[PATCH] D85126: AArch64: use a constpool for blockaddress(...) on MachO

[Tim Northover via Phabricator via llvm-commits]

t.p.northover updated this revision to Diff 283594.
t.p.northover added a comment.

Ahmed pointed out that `getAddr` already results in a `MOVaddrBA` eventually so the ISelLowering change was pointless.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85126/new/

https://reviews.llvm.org/D85126

Files:
  llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
  llvm/test/CodeGen/AArch64/arm64-blockaddress.ll
  llvm/test/CodeGen/AArch64/arm64_32.ll


Index: llvm/test/CodeGen/AArch64/arm64_32.ll
===================================================================
--- llvm/test/CodeGen/AArch64/arm64_32.ll
+++ llvm/test/CodeGen/AArch64/arm64_32.ll
@@ -450,8 +450,8 @@
 define i8* @test_blockaddress() {
 ; CHECK-LABEL: test_blockaddress:
 ; CHECK: [[BLOCK:Ltmp[0-9]+]]:
-; CHECK: adrp [[PAGE:x[0-9]+]], [[BLOCK]]@PAGE
-; CHECK: add x0, [[PAGE]], [[BLOCK]]@PAGEOFF
+; CHECK: adrp x[[PAGE:[0-9]+]], lCPI{{[0-9]+_[0-9]+}}@PAGE
+; CHECK: ldr x0, [x[[PAGE]], lCPI{{[0-9]+_[0-9]+}}@PAGEOFF]
   br label %dest
 dest:
   ret i8* blockaddress(@test_blockaddress, %dest)
Index: llvm/test/CodeGen/AArch64/arm64-blockaddress.ll
===================================================================
--- llvm/test/CodeGen/AArch64/arm64-blockaddress.ll
+++ llvm/test/CodeGen/AArch64/arm64-blockaddress.ll
@@ -1,4 +1,5 @@
-; RUN: llc < %s -mtriple=arm64-apple-ios | FileCheck %s
+; RUN: llc < %s -mtriple=arm64-apple-ios | FileCheck %s --check-prefix=CHECK-IOS
+; RUN: llc < %s -mtriple=arm64-apple-ios -global-isel | FileCheck %s --check-prefix=CHECK-IOS
 ; RUN: llc < %s -mtriple=arm64-linux-gnu | FileCheck %s --check-prefix=CHECK-LINUX
 ; RUN: llc < %s -mtriple=arm64-linux-gnu -code-model=large| FileCheck %s --check-prefix=CHECK-LARGE
 
@@ -6,9 +7,11 @@
 
 define i64 @t() nounwind ssp {
 entry:
-; CHECK-LABEL: t:
-; CHECK: adrp [[REG:x[0-9]+]], Ltmp0 at PAGE
-; CHECK: add {{x[0-9]+}}, [[REG]], Ltmp0 at PAGEOFF
+; CHECK-IOS: lCPI0_0:
+; CHECK-IOS:     .quad Ltmp0
+; CHECK-IOS-LABEL: _t:
+; CHECK-IOS: adrp x[[TMP:[0-9]+]], lCPI0_0 at PAGE
+; CHECK-IOS: ldr {{x[0-9]+}}, [x[[TMP]], lCPI0_0 at PAGEOFF]
 
 ; CHECK-LINUX-LABEL: t:
 ; CHECK-LINUX: adrp [[REG:x[0-9]+]], .Ltmp0
Index: llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
+++ llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
@@ -23,6 +23,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/LivePhysRegs.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstr.h"
@@ -835,11 +836,36 @@
     MI.eraseFromParent();
     return true;
   }
+  case AArch64::MOVaddrBA: {
+    MachineFunction &MF = *MI.getParent()->getParent();
+    if (MF.getSubtarget<AArch64Subtarget>().isTargetMachO()) {
+      // blockaddress expressions have to come from a constant pool because the
+      // largest addend (and hence offset within a function) allowed for ADRP is
+      // only 8MB.
+      const BlockAddress *BA = MI.getOperand(1).getBlockAddress();
+      assert(MI.getOperand(1).getOffset() == 0 && "unexpected offset");
+
+      MachineConstantPool *MCP = MF.getConstantPool();
+      unsigned CPIdx = MCP->getConstantPoolIndex(BA, Align(8));
 
+      Register DstReg = MI.getOperand(0).getReg();
+      auto MIB1 =
+          BuildMI(MBB, MBBI, MI.getDebugLoc(), TII->get(AArch64::ADRP), DstReg)
+              .addConstantPoolIndex(CPIdx, 0, AArch64II::MO_PAGE);
+      auto MIB2 = BuildMI(MBB, MBBI, MI.getDebugLoc(),
+                          TII->get(AArch64::LDRXui), DstReg)
+                      .addUse(DstReg)
+                      .addConstantPoolIndex(
+                          CPIdx, 0, AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
+      transferImpOps(MI, MIB1, MIB2);
+      MI.eraseFromParent();
+      return true;
+    }
+  }
+    LLVM_FALLTHROUGH;
   case AArch64::MOVaddr:
   case AArch64::MOVaddrJT:
   case AArch64::MOVaddrCP:
-  case AArch64::MOVaddrBA:
   case AArch64::MOVaddrTLS:
   case AArch64::MOVaddrEXT: {
     // Expand into ADRP + ADD.


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