diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs index c8360b6a5fdd2..31f0c177b033b 100644 --- a/compiler/rustc_mir_build/src/build/expr/into.rs +++ b/compiler/rustc_mir_build/src/build/expr/into.rs @@ -148,43 +148,90 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { ExprKind::LogicalOp { op, lhs, rhs } => { let condition_scope = this.local_scope(); let source_info = this.source_info(expr.span); - // We first evaluate the left-hand side of the predicate ... - let (then_block, else_block) = - this.in_if_then_scope(condition_scope, expr.span, |this| { - this.then_else_break( - block, - lhs, - Some(condition_scope), // Temp scope - source_info, - // This flag controls how inner `let` expressions are lowered, - // but either way there shouldn't be any of those in here. - true, - ) - }); - let (short_circuit, continuation, constant) = match op { - LogicalOp::And => (else_block, then_block, false), - LogicalOp::Or => (then_block, else_block, true), + + let push_constant_bool = |this: &mut Builder<'a, 'tcx>, bb, dest, value| { + this.cfg.push_assign_constant( + bb, + source_info, + dest, + ConstOperand { + span: expr.span, + user_ty: None, + const_: Const::from_bool(this.tcx, value), + }, + ); }; - // At this point, the control flow splits into a short-circuiting path - // and a continuation path. - // - If the operator is `&&`, passing `lhs` leads to continuation of evaluation on `rhs`; - // failing it leads to the short-circuting path which assigns `false` to the place. - // - If the operator is `||`, failing `lhs` leads to continuation of evaluation on `rhs`; - // passing it leads to the short-circuting path which assigns `true` to the place. - this.cfg.push_assign_constant( - short_circuit, - source_info, - destination, - ConstOperand { - span: expr.span, - user_ty: None, - const_: Const::from_bool(this.tcx, constant), - }, - ); - let rhs = unpack!(this.expr_into_dest(destination, continuation, rhs)); + // A simple optimization on boolean expression with short-circuit + // operators is to not create a branch for the last operand. + // Example: + // let x: bool = a && b; + // would be compiled into something semantically closer to + // let x = if a { b } else { false }; + // rather than + // let x = if a && b { true } else { false }; + // + // In case `a` is true, evaluate `b` and assign it to `x`, + // thus there is no need to create an actual branch for `b`. + // Otherwise, assign false to `x`. + // + // The exception is when we instrument the code for condition coverage, + // which tracks the outcome of all operands of boolean expressions. + + let (outcome1, outcome2) = if this.tcx.sess.instrument_coverage_condition() { + // We first evaluate the left-hand side of the predicate ... + let (then_block, else_block) = + this.in_if_then_scope(condition_scope, expr.span, |this| { + this.then_else_break( + block, + expr_id, + Some(condition_scope), // Temp scope + source_info, + // This flag controls how inner `let` expressions are lowered, + // but either way there shouldn't be any of those in here. + true, + ) + }); + + // Write true on expression success... + push_constant_bool(this, then_block, destination, true); + // ...and false on failure. + push_constant_bool(this, else_block, destination, false); + + (then_block, else_block) + } else { + // We first evaluate the left-hand side of the predicate ... + let (then_block, else_block) = + this.in_if_then_scope(condition_scope, expr.span, |this| { + this.then_else_break( + block, + lhs, + Some(condition_scope), // Temp scope + source_info, + // This flag controls how inner `let` expressions are lowered, + // but either way there shouldn't be any of those in here. + true, + ) + }); + let (short_circuit, continuation, constant) = match op { + LogicalOp::And => (else_block, then_block, false), + LogicalOp::Or => (then_block, else_block, true), + }; + // At this point, the control flow splits into a short-circuiting path + // and a continuation path. + // - If the operator is `&&`, passing `lhs` leads to continuation of evaluation on `rhs`; + // failing it leads to the short-circuting path which assigns `false` to the place. + // - If the operator is `||`, failing `lhs` leads to continuation of evaluation on `rhs`; + // passing it leads to the short-circuting path which assigns `true` to the place. + push_constant_bool(this, short_circuit, destination, constant); + + let rhs = unpack!(this.expr_into_dest(destination, continuation, rhs)); + + (short_circuit, rhs) + }; + let target = this.cfg.start_new_block(); - this.cfg.goto(rhs, source_info, target); - this.cfg.goto(short_circuit, source_info, target); + this.cfg.goto(outcome1, source_info, target); + this.cfg.goto(outcome2, source_info, target); target.unit() } ExprKind::Loop { body } => { diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs index a3978cc14a43f..e7a5b699124b4 100644 --- a/compiler/rustc_session/src/config.rs +++ b/compiler/rustc_session/src/config.rs @@ -157,8 +157,24 @@ pub enum CoverageLevel { Block, /// Also instrument branch points (includes block coverage). Branch, - /// Instrument for MC/DC. Mostly a superset of branch coverage, but might - /// differ in some corner cases. + /// Same as branch condition, with a single different case: + /// In boolean expressions that are not inside a control-flow decision, + /// it will intentionally insert an instrumented branch for the last operand. + /// + /// Example: + /// ``` + /// # let (a, b) = (false, true); + /// let x = a && b; + /// // ^ last operand + /// ``` + /// Condition coverage does track true/false coverage for `b`, + /// but branch coverage doesn't. + /// + /// The main purpose of this coverage level is to be reused by MCDC. + Condition, + /// Instrument for MC/DC. Enables condition coverage under the hood. + /// Mostly a superset of branch coverage, but might differ in some + /// corner cases. Mcdc, } diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs index 7355e5b695347..a2cc13324fa2a 100644 --- a/compiler/rustc_session/src/options.rs +++ b/compiler/rustc_session/src/options.rs @@ -948,6 +948,7 @@ mod parse { match option { "block" => slot.level = CoverageLevel::Block, "branch" => slot.level = CoverageLevel::Branch, + "condition" => slot.level = CoverageLevel::Condition, "mcdc" => slot.level = CoverageLevel::Mcdc, _ => return false, } diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs index db01bb90d6fac..57afab315b349 100644 --- a/compiler/rustc_session/src/session.rs +++ b/compiler/rustc_session/src/session.rs @@ -353,6 +353,11 @@ impl Session { && self.opts.unstable_opts.coverage_options.level >= CoverageLevel::Branch } + pub fn instrument_coverage_condition(&self) -> bool { + self.instrument_coverage() + && self.opts.unstable_opts.coverage_options.level >= CoverageLevel::Condition + } + pub fn instrument_coverage_mcdc(&self) -> bool { self.instrument_coverage() && self.opts.unstable_opts.coverage_options.level >= CoverageLevel::Mcdc diff --git a/tests/coverage/branch/conditions.cov-map b/tests/coverage/branch/conditions.cov-map new file mode 100644 index 0000000000000..e2f6fb264ccab --- /dev/null +++ b/tests/coverage/branch/conditions.cov-map @@ -0,0 +1,152 @@ +Function name: conditions::assign_3 +Raw bytes (73): 0x[01, 01, 09, 07, 0b, 05, 09, 0d, 11, 01, 05, 01, 05, 22, 11, 01, 05, 22, 11, 01, 05, 09, 01, 17, 01, 00, 28, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 22, 00, 0d, 00, 0e, 22, 00, 12, 00, 13, 20, 1e, 11, 00, 12, 00, 13, 1e, 00, 17, 00, 18, 20, 09, 0d, 00, 17, 00, 18, 03, 01, 05, 01, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 9 +- expression 0 operands: lhs = Expression(1, Add), rhs = Expression(2, Add) +- expression 1 operands: lhs = Counter(1), rhs = Counter(2) +- expression 2 operands: lhs = Counter(3), rhs = Counter(4) +- expression 3 operands: lhs = Counter(0), rhs = Counter(1) +- expression 4 operands: lhs = Counter(0), rhs = Counter(1) +- expression 5 operands: lhs = Expression(8, Sub), rhs = Counter(4) +- expression 6 operands: lhs = Counter(0), rhs = Counter(1) +- expression 7 operands: lhs = Expression(8, Sub), rhs = Counter(4) +- expression 8 operands: lhs = Counter(0), rhs = Counter(1) +Number of file 0 mappings: 9 +- Code(Counter(0)) at (prev + 23, 1) to (start + 0, 40) +- Code(Expression(0, Add)) at (prev + 1, 9) to (start + 0, 10) + = ((c1 + c2) + (c3 + c4)) +- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 14) +- Branch { true: Counter(1), false: Expression(8, Sub) } at (prev + 0, 13) to (start + 0, 14) + true = c1 + false = (c0 - c1) +- Code(Expression(8, Sub)) at (prev + 0, 18) to (start + 0, 19) + = (c0 - c1) +- Branch { true: Expression(7, Sub), false: Counter(4) } at (prev + 0, 18) to (start + 0, 19) + true = ((c0 - c1) - c4) + false = c4 +- Code(Expression(7, Sub)) at (prev + 0, 23) to (start + 0, 24) + = ((c0 - c1) - c4) +- Branch { true: Counter(2), false: Counter(3) } at (prev + 0, 23) to (start + 0, 24) + true = c2 + false = c3 +- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2) + = ((c1 + c2) + (c3 + c4)) + +Function name: conditions::assign_3_bis +Raw bytes (69): 0x[01, 01, 07, 07, 11, 09, 0d, 01, 05, 05, 09, 16, 1a, 05, 09, 01, 05, 09, 01, 1c, 01, 00, 2c, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 1a, 00, 0d, 00, 0e, 05, 00, 12, 00, 13, 20, 09, 16, 00, 12, 00, 13, 13, 00, 17, 00, 18, 20, 0d, 11, 00, 17, 00, 18, 03, 01, 05, 01, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 7 +- expression 0 operands: lhs = Expression(1, Add), rhs = Counter(4) +- expression 1 operands: lhs = Counter(2), rhs = Counter(3) +- expression 2 operands: lhs = Counter(0), rhs = Counter(1) +- expression 3 operands: lhs = Counter(1), rhs = Counter(2) +- expression 4 operands: lhs = Expression(5, Sub), rhs = Expression(6, Sub) +- expression 5 operands: lhs = Counter(1), rhs = Counter(2) +- expression 6 operands: lhs = Counter(0), rhs = Counter(1) +Number of file 0 mappings: 9 +- Code(Counter(0)) at (prev + 28, 1) to (start + 0, 44) +- Code(Expression(0, Add)) at (prev + 1, 9) to (start + 0, 10) + = ((c2 + c3) + c4) +- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 14) +- Branch { true: Counter(1), false: Expression(6, Sub) } at (prev + 0, 13) to (start + 0, 14) + true = c1 + false = (c0 - c1) +- Code(Counter(1)) at (prev + 0, 18) to (start + 0, 19) +- Branch { true: Counter(2), false: Expression(5, Sub) } at (prev + 0, 18) to (start + 0, 19) + true = c2 + false = (c1 - c2) +- Code(Expression(4, Add)) at (prev + 0, 23) to (start + 0, 24) + = ((c1 - c2) + (c0 - c1)) +- Branch { true: Counter(3), false: Counter(4) } at (prev + 0, 23) to (start + 0, 24) + true = c3 + false = c4 +- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2) + = ((c2 + c3) + c4) + +Function name: conditions::assign_and +Raw bytes (51): 0x[01, 01, 04, 09, 07, 0d, 0e, 01, 05, 01, 05, 07, 01, 0d, 01, 00, 21, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 0e, 00, 0d, 00, 0e, 05, 00, 12, 00, 13, 20, 09, 0d, 00, 12, 00, 13, 03, 01, 05, 01, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 4 +- expression 0 operands: lhs = Counter(2), rhs = Expression(1, Add) +- expression 1 operands: lhs = Counter(3), rhs = Expression(3, Sub) +- expression 2 operands: lhs = Counter(0), rhs = Counter(1) +- expression 3 operands: lhs = Counter(0), rhs = Counter(1) +Number of file 0 mappings: 7 +- Code(Counter(0)) at (prev + 13, 1) to (start + 0, 33) +- Code(Expression(0, Add)) at (prev + 1, 9) to (start + 0, 10) + = (c2 + (c3 + (c0 - c1))) +- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 14) +- Branch { true: Counter(1), false: Expression(3, Sub) } at (prev + 0, 13) to (start + 0, 14) + true = c1 + false = (c0 - c1) +- Code(Counter(1)) at (prev + 0, 18) to (start + 0, 19) +- Branch { true: Counter(2), false: Counter(3) } at (prev + 0, 18) to (start + 0, 19) + true = c2 + false = c3 +- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2) + = (c2 + (c3 + (c0 - c1))) + +Function name: conditions::assign_or +Raw bytes (51): 0x[01, 01, 04, 07, 0d, 05, 09, 01, 05, 01, 05, 07, 01, 12, 01, 00, 20, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 0e, 00, 0d, 00, 0e, 0e, 00, 12, 00, 13, 20, 09, 0d, 00, 12, 00, 13, 03, 01, 05, 01, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 4 +- expression 0 operands: lhs = Expression(1, Add), rhs = Counter(3) +- expression 1 operands: lhs = Counter(1), rhs = Counter(2) +- expression 2 operands: lhs = Counter(0), rhs = Counter(1) +- expression 3 operands: lhs = Counter(0), rhs = Counter(1) +Number of file 0 mappings: 7 +- Code(Counter(0)) at (prev + 18, 1) to (start + 0, 32) +- Code(Expression(0, Add)) at (prev + 1, 9) to (start + 0, 10) + = ((c1 + c2) + c3) +- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 14) +- Branch { true: Counter(1), false: Expression(3, Sub) } at (prev + 0, 13) to (start + 0, 14) + true = c1 + false = (c0 - c1) +- Code(Expression(3, Sub)) at (prev + 0, 18) to (start + 0, 19) + = (c0 - c1) +- Branch { true: Counter(2), false: Counter(3) } at (prev + 0, 18) to (start + 0, 19) + true = c2 + false = c3 +- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2) + = ((c1 + c2) + c3) + +Function name: conditions::foo +Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 01, 02, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 0 +Number of file 0 mappings: 1 +- Code(Counter(0)) at (prev + 33, 1) to (start + 2, 2) + +Function name: conditions::func_call +Raw bytes (39): 0x[01, 01, 03, 01, 05, 09, 0b, 0d, 02, 05, 01, 25, 01, 01, 0a, 20, 05, 02, 01, 09, 00, 0a, 05, 00, 0e, 00, 0f, 20, 09, 0d, 00, 0e, 00, 0f, 07, 01, 01, 00, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 3 +- expression 0 operands: lhs = Counter(0), rhs = Counter(1) +- expression 1 operands: lhs = Counter(2), rhs = Expression(2, Add) +- expression 2 operands: lhs = Counter(3), rhs = Expression(0, Sub) +Number of file 0 mappings: 5 +- Code(Counter(0)) at (prev + 37, 1) to (start + 1, 10) +- Branch { true: Counter(1), false: Expression(0, Sub) } at (prev + 1, 9) to (start + 0, 10) + true = c1 + false = (c0 - c1) +- Code(Counter(1)) at (prev + 0, 14) to (start + 0, 15) +- Branch { true: Counter(2), false: Counter(3) } at (prev + 0, 14) to (start + 0, 15) + true = c2 + false = c3 +- Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2) + = (c2 + (c3 + (c0 - c1))) + +Function name: conditions::simple_assign +Raw bytes (9): 0x[01, 01, 00, 01, 01, 08, 01, 03, 02] +Number of files: 1 +- file 0 => global file 1 +Number of expressions: 0 +Number of file 0 mappings: 1 +- Code(Counter(0)) at (prev + 8, 1) to (start + 3, 2) + diff --git a/tests/coverage/branch/conditions.coverage b/tests/coverage/branch/conditions.coverage new file mode 100644 index 0000000000000..96b741f321216 --- /dev/null +++ b/tests/coverage/branch/conditions.coverage @@ -0,0 +1,97 @@ + LL| |#![feature(coverage_attribute)] + LL| |//@ edition: 2021 + LL| |//@ compile-flags: -Zcoverage-options=condition + LL| |//@ llvm-cov-flags: --show-branches=count + LL| | + LL| |use core::hint::black_box; + LL| | + LL| 2|fn simple_assign(a: bool) { + LL| 2| let x = a; + LL| 2| black_box(x); + LL| 2|} + LL| | + LL| 3|fn assign_and(a: bool, b: bool) { + LL| 3| let x = a && b; + ^2 + ------------------ + | Branch (LL:13): [True: 2, False: 1] + | Branch (LL:18): [True: 1, False: 1] + ------------------ + LL| 3| black_box(x); + LL| 3|} + LL| | + LL| 3|fn assign_or(a: bool, b: bool) { + LL| 3| let x = a || b; + ^1 + ------------------ + | Branch (LL:13): [True: 2, False: 1] + | Branch (LL:18): [True: 0, False: 1] + ------------------ + LL| 3| black_box(x); + LL| 3|} + LL| | + LL| 4|fn assign_3(a: bool, b: bool, c: bool) { + LL| 4| let x = a || b && c; + ^2 ^1 + ------------------ + | Branch (LL:13): [True: 2, False: 2] + | Branch (LL:18): [True: 1, False: 1] + | Branch (LL:23): [True: 1, False: 0] + ------------------ + LL| 4| black_box(x); + LL| 4|} + LL| | + LL| 4|fn assign_3_bis(a: bool, b: bool, c: bool) { + LL| 4| let x = a && b || c; + ^2 ^3 + ------------------ + | Branch (LL:13): [True: 2, False: 2] + | Branch (LL:18): [True: 1, False: 1] + | Branch (LL:23): [True: 2, False: 1] + ------------------ + LL| 4| black_box(x); + LL| 4|} + LL| | + LL| 3|fn foo(a: bool) -> bool { + LL| 3| black_box(a) + LL| 3|} + LL| | + LL| 3|fn func_call(a: bool, b: bool) { + LL| 3| foo(a && b); + ^2 + ------------------ + | Branch (LL:9): [True: 2, False: 1] + | Branch (LL:14): [True: 1, False: 1] + ------------------ + LL| 3|} + LL| | + LL| | + LL| | + LL| |#[coverage(off)] + LL| |fn main() { + LL| | simple_assign(true); + LL| | simple_assign(false); + LL| | + LL| | assign_and(true, false); + LL| | assign_and(true, true); + LL| | assign_and(false, false); + LL| | + LL| | assign_or(true, false); + LL| | assign_or(true, true); + LL| | assign_or(false, false); + LL| | + LL| | assign_3(true, false, false); + LL| | assign_3(true, true, false); + LL| | assign_3(false, false, true); + LL| | assign_3(false, true, true); + LL| | + LL| | assign_3_bis(true, false, false); + LL| | assign_3_bis(true, true, false); + LL| | assign_3_bis(false, false, true); + LL| | assign_3_bis(false, true, true); + LL| | + LL| | func_call(true, false); + LL| | func_call(true, true); + LL| | func_call(false, false); + LL| |} + diff --git a/tests/coverage/branch/conditions.rs b/tests/coverage/branch/conditions.rs new file mode 100644 index 0000000000000..a5d6826d4ccf4 --- /dev/null +++ b/tests/coverage/branch/conditions.rs @@ -0,0 +1,69 @@ +#![feature(coverage_attribute)] +//@ edition: 2021 +//@ compile-flags: -Zcoverage-options=condition +//@ llvm-cov-flags: --show-branches=count + +use core::hint::black_box; + +fn simple_assign(a: bool) { + let x = a; + black_box(x); +} + +fn assign_and(a: bool, b: bool) { + let x = a && b; + black_box(x); +} + +fn assign_or(a: bool, b: bool) { + let x = a || b; + black_box(x); +} + +fn assign_3(a: bool, b: bool, c: bool) { + let x = a || b && c; + black_box(x); +} + +fn assign_3_bis(a: bool, b: bool, c: bool) { + let x = a && b || c; + black_box(x); +} + +fn foo(a: bool) -> bool { + black_box(a) +} + +fn func_call(a: bool, b: bool) { + foo(a && b); +} + + + +#[coverage(off)] +fn main() { + simple_assign(true); + simple_assign(false); + + assign_and(true, false); + assign_and(true, true); + assign_and(false, false); + + assign_or(true, false); + assign_or(true, true); + assign_or(false, false); + + assign_3(true, false, false); + assign_3(true, true, false); + assign_3(false, false, true); + assign_3(false, true, true); + + assign_3_bis(true, false, false); + assign_3_bis(true, true, false); + assign_3_bis(false, false, true); + assign_3_bis(false, true, true); + + func_call(true, false); + func_call(true, true); + func_call(false, false); +}