[Thumb,ELF] Fix access to dso_preemptable __stack_chk_guard with static relocation model (#78950)

PR #70014 fixes A32 to use GOT for dso_preemptable `__stack_chk_guard`
with static relocation model (e.g. -fPIE/-fPIC LTO compiles with -no-pie
linking).

This patch fixes such `__stack_chk_guard` access for Thumb1 and Thumb2.
Note: `t2LDRLIT_ga_pcrel` is only for ELF. mingw needs
`.refptr.__stack_chk_guard` (https://reviews.llvm.org/D92738).

Fix #64999

Author: MaskRay

llvm/lib/Target/ARM/Thumb1InstrInfo.cpp

@@ -135,14 +135,14 @@ void Thumb1InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
 void Thumb1InstrInfo::expandLoadStackGuard(
     MachineBasicBlock::iterator MI) const {
   MachineFunction &MF = *MI->getParent()->getParent();
-  const TargetMachine &TM = MF.getTarget();
   const ARMSubtarget &ST = MF.getSubtarget<ARMSubtarget>();
+  const auto *GV = cast<GlobalValue>((*MI->memoperands_begin())->getValue());
 
   assert(MF.getFunction().getParent()->getStackProtectorGuard() != "tls" &&
          "TLS stack protector not supported for Thumb1 targets");
 
   unsigned Instr;
-  if (TM.isPositionIndependent())
+  if (!GV->isDSOLocal())
     Instr = ARM::tLDRLIT_ga_pcrel;
   else if (ST.genExecuteOnly() && ST.hasV8MBaselineOps())
     Instr = ARM::t2MOVi32imm;

llvm/lib/Target/ARM/Thumb2InstrInfo.cpp

@@ -261,10 +261,8 @@ void Thumb2InstrInfo::expandLoadStackGuard(
     return;
   }
 
-  const GlobalValue *GV =
-      cast<GlobalValue>((*MI->memoperands_begin())->getValue());
-
-  if (MF.getSubtarget<ARMSubtarget>().isGVInGOT(GV))
+  const auto *GV = cast<GlobalValue>((*MI->memoperands_begin())->getValue());
+  if (MF.getSubtarget<ARMSubtarget>().isTargetELF() && !GV->isDSOLocal())
     expandLoadStackGuardBase(MI, ARM::t2LDRLIT_ga_pcrel, ARM::t2LDRi12);
   else if (MF.getTarget().isPositionIndependent())
     expandLoadStackGuardBase(MI, ARM::t2MOV_ga_pcrel, ARM::t2LDRi12);

llvm/test/CodeGen/ARM/stack-guard-elf.ll

@@ -59,6 +59,8 @@ define i32 @test1() #0 {
 ; THUMB1-NEXT:    .pad #16
 ; THUMB1-NEXT:    sub sp, #16
 ; THUMB1-NEXT:    ldr r0, .LCPI0_0
+; THUMB1-NEXT:  .LPC0_0:
+; THUMB1-NEXT:    add r0, pc
 ; THUMB1-NEXT:    ldr r0, [r0]
 ; THUMB1-NEXT:    ldr r0, [r0]
 ; THUMB1-NEXT:    add r1, sp, #904
@@ -67,7 +69,9 @@ define i32 @test1() #0 {
 ; THUMB1-NEXT:    bl foo
 ; THUMB1-NEXT:    add r0, sp, #904
 ; THUMB1-NEXT:    ldr r0, [r0, #124]
-; THUMB1-NEXT:    ldr r1, .LCPI0_0
+; THUMB1-NEXT:    ldr r1, .LCPI0_1
+; THUMB1-NEXT:  .LPC0_1:
+; THUMB1-NEXT:    add r1, pc
 ; THUMB1-NEXT:    ldr r1, [r1]
 ; THUMB1-NEXT:    ldr r1, [r1]
 ; THUMB1-NEXT:    cmp r1, r0
@@ -83,7 +87,11 @@ define i32 @test1() #0 {
 ; THUMB1-NEXT:    .p2align 2
 ; THUMB1-NEXT:  @ %bb.3:
 ; THUMB1-NEXT:  .LCPI0_0:
-; THUMB1-NEXT:    .long __stack_chk_guard
+; THUMB1-NEXT:  .Ltmp0:
+; THUMB1-NEXT:    .long __stack_chk_guard(GOT_PREL)-((.LPC0_0+4)-.Ltmp0)
+; THUMB1-NEXT:  .LCPI0_1:
+; THUMB1-NEXT:  .Ltmp1:
+; THUMB1-NEXT:    .long __stack_chk_guard(GOT_PREL)-((.LPC0_1+4)-.Ltmp1)
 ;
 ; THUMB1-PIC-LABEL: test1:
 ; THUMB1-PIC:       @ %bb.0:
@@ -136,16 +144,18 @@ define i32 @test1() #0 {
 ; THUMB2-NEXT:    push {r7, lr}
 ; THUMB2-NEXT:    .pad #1032
 ; THUMB2-NEXT:    sub.w sp, sp, #1032
-; THUMB2-NEXT:    movw r0, :lower16:__stack_chk_guard
-; THUMB2-NEXT:    movt r0, :upper16:__stack_chk_guard
+; THUMB2-NEXT:    ldr r0, .LCPI0_0
+; THUMB2-NEXT:  .LPC0_0:
+; THUMB2-NEXT:    add r0, pc
 ; THUMB2-NEXT:    ldr r0, [r0]
 ; THUMB2-NEXT:    ldr r0, [r0]
 ; THUMB2-NEXT:    str.w r0, [sp, #1028]
 ; THUMB2-NEXT:    add r0, sp, #4
 ; THUMB2-NEXT:    bl foo
-; THUMB2-NEXT:    movw r1, :lower16:__stack_chk_guard
 ; THUMB2-NEXT:    ldr.w r0, [sp, #1028]
-; THUMB2-NEXT:    movt r1, :upper16:__stack_chk_guard
+; THUMB2-NEXT:    ldr r1, .LCPI0_1
+; THUMB2-NEXT:  .LPC0_1:
+; THUMB2-NEXT:    add r1, pc
 ; THUMB2-NEXT:    ldr r1, [r1]
 ; THUMB2-NEXT:    ldr r1, [r1]
 ; THUMB2-NEXT:    cmp r1, r0
@@ -155,6 +165,14 @@ define i32 @test1() #0 {
 ; THUMB2-NEXT:    popeq {r7, pc}
 ; THUMB2-NEXT:  .LBB0_1:
 ; THUMB2-NEXT:    bl __stack_chk_fail
+; THUMB2-NEXT:    .p2align 2
+; THUMB2-NEXT:  @ %bb.2:
+; THUMB2-NEXT:  .LCPI0_0:
+; THUMB2-NEXT:  .Ltmp0:
+; THUMB2-NEXT:    .long __stack_chk_guard(GOT_PREL)-((.LPC0_0+4)-.Ltmp0)
+; THUMB2-NEXT:  .LCPI0_1:
+; THUMB2-NEXT:  .Ltmp1:
+; THUMB2-NEXT:    .long __stack_chk_guard(GOT_PREL)-((.LPC0_1+4)-.Ltmp1)
 ;
 ; THUMB2-PIC-LABEL: test1:
 ; THUMB2-PIC:       @ %bb.0: