| /*============================================================================ |
| 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. |
| this->ComputeFinalDepends(ccg); |
| if(this->DebugMode) |
| { |
| this->DisplayGraph(this->FinalGraph, "final"); |
| } |
| |
| return true; |
| } |
| |
| //---------------------------------------------------------------------------- |
| void |
| cmComputeTargetDepends::GetTargetDirectDepends(cmTarget* t, |
| std::set<cmTarget*>& 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. |
| NodeList const& nl = this->FinalGraph[i]; |
| for(NodeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) |
| { |
| deps.insert(this->Targets[*ni]); |
| } |
| } |
| |
| //---------------------------------------------------------------------------- |
| 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]; |
| |
| // Keep track of dependencies already listed. |
| std::set<cmStdString> emitted; |
| |
| // A target should not depend on itself. |
| emitted.insert(depender->GetName()); |
| |
| // Loop over all targets linked directly. |
| cmTarget::LinkLibraryVectorType const& tlibs = |
| depender->GetOriginalLinkLibraries(); |
| 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(); |
| 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()->FindTarget(dependee_name); |
| |
| // Then search globally. |
| if(!dependee) |
| { |
| dependee = this->GlobalGenerator->FindTarget(0, 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 not found then skip then the dependee. |
| if(!dependee) |
| { |
| return; |
| } |
| |
| // No imported targets should have been found. |
| assert(!dependee->IsImported()); |
| |
| // 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(dependee_index); |
| } |
| |
| //---------------------------------------------------------------------------- |
| 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) |
| { |
| NodeList const& nl = graph[depender_index]; |
| cmTarget* depender = this->Targets[depender_index]; |
| fprintf(stderr, "target %d is [%s]\n", |
| depender_index, depender->GetName()); |
| for(NodeList::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]\n", dependee_index, |
| dependee->GetName()); |
| } |
| } |
| 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) |
| { |
| // 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::TargetTypeNames[depender->GetType()] << "\n"; |
| |
| // List its dependencies that are inside the component. |
| NodeList const& nl = this->InitialGraph[i]; |
| for(NodeList::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() << "\"\n"; |
| } |
| } |
| } |
| 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()); |
| } |
| |
| //---------------------------------------------------------------------------- |
| void |
| 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()); |
| |
| // 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 = components[depender_component].back(); |
| NodeList const& nl = cgraph[depender_component]; |
| for(NodeList::const_iterator ni = nl.begin(); ni != nl.end(); ++ni) |
| { |
| int dependee_component = *ni; |
| int dependee_component_head = components[dependee_component].front(); |
| this->FinalGraph[depender_component_tail] |
| .push_back(dependee_component_head); |
| } |
| } |
| |
| // Compute intra-component edges. |
| int nc = static_cast<int>(components.size()); |
| for(int c=0; c < nc; ++c) |
| { |
| // Within the component each target depends on that following it. |
| NodeList const& nl = components[c]; |
| NodeList::const_iterator ni = nl.begin(); |
| int last_i = *ni; |
| for(++ni; ni != nl.end(); ++ni) |
| { |
| int i = *ni; |
| this->FinalGraph[last_i].push_back(i); |
| last_i = i; |
| } |
| } |
| } |