From 34b26d6a77c45776cbbef182b4c1b0b96ac326fe Mon Sep 17 00:00:00 2001 From: Rich Kadel Date: Thu, 30 Jul 2020 12:25:39 -0700 Subject: [PATCH] Rust function-level coverage now works on external crates Fixed a known issue in the coverage map where some regions had nonsensical source code locations. External crate functions are already included in their own coverage maps, per library, and don't need to also be added to the importing crate's coverage map. (In fact, their source start and end byte positions are not relevant to the importing crate's SourceMap.) The fix was to simply skip trying to add imported coverage info to the coverage map if the instrumented function is not "local". The injected counters are still relevant, however, and the LLVM `instrprof.increment` intrinsic call parameters will map those counters to the external crates' coverage maps, when generating runtime coverage data. --- src/librustc_codegen_llvm/intrinsic.rs | 109 ++++++++++--------- src/librustc_codegen_ssa/coverageinfo/map.rs | 6 +- 2 files changed, 62 insertions(+), 53 deletions(-) diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs index 236f7f696533d..728af7b0a8cd1 100644 --- a/src/librustc_codegen_llvm/intrinsic.rs +++ b/src/librustc_codegen_llvm/intrinsic.rs @@ -90,64 +90,69 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> { args: &Vec>, caller_instance: ty::Instance<'tcx>, ) -> bool { + let mut is_codegen_intrinsic = true; + // Set `is_codegen_intrinsic` to `false` to bypass `codegen_intrinsic_call()`. + if self.tcx.sess.opts.debugging_opts.instrument_coverage { - // Add the coverage information from the MIR to the Codegen context. Some coverage - // intrinsics are used only to pass along the coverage information (returns `false` - // for `is_codegen_intrinsic()`), but `count_code_region` is also converted into an - // LLVM intrinsic to increment a coverage counter. - match intrinsic { - sym::count_code_region => { - use coverage::count_code_region_args::*; - self.add_counter_region( - caller_instance, - op_to_u64(&args[FUNCTION_SOURCE_HASH]), - op_to_u32(&args[COUNTER_ID]), - op_to_u32(&args[START_BYTE_POS]), - op_to_u32(&args[END_BYTE_POS]), - ); - return true; // Also inject the counter increment in the backend - } - sym::coverage_counter_add | sym::coverage_counter_subtract => { - use coverage::coverage_counter_expression_args::*; - self.add_counter_expression_region( - caller_instance, - op_to_u32(&args[EXPRESSION_ID]), - op_to_u32(&args[LEFT_ID]), - if intrinsic == sym::coverage_counter_add { - ExprKind::Add - } else { - ExprKind::Subtract - }, - op_to_u32(&args[RIGHT_ID]), - op_to_u32(&args[START_BYTE_POS]), - op_to_u32(&args[END_BYTE_POS]), - ); - return false; // Does not inject backend code + // If the intrinsic is from the local MIR, add the coverage information to the Codegen + // context, to be encoded into the local crate's coverage map. + if caller_instance.def_id().is_local() { + // FIXME(richkadel): Make sure to add coverage analysis tests on a crate with + // external crate dependencies, where: + // 1. Both binary and dependent crates are compiled with `-Zinstrument-coverage` + // 2. Only binary is compiled with `-Zinstrument-coverage` + // 3. Only dependent crates are compiled with `-Zinstrument-coverage` + match intrinsic { + sym::count_code_region => { + use coverage::count_code_region_args::*; + self.add_counter_region( + caller_instance, + op_to_u64(&args[FUNCTION_SOURCE_HASH]), + op_to_u32(&args[COUNTER_ID]), + op_to_u32(&args[START_BYTE_POS]), + op_to_u32(&args[END_BYTE_POS]), + ); + } + sym::coverage_counter_add | sym::coverage_counter_subtract => { + use coverage::coverage_counter_expression_args::*; + self.add_counter_expression_region( + caller_instance, + op_to_u32(&args[EXPRESSION_ID]), + op_to_u32(&args[LEFT_ID]), + if intrinsic == sym::coverage_counter_add { + ExprKind::Add + } else { + ExprKind::Subtract + }, + op_to_u32(&args[RIGHT_ID]), + op_to_u32(&args[START_BYTE_POS]), + op_to_u32(&args[END_BYTE_POS]), + ); + } + sym::coverage_unreachable => { + use coverage::coverage_unreachable_args::*; + self.add_unreachable_region( + caller_instance, + op_to_u32(&args[START_BYTE_POS]), + op_to_u32(&args[END_BYTE_POS]), + ); + } + _ => {} } - sym::coverage_unreachable => { - use coverage::coverage_unreachable_args::*; - self.add_unreachable_region( - caller_instance, - op_to_u32(&args[START_BYTE_POS]), - op_to_u32(&args[END_BYTE_POS]), - ); - return false; // Does not inject backend code + } + + // Only the `count_code_region` coverage intrinsic is translated into an actual LLVM + // intrinsic call (local or not); otherwise, set `is_codegen_intrinsic` to `false`. + match intrinsic { + sym::coverage_counter_add + | sym::coverage_counter_subtract + | sym::coverage_unreachable => { + is_codegen_intrinsic = false; } _ => {} } - } else { - // NOT self.tcx.sess.opts.debugging_opts.instrument_coverage - if intrinsic == sym::count_code_region { - // An external crate may have been pre-compiled with coverage instrumentation, and - // some references from the current crate to the external crate might carry along - // the call terminators to coverage intrinsics, like `count_code_region` (for - // example, when instantiating a generic function). If the current crate has - // `instrument_coverage` disabled, the `count_code_region` call terminators should - // be ignored. - return false; // Do not inject coverage counters inlined from external crates - } } - true // Unhandled intrinsics should be passed to `codegen_intrinsic_call()` + is_codegen_intrinsic } fn codegen_intrinsic_call( diff --git a/src/librustc_codegen_ssa/coverageinfo/map.rs b/src/librustc_codegen_ssa/coverageinfo/map.rs index 1e36c90baafdf..72138065a90ba 100644 --- a/src/librustc_codegen_ssa/coverageinfo/map.rs +++ b/src/librustc_codegen_ssa/coverageinfo/map.rs @@ -86,7 +86,11 @@ impl Region { pub fn new(source_map: &SourceMap, start_byte_pos: u32, end_byte_pos: u32) -> Self { let start = source_map.lookup_char_pos(BytePos::from_u32(start_byte_pos)); let end = source_map.lookup_char_pos(BytePos::from_u32(end_byte_pos)); - assert_eq!(start.file.name, end.file.name); + assert_eq!( + start.file.name, end.file.name, + "Region start ({} -> {:?}) and end ({} -> {:?}) don't come from the same source file!", + start_byte_pos, start, end_byte_pos, end + ); Self { start, end } }