From 463e30f51fd07921f32c6630afb3f8dd18d6d2f5 Mon Sep 17 00:00:00 2001 From: Corentin Jabot Date: Fri, 26 Aug 2022 10:20:12 +0200 Subject: [PATCH] [Clang] Fix crash in coverage of if consteval. Clang crashes when encountering an `if consteval` statement. This is the minimum fix not to crash. The fix is consistent with the current behavior of if constexpr, which does generate coverage data for the discarded branches. This is of course not correct and a better solution is needed for both if constexpr and if consteval. See https://github.com/llvm/llvm-project/issues/54419. Fixes #57377 Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D132723 --- clang/docs/ReleaseNotes.rst | 4 ++++ clang/lib/CodeGen/CoverageMappingGen.cpp | 32 +++++++++++++++++++------------- clang/test/CoverageMapping/if.cpp | 22 +++++++++++++++++++++- 3 files changed, 44 insertions(+), 14 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 3f7eec1..b6d1dbe 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -78,6 +78,10 @@ Bug Fixes - ``-Wtautological-compare`` missed warnings for tautological comparisons involving a negative integer literal. This fixes `Issue 42918 `_. +- Fix a crash when generating code coverage information for an + ``if consteval`` statement. This fixes + `Issue 57377 `_. + Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp index 0fe084b..836aabf 100644 --- a/clang/lib/CodeGen/CoverageMappingGen.cpp +++ b/clang/lib/CodeGen/CoverageMappingGen.cpp @@ -1377,19 +1377,23 @@ struct CounterCoverageMappingBuilder // Extend into the condition before we propagate through it below - this is // needed to handle macros that generate the "if" but not the condition. - extendRegion(S->getCond()); + if (!S->isConsteval()) + extendRegion(S->getCond()); Counter ParentCount = getRegion().getCounter(); Counter ThenCount = getRegionCounter(S); - // Emitting a counter for the condition makes it easier to interpret the - // counter for the body when looking at the coverage. - propagateCounts(ParentCount, S->getCond()); + if (!S->isConsteval()) { + // Emitting a counter for the condition makes it easier to interpret the + // counter for the body when looking at the coverage. + propagateCounts(ParentCount, S->getCond()); - // The 'then' count applies to the area immediately after the condition. - auto Gap = findGapAreaBetween(S->getRParenLoc(), getStart(S->getThen())); - if (Gap) - fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ThenCount); + // The 'then' count applies to the area immediately after the condition. + Optional Gap = + findGapAreaBetween(S->getRParenLoc(), getStart(S->getThen())); + if (Gap) + fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ThenCount); + } extendRegion(S->getThen()); Counter OutCount = propagateCounts(ThenCount, S->getThen()); @@ -1398,9 +1402,9 @@ struct CounterCoverageMappingBuilder if (const Stmt *Else = S->getElse()) { bool ThenHasTerminateStmt = HasTerminateStmt; HasTerminateStmt = false; - // The 'else' count applies to the area immediately after the 'then'. - Gap = findGapAreaBetween(getEnd(S->getThen()), getStart(Else)); + Optional Gap = + findGapAreaBetween(getEnd(S->getThen()), getStart(Else)); if (Gap) fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ElseCount); extendRegion(Else); @@ -1416,9 +1420,11 @@ struct CounterCoverageMappingBuilder GapRegionCounter = OutCount; } - // Create Branch Region around condition. - createBranchRegion(S->getCond(), ThenCount, - subtractCounters(ParentCount, ThenCount)); + if (!S->isConsteval()) { + // Create Branch Region around condition. + createBranchRegion(S->getCond(), ThenCount, + subtractCounters(ParentCount, ThenCount)); + } } void VisitCXXTryStmt(const CXXTryStmt *S) { diff --git a/clang/test/CoverageMapping/if.cpp b/clang/test/CoverageMapping/if.cpp index 5b705cd..de3554c 100644 --- a/clang/test/CoverageMapping/if.cpp +++ b/clang/test/CoverageMapping/if.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -std=c++1z -triple %itanium_abi_triple -main-file-name if.cpp %s | FileCheck %s +// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -std=c++2b -triple %itanium_abi_triple -main-file-name if.cpp %s | FileCheck %s int nop() { return 0; } @@ -13,6 +13,22 @@ void foo() { // CHECK-NEXT: Gap,File 0, [[@LINE+1]]:21 -> [[@ ++j; // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:7 -> [[@LINE-1]]:8 = #1, (#0 - #1) } // CHECK-NEXT: [[@LINE-2]]:9 -> [[@LINE-1]]:5 = #1 // CHECK-NEXT: [[@LINE-2]]:5 -> [[@LINE-2]]:8 = #1 + +// FIXME: Do not generate coverage for discarded branches in if consteval and if constexpr statements +constexpr int check_consteval(int i) { + if consteval { + i++; + } + if !consteval { + i++; + } + if consteval { + return 42; + } else { + return i; + } +} + // CHECK-LABEL: main: int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 = #0 int i = 0; @@ -50,6 +66,10 @@ int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 = // CHECK-NEXT: File 0, [[@LINE+1]]:14 -> [[@LINE+1]]:20 = #6 i = i == 0?i + 12:i + 10; // CHECK-NEXT: File 0, [[@LINE]]:21 -> [[@LINE]]:27 = (#0 - #6) + // GH-57377 + constexpr int c_i = check_consteval(0); + check_consteval(i); + return 0; } -- 2.7.4