148836