first stage of implementing LLVM code coverage #73011
Addresses feedback from @oli-obk (Thanks!)
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@@ -389,6 +389,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { | |
| ); | ||
| self.copy_op(self.operand_index(args[0], index)?, dest)?; | ||
| } | ||
| // FIXME(#73156): Handle source code coverage in const eval | ||
| sym::count_code_region => (), | ||
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There was a problem hiding this comment. Please always ping @rust-lang/wg-const-eval for new intrinsics in CTFE. There was a problem hiding this comment. Also, note that as per this comment, T-lang should have been involved as well: rust/src/libcore/intrinsics.rs Lines 8 to 9 in 394e1b4 There was a problem hiding this comment. amusingly this intrinsic is not marked as const at all. The static checks preventing non-const intrinsics from being invoked happen before mir optimizations. Since instrumentation is a MIR transformation... this isn't caught. Maybe instrumentation should happen before const checking and such? There was a problem hiding this comment. Oh, so this intrinsic is not called by users, but the call is inserted by an instrumentation pass later? Interesting. That reduces my T-lang concern.
Maybe -- I am not sure to what extend it would be useful to check the instrumented code as if it was user-written. There was a problem hiding this comment. If I write const fn a() -> u8 {
42
}
const A: u8 = a();
fn main() {
println!("{}", A);
}Then currently There was a problem hiding this comment. Sorry about that @RalfJung! That was my fault; I didn't realize we should be pinging that group. I will try to keep that in mind in the future. Do you think we still need to get the lang team involved? This intrinsic is used by an unstable There was a problem hiding this comment. I doubt they will have any objections, but sending T-lang an "FYI this is what we did here" would still be a good idea I think. There was a problem hiding this comment. Thanks for flagging the issue @RalfJung ... Note also, the next PR increment is under review, and adds some additional Rust intrinsics that I believe we need for coverage map generation. See this related note: Since the MIR analysis is minimal at the moment (injecting at the function level only) I'm not generating calls to these intrinsics yet, but when I do, I suspect I may need to add these new intrinsics to src/librustc_mir/interpret/intrinsics.rs as well, similarly stubbed out. |
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| _ => return Ok(false), | ||
| } | ||
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| @@ -0,0 +1,19 @@ | ||
| // Test that the initial version of Rust coverage injects count_code_region() placeholder calls, | ||
| // at the top of each function. The placeholders are later converted into LLVM instrprof.increment | ||
| // intrinsics, during codegen. | ||
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| // compile-flags: -Zinstrument-coverage | ||
| // EMIT_MIR rustc.main.InstrumentCoverage.diff | ||
| // EMIT_MIR rustc.bar.InstrumentCoverage.diff | ||
| fn main() { | ||
| loop { | ||
| if bar() { | ||
| break; | ||
| } | ||
| } | ||
| } | ||
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| #[inline(never)] | ||
| fn bar() -> bool { | ||
| true | ||
| } |
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| @@ -0,0 +1,41 @@ | ||
| - // MIR for `bar` before InstrumentCoverage | ||
| + // MIR for `bar` after InstrumentCoverage | ||
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| fn bar() -> bool { | ||
| let mut _0: bool; // return place in scope 0 at $DIR/instrument_coverage.rs:17:13: 17:17 | ||
| + let mut _1: (); // in scope 0 at $DIR/instrument_coverage.rs:17:1: 19:2 | ||
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| bb0: { | ||
| + StorageLive(_1); // scope 0 at $DIR/instrument_coverage.rs:17:1: 19:2 | ||
| + _1 = const std::intrinsics::count_code_region(const 0u32) -> bb2; // scope 0 at $DIR/instrument_coverage.rs:17:1: 19:2 | ||
| + // ty::Const | ||
| + // + ty: unsafe extern "rust-intrinsic" fn(u32) {std::intrinsics::count_code_region} | ||
| + // + val: Value(Scalar(<ZST>)) | ||
| + // mir::Constant | ||
| + // + span: $DIR/instrument_coverage.rs:17:1: 17:1 | ||
| + // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(u32) {std::intrinsics::count_code_region}, val: Value(Scalar(<ZST>)) } | ||
| + // ty::Const | ||
| + // + ty: u32 | ||
| + // + val: Value(Scalar(0x00000000)) | ||
| + // mir::Constant | ||
| + // + span: $DIR/instrument_coverage.rs:17:1: 17:1 | ||
| + // + literal: Const { ty: u32, val: Value(Scalar(0x00000000)) } | ||
| + } | ||
| + | ||
| + bb1 (cleanup): { | ||
| + resume; // scope 0 at $DIR/instrument_coverage.rs:17:1: 19:2 | ||
| + } | ||
| + | ||
| + bb2: { | ||
| + StorageDead(_1); // scope 0 at $DIR/instrument_coverage.rs:18:5: 18:9 | ||
| _0 = const true; // scope 0 at $DIR/instrument_coverage.rs:18:5: 18:9 | ||
| // ty::Const | ||
| // + ty: bool | ||
| // + val: Value(Scalar(0x01)) | ||
| // mir::Constant | ||
| // + span: $DIR/instrument_coverage.rs:18:5: 18:9 | ||
| // + literal: Const { ty: bool, val: Value(Scalar(0x01)) } | ||
| return; // scope 0 at $DIR/instrument_coverage.rs:19:2: 19:2 | ||
| } | ||
| } | ||
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|---|---|---|
| @@ -0,0 +1,82 @@ | ||
| - // MIR for `main` before InstrumentCoverage | ||
| + // MIR for `main` after InstrumentCoverage | ||
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| fn main() -> () { | ||
| let mut _0: (); // return place in scope 0 at $DIR/instrument_coverage.rs:8:11: 8:11 | ||
| let mut _1: (); // in scope 0 at $DIR/instrument_coverage.rs:8:1: 14:2 | ||
| let mut _2: bool; // in scope 0 at $DIR/instrument_coverage.rs:10:12: 10:17 | ||
| let mut _3: !; // in scope 0 at $DIR/instrument_coverage.rs:10:18: 12:10 | ||
| + let mut _4: (); // in scope 0 at $DIR/instrument_coverage.rs:8:1: 14:2 | ||
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| bb0: { | ||
| - falseUnwind -> [real: bb1, cleanup: bb6]; // scope 0 at $DIR/instrument_coverage.rs:9:5: 13:6 | ||
| + StorageLive(_4); // scope 0 at $DIR/instrument_coverage.rs:8:1: 14:2 | ||
| + _4 = const std::intrinsics::count_code_region(const 0u32) -> bb7; // scope 0 at $DIR/instrument_coverage.rs:8:1: 14:2 | ||
| + // ty::Const | ||
| + // + ty: unsafe extern "rust-intrinsic" fn(u32) {std::intrinsics::count_code_region} | ||
| + // + val: Value(Scalar(<ZST>)) | ||
| + // mir::Constant | ||
| + // + span: $DIR/instrument_coverage.rs:8:1: 8:1 | ||
| + // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(u32) {std::intrinsics::count_code_region}, val: Value(Scalar(<ZST>)) } | ||
| + // ty::Const | ||
| + // + ty: u32 | ||
| + // + val: Value(Scalar(0x00000000)) | ||
| + // mir::Constant | ||
| + // + span: $DIR/instrument_coverage.rs:8:1: 8:1 | ||
| + // + literal: Const { ty: u32, val: Value(Scalar(0x00000000)) } | ||
| } | ||
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| bb1: { | ||
| StorageLive(_2); // scope 0 at $DIR/instrument_coverage.rs:10:12: 10:17 | ||
| _2 = const bar() -> [return: bb2, unwind: bb6]; // scope 0 at $DIR/instrument_coverage.rs:10:12: 10:17 | ||
| // ty::Const | ||
| // + ty: fn() -> bool {bar} | ||
| // + val: Value(Scalar(<ZST>)) | ||
| // mir::Constant | ||
| // + span: $DIR/instrument_coverage.rs:10:12: 10:15 | ||
| // + literal: Const { ty: fn() -> bool {bar}, val: Value(Scalar(<ZST>)) } | ||
| } | ||
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| bb2: { | ||
| FakeRead(ForMatchedPlace, _2); // scope 0 at $DIR/instrument_coverage.rs:10:12: 10:17 | ||
| switchInt(_2) -> [false: bb4, otherwise: bb3]; // scope 0 at $DIR/instrument_coverage.rs:10:9: 12:10 | ||
| } | ||
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| bb3: { | ||
| falseEdges -> [real: bb5, imaginary: bb4]; // scope 0 at $DIR/instrument_coverage.rs:10:9: 12:10 | ||
| } | ||
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| bb4: { | ||
| _1 = const (); // scope 0 at $DIR/instrument_coverage.rs:10:9: 12:10 | ||
| // ty::Const | ||
| // + ty: () | ||
| // + val: Value(Scalar(<ZST>)) | ||
| // mir::Constant | ||
| // + span: $DIR/instrument_coverage.rs:10:9: 12:10 | ||
| // + literal: Const { ty: (), val: Value(Scalar(<ZST>)) } | ||
| StorageDead(_2); // scope 0 at $DIR/instrument_coverage.rs:13:5: 13:6 | ||
| goto -> bb0; // scope 0 at $DIR/instrument_coverage.rs:9:5: 13:6 | ||
| } | ||
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| bb5: { | ||
| _0 = const (); // scope 0 at $DIR/instrument_coverage.rs:11:13: 11:18 | ||
| // ty::Const | ||
| // + ty: () | ||
| // + val: Value(Scalar(<ZST>)) | ||
| // mir::Constant | ||
| // + span: $DIR/instrument_coverage.rs:11:13: 11:18 | ||
| // + literal: Const { ty: (), val: Value(Scalar(<ZST>)) } | ||
| StorageDead(_2); // scope 0 at $DIR/instrument_coverage.rs:13:5: 13:6 | ||
| return; // scope 0 at $DIR/instrument_coverage.rs:14:2: 14:2 | ||
| } | ||
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| bb6 (cleanup): { | ||
| resume; // scope 0 at $DIR/instrument_coverage.rs:8:1: 14:2 | ||
| + } | ||
| + | ||
| + bb7: { | ||
| + StorageDead(_4); // scope 0 at $DIR/instrument_coverage.rs:9:5: 13:6 | ||
| + falseUnwind -> [real: bb1, cleanup: bb6]; // scope 0 at $DIR/instrument_coverage.rs:9:5: 13:6 | ||
| } | ||
| } | ||
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