[llvm-commits] [llvm] r42418 - in /llvm/trunk: include/llvm/CodeGen/CollectorMetadata.h lib/CodeGen/CollectorMetadata.cpp
Gordon Henriksen
gordonhenriksen at mac.com
Thu Sep 27 15:18:46 PDT 2007
Author: gordon
Date: Thu Sep 27 17:18:46 2007
New Revision: 42418
URL: http://llvm.org/viewvc/llvm-project?rev=42418&view=rev
Log:
CollectorMetadata abstractly describes stack maps for a function.
It includes:
- location and of each safe point in machine code (identified by a
label)
- location of each root within the stack frame (identified by an
offset), including the metadata tag provided to llvm.gcroot in
the user program
- size of the stack frame (for collectors which want to cheat on
stack crawling :)
- and eventually will include liveness
It is to be populated by back-ends during code-generation.
CollectorModuleMetadata aggregates this information across the
entire module.
Added:
llvm/trunk/include/llvm/CodeGen/CollectorMetadata.h
llvm/trunk/lib/CodeGen/CollectorMetadata.cpp
Added: llvm/trunk/include/llvm/CodeGen/CollectorMetadata.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/CollectorMetadata.h?rev=42418&view=auto
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/CollectorMetadata.h (added)
+++ llvm/trunk/include/llvm/CodeGen/CollectorMetadata.h Thu Sep 27 17:18:46 2007
@@ -0,0 +1,195 @@
+//===-- CollectorMetadata.h - Garbage collector metadata ------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the CollectorMetadata and CollectorModuleMetadata classes,
+// which are used as a communication channel from the target code generator
+// to the target garbage collector. This interface allows code generators and
+// garbage collectors to be developed independently.
+//
+// The CollectorMetadata class records the data necessary to build a type
+// accurate stack map. Roots are specified in the LLVM IR using the llvm.gcroot
+// intrinsic, which the code generator understands. The code generator records
+// the stack offset for each GC root. Safe points are generated by the code
+// generator according to the collector's declared needs (generally at function
+// calls).
+//
+// Safe points and roots are sufficient to build type-accurate stack maps. As a
+// refinement, liveness analysis calculates the set of live roots at each safe
+// point. Liveness analysis is not presently performed, so all roots are assumed
+// live.
+//
+// CollectorModuleMetadata simply collects CollectorMetadata structures for each
+// Function as it is compiled. This is necessary for collectors which must emit
+// a stack map for the entire compilation unit. CollectorMetadata outlives the
+// MachineFunction from which it is derived, so must not refer to any code
+// generator data structures.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_COLLECTORMETADATA_H
+#define LLVM_CODEGEN_COLLECTORMETADATA_H
+
+#include "llvm/Pass.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace llvm {
+
+ class Constant;
+
+
+ /// Creates a pass to print collector metadata.
+ ///
+ Pass *createCollectorMetadataPrinter(std::ostream &OS);
+
+ /// Creates a pass to destroy collector metadata.
+ ///
+ Pass *createCollectorMetadataDeleter();
+
+
+ namespace GC {
+ /// PointKind - The type of a collector-safe point.
+ ///
+ enum PointKind {
+ Loop, //< Instr is a loop (backwards branch).
+ Return, //< Instr is a return instruction.
+ PreCall, //< Instr is a call instruction.
+ PostCall //< Instr is the return address of a call.
+ };
+ }
+
+ /// GCPoint - Metadata for a collector-safe point in machine code.
+ ///
+ struct GCPoint {
+ GC::PointKind Kind; //< The kind of the safe point.
+ unsigned Num; //< Usually a label.
+
+ GCPoint(GC::PointKind K, unsigned N) : Kind(K), Num(N) {}
+ };
+
+ /// GCRoot - Metadata for a pointer to an object managed by the garbage
+ /// collector.
+ struct GCRoot {
+ int Num; //< Usually a frame index.
+ int StackOffset; //< Offset from the stack pointer.
+ Constant *Metadata; //< From the call to llvm.gcroot.
+
+ GCRoot(int N, Constant *MD) : Num(N), StackOffset(-1), Metadata(MD) {}
+ };
+
+
+ /// CollectorMetadata - Garbage collection metadata for a function.
+ ///
+ class CollectorMetadata {
+ public:
+ typedef std::vector<GCPoint>::iterator iterator;
+ typedef std::vector<GCRoot>::iterator roots_iterator;
+ typedef std::vector<GCRoot>::const_iterator live_iterator;
+
+ private:
+ const Function &F;
+ uint64_t FrameSize;
+ std::vector<GCRoot> Roots;
+ std::vector<GCPoint> SafePoints;
+
+ // FIXME: Liveness. A 2D BitVector, perhaps?
+ //
+ // BitVector Liveness;
+ //
+ // bool islive(int point, int root) =
+ // Liveness[point * SafePoints.size() + root]
+ //
+ // The bit vector is the more compact representation where >3.2% of roots
+ // are live per safe point (1.5% on 64-bit hosts).
+
+ friend class CollectorModuleMetadata;
+ CollectorMetadata(const Function &F);
+
+ public:
+ ~CollectorMetadata();
+
+ const Function &getFunction() const { return F; }
+
+ /// addStackRoot - Registers a root that lives on the stack. Num is the
+ /// stack object ID for the alloca (if the code generator is using
+ /// MachineFrameInfo).
+ void addStackRoot(int Num, Constant *Metadata) {
+ Roots.push_back(GCRoot(Num, Metadata));
+ }
+
+ /// addSafePoint - Notes the existence of a safe point. Num is the ID of the
+ /// label just prior to the safe point (if the code generator is using
+ /// MachineModuleInfo).
+ void addSafePoint(GC::PointKind Kind, unsigned Num) {
+ SafePoints.push_back(GCPoint(Kind, Num));
+ }
+
+ /// getFrameSize/setFrameSize - Records the function's frame size.
+ ///
+ uint64_t getFrameSize() const { return FrameSize; }
+ void setFrameSize(uint64_t S) { FrameSize = S; }
+
+ /// begin/end - Iterators for safe points.
+ ///
+ iterator begin() { return SafePoints.begin(); }
+ iterator end() { return SafePoints.end(); }
+ size_t size() const { return SafePoints.size(); }
+
+ /// roots_begin/roots_end - Iterators for all roots in the function.
+ ///
+ roots_iterator roots_begin() { return Roots.begin(); }
+ roots_iterator roots_end () { return Roots.end(); }
+ size_t roots_size() const { return Roots.size(); }
+
+ /// live_begin/live_end - Iterators for live roots at a given safe point.
+ ///
+ live_iterator live_begin(const iterator &p) { return roots_begin(); }
+ live_iterator live_end (const iterator &p) { return roots_end(); }
+ size_t live_size(const iterator &p) const { return roots_size(); }
+ };
+
+
+ /// CollectorModuleMetadata - Garbage collection metadata for a whole module.
+ ///
+ class CollectorModuleMetadata : public ImmutablePass {
+ typedef std::vector<CollectorMetadata*> list_type;
+ typedef DenseMap<const Function*,CollectorMetadata*> map_type;
+
+ Module *Mod;
+ list_type Functions;
+ map_type Map;
+
+ public:
+ typedef list_type::iterator iterator;
+
+ static char ID;
+
+ CollectorModuleMetadata();
+ ~CollectorModuleMetadata();
+
+ /// clear - Used to delete module metadata. Collector invokes this as
+ /// necessary.
+ void clear();
+
+ /// begin/end - Iterators for function metadata.
+ ///
+ iterator begin() { return Functions.begin(); }
+ iterator end() { return Functions.end(); }
+
+ /// insert - Creates metadata for a function.
+ ///
+ CollectorMetadata& insert(const Function *F);
+
+ /// get - Looks up existing function metadata.
+ ///
+ CollectorMetadata* get(const Function *F) const;
+ };
+
+}
+
+#endif
Added: llvm/trunk/lib/CodeGen/CollectorMetadata.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CollectorMetadata.cpp?rev=42418&view=auto
==============================================================================
--- llvm/trunk/lib/CodeGen/CollectorMetadata.cpp (added)
+++ llvm/trunk/lib/CodeGen/CollectorMetadata.cpp Thu Sep 27 17:18:46 2007
@@ -0,0 +1,185 @@
+//===-- CollectorMetadata.cpp - Garbage collector metadata ----------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the CollectorMetadata and CollectorModuleMetadata
+// classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/CollectorMetadata.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/Function.h"
+#include "llvm/Support/Compiler.h"
+
+using namespace llvm;
+
+namespace {
+
+ class VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
+ static char ID;
+ std::ostream &OS;
+
+ public:
+ Printer(std::ostream &OS = *cerr);
+
+ const char *getPassName() const;
+ void getAnalysisUsage(AnalysisUsage &AU) const;
+
+ bool runOnMachineFunction(MachineFunction &MF);
+ };
+
+ class VISIBILITY_HIDDEN Deleter : public MachineFunctionPass {
+ static char ID;
+
+ public:
+ Deleter();
+
+ const char *getPassName() const;
+ void getAnalysisUsage(AnalysisUsage &AU) const;
+
+ bool runOnMachineFunction(MachineFunction &MF);
+ bool doFinalization(Module &M);
+ };
+
+ RegisterPass<CollectorModuleMetadata>
+ X("collector-metadata", "Create Garbage Collector Module Metadata");
+
+}
+
+// -----------------------------------------------------------------------------
+
+CollectorMetadata::CollectorMetadata(const Function &F)
+ : F(F), FrameSize(~0LL) {}
+
+CollectorMetadata::~CollectorMetadata() {}
+
+// -----------------------------------------------------------------------------
+
+char CollectorModuleMetadata::ID = 0;
+
+CollectorModuleMetadata::CollectorModuleMetadata()
+ : ImmutablePass((intptr_t)&ID) {}
+
+CollectorModuleMetadata::~CollectorModuleMetadata() {
+ clear();
+}
+
+CollectorMetadata& CollectorModuleMetadata::insert(const Function *F) {
+ assert(Map.find(F) == Map.end() && "Function GC metadata already exists!");
+ CollectorMetadata *FMD = new CollectorMetadata(*F);
+ Functions.push_back(FMD);
+ Map[F] = FMD;
+ return *FMD;
+}
+
+CollectorMetadata* CollectorModuleMetadata::get(const Function *F) const {
+ map_type::iterator I = Map.find(F);
+ if (I == Map.end())
+ return 0;
+ return I->second;
+}
+
+void CollectorModuleMetadata::clear() {
+ for (iterator I = begin(), E = end(); I != E; ++I)
+ delete *I;
+
+ Functions.clear();
+ Map.clear();
+}
+
+// -----------------------------------------------------------------------------
+
+char Printer::ID = 0;
+
+Pass *llvm::createCollectorMetadataPrinter(std::ostream &OS) {
+ return new Printer(OS);
+}
+
+Printer::Printer(std::ostream &OS)
+ : MachineFunctionPass(intptr_t(&ID)), OS(OS) {}
+
+const char *Printer::getPassName() const {
+ return "Print Garbage Collector Information";
+}
+
+void Printer::getAnalysisUsage(AnalysisUsage &AU) const {
+ MachineFunctionPass::getAnalysisUsage(AU);
+ AU.setPreservesAll();
+ AU.addRequired<CollectorModuleMetadata>();
+}
+
+static const char *DescKind(GC::PointKind Kind) {
+ switch (Kind) {
+ default: assert(0 && "Unknown GC point kind");
+ case GC::Loop: return "loop";
+ case GC::Return: return "return";
+ case GC::PreCall: return "pre-call";
+ case GC::PostCall: return "post-call";
+ }
+}
+
+bool Printer::runOnMachineFunction(MachineFunction &MF) {
+ if (CollectorMetadata *FD =
+ getAnalysis<CollectorModuleMetadata>().get(MF.getFunction())) {
+
+ OS << "GC roots for " << FD->getFunction().getNameStart() << ":\n";
+ for (CollectorMetadata::roots_iterator RI = FD->roots_begin(),
+ RE = FD->roots_end();
+ RI != RE; ++RI)
+ OS << "\t" << RI->Num << "\t" << RI->StackOffset << "[sp]\n";
+
+ OS << "GC safe points for " << FD->getFunction().getNameStart() << ":\n";
+ for (CollectorMetadata::iterator PI = FD->begin(),
+ PE = FD->end(); PI != PE; ++PI) {
+
+ OS << "\tlabel " << PI->Num << ": " << DescKind(PI->Kind) << ", live = {";
+
+ for (CollectorMetadata::live_iterator RI = FD->live_begin(PI),
+ RE = FD->live_end(PI);;) {
+ OS << " " << RI->Num;
+ if (++RI == RE)
+ break;
+ OS << ",";
+ }
+
+ OS << " }\n";
+ }
+ }
+
+ return false;
+}
+
+// -----------------------------------------------------------------------------
+
+char Deleter::ID = 0;
+
+Pass *llvm::createCollectorMetadataDeleter() {
+ return new Deleter();
+}
+
+Deleter::Deleter() : MachineFunctionPass(intptr_t(&ID)) {}
+
+const char *Deleter::getPassName() const {
+ return "Delete Garbage Collector Information";
+}
+
+void Deleter::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<CollectorModuleMetadata>();
+}
+
+bool Deleter::runOnMachineFunction(MachineFunction &MF) {
+ return false;
+}
+
+bool Deleter::doFinalization(Module &M) {
+ getAnalysis<CollectorModuleMetadata>().clear();
+ return false;
+}
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