[ARM] GlobalISel: Support global variables for RWPI

In RWPI code, globals that are not read-only are accessed relative to
the SB register (R9). This is achieved by explicitly generating an ADD
instruction between SB and an offset that we either load from a constant
pool or movw + movt into a register.

llvm-svn: 312521

3 files changed, 72 insertions, 12 deletions

diff --git a/llvm/test/CodeGen/ARM/GlobalISel/arm-isel-globals-ropi-rwpi.ll b/llvm/test/CodeGen/ARM/GlobalISel/arm-isel-globals-ropi-rwpi.ll
index 2616540003d..f52fb769c1e 100644
--- a/llvm/test/CodeGen/ARM/GlobalISel/arm-isel-globals-ropi-rwpi.ll
+++ b/llvm/test/CodeGen/ARM/GlobalISel/arm-isel-globals-ropi-rwpi.ll
@@ -1,5 +1,9 @@
 ; RUN: llc -mtriple armv7-linux -relocation-model=ropi -mattr=-no-movt,+v8m -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,RW-DEFAULT-MOVT,RW-DEFAULT,ROPI-MOVT,ROPI
 ; RUN: llc -mtriple armv7-linux -relocation-model=ropi -mattr=+no-movt -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,RW-DEFAULT-NOMOVT,RW-DEFAULT,ROPI-NOMOVT,ROPI
+; RUN: llc -mtriple armv7-linux -relocation-model=rwpi -mattr=-no-movt,+v8m -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,RO-DEFAULT-MOVT,RO-DEFAULT,RWPI-MOVT,RWPI
+; RUN: llc -mtriple armv7-linux -relocation-model=rwpi -mattr=+no-movt -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,RO-DEFAULT-NOMOVT,RO-DEFAULT,RWPI-NOMOVT,RWPI
+; RUN: llc -mtriple armv7-linux -relocation-model=ropi-rwpi -mattr=-no-movt,+v8m -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,ROPI-MOVT,ROPI,RWPI-MOVT,RWPI
+; RUN: llc -mtriple armv7-linux -relocation-model=ropi-rwpi -mattr=+no-movt -global-isel %s -o - | FileCheck %s -check-prefixes=CHECK,ROPI-NOMOVT,ROPI,RWPI-NOMOVT,RWPI
 
 @internal_global = internal global i32 42
 define i32 @test_internal_global() {
@@ -11,6 +15,15 @@ define i32 @test_internal_global() {
 ; RW-DEFAULT-NEXT: bx lr
 ; RW-DEFAULT-NOMOVT: [[LABEL]]:
 ; RW-DEFAULT-NOMOVT-NEXT: .long internal_global
+
+; RWPI-MOVT: movw [[OFFSET:r[0-9]+]], :lower16:internal_global(sbrel)
+; RWPI-MOVT-NEXT: movt [[OFFSET]], :upper16:internal_global(sbrel)
+; RWPI-NOMOVT: ldr [[OFFSET:r[0-9]+]], [[LABEL:.L[[:alnum:]_]+]]
+; RWPI-NEXT: add r[[ADDR:[0-9]+]], r9, [[OFFSET]]
+; RWPI-NEXT: ldr r0, [r[[ADDR]]]
+; RWPI-NEXT: bx lr
+; RWPI-NOMOVT: [[LABEL]]:
+; RWPI-NOMOVT-NEXT: .long internal_global(sbrel)
 entry:
   %v = load i32, i32* @internal_global
   ret i32 %v
@@ -26,6 +39,15 @@ define i32 @test_external_global() {
 ; RW-DEFAULT-NEXT: bx lr
 ; RW-DEFAULT-NOMOVT: [[LABEL]]:
 ; RW-DEFAULT-NOMOVT: .long external_global
+
+; RWPI-MOVT: movw [[OFFSET:r[0-9]+]], :lower16:external_global(sbrel)
+; RWPI-MOVT-NEXT: movt [[OFFSET]], :upper16:external_global(sbrel)
+; RWPI-NOMOVT: ldr [[OFFSET:r[0-9]+]], [[LABEL:.L[[:alnum:]_]+]]
+; RWPI-NEXT: add r[[ADDR:[0-9]+]], r9, [[OFFSET]]
+; RWPI-NEXT: ldr r0, [r[[ADDR]]]
+; RWPI-NEXT: bx lr
+; RWPI-NOMOVT: [[LABEL]]:
+; RWPI-NOMOVT-NEXT: .long external_global(sbrel)
 entry:
   %v = load i32, i32* @external_global
   ret i32 %v
@@ -44,6 +66,14 @@ define i32 @test_internal_constant() {
 ; ROPI-NEXT: bx lr
 ; ROPI-NOMOVT: [[LABEL]]:
 ; ROPI-NOMOVT-NEXT: .long internal_constant-([[ANCHOR]]+8)
+
+; RO-DEFAULT-MOVT: movw r[[ADDR:[0-9]+]], :lower16:internal_constant
+; RO-DEFAULT-MOVT-NEXT: movt r[[ADDR]], :upper16:internal_constant
+; RO-DEFAULT-NOMOVT: ldr r[[ADDR:[0-9]+]], [[LABEL:.L[[:alnum:]_]+]]
+; RO-DEFAULT-NEXT: ldr r0, [r[[ADDR]]]
+; RO-DEFAULT-NEXT: bx lr
+; RO-DEFAULT-NOMOVT: [[LABEL]]:
+; RO-DEFAULT-NOMOVT-NEXT: .long internal_constant
 entry:
   %v = load i32, i32* @internal_constant
   ret i32 %v
@@ -62,6 +92,14 @@ define i32 @test_external_constant() {
 ; ROPI-NEXT: bx lr
 ; ROPI-NOMOVT: [[LABEL]]:
 ; ROPI-NOMOVT-NEXT: .long external_constant-([[ANCHOR]]+8)
+
+; RO-DEFAULT-MOVT: movw r[[ADDR:[0-9]+]], :lower16:external_constant
+; RO-DEFAULT-MOVT-NEXT: movt r[[ADDR]], :upper16:external_constant
+; RO-DEFAULT-NOMOVT: ldr r[[ADDR:[0-9]+]], [[LABEL:.L[[:alnum:]_]+]]
+; RO-DEFAULT-NEXT: ldr r0, [r[[ADDR]]]
+; RO-DEFAULT-NEXT: bx lr
+; RO-DEFAULT-NOMOVT: [[LABEL]]:
+; RO-DEFAULT-NOMOVT: .long external_constant
 entry:
   %v = load i32, i32* @external_constant
   ret i32 %v
@@ -71,6 +109,14 @@ entry:
 ; RW-DEFAULT-NOMOVT: .long 42
 ; RW-DEFAULT-NOMOVT: .size internal_global, 4
 
+; RWPI-NOMOVT: internal_global:
+; RWPI-NOMOVT: .long 42
+; RWPI-NOMOVT: .size internal_global, 4
+
 ; ROPI-NOMOVT: internal_constant:
 ; ROPI-NOMOVT: .long 42
 ; ROPI-NOMOVT: .size internal_constant, 4
+
+; RO-DEFAULT-NOMOVT: internal_constant:
+; RO-DEFAULT-NOMOVT: .long 42
+; RO-DEFAULT-NOMOVT: .size internal_constant, 4
diff --git a/llvm/test/CodeGen/ARM/GlobalISel/arm-select-globals-ropi-rwpi.mir b/llvm/test/CodeGen/ARM/GlobalISel/arm-select-globals-ropi-rwpi.mir
index fc8d3bc4152..c31893cf229 100644
--- a/llvm/test/CodeGen/ARM/GlobalISel/arm-select-globals-ropi-rwpi.mir
+++ b/llvm/test/CodeGen/ARM/GlobalISel/arm-select-globals-ropi-rwpi.mir
@@ -1,5 +1,9 @@
 # RUN: llc -O0 -mtriple arm-linux -relocation-model=ropi -mattr=-no-movt,+v8m -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RW-DEFAULT-MOVT,RW-DEFAULT,ROPI-MOVT,ROPI
 # RUN: llc -O0 -mtriple arm-linux -relocation-model=ropi -mattr=+no-movt -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RW-DEFAULT-NOMOVT,RW-DEFAULT,ROPI-NOMOVT,ROPI
+# RUN: llc -O0 -mtriple arm-linux -relocation-model=rwpi -mattr=-no-movt,+v8m -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RWPI-MOVT,RWPI,RO-DEFAULT-MOVT,RO-DEFAULT
+# RUN: llc -O0 -mtriple arm-linux -relocation-model=rwpi -mattr=+no-movt -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RWPI-NOMOVT,RWPI,RO-DEFAULT-NOMOVT,RO-DEFAULT
+# RUN: llc -O0 -mtriple arm-linux -relocation-model=ropi-rwpi -mattr=-no-movt,+v8m -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RWPI-MOVT,RWPI,ROPI-MOVT,ROPI
+# RUN: llc -O0 -mtriple arm-linux -relocation-model=ropi-rwpi -mattr=+no-movt -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=CHECK,RWPI-NOMOVT,RWPI,ROPI-NOMOVT,ROPI
 --- |
   @internal_global = internal global i32 42
   define void @test_internal_global() { ret void }
@@ -26,11 +30,17 @@ registers:
 # RW-DEFAULT-NOMOVT: constants:
 # RW-DEFAULT-NOMOVT: id: 0
 # RW-DEFAULT-NOMOVT: value: 'i32* @internal_global'
+# RWPI-NOMOVT: constants:
+# RWPI-NOMOVT: id: 0
+# RWPI-NOMOVT: value: 'internal_global(SBREL)'
 body:             |
   bb.0:
     %0(p0) = G_GLOBAL_VALUE @internal_global
     ; RW-DEFAULT-MOVT: [[G:%[0-9]+]] = MOVi32imm @internal_global
     ; RW-DEFAULT-NOMOVT: [[G:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
+    ; RWPI-MOVT: [[OFF:%[0-9]+]] = MOVi32imm {{.*}} @internal_global
+    ; RWPI-NOMOVT: [[OFF:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
+    ; RWPI: [[G:%[0-9]+]] = ADDrr %r9, [[OFF]], 14, _, _
 
     %1(s32) = G_LOAD %0(p0) :: (load 4 from @internal_global)
     ; CHECK: [[V:%[0-9]+]] = LDRi12 [[G]], 0, 14, _ :: (load 4 from @internal_global)
@@ -54,11 +64,17 @@ registers:
 # RW-DEFAULT-NOMOVT: constants:
 # RW-DEFAULT-NOMOVT: id: 0
 # RW-DEFAULT-NOMOVT: value: 'i32* @external_global'
+# RWPI-NOMOVT: constants:
+# RWPI-NOMOVT: id: 0
+# RWPI-NOMOVT: value: 'external_global(SBREL)'
 body:             |
   bb.0:
     %0(p0) = G_GLOBAL_VALUE @external_global
     ; RW-DEFAULT-MOVT: [[G:%[0-9]+]] = MOVi32imm @external_global
     ; RW-DEFAULT-NOMOVT: [[G:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
+    ; RWPI-MOVT: [[OFF:%[0-9]+]] = MOVi32imm {{.*}} @external_global
+    ; RWPI-NOMOVT: [[OFF:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
+    ; RWPI: [[G:%[0-9]+]] = ADDrr %r9, [[OFF]], 14, _, _
 
     %1(s32) = G_LOAD %0(p0) :: (load 4 from @external_global)
     ; CHECK: [[V:%[0-9]+]] = LDRi12 [[G]], 0, 14, _ :: (load 4 from @external_global)
@@ -79,11 +95,16 @@ selected:        false
 registers:
   - { id: 0, class: gprb }
   - { id: 1, class: gprb }
+# RO-DEFAULT-NOMOVT: constants:
+# RO-DEFAULT-NOMOVT: id: 0
+# RO-DEFAULT-NOMOVT: value: 'i32* @internal_constant'
 body:             |
   bb.0:
     %0(p0) = G_GLOBAL_VALUE @internal_constant
     ; ROPI-MOVT: [[G:%[0-9]+]] = MOV_ga_pcrel @internal_constant
     ; ROPI-NOMOVT: [[G:%[0-9]+]] = LDRLIT_ga_pcrel @internal_constant
+    ; RO-DEFAULT-MOVT: [[G:%[0-9]+]] = MOVi32imm @internal_constant
+    ; RO-DEFAULT-NOMOVT: [[G:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
 
     %1(s32) = G_LOAD %0(p0) :: (load 4 from @internal_constant)
     ; CHECK: [[V:%[0-9]+]] = LDRi12 [[G]], 0, 14, _ :: (load 4 from @internal_constant)
@@ -104,11 +125,16 @@ selected:        false
 registers:
   - { id: 0, class: gprb }
   - { id: 1, class: gprb }
+# RO-DEFAULT-NOMOVT: constants:
+# RO-DEFAULT-NOMOVT: id: 0
+# RO-DEFAULT-NOMOVT: value: 'i32* @external_constant'
 body:             |
   bb.0:
     %0(p0) = G_GLOBAL_VALUE @external_constant
     ; ROPI-MOVT: [[G:%[0-9]+]] = MOV_ga_pcrel @external_constant
     ; ROPI-NOMOVT: [[G:%[0-9]+]] = LDRLIT_ga_pcrel @external_constant
+    ; RO-DEFAULT-MOVT: [[G:%[0-9]+]] = MOVi32imm @external_constant
+    ; RO-DEFAULT-NOMOVT: [[G:%[0-9]+]] = LDRi12 %const.0, 0, 14, _ :: (load 4 from constant-pool)
 
     %1(s32) = G_LOAD %0(p0) :: (load 4 from @external_constant)
     ; CHECK: [[V:%[0-9]+]] = LDRi12 [[G]], 0, 14, _ :: (load 4 from @external_constant)
diff --git a/llvm/test/CodeGen/ARM/GlobalISel/arm-unsupported.ll b/llvm/test/CodeGen/ARM/GlobalISel/arm-unsupported.ll
index 19ccc1773e3..bdba5356390 100644
--- a/llvm/test/CodeGen/ARM/GlobalISel/arm-unsupported.ll
+++ b/llvm/test/CodeGen/ARM/GlobalISel/arm-unsupported.ll
@@ -113,16 +113,4 @@ define i32 @test_thread_local_global() {
   ret i32 %v
 }
 
-@a_global = external global i32
-
-define i32 @test_global_reloc_models() {
-; This is only unsupported for the RWPI relocation modes.
-; RWPI: remark: {{.*}} cannot select: {{.*}} G_GLOBAL_VALUE
-; RWPI-LABEL: warning: Instruction selection used fallback path for test_global_reloc_models
-; ROPI-RWPI: remark: {{.*}} cannot select: {{.*}} G_GLOBAL_VALUE
-; ROPI-RWPI-LABEL: warning: Instruction selection used fallback path for test_global_reloc_models
-  %v = load i32, i32* @a_global
-  ret i32 %v
-}
-
 attributes #0 = { "target-features"="+thumb-mode" }