Author: vedantk Date: Wed Apr 19 12:58:30 2017 New Revision: 300723 URL: http://llvm.org/viewvc/llvm-project?rev=300723&view=rev Log: [Coverage] Don't emit mappings for functions in dependent contexts (fixes PR32679)
The coverage implementation marks functions which won't be emitted as 'deferred', so that it can emit empty coverage regions for them later (once their linkages are known). Functions in dependent contexts are an exception: if there isn't a full instantiation of a function, it shouldn't be marked 'deferred'. We've been breaking that rule without much consequence because we just ended up with useless, extra, empty coverage mappings. With PR32679, this behavior finally caused a crash, because clang marked a partial template specialization as 'deferred', causing the MS mangler to choke in its delayed-template-parsing mode: error: cannot mangle this template type parameter type yet (http://bugs.llvm.org/show_bug.cgi?id=32679) Fix this by checking if a decl's context is a dependent context before marking it 'deferred'. Based on a patch by Adam Folwarczny! Differential Revision: https://reviews.llvm.org/D32144 Added: cfe/trunk/test/CoverageMapping/pr32679.cpp Modified: cfe/trunk/lib/CodeGen/ModuleBuilder.cpp Modified: cfe/trunk/lib/CodeGen/ModuleBuilder.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ModuleBuilder.cpp?rev=300723&r1=300722&r2=300723&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/ModuleBuilder.cpp (original) +++ cfe/trunk/lib/CodeGen/ModuleBuilder.cpp Wed Apr 19 12:58:30 2017 @@ -197,7 +197,7 @@ namespace { // Provide some coverage mapping even for methods that aren't emitted. // Don't do this for templated classes though, as they may not be // instantiable. - if (!MD->getParent()->getDescribedClassTemplate()) + if (!MD->getParent()->isDependentContext()) Builder->AddDeferredUnusedCoverageMapping(MD); } Added: cfe/trunk/test/CoverageMapping/pr32679.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CoverageMapping/pr32679.cpp?rev=300723&view=auto ============================================================================== --- cfe/trunk/test/CoverageMapping/pr32679.cpp (added) +++ cfe/trunk/test/CoverageMapping/pr32679.cpp Wed Apr 19 12:58:30 2017 @@ -0,0 +1,32 @@ +// RUN: %clang_cc1 -cc1 -triple i686-pc-windows-msvc19.0.0 -emit-obj -fprofile-instrument=clang -std=c++14 -fdelayed-template-parsing -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name pr32679.cpp -o - %s | FileCheck %s -check-prefix=MSABI -implicit-check-not=f2 +// RUN: %clang_cc1 -cc1 -triple %itanium_abi_triple -emit-obj -fprofile-instrument=clang -std=c++14 -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name pr32679.cpp -o - %s | FileCheck %s -check-prefix=ITANIUM -implicit-check-not=f2 + +template <typename T, int S1> +struct CreateSpecialization; + +template <typename T> +struct CreateSpecialization<T, 0> { + static constexpr T f1() { return 0; } + static constexpr T f2() { return 0; } +}; + +int main() { + CreateSpecialization<int, 0>::f1(); + + // Don't emit coverage mapping info for functions in dependent contexts. + // + // E.g we never fully instantiate CreateSpecialization<T, 0>::f2(), so there + // should be no mapping for it. + + return 0; +} + +// MSABI: main: +// MSABI-NEXT: File 0, [[@LINE-12]]:12 -> [[@LINE-3]]:2 = #0 +// MSABI-NEXT: ?f1@?$CreateSpecialization@H$0A@@@SAHXZ: +// MSABI-NEXT: File 0, [[@LINE-18]]:27 -> [[@LINE-18]]:40 = #0 + +// ITANIUM: main: +// ITANIUM-NEXT: File 0, [[@LINE-17]]:12 -> [[@LINE-8]]:2 = #0 +// ITANIUM-NEXT: _ZN20CreateSpecializationIiLi0EE2f1Ev: +// ITANIUM-NEXT: File 0, [[@LINE-23]]:27 -> [[@LINE-23]]:40 = #0 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
