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[ARM] mlong-calls generate PIC code using GOT #39970 #147313

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[ARM] mlong-calls generate PIC code using GOT #39970 #147313

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16 changes: 12 additions & 4 deletions llvm/lib/Target/ARM/ARMISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2815,13 +2815,20 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
auto PtrVt = getPointerTy(DAG.getDataLayout());

if (Subtarget->genLongCalls()) {
assert((!isPositionIndependent() || Subtarget->isTargetWindows()) &&
"long-calls codegen is not position independent!");
// Handle a global address or an external symbol. If it's not one of
// those, the target's already in a register, so we don't need to do
// anything extra.
if (isa<GlobalAddressSDNode>(Callee)) {
if (Subtarget->genExecuteOnly()) {
if (isPositionIndependent() && !Subtarget->isTargetWindows() &&
!Subtarget->genExecuteOnly()) {
SDValue G = DAG.getTargetGlobalAddress(
GVal, dl, PtrVt, 0, GVal->isDSOLocal() ? 0 : ARMII::MO_GOT);
Callee = DAG.getNode(ARMISD::WrapperPIC, dl, PtrVt, G);
if (!GVal->isDSOLocal())
Callee =
DAG.getLoad(PtrVt, dl, DAG.getEntryNode(), Callee,
MachinePointerInfo::getGOT(DAG.getMachineFunction()));
} else if (Subtarget->genExecuteOnly()) {
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Does the execute-only codepath work correctly with PIC?

if (Subtarget->useMovt())
++NumMovwMovt;
Callee = DAG.getNode(ARMISD::Wrapper, dl, PtrVt,
Expand All @@ -2839,7 +2846,8 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
PtrVt, dl, DAG.getEntryNode(), Addr,
MachinePointerInfo::getConstantPool(DAG.getMachineFunction()));
}
} else if (ExternalSymbolSDNode *S=dyn_cast<ExternalSymbolSDNode>(Callee)) {
} else if (ExternalSymbolSDNode *S =
dyn_cast<ExternalSymbolSDNode>(Callee)) {
const char *Sym = S->getSymbol();

if (Subtarget->genExecuteOnly()) {
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Does the external-symbol codepath work correctly with PIC? (I think you can trigger this with llvm.memset or something like that.)

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32 changes: 32 additions & 0 deletions llvm/test/CodeGen/ARM/long-calls.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=armv7-unknown-linux-gnueabi -relocation-model pic -mattr=+long-calls -o - %s \
; RUN: | FileCheck %s
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Can this be integrated into llvm/test/CodeGen/ARM/subtarget-features-long-calls.ll?


@msg = private unnamed_addr constant [12 x i8] c"hello world\00", align 1

declare i32 @puts(ptr)

define void @test() {
; CHECK-LABEL: test:
; CHECK: @ %bb.0: @ %entry
; CHECK-NEXT: .save {r11, lr}
; CHECK-NEXT: push {r11, lr}
; CHECK-NEXT: ldr r0, .LCPI0_0
; CHECK-NEXT: ldr r1, .LCPI0_1
; CHECK-NEXT: .LPC0_0:
; CHECK-NEXT: add r0, pc, r0
; CHECK-NEXT: .LPC0_1:
; CHECK-NEXT: ldr r1, [pc, r1]
; CHECK-NEXT: blx r1
; CHECK-NEXT: pop {r11, pc}
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: @ %bb.1:
; CHECK-NEXT: .LCPI0_0:
; CHECK-NEXT: .long .Lmsg-(.LPC0_0+8)
; CHECK-NEXT: .LCPI0_1:
; CHECK-NEXT: .Ltmp0:
; CHECK-NEXT: .long puts(GOT_PREL)-(.LPC0_1+8-.Ltmp0)
entry:
%call = call i32 @puts(ptr @msg)
ret void
}
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