// callgraph node keeps track of which functions the are called by the function
// corresponding to the node.
//
-// A call graph will contain nodes where the function that they correspond to is
-// null. This 'external' node is used to represent control flow that is not
-// represented (or analyzable) in the module. As such, the external node will
-// have edges to functions with the following properties:
-// 1. All functions in the module without internal linkage, since they could
-// be called by functions outside of the our analysis capability.
+// A call graph may contain nodes where the function that they correspond to is
+// null. These 'external' nodes are used to represent control flow that is not
+// represented (or analyzable) in the module. In particular, this analysis
+// builds one external node such that:
+// 1. All functions in the module without internal linkage will have edges
+// from this external node, indicating that they could be called by
+// functions outside of the module.
// 2. All functions whose address is used for something more than a direct
-// call, for example being stored into a memory location. Since they may
-// be called by an unknown caller later, they must be tracked as such.
+// call, for example being stored into a memory location will also have an
+// edge from this external node. Since they may be called by an unknown
+// caller later, they must be tracked as such.
//
-// Similarly, functions have a call edge to the external node iff:
+// There is a second external node added for calls that leave this module.
+// Functions have a call edge to the external node iff:
// 1. The function is external, reflecting the fact that they could call
// anything without internal linkage or that has its address taken.
// 2. The function contains an indirect function call.
FunctionMapTy FunctionMap; // Map from a function to its node
// Root is root of the call graph, or the external node if a 'main' function
- // couldn't be found. ExternalNode is equivalent to (*this)[0].
+ // couldn't be found.
//
- CallGraphNode *Root, *ExternalNode;
+ CallGraphNode *Root;
+
+ // ExternalCallingNode - This node has edges to all external functions and
+ // those internal functions that have their address taken.
+ CallGraphNode *ExternalCallingNode;
+
+ // CallsExternalNode - This node has edges to it from all functions making
+ // indirect calls or calling an external function.
+ CallGraphNode *CallsExternalNode;
+
public:
//===---------------------------------------------------------------------
typedef FunctionMapTy::iterator iterator;
typedef FunctionMapTy::const_iterator const_iterator;
- // getExternalNode - Return the node that points to all functions that are
- // accessable from outside of the current program.
- //
- CallGraphNode *getExternalNode() { return ExternalNode; }
- const CallGraphNode *getExternalNode() const { return ExternalNode; }
+ CallGraphNode *getExternalCallingNode() const { return ExternalCallingNode; }
+ CallGraphNode *getCallsExternalNode() const { return CallsExternalNode; }
// getRoot - Return the root of the call graph, which is either main, or if
// main cannot be found, the external node.
CalledFunctions.clear();
}
-private: // Stuff to construct the node, used by CallGraph
- friend class CallGraph;
-
- // CallGraphNode ctor - Create a node for the specified function...
- inline CallGraphNode(Function *f) : F(f) {}
-
// addCalledFunction add a function to the list of functions called by this
// one
void addCalledFunction(CallGraphNode *M) {
CalledFunctions.push_back(M);
}
+
+ void removeCallEdgeTo(CallGraphNode *Callee);
+
+private: // Stuff to construct the node, used by CallGraph
+ friend class CallGraph;
+
+ // CallGraphNode ctor - Create a node for the specified function...
+ inline CallGraphNode(Function *f) : F(f) {}
};
template<> struct GraphTraits<CallGraph*> : public GraphTraits<CallGraphNode*> {
static NodeType *getEntryNode(CallGraph *CGN) {
- return CGN->getExternalNode(); // Start at the external node!
+ return CGN->getExternalCallingNode(); // Start at the external node!
}
typedef std::pair<const Function*, CallGraphNode*> PairTy;
typedef std::pointer_to_unary_function<PairTy, CallGraphNode&> DerefFun;
template<> struct GraphTraits<const CallGraph*> :
public GraphTraits<const CallGraphNode*> {
static NodeType *getEntryNode(const CallGraph *CGN) {
- return CGN->getExternalNode();
+ return CGN->getExternalCallingNode();
}
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
typedef CallGraph::const_iterator nodes_iterator;
//
//===----------------------------------------------------------------------===//
//
-// This interface is used to build and manipulate a call graph, which is a very
-// useful tool for interprocedural optimization.
-//
-// Every function in a module is represented as a node in the call graph. The
-// callgraph node keeps track of which functions the are called by the function
-// corresponding to the node.
-//
-// A call graph will contain nodes where the function that they correspond to is
-// null. This 'external' node is used to represent control flow that is not
-// represented (or analyzable) in the module. As such, the external node will
-// have edges to functions with the following properties:
-// 1. All functions in the module without internal linkage, since they could
-// be called by functions outside of the our analysis capability.
-// 2. All functions whose address is used for something more than a direct
-// call, for example being stored into a memory location. Since they may
-// be called by an unknown caller later, they must be tracked as such.
-//
-// Similarly, functions have a call edge to the external node iff:
-// 1. The function is external, reflecting the fact that they could call
-// anything without internal linkage or that has its address taken.
-// 2. The function contains an indirect function call.
-//
-// As an extension in the future, there may be multiple nodes with a null
-// function. These will be used when we can prove (through pointer analysis)
-// that an indirect call site can call only a specific set of functions.
-//
-// Because of these properties, the CallGraph captures a conservative superset
-// of all of the caller-callee relationships, which is useful for
-// transformations.
-//
-// The CallGraph class also attempts to figure out what the root of the
-// CallGraph is, which is currently does by looking for a function named 'main'.
-// If no function named 'main' is found, the external node is used as the entry
-// node, reflecting the fact that any function without internal linkage could
-// be called into (which is common for libraries).
+// This file implements the CallGraph class.
//
//===----------------------------------------------------------------------===//
#include "llvm/iTerminators.h"
#include "llvm/Support/CallSite.h"
#include "Support/STLExtras.h"
-
-namespace llvm {
+using namespace llvm;
static RegisterAnalysis<CallGraph> X("callgraph", "Call Graph Construction");
-static const char * const KnownExternalFunctions[] = {
- // Low-level system calls
- "open",
- "read",
- "write",
- "writev",
- "lseek",
- "poll",
- "ioctl",
-
- // Low-level stdc library functions
- "abort", "exit",
- "getenv", "putenv",
-
- // Standard IO functions
- "printf",
- "sprintf",
- "fopen",
- "freopen",
- "fclose",
- "fwrite",
- "puts",
- "fputs",
- "getc",
- "ungetc",
- "putc",
- "putchar",
- "fread",
- "fileno",
- "ftell",
- "fflush",
- "fseek",
- "fileno",
- "ferror",
- "feof",
- "fdopen",
- "__fxstat",
- "setbuf",
- "setbuffer",
- "etlinebuf",
- "setvbuf",
-
- // Memory functions
- "malloc",
- "free",
- "realloc",
- "calloc",
- "memalign",
-
- // String functions
- "atoi",
- "memmove",
- "memset",
- "memchr",
- "memcmp",
- "strchr",
- "strncpy",
- "strncmp",
- "strcmp",
- "strtok",
- "__strcoll_l",
- "__strxfrm_l",
- "__strftime_l",
- "__strtol_l",
- "__strtoul_l",
- "__strtoll_l",
- "__strtoull_l",
- "__strtof_l",
- "__strtod_l",
- "__strtold_l",
- "isalpha",
-
- // Math functions
- "exp", "sqrt", "cbrt", "hypot",
- "log", "log10", "pow",
- "sin", "cos", "tan",
- "asin", "acos", "atan", "atan2",
-
- // Locale functions
- "__uselocale",
- "__newlocale",
- "__freelocale",
- "__duplocale",
- "__nl_langinfo_l",
-
- // gettext functions used by libstdc++
- "gettext",
- "dgettext",
- "dcgettext",
- "textdomain",
- "bindtextdomain",
-
- // Random stuff
- "__assert_fail",
- "__errno_location",
- "clock", "time",
- "__main",
-};
-
-
-/// ExternalFunctionDoesntCallIntoProgram - This hack is used to indicate to the
-/// call graph that the specified external function is _KNOWN_ to not call back
-/// into the program. This is important, because otherwise functions which call
-/// "printf" for example, end up in a great big SCC that goes from the function
-/// through main.
-///
-static bool ExternalFunctionDoesntCallIntoProgram(const std::string &Name) {
- static std::vector<std::string> Funcs;
-
- // First time this is called?
- if (Funcs.empty()) {
- // Add a whole bunch of functions which are often used...
- Funcs.insert(Funcs.end(), KnownExternalFunctions,
- KnownExternalFunctions+
- sizeof(KnownExternalFunctions)/sizeof(KnownExternalFunctions[0]));
- // Sort the list for efficient access
- std::sort(Funcs.begin(), Funcs.end());
- }
-
- if (Name.size() > 7 && !memcmp("__llvm_", Name.c_str(), 7))
- return true;
-
- // Binary search for the function name...
- std::vector<std::string>::iterator I =
- std::lower_bound(Funcs.begin(), Funcs.end(), Name);
-
- // Found it?
- return I != Funcs.end() && *I == Name;
-}
-
-
-
// getNodeFor - Return the node for the specified function or create one if it
// does not already exist.
//
// If this function has external linkage, anything could call it...
if (!F->hasInternalLinkage()) {
- ExternalNode->addCalledFunction(Node);
+ ExternalCallingNode->addCalledFunction(Node);
// Found the entry point?
if (F->getName() == "main") {
- if (Root)
- Root = ExternalNode; // Found multiple external mains? Don't pick one.
+ if (Root) // Found multiple external mains? Don't pick one.
+ Root = ExternalCallingNode;
else
Root = Node; // Found a main, keep track of it!
}
// If this function is not defined in this translation unit, it could call
// anything.
- if (F->isExternal() && !F->getIntrinsicID() &&
- !ExternalFunctionDoesntCallIntoProgram(F->getName()))
- Node->addCalledFunction(ExternalNode);
+ if (F->isExternal() && !F->getIntrinsicID())
+ Node->addCalledFunction(CallsExternalNode);
// Loop over all of the users of the function... looking for callers...
//
}
}
if (isUsedExternally)
- ExternalNode->addCalledFunction(Node);
+ ExternalCallingNode->addCalledFunction(Node);
// Look for an indirect function call...
for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB)
for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; ++II){
CallSite CS = CallSite::get(II);
if (CS.getInstruction() && !CS.getCalledFunction())
- Node->addCalledFunction(ExternalNode);
+ Node->addCalledFunction(CallsExternalNode);
}
}
destroy();
Mod = &M;
- ExternalNode = getNodeFor(0);
+ ExternalCallingNode = getNodeFor(0);
+ CallsExternalNode = new CallGraphNode(0);
Root = 0;
// Add every function to the call graph...
addToCallGraph(I);
// If we didn't find a main function, use the external call graph node
- if (Root == 0) Root = ExternalNode;
+ if (Root == 0) Root = ExternalCallingNode;
return false;
}
// Functions to keep a call graph up to date with a function that has been
// modified
//
-void CallGraph::addFunctionToModule(Function *Meth) {
+void CallGraph::addFunctionToModule(Function *F) {
assert(0 && "not implemented");
abort();
}
void CallGraph::stub() {}
-} // End llvm namespace
+void CallGraphNode::removeCallEdgeTo(CallGraphNode *Callee) {
+ for (unsigned i = CalledFunctions.size(); ; --i) {
+ assert(i && "Cannot find callee to remove!");
+ if (CalledFunctions[i-1] == Callee) {
+ CalledFunctions.erase(CalledFunctions.begin()+i-1);
+ return;
+ }
+ }
+}
projects / oota-llvm.git / commitdiff