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Don't move objc_autorelease calls past autorelease pool boundaries when

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optimizing autorelease calls on phi nodes with null operands.
This fixes rdar://11207070.

llvm-svn: 154642
This commit is contained in:
Dan Gohman 2012-04-13 00:59:57 +00:00
parent cde3a46455
commit 6a5b02f8ee
2 changed files with 121 additions and 7 deletions
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46
lib/Transforms/Scalar/ObjCARC.cpp
View File

@ -1963,6 +1963,7 @@ namespace {
/// use here.
enum DependenceKind {
NeedsPositiveRetainCount,
AutoreleasePoolBoundary,
CanChangeRetainCount,
RetainAutoreleaseDep, ///< Blocks objc_retainAutorelease.
RetainAutoreleaseRVDep, ///< Blocks objc_retainAutoreleaseReturnValue.
@ -1992,6 +1993,19 @@ Depends(DependenceKind Flavor, Instruction *Inst, const Value *Arg,
}
}
case AutoreleasePoolBoundary: {
InstructionClass Class = GetInstructionClass(Inst);
switch (Class) {
case IC_AutoreleasepoolPop:
case IC_AutoreleasepoolPush:
// These mark the end and begin of an autorelease pool scope.
return true;
default:
// Nothing else does this.
return false;
}
}
case CanChangeRetainCount: {
InstructionClass Class = GetInstructionClass(Inst);
switch (Class) {
@ -2009,6 +2023,7 @@ Depends(DependenceKind Flavor, Instruction *Inst, const Value *Arg,
case RetainAutoreleaseDep:
switch (GetBasicInstructionClass(Inst)) {
case IC_AutoreleasepoolPop:
case IC_AutoreleasepoolPush:
// Don't merge an objc_autorelease with an objc_retain inside a different
// autoreleasepool scope.
return true;
@ -2376,9 +2391,34 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) {
// Check that there is nothing that cares about the reference
// count between the call and the phi.
FindDependencies(NeedsPositiveRetainCount, Arg,
Inst->getParent(), Inst,
DependingInstructions, Visited, PA);
switch (Class) {
case IC_Retain:
case IC_RetainBlock:
// These can always be moved up.
break;
case IC_Release:
// These can't be moved across things that care about the retain count.
FindDependencies(NeedsPositiveRetainCount, Arg,
Inst->getParent(), Inst,
DependingInstructions, Visited, PA);
break;
case IC_Autorelease:
// These can't be moved across autorelease pool scope boundaries.
FindDependencies(AutoreleasePoolBoundary, Arg,
Inst->getParent(), Inst,
DependingInstructions, Visited, PA);
break;
case IC_RetainRV:
case IC_AutoreleaseRV:
// Don't move these; the RV optimization depends on the autoreleaseRV
// being tail called, and the retainRV being immediately after a call
// (which might still happen if we get lucky with codegen layout, but
// it's not worth taking the chance).
continue;
default:
llvm_unreachable("Invalid dependence flavor");
}
if (DependingInstructions.size() == 1 &&
*DependingInstructions.begin() == PN) {
Changed = true;

82
test/Transforms/ObjCARC/basic.ll
View File

@ -3,10 +3,12 @@
target datalayout = "e-p:64:64:64"
declare i8* @objc_retain(i8*)
declare i8* @objc_retainAutoreleasedReturnValue(i8*)
declare void @objc_release(i8*)
declare i8* @objc_autorelease(i8*)
declare i8* @objc_autoreleaseReturnValue(i8*)
declare void @objc_autoreleasePoolPop(i8*)
declare void @objc_autoreleasePoolPush()
declare i8* @objc_autoreleasePoolPush()
declare i8* @objc_retainBlock(i8*)
declare i8* @objc_retainedObject(i8*)
@ -526,7 +528,7 @@ entry:
define void @test13d(i8* %x, i64 %n) {
entry:
call i8* @objc_retain(i8* %x) nounwind
call void @objc_autoreleasePoolPush()
call i8* @objc_autoreleasePoolPush()
call i8* @objc_retain(i8* %x) nounwind
call void @use_pointer(i8* %x)
call void @use_pointer(i8* %x)
@ -1400,7 +1402,7 @@ entry:
; CHECK-NEXT: call i8* @objc_autorelease(i8* %p)
; CHECK-NEXT: call void @use_pointer(i8* %p)
; CHECK-NEXT: call void @use_pointer(i8* %p)
; CHECK-NEXT: call void @objc_autoreleasePoolPush()
; CHECK-NEXT: call i8* @objc_autoreleasePoolPush()
; CHECK-NEXT: ret void
; CHECK-NEXT: }
define void @test43b(i8* %p) {
@ -1410,7 +1412,7 @@ entry:
call i8* @objc_retain(i8* %p)
call void @use_pointer(i8* %p)
call void @use_pointer(i8* %p)
call void @objc_autoreleasePoolPush()
call i8* @objc_autoreleasePoolPush()
call void @objc_release(i8* %p)
ret void
}
@ -1797,6 +1799,78 @@ exit:
ret void
}
; Move an autorelease past a phi with a null.
; CHECK: define i8* @test65(
; CHECK: if.then:
; CHECK: call i8* @objc_autorelease(
; CHECK: return:
; CHECK-NOT: @objc_autorelease
; CHECK: }
define i8* @test65(i1 %x) {
entry:
br i1 %x, label %return, label %if.then
if.then: ; preds = %entry
%c = call i8* @returner()
%s = call i8* @objc_retainAutoreleasedReturnValue(i8* %c) nounwind
br label %return
return: ; preds = %if.then, %entry
%retval = phi i8* [ %s, %if.then ], [ null, %entry ]
%q = call i8* @objc_autorelease(i8* %retval) nounwind
ret i8* %retval
}
; Don't move an autorelease past an autorelease pool boundary.
; CHECK: define i8* @test65b(
; CHECK: if.then:
; CHECK-NOT: @objc_autorelease
; CHECK: return:
; CHECK: call i8* @objc_autorelease(
; CHECK: }
define i8* @test65b(i1 %x) {
entry:
%t = call i8* @objc_autoreleasePoolPush()
br i1 %x, label %return, label %if.then
if.then: ; preds = %entry
%c = call i8* @returner()
%s = call i8* @objc_retainAutoreleasedReturnValue(i8* %c) nounwind
br label %return
return: ; preds = %if.then, %entry
%retval = phi i8* [ %s, %if.then ], [ null, %entry ]
call void @objc_autoreleasePoolPop(i8* %t)
%q = call i8* @objc_autorelease(i8* %retval) nounwind
ret i8* %retval
}
; Don't move an autoreleaseReuturnValue, which would break
; the RV optimization.
; CHECK: define i8* @test65c(
; CHECK: if.then:
; CHECK-NOT: @objc_autorelease
; CHECK: return:
; CHECK: call i8* @objc_autoreleaseReturnValue(
; CHECK: }
define i8* @test65c(i1 %x) {
entry:
br i1 %x, label %return, label %if.then
if.then: ; preds = %entry
%c = call i8* @returner()
%s = call i8* @objc_retainAutoreleasedReturnValue(i8* %c) nounwind
br label %return
return: ; preds = %if.then, %entry
%retval = phi i8* [ %s, %if.then ], [ null, %entry ]
%q = call i8* @objc_autoreleaseReturnValue(i8* %retval) nounwind
ret i8* %retval
}
declare void @bar(i32 ()*)
; A few real-world testcases.