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stdlib: Print the error message in precondition() and preconditionFailure() even in release builds. #26215

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stdlib: Print the error message in precondition() and preconditionFailure() even in release builds. #26215

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100 changes: 92 additions & 8 deletions stdlib/public/core/Assert.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -59,10 +59,12 @@ public func assert(
///
/// * In playgrounds and `-Onone` builds (the default for Xcode's Debug
/// configuration): If `condition` evaluates to `false`, stop program
/// execution in a debuggable state after printing `message`.
/// execution in a debuggable state after printing `message`
/// along with the file and line information..
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Suggested change
/// along with the file and line information..
/// along with the file and line information.

///
/// * In `-O` builds (the default for Xcode's Release configuration): If
/// `condition` evaluates to `false`, stop program execution.
/// `condition` evaluates to `false`, stop program execution state after
/// printing `message`.
///
/// * In `-Ounchecked` builds, `condition` is not evaluated, but the optimizer
/// may assume that it *always* evaluates to `true`. Failure to satisfy that
Expand All @@ -82,7 +84,7 @@ public func assert(
@_transparent
public func precondition(
_ condition: @autoclosure () -> Bool,
_ message: @autoclosure () -> String = String(),
_ message: @autoclosure () -> String,
file: StaticString = #file, line: UInt = #line
) {
// Only check in debug and release mode. In release mode just trap.
Expand All @@ -91,10 +93,55 @@ public func precondition(
_assertionFailure("Precondition failed", message(), file: file, line: line,
flags: _fatalErrorFlags())
}
} else if _isReleaseAssertConfiguration() {
if !_fastPath(condition()) {
_assertionFailure("Precondition failed", message(),
flags: _fatalErrorFlags())
}
}
}

/// Checks a necessary condition for making forward progress.
///
/// Use this function to detect conditions that must prevent the program from
/// proceeding, even in shipping code, but without a failure message.
///
/// * In playgrounds and `-Onone` builds (the default for Xcode's Debug
/// configuration): If `condition` evaluates to `false`, stop program
/// execution in a debuggable state after printing "Precondition failed",
/// along with the file and line information.
///
/// * In `-O` builds (the default for Xcode's Release configuration): If
/// `condition` evaluates to `false`, stop program execution.
///
/// * In `-Ounchecked` builds, `condition` is not evaluated, but the optimizer
/// may assume that it *always* evaluates to `true`. Failure to satisfy that
/// assumption is a serious programming error.
///
/// - Parameters:
/// - condition: The condition to test. `condition` is not evaluated in
/// `-Ounchecked` builds.
/// - file: The file name to print with `message` if the precondition fails.
/// The default is the file where `precondition(_:_:file:line:)` is
/// called.
/// - line: The line number to print along with `message` if the assertion
/// fails. The default is the line number where
/// `precondition(_:_:file:line:)` is called.
@_transparent
public func precondition(
_ condition: @autoclosure () -> Bool,
file: StaticString = #file, line: UInt = #line
) {
// Only check in debug and release mode. In release mode just trap.
if _isDebugAssertConfiguration() {
if !_fastPath(condition()) {
_assertionFailure("Precondition failed", String(), file: file, line: line,
flags: _fatalErrorFlags())
}
} else if _isReleaseAssertConfiguration() {
let error = !condition()
Builtin.condfail_message(error._value,
StaticString("precondition failure").unsafeRawPointer)
StaticString("Precondition failed").unsafeRawPointer)
}
}

Expand Down Expand Up @@ -146,10 +193,10 @@ public func assertionFailure(
///
/// * In playgrounds and `-Onone` builds (the default for Xcode's Debug
/// configuration), stops program execution in a debuggable state after
/// printing `message`.
/// printing `message` along with the file and line information.
///
/// * In `-O` builds (the default for Xcode's Release configuration), stops
/// program execution.
/// program execution after printing `message`.
///
/// * In `-Ounchecked` builds, the optimizer may assume that this function is
/// never called. Failure to satisfy that assumption is a serious
Expand All @@ -164,16 +211,53 @@ public func assertionFailure(
/// line number where `preconditionFailure(_:file:line:)` is called.
@_transparent
public func preconditionFailure(
_ message: @autoclosure () -> String = String(),
_ message: @autoclosure () -> String,
file: StaticString = #file, line: UInt = #line
) -> Never {
// Only check in debug and release mode. In release mode just trap.
if _isDebugAssertConfiguration() {
_assertionFailure("Fatal error", message(), file: file, line: line,
flags: _fatalErrorFlags())
} else if _isReleaseAssertConfiguration() {
_assertionFailure("Precondition failed", message(),
flags: _fatalErrorFlags())
}
_conditionallyUnreachable()
}

/// Indicates that a precondition was violated, without a message.
///
/// Use this function to stop the program when control flow can only reach the
/// call if your API was improperly used. This function's effects vary
/// depending on the build flag used:
///
/// * In playgrounds and `-Onone` builds (the default for Xcode's Debug
/// configuration), stops program execution in a debuggable state after
/// printing "Fatal error".
///
/// * In `-O` builds (the default for Xcode's Release configuration), stops
/// program execution.
///
/// * In `-Ounchecked` builds, the optimizer may assume that this function is
/// never called. Failure to satisfy that assumption is a serious
/// programming error.
///
/// - Parameters:
/// - file: The file name to print with `message`. The default is the file
/// where `preconditionFailure(file:line:)` is called.
/// - line: The line number to print. The default is the
/// line number where `preconditionFailure(file:line:)` is called.
@_transparent
public func preconditionFailure(
file: StaticString = #file, line: UInt = #line
) -> Never {
// Only check in debug and release mode. In release mode just trap.
if _isDebugAssertConfiguration() {
_assertionFailure("Fatal error", String(), file: file, line: line,
flags: _fatalErrorFlags())
} else if _isReleaseAssertConfiguration() {
Builtin.condfail_message(true._value,
StaticString("precondition failure").unsafeRawPointer)
StaticString("Precondition failed").unsafeRawPointer)
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I'd suggest not adding this additional overload. We don't really want people omitting messages from their preconditions to save on code size; that is an unnecessary level of flexibility.

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I didn't add it, but converted the default-argument version to a separate function. Removing the overload would be a source compatibility break.

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Right, I'm saying you could just leave the default-argument version.

}
_conditionallyUnreachable()
}
Expand Down
8 changes: 4 additions & 4 deletions test/Frontend/OptimizationOptions-without-stdlib-checks.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -100,10 +100,10 @@ func test_partial_safety_check(x: Int, y: Int) -> Int {

// In release mode keep succinct library precondition checks (trap).
// RELEASE-LABEL: sil hidden @$s19OptimizationOptions22testprecondition_check1x1yS2i_SitF : $@convention(thin) (Int, Int) -> Int {
// RELEASE-NOT: "Fatal error"
// RELEASE: %[[V2:.+]] = builtin "xor_Int1"(%{{.+}}, %{{.+}})
// RELEASE: cond_fail %[[V2]]
// RELEASE: return
// RELEASE-DAG: "Precondition failed"
// RELEASE-DAG: %[[FATAL_ERROR:.+]] = function_ref @[[FATAL_ERROR_FUNC:.*assertionFailure.*]]
// RELEASE: apply %[[FATAL_ERROR]]({{.*}})
// RELEASE: unreachable

// In unchecked mode remove library precondition checks.
// UNCHECKED-LABEL: sil hidden @$s19OptimizationOptions22testprecondition_check1x1yS2i_SitF : $@convention(thin) (Int, Int) -> Int {
Expand Down
38 changes: 19 additions & 19 deletions test/SILOptimizer/specialize_checked_cast_branch.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ public func ArchetypeToArchetypeCast<T1, T2>(t1 : T1, t2 : T2) -> T2 {
if let x = t1 as? T2 {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA1DCTg5 : $@convention(thin) (@guaranteed C, @guaranteed D) -> @owned D
Expand All @@ -34,7 +34,7 @@ public func ArchetypeToArchetypeCast<T1, T2>(t1 : T1, t2 : T2) -> T2 {
// CHECK: return [[T0]]
//
// CHECK: bb2
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
// CHECK: } // end sil function '$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA1DCTg5'
_ = ArchetypeToArchetypeCast(t1: c, t2: d)
Expand All @@ -58,7 +58,7 @@ _ = ArchetypeToArchetypeCast(t1: b, t2: f)
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA8NotUInt8V_AA1CCTg5 : $@convention(thin) (NotUInt8, @guaranteed C) -> @owned C {
// CHECK: bb0
// CHECK-NOT: bb1
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
// CHECK: } // end sil function '$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA8NotUInt8V_AA1CCTg5'
_ = ArchetypeToArchetypeCast(t1: b, t2: c)
Expand All @@ -67,7 +67,7 @@ _ = ArchetypeToArchetypeCast(t1: b, t2: c)
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA8NotUInt8VTg5 : $@convention(thin) (@guaranteed C, NotUInt8) -> NotUInt8 {
// CHECK: bb0
// CHECK-NOT: bb1
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
// CHECK: } // end sil function '$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA8NotUInt8VTg5'
_ = ArchetypeToArchetypeCast(t1: c, t2: b)
Expand All @@ -84,7 +84,7 @@ _ = ArchetypeToArchetypeCast(t1: d, t2: c)
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA1ECTg5 : $@convention(thin) (@guaranteed C, @guaranteed E) -> @owned E {
// CHECK: bb0
// CHECK-NOT: bb1
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
// CHECK: } // end sil function '$s30specialize_checked_cast_branch011ArchetypeToE4Cast2t12t2q_x_q_tr0_lFAA1CC_AA1ECTg5'
_ = ArchetypeToArchetypeCast(t1: c, t2: e)
Expand All @@ -97,28 +97,28 @@ func ArchetypeToConcreteCastUInt8<T>(t : T) -> NotUInt8 {
if let x = t as? NotUInt8 {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

func ArchetypeToConcreteCastC<T>(t : T) -> C {
if let x = t as? C {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

func ArchetypeToConcreteCastD<T>(t : T) -> D {
if let x = t as? D {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

func ArchetypeToConcreteCastE<T>(t : T) -> E {
if let x = t as? E {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

// uint8 -> uint8
Expand All @@ -135,7 +135,7 @@ _ = ArchetypeToConcreteCastUInt8(t: c)
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch28ArchetypeToConcreteCastUInt81tAA03NotI0Vx_tlFAA0J6UInt64V_Tg5 : $@convention(thin) (NotUInt64) -> NotUInt8 {
// CHECK: bb0
// CHECK-NOT: checked_cast_br
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
_ = ArchetypeToConcreteCastUInt8(t: f)

Expand Down Expand Up @@ -167,7 +167,7 @@ _ = ArchetypeToConcreteCastC(t: d)
// E -> C
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch24ArchetypeToConcreteCastC1tAA1CCx_tlFAA1EC_Tg5 : $@convention(thin) (@guaranteed E) -> @owned C {
// CHECK: bb0
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
_ = ArchetypeToConcreteCastC(t: e)

Expand All @@ -182,15 +182,15 @@ _ = ArchetypeToConcreteCastC(t: e)
// CHECK: return [[T0]] : $D
//
// CHECK: [[FAIL_BB]]:
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
// CHECK: } // end sil function '$s30specialize_checked_cast_branch24ArchetypeToConcreteCastD1tAA1DCx_tlFAA1CC_Tg5'
_ = ArchetypeToConcreteCastD(t: c)

// C -> E
// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch24ArchetypeToConcreteCastE1tAA1ECx_tlFAA1CC_Tg5 : $@convention(thin) (@guaranteed C) -> @owned E {
// CHECK: bb0
// CHECK: cond_fail {{%.*}}, "precondition failure"
// CHECK: cond_fail {{%.*}}, "Precondition failed"
// CHECK: unreachable
_ = ArchetypeToConcreteCastE(t: c)

Expand All @@ -202,19 +202,19 @@ func ConcreteToArchetypeCastUInt8<T>(t: NotUInt8, t2: T) -> T {
if let x = t as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}
func ConcreteToArchetypeCastC<T>(t: C, t2: T) -> T {
if let x = t as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}
func ConcreteToArchetypeCastD<T>(t: D, t2: T) -> T {
if let x = t as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

// x -> x where x is not a class.
Expand Down Expand Up @@ -273,14 +273,14 @@ func SuperToArchetypeCastC<T>(c : C, t : T) -> T {
if let x = c as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

func SuperToArchetypeCastD<T>(d : D, t : T) -> T {
if let x = d as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch21SuperToArchetypeCastC1c1txAA1CC_xtlFAF_Tg5 : $@convention(thin) (@guaranteed C, @guaranteed C) -> @owned C
Expand Down Expand Up @@ -318,7 +318,7 @@ func ExistentialToArchetypeCast<T>(o : AnyObject, t : T) -> T {
if let x = o as? T {
return x
}
preconditionFailure("??? Profit?")
preconditionFailure()
}

// CHECK-LABEL: sil shared @$s30specialize_checked_cast_branch26ExistentialToArchetypeCast1o1txyXl_xtlFAA1CC_Tg5 : $@convention(thin) (@guaranteed AnyObject, @guaranteed C) -> @owned C
Expand Down