[X86] Introduce a large data threshold for the medium code model

Currently clang's medium code model treats all data as large, putting them in a large data section and using more expensive instruction sequences to access them.

Following gcc's -mlarge-data-threshold, which allows putting data under a certain size in a normal data section as opposed to a large data section. This allows using cheaper code sequences to access some portion of data in the binary (which will be implemented in LLVM in a future patch).

And under the medium codel mode, only put data above the large data threshold into large data sections, not all data.

Reviewed By: MaskRay, rnk

Differential Revision: https://reviews.llvm.org/D149288

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 55fb522..622c8ad 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -651,8 +651,8 @@ getELFSectionNameForGlobal(const GlobalObject *GO, SectionKind Kind,
     Name += utostr(EntrySize);
   } else {
     bool IsLarge = false;
-    if (isa<GlobalVariable>(GO))
-      IsLarge = TM.isLargeData();
+    if (auto *GV = dyn_cast<GlobalVariable>(GO))
+      IsLarge = TM.isLargeData(GV);
     Name = getSectionPrefixForGlobal(Kind, IsLarge);
   }
 
@@ -855,8 +855,8 @@ static MCSectionELF *selectELFSectionForGlobal(
     Group = C->getName();
     IsComdat = C->getSelectionKind() == Comdat::Any;
   }
-  if (isa<GlobalVariable>(GO)) {
-    if (TM.isLargeData()) {
+  if (auto *GV = dyn_cast<GlobalVariable>(GO)) {
+    if (TM.isLargeData(GV)) {
       assert(TM.getTargetTriple().getArch() == Triple::x86_64);
       Flags |= ELF::SHF_X86_64_LARGE;
     }