[lanai] Simplify small section check in LowerGlobalAddress and treat …

…ldata sections specially.

Move the check for the code model into isGlobalInSmallSectionImpl and return false (not in small section) for variables placed in sections prefixed with .ldata (workaround for a tool limitation).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289832 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Lanai/LanaiISelLowering.cpp

@@ -1170,8 +1170,7 @@ SDValue LanaiTargetLowering::LowerGlobalAddress(SDValue Op,
   // If the code model is small or global variable will be placed in the small
   // section, then assume address will fit in 21-bits.
   const GlobalObject *GO = GV->getBaseObject();
-  if (getTargetMachine().getCodeModel() == CodeModel::Small ||
-      (GO && TLOF->isGlobalInSmallSection(GO, getTargetMachine()))) {
+  if (TLOF->isGlobalInSmallSection(GO, getTargetMachine())) {
     SDValue Small = DAG.getTargetGlobalAddress(
         GV, DL, getPointerTy(DAG.getDataLayout()), Offset, LanaiII::MO_NO_FLAG);
     return DAG.getNode(ISD::OR, DL, MVT::i32,

lib/Target/Lanai/LanaiTargetObjectFile.cpp

@@ -50,6 +50,9 @@ static bool isInSmallSection(uint64_t Size) {
 // section.
 bool LanaiTargetObjectFile::isGlobalInSmallSection(
     const GlobalObject *GO, const TargetMachine &TM) const {
+  if (GO == nullptr)
+    return false;
+
   // We first check the case where global is a declaration, because finding
   // section kind using getKindForGlobal() is only allowed for global
   // definitions.
@@ -72,12 +75,21 @@ bool LanaiTargetObjectFile::isGlobalInSmallSection(const GlobalObject *GO,
 // section. This method does all the work, except for checking the section
 // kind.
 bool LanaiTargetObjectFile::isGlobalInSmallSectionImpl(
-    const GlobalObject *GO, const TargetMachine & /*TM*/) const {
+    const GlobalObject *GO, const TargetMachine &TM) const {
   // Only global variables, not functions.
   const auto *GVA = dyn_cast<GlobalVariable>(GO);
   if (!GVA)
     return false;
 
+  // Global values placed in sections starting with .ldata do not fit in
+  // 21-bits, so always use large memory access for them. FIXME: This is a
+  // workaround for a tool limitation.
+  if (GVA->getSection().startswith(".ldata"))
+    return false;
+
+  if (TM.getCodeModel() == CodeModel::Small)
+    return true;
+
   if (GVA->hasLocalLinkage())
     return false;
 

test/CodeGen/Lanai/codemodel.ll

@@ -28,3 +28,17 @@ entry:
 	ret i32 %0
 }
 
+@y = local_unnamed_addr global i32* null, section ".ldata,block", align 8
+
+define i32 @foo2() nounwind readonly {
+entry:
+; CHECK-SMALL-LABEL:  foo2:
+; CHECK-SMALL: mov hi(y), %r[[REGISTER:[0-9]+]]
+; CHECK-SMALL: or %r[[REGISTER]], lo(y), %r[[REGISTER]]
+; CHECK-LABEL:  foo2:
+; CHECK: mov hi(y), %r[[REGISTER:[0-9]+]]
+; CHECK: or %r[[REGISTER]], lo(y), %r[[REGISTER]]
+  %0 = load i32*, i32** @y, align 8
+  %1 = load i32, i32* %0, align 4
+  ret i32 %1
+}