From 6f1d02dae741a114256bc13002ef93dc6c5f4553 Mon Sep 17 00:00:00 2001
From: Joel Dice <git@seibutsu.mailsnare.net>
Date: Tue, 28 Oct 2008 15:40:50 -0600
Subject: [PATCH] remove the libstdc++ dependency once and for all

The trick is to make all destructors non-virtual.  This is safe because
we never use the delete operator, which is the only case where virtual
destructors are relevant.  This is a better solution than implementing
our own delete operator, because we want libraries loaded at runtime to
use the libstdc++ version, not ours.
---
 makefile         | 13 +++++--------
 src/allocator.h  |  1 -
 src/assembler.h  |  8 --------
 src/boot.cpp     |  7 ++-----
 src/compiler.cpp |  4 ----
 src/compiler.h   |  4 ----
 src/finder.cpp   |  2 +-
 src/finder.h     |  1 -
 src/heap.h       |  4 ----
 src/machine.h    |  2 +-
 src/processor.h  |  6 ------
 src/stream.h     |  1 -
 src/system.h     | 12 ------------
 src/x86.cpp      |  2 --
 14 files changed, 9 insertions(+), 58 deletions(-)

diff --git a/makefile b/makefile
index 7db5d3de86..3b2cbca49e 100644
--- a/makefile
+++ b/makefile
@@ -50,7 +50,11 @@ strip-all = --strip-all
 
 rdynamic = -rdynamic
 
-warnings = -Wall -Wextra -Werror -Wunused-parameter -Winit-self
+# note that we supress the non-virtual-dtor warning because we never
+# use the delete operator, which means we don't need virtual
+# destructors:
+warnings = -Wall -Wextra -Werror -Wunused-parameter -Winit-self \
+	-Wno-non-virtual-dtor
 
 common-cflags = $(warnings) -fno-rtti -fno-exceptions \
 	"-I$(JAVA_HOME)/include" -idirafter $(src) -I$(native-build) \
@@ -62,15 +66,8 @@ build-cflags = $(common-cflags) -fPIC -fvisibility=hidden \
 
 cflags = $(build-cflags)
 
-use-libstdcpp = true
-
 common-lflags = -lm -lz
 
-ifeq ($(use-libstdcpp),true)
-	common-lflags += -lstdc++
-	common-cflags += -DUSE_LIBSTDCPP
-endif
-
 build-lflags =
 
 lflags = $(common-lflags) -lpthread -ldl
diff --git a/src/allocator.h b/src/allocator.h
index 4951a7be08..c78273ad8e 100644
--- a/src/allocator.h
+++ b/src/allocator.h
@@ -17,7 +17,6 @@ namespace vm {
 
 class Allocator {
  public:
-  virtual ~Allocator() { }
   virtual void* tryAllocate(unsigned size) = 0;
   virtual void* allocate(unsigned size) = 0;
   virtual void free(const void* p, unsigned size) = 0;
diff --git a/src/assembler.h b/src/assembler.h
index cfaa0d5b59..eceedc5993 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -78,8 +78,6 @@ const int AnyRegister = -2;
 
 class Promise {
  public:
-  virtual ~Promise() { }
-
   virtual int64_t value() = 0;
   virtual bool resolved() = 0;
 };
@@ -101,8 +99,6 @@ class ResolvedPromise: public Promise {
 
 class TraceHandler {
  public:
-  virtual ~TraceHandler() { }
-
   virtual void handleTrace(Promise* address) = 0;
 };
 
@@ -146,8 +142,6 @@ class Assembler {
 
   class Client {
    public:
-    virtual ~Client() { }
-
     virtual int acquireTemporary
     (uint32_t mask = ~static_cast<uint32_t>(0)) = 0;
     virtual void releaseTemporary(int r) = 0;
@@ -156,8 +150,6 @@ class Assembler {
     virtual void restore(int r) = 0;
   };
 
-  virtual ~Assembler() { }
-
   virtual void setClient(Client* client) = 0;
 
   virtual unsigned registerCount() = 0;
diff --git a/src/boot.cpp b/src/boot.cpp
index f6f0c95ba6..9f4c96a612 100644
--- a/src/boot.cpp
+++ b/src/boot.cpp
@@ -11,12 +11,9 @@
 #include "stdint.h"
 #include "stdlib.h"
 
-#ifndef USE_LIBSTDCPP
-// since we aren't linking against libstdc++, we must implement some
-// dummy functions:
+// since we aren't linking against libstdc++, we must implement this
+// ourselves:
 extern "C" void __cxa_pure_virtual(void) { abort(); }
-void operator delete(void*) { abort(); }
-#endif
 
 #ifdef __MINGW32__
 #  define EXPORT __declspec(dllexport)
diff --git a/src/compiler.cpp b/src/compiler.cpp
index bf6c4f0d4e..1ef9659829 100644
--- a/src/compiler.cpp
+++ b/src/compiler.cpp
@@ -48,8 +48,6 @@ class Site {
  public:
   Site(): next(0) { }
   
-  virtual ~Site() { }
-
   virtual Site* readTarget(Context*, Read*) { return this; }
 
   virtual unsigned copyCost(Context*, Site*) = 0;
@@ -364,8 +362,6 @@ class Event {
     sequence(sequence), stackReset(false)
   { }
 
-  virtual ~Event() { }
-
   virtual void compile(Context* c) = 0;
 
   virtual bool skipMove(unsigned) { return false; }
diff --git a/src/compiler.h b/src/compiler.h
index 2433b3caba..999b31f220 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -21,8 +21,6 @@ class Compiler {
  public:
   class Client {
    public:
-    virtual ~Client() { }
-
     virtual intptr_t getThunk(UnaryOperation op, unsigned size) = 0;
     virtual intptr_t getThunk(BinaryOperation op, unsigned size) = 0;
   };
@@ -32,8 +30,6 @@ class Compiler {
 
   class Operand { };
 
-  virtual ~Compiler() { }
-
   virtual void pushState() = 0;
   virtual void popState() = 0;
   virtual void saveStack() = 0;
diff --git a/src/finder.cpp b/src/finder.cpp
index dbef2c9bb2..091593d9ea 100644
--- a/src/finder.cpp
+++ b/src/finder.cpp
@@ -60,7 +60,7 @@ equal(const void* a, unsigned al, const void* b, unsigned bl)
 class Element {
  public:
   Element(): next(0) { }
-  virtual ~Element() { }
+
   virtual System::Region* find(const char* name) = 0;
   virtual bool exists(const char* name) = 0;
   virtual void dispose() = 0;
diff --git a/src/finder.h b/src/finder.h
index 6b3a868f68..64eb4c287b 100644
--- a/src/finder.h
+++ b/src/finder.h
@@ -19,7 +19,6 @@ namespace vm {
 
 class Finder {
  public:
-  virtual ~Finder() { }
   virtual System::Region* find(const char* name) = 0;
   virtual bool exists(const char* name) = 0;
   virtual const char* path() = 0;
diff --git a/src/heap.h b/src/heap.h
index bf4dc5a360..bc8f9a5a1c 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -32,19 +32,16 @@ class Heap: public Allocator {
 
   class Visitor {
    public:
-    virtual ~Visitor() { }
     virtual void visit(void*) = 0;
   };
 
   class Walker {
    public:
-    virtual ~Walker() { }
     virtual bool visit(unsigned) = 0;
   };
 
   class Client {
    public:
-    virtual ~Client() { }
     virtual void collect(void* context, CollectionType type) = 0;
     virtual void visitRoots(Visitor*) = 0;
     virtual bool isFixed(void*) = 0;
@@ -54,7 +51,6 @@ class Heap: public Allocator {
     virtual void walk(void*, Walker*) = 0;
   };
 
-  virtual ~Heap() { }
   virtual void setClient(Client* client) = 0;
   virtual void collect(CollectionType type, unsigned footprint) = 0;
   virtual void* allocateFixed(Allocator* allocator, unsigned sizeInWords,
diff --git a/src/machine.h b/src/machine.h
index c27e394c5b..3c12722c21 100644
--- a/src/machine.h
+++ b/src/machine.h
@@ -1212,7 +1212,7 @@ class Thread {
       t->protector = this;
     }
 
-    virtual ~Protector() {
+    ~Protector() {
       t->protector = next;
     }
 
diff --git a/src/processor.h b/src/processor.h
index 459970143e..a0ef3491b2 100644
--- a/src/processor.h
+++ b/src/processor.h
@@ -23,15 +23,11 @@ class Processor {
 
   class StackVisitor {
    public:
-    virtual ~StackVisitor() { }
-
     virtual bool visit(StackWalker* walker) = 0;
   };
 
   class StackWalker {
    public:
-    virtual ~StackWalker() { }
-
     virtual void walk(StackVisitor* v) = 0;
 
     virtual object method() = 0;
@@ -41,8 +37,6 @@ class Processor {
     virtual unsigned count() = 0;
   };
 
-  virtual ~Processor() { }
-
   virtual Thread*
   makeThread(Machine* m, object javaThread, Thread* parent) = 0;
 
diff --git a/src/stream.h b/src/stream.h
index c740d082b1..bf59e41865 100644
--- a/src/stream.h
+++ b/src/stream.h
@@ -19,7 +19,6 @@ class Stream {
  public:
   class Client {
    public:
-    virtual ~Client() { }
     virtual void NO_RETURN handleError() = 0;
   };
 
diff --git a/src/system.h b/src/system.h
index 69d42a25e1..3a5cb3cf22 100644
--- a/src/system.h
+++ b/src/system.h
@@ -28,7 +28,6 @@ class System {
 
   class Thread {
    public:
-    virtual ~Thread() { }
     virtual void interrupt() = 0;
     virtual void join() = 0;
     virtual void dispose() = 0;
@@ -36,13 +35,11 @@ class System {
 
   class ThreadVisitor {
    public:
-    virtual ~ThreadVisitor() { }
     virtual void visit(void* ip, void* base, void* stack) = 0;
   };
 
   class Runnable {
    public:
-    virtual ~Runnable() { }
     virtual void attach(Thread*) = 0;
     virtual void run() = 0;
     virtual bool interrupted() = 0;
@@ -51,7 +48,6 @@ class System {
 
   class Mutex {
    public:
-    virtual ~Mutex() { }
     virtual void acquire() = 0;
     virtual void release() = 0;
     virtual void dispose() = 0;
@@ -59,7 +55,6 @@ class System {
 
   class Monitor {
    public:
-    virtual ~Monitor() { }
     virtual bool tryAcquire(Thread* context) = 0;
     virtual void acquire(Thread* context) = 0;
     virtual void release(Thread* context) = 0;
@@ -72,7 +67,6 @@ class System {
 
   class Local {
    public:
-    virtual ~Local() { }
     virtual void* get() = 0;
     virtual void set(void* p) = 0;
     virtual void dispose() = 0;
@@ -80,7 +74,6 @@ class System {
 
   class Region {
    public:
-    virtual ~Region() { }
     virtual const uint8_t* start() = 0;
     virtual size_t length() = 0;
     virtual void dispose() = 0;
@@ -88,7 +81,6 @@ class System {
 
   class Library {
    public:
-    virtual ~Library() { }
     virtual void* resolve(const char* function) = 0;
     virtual const char* name() = 0;
     virtual bool mapName() = 0;
@@ -99,8 +91,6 @@ class System {
 
   class SignalHandler {
    public:
-    virtual ~SignalHandler() { }
-
     virtual bool handleSignal(void** ip, void** base, void** stack,
                               void** thread) = 0;
   };
@@ -120,8 +110,6 @@ class System {
     System::Monitor* m;
   };
 
-  virtual ~System() { }
-
   virtual bool success(Status) = 0;
   virtual void* tryAllocate(unsigned sizeInBytes) = 0;
   virtual void free(const void* p) = 0;
diff --git a/src/x86.cpp b/src/x86.cpp
index 3b6c050f40..8da31a0d8f 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -130,8 +130,6 @@ class Task {
  public:
   Task(Task* next): next(next) { }
 
-  virtual ~Task() { }
-
   virtual void run(Context* c) = 0;
 
   Task* next;