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author	Brad King <brad.king@kitware.com>	2011-01-20 15:56:49 (GMT)
committer	Brad King <brad.king@kitware.com>	2011-01-20 15:56:49 (GMT)
commit	c4275592a89c3000008d251a1de70e3ffc95916e (patch)
tree	cfaecdebc64d1cf22df0d3855e31b1f790dc4162 /Modules/FindLibXslt.cmake
parent	1c8787f387e9958e5ca4a9e5d268bb942966305f (diff)
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Modules: Include builtin FindPackageHandleStandardArgs directly

The FindPackageHandleStandardArgs module was originally created outside of CMake. It was added for CMake 2.6.0 by commit e118a627 (add a macro FIND_PACKAGE_HANDLE_STANDARD_ARGS..., 2007-07-18). However, it also proliferated into a number of other projects that at the time required only CMake 2.4 and thus could not depend on CMake to provide the module. CMake's own find modules started using the module in commit b5f656e0 (use the new FIND_PACKAGE_HANDLE_STANDARD_ARGS in some of the FindXXX modules..., 2007-07-18). Then commit d358cf5c (add 2nd, more powerful mode to find_package_handle_standard_args, 2010-07-29) added a new feature to the interface of the module that was fully optional and backward compatible with all existing users of the module. Later commit 5f183caa (FindZLIB: use the FPHSA version mode, 2010-08-04) and others shortly thereafter started using the new interface in CMake's own find modules. This change was also backward compatible because it was only an implementation detail within each module. Unforutnately these changes introduced a problem for projects that still have an old copy of FindPackageHandleStandardArgs in CMAKE_MODULE_PATH. When any such project uses one of CMake's builtin find modules the line include(FindPackageHandleStandardArgs) loads the copy from the project which does not have the new interface! Then the including find module tries to use the new interface with the old module and fails. Whether this breakage can be considered a backward incompatible change in CMake is debatable. The situation is analagous to copying a standard library header from one version of a compiler into a project and then observing problems when the next version of the compiler reports errors in its other headers that depend on its new version of the original header. Nevertheless it is a change to CMake that causes problems for projects that worked with previous versions. This problem was discovered during the 2.8.3 release candidate cycle. It is an instance of a more general problem with projects that provide their own versions of CMake modules when other CMake modules depend on them. At the time we resolved this instance of the problem with commit b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake everywhere, 2010-09-28) for the 2.8.3 release. In order to address the more general problem we introduced policy CMP0017 in commit db44848f (Prefer files from CMAKE_ROOT when including from CMAKE_ROOT, 2010-11-17). That change was followed by commit ce28737c (Remove usage of CMAKE_CURRENT_LIST_DIR now that we have CMP0017, 2010-12-20) which reverted the original workaround in favor of using the policy. However, existing project releases do not set the policy behavior to NEW and therefore still exhibit the problem. We introduced in commit a364daf1 (Allow users to specify defaults for unset policies, 2011-01-03) an option for users to build existing projects by adding -DCMAKE_POLICY_DEFAULT_CMP0017=NEW to the command line. Unfortunately this solution still does not allow such projects to build out of the box, and there is no good way to suggest the use of the new option. The only remaining solution to keep existing projects that exhibit this problem building is to restore the change originally made in commit b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake everywhere, 2010-09-28). This also avoids policy CMP0017 warnings for this particular instance of the problem the policy addresses.

Diffstat (limited to 'Modules/FindLibXslt.cmake')

-rw-r--r--

Modules/FindLibXslt.cmake

1 files changed, 1 insertions, 1 deletions

/*============================================================================ CMake - Cross Platform Makefile Generator Copyright 2000-2009 Kitware, Inc., Insight Software Consortium Distributed under the OSI-approved BSD License (the "License"); see accompanying file Copyright.txt for details. This software is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the License for more information. ============================================================================*/ #include "cmComputeTargetDepends.h" #include "cmComputeComponentGraph.h" #include "cmGlobalGenerator.h" #include "cmLocalGenerator.h" #include "cmMakefile.h" #include "cmSystemTools.h" #include "cmTarget.h" #include "cmake.h" #include <algorithm> #include <assert.h> /* This class is meant to analyze inter-target dependencies globally during the generation step. The goal is to produce a set of direct dependencies for each target such that no cycles are left and the build order is safe. For most target types cyclic dependencies are not allowed. However STATIC libraries may depend on each other in a cyclic fasion. In general the directed dependency graph forms a directed-acyclic-graph of strongly connected components. All strongly connected components should consist of only STATIC_LIBRARY targets. In order to safely break dependency cycles we must preserve all other dependencies passing through the corresponding strongly connected component. The approach taken by this class is as follows: - Collect all targets and form the original dependency graph - Run Tarjan's algorithm to extract the strongly connected components (error if any member of a non-trivial component is not STATIC) - The original dependencies imply a DAG on the components. Use the implied DAG to construct a final safe set of dependencies. The final dependency set is constructed as follows: - For each connected component targets are placed in an arbitrary order. Each target depends on the target following it in the order. The first target is designated the head and the last target the tail. (most components will be just 1 target anyway) - Original dependencies between targets in different components are converted to connect the depender's component tail to the dependee's component head. In most cases this will reproduce the original dependencies. However when there are cycles of static libraries they will be broken in a safe manner. For example, consider targets A0, A1, A2, B0, B1, B2, and C with these dependencies: A0 -> A1 -> A2 -> A0 , B0 -> B1 -> B2 -> B0 -> A0 , C -> B0 Components may be identified as Component 0: A0, A1, A2 Component 1: B0, B1, B2 Component 2: C Intra-component dependencies are: 0: A0 -> A1 -> A2 , head=A0, tail=A2 1: B0 -> B1 -> B2 , head=B0, tail=B2 2: head=C, tail=C The inter-component dependencies are converted as: B0 -> A0 is component 1->0 and becomes B2 -> A0 C -> B0 is component 2->1 and becomes C -> B0 This leads to the final target dependencies: C -> B0 -> B1 -> B2 -> A0 -> A1 -> A2 These produce a safe build order since C depends directly or transitively on all the static libraries it links. */ //---------------------------------------------------------------------------- cmComputeTargetDepends::cmComputeTargetDepends(cmGlobalGenerator* gg) { this->GlobalGenerator = gg; cmake* cm = this->GlobalGenerator->GetCMakeInstance(); this->DebugMode = cm->GetPropertyAsBool("GLOBAL_DEPENDS_DEBUG_MODE"); this->NoCycles = cm->GetPropertyAsBool("GLOBAL_DEPENDS_NO_CYCLES"); } //---------------------------------------------------------------------------- cmComputeTargetDepends::~cmComputeTargetDepends() { } //---------------------------------------------------------------------------- bool cmComputeTargetDepends::Compute() { // Build the original graph. this->CollectTargets(); this->CollectDepends(); if(this->DebugMode) { this->DisplayGraph(this->InitialGraph, "initial"); } // Identify components. cmComputeComponentGraph ccg(this->InitialGraph); if(this->DebugMode) { this->DisplayComponents(ccg); } if(!this->CheckComponents(ccg)) { return false; } // Compute the final dependency graph. if(!this->ComputeFinalDepends(ccg)) { return false; } if(this->DebugMode) { this->DisplayGraph(this->FinalGraph, "final"); } return true; } //---------------------------------------------------------------------------- void cmComputeTargetDepends::GetTargetDirectDepends(cmTarget* t, cmTargetDependSet& deps) { // Lookup the index for this target. All targets should be known by // this point. std::map<cmTarget*, int>::const_iterator tii = this->TargetIndex.find(t); assert(tii != this->TargetIndex.end()); int i = tii->second; // Get its final dependencies. EdgeList const& nl = this->FinalGraph[i]; for(EdgeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { cmTarget* dep = this->Targets[*ni]; cmTargetDependSet::iterator di = deps.insert(dep).first; di->SetType(ni->IsStrong()); } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::CollectTargets() { // Collect all targets from all generators. std::vector<cmLocalGenerator*> const& lgens = this->GlobalGenerator->GetLocalGenerators(); for(unsigned int i = 0; i < lgens.size(); ++i) { cmTargets& targets = lgens[i]->GetMakefile()->GetTargets(); for(cmTargets::iterator ti = targets.begin(); ti != targets.end(); ++ti) { cmTarget* target = &ti->second; int index = static_cast<int>(this->Targets.size()); this->TargetIndex[target] = index; this->Targets.push_back(target); } } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::CollectDepends() { // Allocate the dependency graph adjacency lists. this->InitialGraph.resize(this->Targets.size()); // Compute each dependency list. for(unsigned int i=0; i < this->Targets.size(); ++i) { this->CollectTargetDepends(i); } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::CollectTargetDepends(int depender_index) { // Get the depender. cmTarget* depender = this->Targets[depender_index]; // Loop over all targets linked directly. { cmTarget::LinkLibraryVectorType const& tlibs = depender->GetOriginalLinkLibraries(); std::set<cmStdString> emitted; // A target should not depend on itself. emitted.insert(depender->GetName()); for(cmTarget::LinkLibraryVectorType::const_iterator lib = tlibs.begin(); lib != tlibs.end(); ++lib) { // Don't emit the same library twice for this target. if(emitted.insert(lib->first).second) { this->AddTargetDepend(depender_index, lib->first.c_str(), true); } } } // Loop over all utility dependencies. { std::set<cmStdString> const& tutils = depender->GetUtilities(); std::set<cmStdString> emitted; // A target should not depend on itself. emitted.insert(depender->GetName()); for(std::set<cmStdString>::const_iterator util = tutils.begin(); util != tutils.end(); ++util) { // Don't emit the same utility twice for this target. if(emitted.insert(*util).second) { this->AddTargetDepend(depender_index, util->c_str(), false); } } } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::AddTargetDepend(int depender_index, const char* dependee_name, bool linking) { // Get the depender. cmTarget* depender = this->Targets[depender_index]; // Check the target's makefile first. cmTarget* dependee = depender->GetMakefile()->FindTargetToUse(dependee_name); // Skip targets that will not really be linked. This is probably a // name conflict between an external library and an executable // within the project. if(linking && dependee && dependee->GetType() == cmTarget::EXECUTABLE && !dependee->IsExecutableWithExports()) { dependee = 0; } if(dependee) { this->AddTargetDepend(depender_index, dependee, linking); } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::AddTargetDepend(int depender_index, cmTarget* dependee, bool linking) { if(dependee->IsImported()) { // Skip imported targets but follow their utility dependencies. std::set<cmStdString> const& utils = dependee->GetUtilities(); for(std::set<cmStdString>::const_iterator i = utils.begin(); i != utils.end(); ++i) { if(cmTarget* transitive_dependee = dependee->GetMakefile()->FindTargetToUse(i->c_str())) { this->AddTargetDepend(depender_index, transitive_dependee, false); } } } else { // Lookup the index for this target. All targets should be known by // this point. std::map<cmTarget*, int>::const_iterator tii = this->TargetIndex.find(dependee); assert(tii != this->TargetIndex.end()); int dependee_index = tii->second; // Add this entry to the dependency graph. this->InitialGraph[depender_index].push_back( cmGraphEdge(dependee_index, !linking)); } } //---------------------------------------------------------------------------- void cmComputeTargetDepends::DisplayGraph(Graph const& graph, const char* name) { fprintf(stderr, "The %s target dependency graph is:\n", name); int n = static_cast<int>(graph.size()); for(int depender_index = 0; depender_index < n; ++depender_index) { EdgeList const& nl = graph[depender_index]; cmTarget* depender = this->Targets[depender_index]; fprintf(stderr, "target %d is [%s]\n", depender_index, depender->GetName()); for(EdgeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { int dependee_index = *ni; cmTarget* dependee = this->Targets[dependee_index]; fprintf(stderr, " depends on target %d [%s] (%s)\n", dependee_index, dependee->GetName(), ni->IsStrong()? "strong" : "weak"); } } fprintf(stderr, "\n"); } //---------------------------------------------------------------------------- void cmComputeTargetDepends ::DisplayComponents(cmComputeComponentGraph const& ccg) { fprintf(stderr, "The strongly connected components are:\n"); std::vector<NodeList> const& components = ccg.GetComponents(); int n = static_cast<int>(components.size()); for(int c = 0; c < n; ++c) { NodeList const& nl = components[c]; fprintf(stderr, "Component (%d):\n", c); for(NodeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { int i = *ni; fprintf(stderr, " contains target %d [%s]\n", i, this->Targets[i]->GetName()); } } fprintf(stderr, "\n"); } //---------------------------------------------------------------------------- bool cmComputeTargetDepends ::CheckComponents(cmComputeComponentGraph const& ccg) { // All non-trivial components should consist only of static // libraries. std::vector<NodeList> const& components = ccg.GetComponents(); int nc = static_cast<int>(components.size()); for(int c=0; c < nc; ++c) { // Get the current component. NodeList const& nl = components[c]; // Skip trivial components. if(nl.size() < 2) { continue; } // Immediately complain if no cycles are allowed at all. if(this->NoCycles) { this->ComplainAboutBadComponent(ccg, c); return false; } // Make sure the component is all STATIC_LIBRARY targets. for(NodeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { if(this->Targets[*ni]->GetType() != cmTarget::STATIC_LIBRARY) { this->ComplainAboutBadComponent(ccg, c); return false; } } } return true; } //---------------------------------------------------------------------------- void cmComputeTargetDepends ::ComplainAboutBadComponent(cmComputeComponentGraph const& ccg, int c, bool strong) { // Construct the error message. cmOStringStream e; e << "The inter-target dependency graph contains the following " << "strongly connected component (cycle):\n"; std::vector<NodeList> const& components = ccg.GetComponents(); std::vector<int> const& cmap = ccg.GetComponentMap(); NodeList const& cl = components[c]; for(NodeList::const_iterator ci = cl.begin(); ci != cl.end(); ++ci) { // Get the depender. int i = *ci; cmTarget* depender = this->Targets[i]; // Describe the depender. e << " \"" << depender->GetName() << "\" of type " << cmTarget::GetTargetTypeName(depender->GetType()) << "\n"; // List its dependencies that are inside the component. EdgeList const& nl = this->InitialGraph[i]; for(EdgeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { int j = *ni; if(cmap[j] == c) { cmTarget* dependee = this->Targets[j]; e << " depends on \"" << dependee->GetName() << "\"" << " (" << (ni->IsStrong()? "strong" : "weak") << ")\n"; } } } if(strong) { // Custom command executable dependencies cannot occur within a // component of static libraries. The cycle must appear in calls // to add_dependencies. e << "The component contains at least one cycle consisting of strong " << "dependencies (created by add_dependencies) that cannot be broken."; } else if(this->NoCycles) { e << "The GLOBAL_DEPENDS_NO_CYCLES global property is enabled, so " << "cyclic dependencies are not allowed even among static libraries."; } else { e << "At least one of these targets is not a STATIC_LIBRARY. " << "Cyclic dependencies are allowed only among static libraries."; } cmSystemTools::Error(e.str().c_str()); } //---------------------------------------------------------------------------- bool cmComputeTargetDepends ::IntraComponent(std::vector<int> const& cmap, int c, int i, int* head, std::set<int>& emitted, std::set<int>& visited) { if(!visited.insert(i).second) { // Cycle in utility depends! return false; } if(emitted.insert(i).second) { // Honor strong intra-component edges in the final order. EdgeList const& el = this->InitialGraph[i]; for(EdgeList::const_iterator ei = el.begin(); ei != el.end(); ++ei) { int j = *ei; if(cmap[j] == c && ei->IsStrong()) { this->FinalGraph[i].push_back(cmGraphEdge(j, true)); if(!this->IntraComponent(cmap, c, j, head, emitted, visited)) { return false; } } } // Prepend to a linear linked-list of intra-component edges. if(*head >= 0) { this->FinalGraph[i].push_back(cmGraphEdge(*head, false)); } else { this->ComponentTail[c] = i; } *head = i; } return true; } //---------------------------------------------------------------------------- bool cmComputeTargetDepends ::ComputeFinalDepends(cmComputeComponentGraph const& ccg) { // Get the component graph information. std::vector<NodeList> const& components = ccg.GetComponents(); Graph const& cgraph = ccg.GetComponentGraph(); // Allocate the final graph. this->FinalGraph.resize(0); this->FinalGraph.resize(this->InitialGraph.size()); // Choose intra-component edges to linearize dependencies. std::vector<int> const& cmap = ccg.GetComponentMap(); this->ComponentHead.resize(components.size()); this->ComponentTail.resize(components.size()); int nc = static_cast<int>(components.size()); for(int c=0; c < nc; ++c) { int head = -1; std::set<int> emitted; NodeList const& nl = components[c]; for(NodeList::const_reverse_iterator ni = nl.rbegin(); ni != nl.rend(); ++ni) { std::set<int> visited; if(!this->IntraComponent(cmap, c, *ni, &head, emitted, visited)) { // Cycle in add_dependencies within component! this->ComplainAboutBadComponent(ccg, c, true); return false; } } this->ComponentHead[c] = head; } // Convert inter-component edges to connect component tails to heads. int n = static_cast<int>(cgraph.size()); for(int depender_component=0; depender_component < n; ++depender_component) { int depender_component_tail = this->ComponentTail[depender_component]; EdgeList const& nl = cgraph[depender_component]; for(EdgeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) { int dependee_component = *ni; int dependee_component_head = this->ComponentHead[dependee_component]; this->FinalGraph[depender_component_tail] .push_back(cmGraphEdge(dependee_component_head, ni->IsStrong())); } } return true; }


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