Author: vedantk Date: Fri Sep 22 11:23:04 2017 New Revision: 314002 URL: http://llvm.org/viewvc/llvm-project?rev=314002&view=rev Log: [Coverage] Add an option to emit limited coverage info
Add an option to emit limited coverage info for unused decls. It's just a cl::opt for now to allow us to experiment quickly. When building llc, this results in an 84% size reduction in the llvm_covmap section, and a similar size reduction in the llvm_prf_names section. In practice I expect the size reduction to be roughly quadratic with the size of the program. The downside is that coverage for headers will no longer be complete. This will make the line/function/region coverage metrics incorrect, since they will be artificially high. One mitigation would be to somehow disable those metrics when using limited-coverage=true. This is related to: llvm.org/PR34533 (make SourceBasedCodeCoverage scale) Differential Revision: https://reviews.llvm.org/D38107 Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp cfe/trunk/test/CoverageMapping/header.cpp Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=314002&r1=314001&r2=314002&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original) +++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Fri Sep 22 11:23:04 2017 @@ -61,6 +61,11 @@ using namespace clang; using namespace CodeGen; +static llvm::cl::opt<bool> LimitedCoverage( + "limited-coverage-experimental", llvm::cl::ZeroOrMore, + llvm::cl::desc("Emit limited coverage mapping information (experimental)"), + llvm::cl::init(false)); + static const char AnnotationSection[] = "llvm.metadata"; static CGCXXABI *createCXXABI(CodeGenModule &CGM) { @@ -4231,6 +4236,9 @@ void CodeGenModule::AddDeferredUnusedCov case Decl::CXXDestructor: { if (!cast<FunctionDecl>(D)->doesThisDeclarationHaveABody()) return; + SourceManager &SM = getContext().getSourceManager(); + if (LimitedCoverage && SM.getMainFileID() != SM.getFileID(D->getLocStart())) + return; auto I = DeferredEmptyCoverageMappingDecls.find(D); if (I == DeferredEmptyCoverageMappingDecls.end()) DeferredEmptyCoverageMappingDecls[D] = true; Modified: cfe/trunk/test/CoverageMapping/header.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CoverageMapping/header.cpp?rev=314002&r1=314001&r2=314002&view=diff ============================================================================== --- cfe/trunk/test/CoverageMapping/header.cpp (original) +++ cfe/trunk/test/CoverageMapping/header.cpp Fri Sep 22 11:23:04 2017 @@ -2,6 +2,9 @@ // RUN: FileCheck -input-file %tmapping %s --check-prefix=CHECK-FUNC // RUN: FileCheck -input-file %tmapping %s --check-prefix=CHECK-STATIC-FUNC // RUN: FileCheck -input-file %tmapping %s --check-prefix=CHECK-STATIC-FUNC2 +// +// RUN: %clang_cc1 -fprofile-instrument=clang -fcoverage-mapping -mllvm -limited-coverage-experimental=true -dump-coverage-mapping -emit-llvm-only -main-file-name header.cpp %s > %tmapping.limited +// RUN: FileCheck -input-file %tmapping.limited %s --check-prefix=CHECK-LIMITED #include "Inputs/header1.h" @@ -22,3 +25,5 @@ int main() { // CHECK-STATIC-FUNC2: static_func2 // CHECK-STATIC-FUNC2: File 0, 21:33 -> 29:2 = 0 + +// CHECK-LIMITED-NOT: static_func2 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits