[llvm][LoongArch] Support per-global code model attribute for LoongArch

[heiher]

This patch gets the code model from global variable attribute if it has, otherwise the target's will be used.

[llvmbot]

@llvm/pr-subscribers-clang
@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-backend-loongarch

Author: hev (heiher)

Changes

This gets the code model from global variable if it has, otherwise the target's will be used.

---

Full diff: https://github.com/llvm/llvm-project/pull/72079.diff

3 Files Affected:

• (modified) llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp (+11-6)
• (modified) llvm/lib/Target/LoongArch/LoongArchISelLowering.h (+2-1)
• (added) llvm/test/CodeGen/LoongArch/global-variable-code-model.ll (+44)

diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
index f3f72e74ef085a2..873ee87ae14bcd2 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -599,12 +599,12 @@ static SDValue getTargetNode(JumpTableSDNode *N, SDLoc DL, EVT Ty,
 
 template <class NodeTy>
 SDValue LoongArchTargetLowering::getAddr(NodeTy *N, SelectionDAG &DAG,
-                                         bool IsLocal) const {
+                                         CodeModel::Model M, bool IsLocal) const {
   SDLoc DL(N);
   EVT Ty = getPointerTy(DAG.getDataLayout());
   SDValue Addr = getTargetNode(N, DL, Ty, DAG, 0);
 
-  switch (DAG.getTarget().getCodeModel()) {
+  switch (M) {
   default:
     report_fatal_error("Unsupported code model");
 
@@ -645,24 +645,29 @@ SDValue LoongArchTargetLowering::getAddr(NodeTy *N, SelectionDAG &DAG,
 
 SDValue LoongArchTargetLowering::lowerBlockAddress(SDValue Op,
                                                    SelectionDAG &DAG) const {
-  return getAddr(cast<BlockAddressSDNode>(Op), DAG);
+  return getAddr(cast<BlockAddressSDNode>(Op), DAG, DAG.getTarget().getCodeModel());
 }
 
 SDValue LoongArchTargetLowering::lowerJumpTable(SDValue Op,
                                                 SelectionDAG &DAG) const {
-  return getAddr(cast<JumpTableSDNode>(Op), DAG);
+  return getAddr(cast<JumpTableSDNode>(Op), DAG, DAG.getTarget().getCodeModel());
 }
 
 SDValue LoongArchTargetLowering::lowerConstantPool(SDValue Op,
                                                    SelectionDAG &DAG) const {
-  return getAddr(cast<ConstantPoolSDNode>(Op), DAG);
+  return getAddr(cast<ConstantPoolSDNode>(Op), DAG, DAG.getTarget().getCodeModel());
 }
 
 SDValue LoongArchTargetLowering::lowerGlobalAddress(SDValue Op,
                                                     SelectionDAG &DAG) const {
   GlobalAddressSDNode *N = cast<GlobalAddressSDNode>(Op);
   assert(N->getOffset() == 0 && "unexpected offset in global node");
-  return getAddr(N, DAG, N->getGlobal()->isDSOLocal());
+  auto CM = DAG.getTarget().getCodeModel();
+  const GlobalValue *GV = N->getGlobal();
+  const auto *GO = dyn_cast<GlobalObject>(GV);
+  if (GV->isDSOLocal() && GO && GO->hasCodeModel())
+    CM = GO->getCodeModel();
+  return getAddr(N, DAG, CM, GV->isDSOLocal());
 }
 
 SDValue LoongArchTargetLowering::getStaticTLSAddr(GlobalAddressSDNode *N,
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
index 3141286671055dd..d7e28608890ac1a 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
@@ -247,7 +247,8 @@ class LoongArchTargetLowering : public TargetLowering {
                          LoongArchCCAssignFn Fn) const;
 
   template <class NodeTy>
-  SDValue getAddr(NodeTy *N, SelectionDAG &DAG, bool IsLocal = true) const;
+  SDValue getAddr(NodeTy *N, SelectionDAG &DAG, CodeModel::Model M,
+                  bool IsLocal = true) const;
   SDValue getStaticTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG,
                            unsigned Opc, bool Large = false) const;
   SDValue getDynamicTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG,
diff --git a/llvm/test/CodeGen/LoongArch/global-variable-code-model.ll b/llvm/test/CodeGen/LoongArch/global-variable-code-model.ll
new file mode 100644
index 000000000000000..db2feb5c0acdb38
--- /dev/null
+++ b/llvm/test/CodeGen/LoongArch/global-variable-code-model.ll
@@ -0,0 +1,44 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc --mtriple=loongarch64 < %s | FileCheck %s
+
+@a= external dso_local global i32, code_model "small", align 4
+
+define dso_local signext i32 @local_small() #0 {
+; CHECK-LABEL: local_small:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pcalau12i $a0, %pc_hi20(a)
+; CHECK-NEXT:    addi.d $a0, $a0, %pc_lo12(a)
+; CHECK-NEXT:    ld.w $a0, $a0, 0
+; CHECK-NEXT:    ret
+  %1 = load i32, ptr @a, align 4
+  ret i32 %1
+}
+
+@b= external dso_local global i32, code_model "large", align 4
+
+define dso_local signext i32 @local_large() #0 {
+; CHECK-LABEL: local_large:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pcalau12i $a0, %pc_hi20(b)
+; CHECK-NEXT:    addi.d $a1, $zero, %pc_lo12(b)
+; CHECK-NEXT:    lu32i.d $a1, %pc64_lo20(b)
+; CHECK-NEXT:    lu52i.d $a1, $a1, %pc64_hi12(b)
+; CHECK-NEXT:    add.d $a0, $a1, $a0
+; CHECK-NEXT:    ld.w $a0, $a0, 0
+; CHECK-NEXT:    ret
+  %1 = load i32, ptr @b, align 4
+  ret i32 %1
+}
+
+@c= external global i32, code_model "large", align 4
+
+define dso_local signext i32 @non_local_large() #0 {
+; CHECK-LABEL: non_local_large:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pcalau12i $a0, %got_pc_hi20(c)
+; CHECK-NEXT:    ld.d $a0, $a0, %got_pc_lo12(c)
+; CHECK-NEXT:    ld.w $a0, $a0, 0
+; CHECK-NEXT:    ret
+  %1 = load i32, ptr @c, align 4
+  ret i32 %1
+}

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[heiher]

Part 1/3: #72077
Part 2/3: #72078

[heiher]

cc @xen0n @xry111

[xen0n]

I think we should initially only support the attribute on LoongArch. GCC's model attribute is only ever supported on ia64 and loongarch, yet the patch currently seems to allow other architectures to use this attribute, with LLVM code model names accepted -- this may or may not be what the targets actually want, if they decide to add support for the attribute in GCC.

[heiher]

I think we should initially only support the attribute on LoongArch. GCC's model attribute is only ever supported on ia64 and loongarch, yet the patch currently seems to allow other architectures to use this attribute, with LLVM code model names accepted -- this may or may not be what the targets actually want, if they decide to add support for the attribute in GCC.

Done. Thanks

[SixWeining]

LGTM with a small nit.