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Reland "[Intrinsics][ObjC] Mark objc_retain and friends as thisreturn."
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This reverts commit cb62f67.

Fixes: #69658
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@jroelofs
jroelofs committed Nov 6, 2023
1 parent 521ac12 commit 30414fc
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Showing 6 changed files with 54 additions and 25 deletions.
6 changes: 3 additions & 3 deletions clang/lib/CodeGen/CGCall.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3448,9 +3448,9 @@ static llvm::Value *tryRemoveRetainOfSelf(CodeGenFunction &CGF,
const VarDecl *self = method->getSelfDecl();
if (!self->getType().isConstQualified()) return nullptr;

// Look for a retain call.
llvm::CallInst *retainCall =
dyn_cast<llvm::CallInst>(result->stripPointerCasts());
// Look for a retain call. Note: stripPointerCasts looks through returned arg
// functions, which would cause us to miss the retain.
llvm::CallInst *retainCall = dyn_cast<llvm::CallInst>(result);
if (!retainCall || retainCall->getCalledOperand() !=
CGF.CGM.getObjCEntrypoints().objc_retain)
return nullptr;
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20 changes: 10 additions & 10 deletions clang/test/CodeGenObjC/arc.m
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Expand Up @@ -7,30 +7,30 @@
// RUN: %clang_cc1 -fobjc-runtime=macosx-10.7.0 -triple x86_64-apple-darwin11 -Wno-objc-root-class -Wno-incompatible-pointer-types -Wno-arc-unsafe-retained-assign -emit-llvm -fblocks -fobjc-arc -fobjc-runtime-has-weak -o - %s | FileCheck -check-prefix=ARC-NATIVE %s

// ARC-ALIEN: declare extern_weak void @llvm.objc.storeStrong(ptr, ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retain(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.autoreleaseReturnValue(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retain(ptr returned)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.autoreleaseReturnValue(ptr returned)
// ARC-ALIEN: declare ptr @objc_msgSend(ptr, ptr, ...) [[NLB:#[0-9]+]]
// ARC-ALIEN: declare extern_weak void @llvm.objc.release(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retainAutoreleasedReturnValue(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retainAutoreleasedReturnValue(ptr returned)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.initWeak(ptr, ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.storeWeak(ptr, ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.loadWeakRetained(ptr)
// ARC-ALIEN: declare extern_weak void @llvm.objc.destroyWeak(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.autorelease(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retainAutorelease(ptr)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.autorelease(ptr returned)
// ARC-ALIEN: declare extern_weak ptr @llvm.objc.retainAutorelease(ptr returned)

// ARC-NATIVE: declare void @llvm.objc.storeStrong(ptr, ptr)
// ARC-NATIVE: declare ptr @llvm.objc.retain(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.autoreleaseReturnValue(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.retain(ptr returned)
// ARC-NATIVE: declare ptr @llvm.objc.autoreleaseReturnValue(ptr returned)
// ARC-NATIVE: declare ptr @objc_msgSend(ptr, ptr, ...) [[NLB:#[0-9]+]]
// ARC-NATIVE: declare void @llvm.objc.release(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.retainAutoreleasedReturnValue(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.retainAutoreleasedReturnValue(ptr returned)
// ARC-NATIVE: declare ptr @llvm.objc.initWeak(ptr, ptr)
// ARC-NATIVE: declare ptr @llvm.objc.storeWeak(ptr, ptr)
// ARC-NATIVE: declare ptr @llvm.objc.loadWeakRetained(ptr)
// ARC-NATIVE: declare void @llvm.objc.destroyWeak(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.autorelease(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.retainAutorelease(ptr)
// ARC-NATIVE: declare ptr @llvm.objc.autorelease(ptr returned)
// ARC-NATIVE: declare ptr @llvm.objc.retainAutorelease(ptr returned)

// CHECK-LABEL: define{{.*}} void @test0
void test0(id x) {
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5 changes: 5 additions & 0 deletions clang/test/CodeGenObjC/convert-messages-to-runtime-calls.m
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,11 @@ void test1(id x) {
// MSGS: {{call.*@objc_msgSend}}
// CALLS: {{call.*@objc_alloc}}
// CALLS: {{call.*@objc_allocWithZone}}

// Note that calls to the intrinsics are not allowed for
// retain/release/autorelease they're marked `thisreturn`, which isn't
// guaranteed to be true for classes that define their own `-retain`, for
// example. Be sure to keep these as normal function calls:
// CALLS: {{call.*@objc_retain}}
// CALLS: {{call.*@objc_release}}
// CALLS: {{tail call.*@objc_autorelease}}
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18 changes: 12 additions & 6 deletions llvm/include/llvm/IR/Intrinsics.td
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Expand Up @@ -720,11 +720,13 @@ def int_gcwrite : Intrinsic<[],
// eliminate retain and releases where possible.

def int_objc_autorelease : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_autoreleasePoolPop : Intrinsic<[], [llvm_ptr_ty]>;
def int_objc_autoreleasePoolPush : Intrinsic<[llvm_ptr_ty], []>;
def int_objc_autoreleaseReturnValue : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_copyWeak : Intrinsic<[],
[llvm_ptr_ty,
llvm_ptr_ty]>;
Expand All @@ -741,11 +743,14 @@ def int_objc_moveWeak : Intrinsic<[],
llvm_ptr_ty]>;
def int_objc_release : Intrinsic<[], [llvm_ptr_ty]>;
def int_objc_retain : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_retainAutorelease : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_retainAutoreleaseReturnValue : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_retainAutoreleasedReturnValue : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
def int_objc_retainBlock : Intrinsic<[llvm_ptr_ty],
Expand All @@ -770,7 +775,8 @@ def int_objc_unretainedObject : Intrinsic<[llvm_ptr_ty],
def int_objc_unretainedPointer : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
def int_objc_retain_autorelease : Intrinsic<[llvm_ptr_ty],
[llvm_ptr_ty]>;
[llvm_ptr_ty],
[Returned<ArgIndex<0>>]>;
def int_objc_sync_enter : Intrinsic<[llvm_i32_ty],
[llvm_ptr_ty]>;
def int_objc_sync_exit : Intrinsic<[llvm_i32_ty],
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10 changes: 10 additions & 0 deletions llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
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Expand Up @@ -162,6 +162,16 @@ static bool lowerObjCCall(Function &F, const char *NewFn,
CallInst::TailCallKind TCK = CI->getTailCallKind();
NewCI->setTailCallKind(std::max(TCK, OverridingTCK));

// Transfer the 'returned' attribute from the intrinsic to the call site.
// By applying this only to intrinsic call sites, we avoid applying it to
// non-ARC explicit calls to things like objc_retain which have not been
// auto-upgraded to use the intrinsics.
unsigned Index;
if (F.getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
Index)
NewCI->addParamAttr(Index - AttributeList::FirstArgIndex,
Attribute::Returned);

if (!CI->use_empty())
CI->replaceAllUsesWith(NewCI);
CI->eraseFromParent();
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20 changes: 14 additions & 6 deletions llvm/test/Transforms/PreISelIntrinsicLowering/X86/objc-arc.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ declare i32 @__gxx_personality_v0(...)
define ptr @test_objc_autorelease(ptr %arg0) {
; CHECK-LABEL: test_objc_autorelease
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = notail call ptr @objc_autorelease(ptr %arg0)
; CHECK-NEXT: %0 = notail call ptr @objc_autorelease(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = call ptr @llvm.objc.autorelease(ptr %arg0)
Expand Down Expand Up @@ -39,7 +39,7 @@ entry:
define ptr @test_objc_autoreleaseReturnValue(ptr %arg0) {
; CHECK-LABEL: test_objc_autoreleaseReturnValue
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = tail call ptr @objc_autoreleaseReturnValue(ptr %arg0)
; CHECK-NEXT: %0 = tail call ptr @objc_autoreleaseReturnValue(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = call ptr @llvm.objc.autoreleaseReturnValue(ptr %arg0)
Expand Down Expand Up @@ -119,7 +119,7 @@ entry:
define ptr @test_objc_retain(ptr %arg0) {
; CHECK-LABEL: test_objc_retain
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = tail call ptr @objc_retain(ptr %arg0)
; CHECK-NEXT: %0 = tail call ptr @objc_retain(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = call ptr @llvm.objc.retain(ptr %arg0)
Expand All @@ -129,7 +129,7 @@ entry:
define ptr @test_objc_retainAutorelease(ptr %arg0) {
; CHECK-LABEL: test_objc_retainAutorelease
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = call ptr @objc_retainAutorelease(ptr %arg0)
; CHECK-NEXT: %0 = call ptr @objc_retainAutorelease(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = call ptr @llvm.objc.retainAutorelease(ptr %arg0)
Expand All @@ -139,13 +139,17 @@ entry:
define ptr @test_objc_retainAutoreleaseReturnValue(ptr %arg0) {
; CHECK-LABEL: test_objc_retainAutoreleaseReturnValue
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = tail call ptr @objc_retainAutoreleaseReturnValue(ptr %arg0)
; CHECK-NEXT: %0 = tail call ptr @objc_retainAutoreleaseReturnValue(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = tail call ptr @llvm.objc.retainAutoreleaseReturnValue(ptr %arg0)
ret ptr %0
}

; Note: we don't want this intrinsic to have its argument marked 'returned',
; since that breaks the autorelease elision marker optimization when
; save/restores of the reciever are introduced between the msg send and the
; retain. See issue#69658.
define ptr @test_objc_retainAutoreleasedReturnValue(ptr %arg0) {
; CHECK-LABEL: test_objc_retainAutoreleasedReturnValue
; CHECK-NEXT: entry
Expand Down Expand Up @@ -210,6 +214,10 @@ entry:
ret ptr %0
}

; Note: we don't want this intrinsic to have its argument marked 'returned',
; since that breaks the autorelease elision marker optimization when
; save/restores of the reciever are introduced between the msg send and the
; claim. See issue#69658.
define ptr @test_objc_unsafeClaimAutoreleasedReturnValue(ptr %arg0) {
; CHECK-LABEL: test_objc_unsafeClaimAutoreleasedReturnValue
; CHECK-NEXT: entry
Expand Down Expand Up @@ -260,7 +268,7 @@ entry:
define ptr @test_objc_retain_autorelease(ptr %arg0) {
; CHECK-LABEL: test_objc_retain_autorelease
; CHECK-NEXT: entry
; CHECK-NEXT: %0 = call ptr @objc_retain_autorelease(ptr %arg0)
; CHECK-NEXT: %0 = call ptr @objc_retain_autorelease(ptr returned %arg0)
; CHECK-NEXT: ret ptr %0
entry:
%0 = call ptr @llvm.objc.retain.autorelease(ptr %arg0)
Expand Down

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