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0f0aa0c17b
These two new invariants eliminate corner cases which caused bugs if optimization didn't handle them. Also, it will significantly simplify lifetime completion. The implementation basically consists of these changes: * add a flag in SILFunction which tells optimization if they need to take care of infinite loops * add a utility to break infinite loops * let all optimizations remove unreachable blocks and break infinite loops if necessary * add verification to check the new SIL invariants The new `breakIfniniteLoops` utility breaks infinite loops in the control flow by inserting an "artificial" loop exit to a new dead-end block with an `unreachable`. It inserts a `cond_br` with a `builtin "infinite_loop_true_condition"`: ``` bb0: br bb1 bb1: br bb1 // back-end branch ``` -> ``` bb0: br bb1 bb1: %1 = builtin "infinite_loop_true_condition"() // always true, but the compiler doesn't know cond_br %1, bb2, bb3 bb2: // new back-end block br bb1 bb3: // new dead-end block unreachable ```
86 lines
4.2 KiB
Swift
86 lines
4.2 KiB
Swift
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// RUN: %target-swift-emit-sil -Xllvm -sil-print-types -module-name rethrows -Xllvm -sil-disable-pass=simplification -verify %s | %FileCheck %s
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@discardableResult
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func rethrower(_ fn: () throws -> Int) rethrows -> Int {
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return try fn()
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}
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func thrower() throws -> Int { return 0 }
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func nonthrower() -> Int { return 0 }
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// CHECK-LABEL: sil hidden @$s8rethrows5test0yyKF : $@convention(thin) () -> @error any Error {
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// CHECK: [[THROWER:%.*]] = function_ref @$s8rethrows7throwerSiyKF : $@convention(thin) () -> (Int, @error any Error)
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// CHECK: [[T0:%.*]] = thin_to_thick_function [[THROWER]]
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// CHECK: [[CVT:%.*]] = convert_escape_to_noescape [[T0]]
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// CHECK: [[RETHROWER:%.*]] = function_ref @$s8rethrows9rethroweryS2iyKXEKF :
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// CHECK: try_apply [[RETHROWER]]([[CVT]]) : {{.*}}, normal [[NORMAL:bb1]], error [[ERROR:bb2]]
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// CHECK: [[NORMAL]]([[RESULT_T0:%.*]] : $Int):
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// CHECK-NEXT: strong_release [[T0]]
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// CHECK-NEXT: [[T1:%.*]] = tuple ()
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// CHECK-NEXT: return [[T1]]
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// CHECK: [[ERROR]]([[RESULT_T0:%.*]] : $any Error):
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// CHECK-NEXT: strong_release [[T0]]
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// CHECK-NEXT: throw [[RESULT_T0]]
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func test0() throws {
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try rethrower(thrower)
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}
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// CHECK-LABEL: sil hidden @$s8rethrows5test1yyKF : $@convention(thin) () -> @error any Error {
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// CHECK: [[CLOSURE:%.*]] = function_ref @$s8rethrows5test1yyKFSiyKXEfU_ : $@convention(thin) () -> (Int, @error any Error)
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// CHECK: [[T0:%.*]] = thin_to_thick_function [[CLOSURE]]
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// CHECK: [[RETHROWER:%.*]] = function_ref @$s8rethrows9rethroweryS2iyKXEKF :
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// CHECK: try_apply [[RETHROWER]]([[T0]]) :{{.*}}, normal [[NORMAL:bb1]], error [[ERROR:bb2]]
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// CHECK: [[NORMAL]]({{%.*}} : $Int):
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// CHECK-NEXT: [[T1:%.*]] = tuple ()
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// CHECK-NEXT: return [[T1]]
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// CHECK: [[ERROR]]([[ERROR:%.*]] : $any Error):
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// CHECK-NEXT: throw [[ERROR]]
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// Closure.
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// CHECK-LABEL: sil private @$s8rethrows5test1yyKFSiyKXEfU_ : $@convention(thin) () -> (Int, @error any Error) {
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// CHECK: [[THROWER:%.*]] = function_ref @$s8rethrows7throwerSiyKF : $@convention(thin) () -> (Int, @error any Error)
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// CHECK: [[T0:%.*]] = thin_to_thick_function [[THROWER]]
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// CHECK: [[CVT:%.*]] = convert_escape_to_noescape [[T0]]
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// CHECK: [[RETHROWER:%.*]] = function_ref @$s8rethrows9rethroweryS2iyKXEKF :
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// CHECK: try_apply [[RETHROWER]]([[CVT]]) : {{.*}}, normal [[NORMAL:bb1]], error [[ERROR:bb2]]
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// CHECK: [[NORMAL]]([[RESULT:%.*]] : $Int):
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// CHECK-NEXT: strong_release [[T0]]
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// CHECK-NEXT: return [[RESULT]]
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// CHECK: [[ERROR]]([[ERROR:%.*]] : $any Error):
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// CHECK-NEXT: strong_release [[T0]]
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// CHECK-NEXT: throw [[ERROR]]
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func test1() throws {
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try rethrower { try rethrower(thrower) }
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}
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// CHECK-LABEL: sil hidden @$s8rethrows5test2yyF : $@convention(thin) () -> () {
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// CHECK: [[NONTHROWER:%.*]] = function_ref @$s8rethrows10nonthrowerSiyF : $@convention(thin) () -> Int
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// CHECK: [[T0:%.*]] = thin_to_thick_function [[NONTHROWER]]
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// CHECK: [[T1:%.*]] = convert_function [[T0]] : $@callee_guaranteed () -> Int to $@callee_guaranteed () -> (Int, @error any Error)
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// CHECK: [[T2:%.*]] = convert_escape_to_noescape [[T1]]
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// CHECK: [[RETHROWER:%.*]] = function_ref @$s8rethrows9rethroweryS2iyKXEKF :
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// CHECK: try_apply [[RETHROWER]]([[T2]]) : {{.*}}, normal [[NORMAL:bb1]], error [[ERROR:bb2]]
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// CHECK: [[NORMAL]]([[T0:%.*]] : $Int):
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// CHECK-NEXT: strong_release [[T1]]
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// CHECK-NEXT: [[RESULT:%.*]] = tuple ()
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// CHECK-NEXT: return [[RESULT]]
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// CHECK: [[ERROR]]([[T0:%.*]] : $any Error):
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// CHECK-NEXT: unreachable
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func test2() {
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rethrower(nonthrower)
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}
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// CHECK-LABEL: sil hidden @$s8rethrows5test3yyF : $@convention(thin) () -> () {
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// CHECK: [[CLOSURE:%.*]] = function_ref @$s8rethrows5test3yyFSiyXEfU_ :
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// CHECK: [[T0:%.*]] = thin_to_thick_function [[CLOSURE]]
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// CHECK: [[RETHROWER:%.*]] = function_ref @$s8rethrows9rethroweryS2iyKXEKF :
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// CHECK: try_apply [[RETHROWER]]([[T0]])
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// CHECK: [[NORMAL]]({{%.*}} : $Int):
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// CHECK-NEXT: [[RESULT:%.*]] = tuple ()
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// CHECK-NEXT: return [[RESULT]]
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// CHECK: [[ERROR]]([[ERROR:%.*]] : $any Error):
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// CHECK-NEXT: unreachable
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// CHECK-LABEL: // end sil function '$s8rethrows5test3yyF'
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func test3() {
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rethrower { rethrower(nonthrower) }
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}
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