From 625b8f9076080b3831ef7821812461b694ef5586 Mon Sep 17 00:00:00 2001 From: Brad King Date: Wed, 25 Apr 2018 11:33:53 -0400 Subject: Ninja: Avoid empty phony edges for target ordering Since commit v3.9.0-rc1~230^2~2 (ninja: break unnecessary target dependencies, 2017-04-17) we unconditionally generate a phony edge for target ordering. It is needed in case a later target depends on it. However, if the phony edge has no inputs then `ninja -d explain` prints: ninja explain: output ... of phony edge with no inputs doesn't exist Furthermore the phony edge's output is considered dirty and can cause dependents to be incorrectly considered dirty. Avoid this by always generating at least one input to the target ordering phony edges. If we have no real dependencies just use a path that always exists. Fixes: #17942 --- Source/cmNinjaTargetGenerator.cxx | 13 +++++++++++++ Tests/RunCMake/Ninja/NoWorkToDo-nowork-stdout.txt | 1 + Tests/RunCMake/Ninja/NoWorkToDo.cmake | 2 ++ Tests/RunCMake/Ninja/RunCMakeTest.cmake | 9 +++++++++ 4 files changed, 25 insertions(+) create mode 100644 Tests/RunCMake/Ninja/NoWorkToDo-nowork-stdout.txt create mode 100644 Tests/RunCMake/Ninja/NoWorkToDo.cmake diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx index 4ce3cef..7dfce57 100644 --- a/Source/cmNinjaTargetGenerator.cxx +++ b/Source/cmNinjaTargetGenerator.cxx @@ -821,6 +821,19 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements() orderOnlyDeps.erase(std::unique(orderOnlyDeps.begin(), orderOnlyDeps.end()), orderOnlyDeps.end()); + // The phony target must depend on at least one input or ninja will explain + // that "output ... of phony edge with no inputs doesn't exist" and consider + // the phony output "dirty". + if (orderOnlyDeps.empty()) { + // Any path that always exists will work here. It would be nice to + // use just "." but that is not supported by Ninja < 1.7. + std::string tgtDir; + tgtDir += this->LocalGenerator->GetCurrentBinaryDirectory(); + tgtDir += "/"; + tgtDir += this->LocalGenerator->GetTargetDirectory(this->GeneratorTarget); + orderOnlyDeps.push_back(this->ConvertToNinjaPath(tgtDir)); + } + { cmNinjaDeps orderOnlyTarget; orderOnlyTarget.push_back(this->OrderDependsTargetForTarget()); diff --git a/Tests/RunCMake/Ninja/NoWorkToDo-nowork-stdout.txt b/Tests/RunCMake/Ninja/NoWorkToDo-nowork-stdout.txt new file mode 100644 index 0000000..60a9228 --- /dev/null +++ b/Tests/RunCMake/Ninja/NoWorkToDo-nowork-stdout.txt @@ -0,0 +1 @@ +^ninja: no work to do diff --git a/Tests/RunCMake/Ninja/NoWorkToDo.cmake b/Tests/RunCMake/Ninja/NoWorkToDo.cmake new file mode 100644 index 0000000..a2fa0cb --- /dev/null +++ b/Tests/RunCMake/Ninja/NoWorkToDo.cmake @@ -0,0 +1,2 @@ +enable_language(C) +add_executable(hello hello.c) diff --git a/Tests/RunCMake/Ninja/RunCMakeTest.cmake b/Tests/RunCMake/Ninja/RunCMakeTest.cmake index 3bb2b6b..b6e6cd4 100644 --- a/Tests/RunCMake/Ninja/RunCMakeTest.cmake +++ b/Tests/RunCMake/Ninja/RunCMakeTest.cmake @@ -21,6 +21,15 @@ function(run_NinjaToolMissing) endfunction() run_NinjaToolMissing() +function(run_NoWorkToDo) + run_cmake(NoWorkToDo) + set(RunCMake_TEST_NO_CLEAN 1) + set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/NoWorkToDo-build) + run_cmake_command(NoWorkToDo-build ${CMAKE_COMMAND} --build .) + run_cmake_command(NoWorkToDo-nowork ${CMAKE_COMMAND} --build . -- -d explain) +endfunction() +run_NoWorkToDo() + function(run_CMP0058 case) # Use a single build tree for a few tests without cleaning. set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/CMP0058-${case}-build) -- cgit v0.12