[PATCH] D57183: [COFF, ARM64] Fix localaddress to handle stack realignment

[Mandeep Singh Grang via Phabricator via llvm-commits]

mgrang created this revision.
mgrang added reviewers: rnk, efriedma, ssijaric.
Herald added subscribers: kristof.beyls, javed.absar.

When stack realignment is needed (ie: when there are highly aligned objects on stack), the base pointer should be used.


Repository:
  rL LLVM

https://reviews.llvm.org/D57183

Files:
  lib/Target/AArch64/AArch64ISelLowering.cpp
  test/CodeGen/AArch64/seh-localaddress.ll


Index: test/CodeGen/AArch64/seh-localaddress.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/seh-localaddress.ll
@@ -0,0 +1,55 @@
+; RUN: llc -mtriple arm64-windows -o - %s | FileCheck %s
+
+; struct S { int x; };
+; void foo() {
+;   struct S __declspec(align(32)) o;
+;   __try { o.x; }
+;   __finally { o.x; }
+; }
+; void bar() {
+;   struct S o;
+;   __try { o.x; }
+;   __finally { o.x; }
+; }
+
+%struct.S = type { i32 }
+
+define dso_local void @"?foo@@YAXXZ"() #0 {
+entry:
+; CHECK-LABEL: foo
+; CHECK: mov x1, x19
+; CHECK-NOT: mov x1, x29
+
+  %o = alloca %struct.S, align 32
+  call void (...) @llvm.localescape(%struct.S* %o)
+  %x = getelementptr inbounds %struct.S, %struct.S* %o, i32 0, i32 0
+  %0 = call i8* @llvm.localaddress()
+  call void @"?fin$0 at 0@foo@@"(i8 0, i8* %0)
+  ret void
+}
+
+define dso_local void @"?bar@@YAXXZ"() {
+entry:
+; CHECK-LABEL: bar
+; CHECK: mov x1, x29
+; CHECK-NOT: mov x1, x19
+
+  %o = alloca %struct.S, align 4
+  call void (...) @llvm.localescape(%struct.S* %o)
+  %x = getelementptr inbounds %struct.S, %struct.S* %o, i32 0, i32 0
+  %0 = call i8* @llvm.localaddress()
+  call void @"?fin$0 at 0@bar@@"(i8 0, i8* %0)
+  ret void
+}
+
+declare void @"?fin$0 at 0@foo@@"(i8 %abnormal_termination, i8* %frame_pointer)
+
+declare void @"?fin$0 at 0@bar@@"(i8 %abnormal_termination, i8* %frame_pointer)
+
+declare i8* @llvm.localrecover(i8*, i8*, i32)
+
+declare i8* @llvm.localaddress()
+
+declare void @llvm.localescape(...)
+
+attributes #0 = { noinline optnone uwtable }
Index: lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- lib/Target/AArch64/AArch64ISelLowering.cpp
+++ lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -2744,15 +2744,13 @@
                        Op.getOperand(1), Op.getOperand(2));
 
   case Intrinsic::localaddress: {
-    // Returns one of the stack, base, or frame pointer registers, depending on
-    // which is used to reference local variables.
-    MachineFunction &MF = DAG.getMachineFunction();
-    const AArch64RegisterInfo *RegInfo = Subtarget->getRegisterInfo();
-    unsigned Reg;
-    if (RegInfo->hasBasePointer(MF))
-      Reg = RegInfo->getBaseRegister();
-    else // This function handles the SP or FP case.
-      Reg = RegInfo->getFrameRegister(MF);
+    auto &MF = DAG.getMachineFunction();
+    const auto *RegInfo = Subtarget->getRegisterInfo();
+
+    auto Reg = RegInfo->needsStackRealignment(MF) ?
+               RegInfo->getBaseRegister() :
+               RegInfo->getFrameRegister(MF);
+
     return DAG.getCopyFromReg(DAG.getEntryNode(), dl, Reg,
                               Op.getSimpleValueType());
   }


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