A module that hooks into the debugger to provide it with a demangle() so at least when using C++ in the kernel stack crawls are meaningful.

It does its job by using part of libsupc++, with fake malloc and friends to make sure it won't double fault.
Works here, but cp-demangle must be extracted by hand from the lib, can't get the rule to work as I want, Ingo ?
Maybe using it directly without malloc hack would be ok with 16KB buffer, but I'm not sure of that.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26581 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/debug.h

@@ -111,6 +111,9 @@ extern bool		print_debugger_command_usage(const char* command);
 
 extern void		_user_debug_output(const char *userString);
 
+extern void debug_set_demangle_hook(const char *(*hook)(const char *));
+extern const char *debug_demangle(const char *);
+
 #ifdef __cplusplus
 }
 #endif

src/add-ons/kernel/debugger/Jamfile

@@ -2,6 +2,7 @@ SubDir HAIKU_TOP src add-ons kernel debugger ;
 
 SubInclude HAIKU_TOP src add-ons kernel debugger auto_stack_trace ;
 SubInclude HAIKU_TOP src add-ons kernel debugger bochs ;
+SubInclude HAIKU_TOP src add-ons kernel debugger demangle ;
 SubInclude HAIKU_TOP src add-ons kernel debugger hangman ;
 SubInclude HAIKU_TOP src add-ons kernel debugger invalidate_on_exit ;
 SubInclude HAIKU_TOP src add-ons kernel debugger laplinkll ;

src/add-ons/kernel/debugger/demangle/Jamfile

@@ -0,0 +1,43 @@
+SubDir HAIKU_TOP src add-ons kernel debugger demangle ;
+
+if $(HAIKU_GCC_VERSION[1]) >= 4 {
+
+UsePrivateHeaders kernel ;
+UseHeaders [ FDirName $(HAIKU_TOP) src system kernel debug ] ;
+
+
+rule ExtractObject
+{
+	SetupKernel $(2) ;
+	Depends $(1) : $(2) ;
+	Objects $(1) ;
+
+	MakeLocateDebug $(1) ;
+}
+
+actions ExtractObject
+{
+	#$(TARGET_AR) $(LINKFLAGS) -o "$(1)" "$(2)" $(LINKLIBS) ;
+	pwd
+	echo $(TARGET_AR) -x "$(2)" "$(1)"
+}
+
+ExtractObject cp-demangle.o : $(TARGET_STATIC_LIBSUPC++) foo ;
+
+KernelMergeObject demangle_module.o :
+        demangle.cpp
+	:
+	: 
+;
+
+
+
+KernelAddon <kdebug>demangle :
+	demangle.cpp
+	#demangle_module.o
+	cp-demangle.o
+	;
+
+#LINKFLAGS on <kdebug>demangle = -lsupc++ ;
+
+}

src/add-ons/kernel/debugger/demangle/demangle.cpp

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2008, François Revol, [email protected]
+ * Distributed under the terms of the MIT License.
+ */
+#include <ctype.h>
+#include <cxxabi.h>
+#include <debug.h>
+#include <malloc.h>
+#include <string.h>
+
+#define DEMANGLE_BUFFER_SIZE (16*1024)
+static char sDemangleBuffer[DEMANGLE_BUFFER_SIZE];
+
+extern "C" void set_debug_demangle_hook(const char *(*demangle_hook)(const char *));
+
+/* gcc's __cxa_demangle calls malloc and friends...
+ * we don't want to let it call the real one from inside the kernel debugger... 
+ * instead we just return it a static buffer.
+ */
+
+void *malloc(size_t len)
+{
+	if (len < DEMANGLE_BUFFER_SIZE)
+		return sDemangleBuffer;
+	return NULL;
+}
+
+
+void free(void *ptr)
+{
+}
+
+
+void *realloc(void * old_ptr, size_t new_size)
+{
+	return NULL;
+}
+
+
+/* doesn't work, va_list sux... */
+#if 0
+class DemangleDebugOutputFilter : public DebugOutputFilter {
+public:
+        DemangleDebugOutputFilter();
+	virtual ~DemangleDebugOutputFilter();
+        void SetChain(DebugOutputFilter *chain);
+	virtual void PrintString(const char* string);
+	virtual void Print(const char* format, va_list args);
+private:
+	DebugOutputFilter *fChained;
+};
+
+
+DemangleDebugOutputFilter::DemangleDebugOutputFilter()
+{
+}
+
+
+DemangleDebugOutputFilter::~DemangleDebugOutputFilter()
+{
+}
+
+
+void
+DemangleDebugOutputFilter::SetChain(DebugOutputFilter *chain)
+{
+	fChained = chain;
+}
+
+
+void
+DemangleDebugOutputFilter::PrintString(const char* string)
+{
+	fChained->PrintString(string);
+}
+
+
+void
+DemangleDebugOutputFilter::Print(const char* format, va_list args)
+{
+	int i;
+	const char *p = format;
+	while ((p = strchr(p, '%'))) {
+		if (p[1] == '%') {
+			p+=2;
+			continue;
+		}
+		p++;
+		while (*p && !isalpha(*p))
+			p++;
+		switch (*p) {
+			case 's':
+			{
+				const char **ptr = &va_arg(args, char *);
+				//char *symbol = va_arg(args, char *);
+				char *symbol = *ptr;
+				char *demangled;
+				size_t length = DEMANGLE_BUFFER_SIZE;
+				int status;
+
+				demangled = abi::__cxa_demangle(symbol, sDemangleBuffer, &length, &status);
+				if (status > 0)	{
+				}
+				break;
+			}
+			case 'd':
+			case 'i':
+			{
+				int d;
+				d = va_arg(args, int);
+				break;
+			}
+			case 'L':
+			{
+				long long d;
+				d = va_arg(args, long long);
+				break;
+			}
+			case 'f':
+			{
+				float f;
+				f = va_arg(args, float);
+				break;
+			}
+			case '\0':
+				break;
+			default:
+				panic("unknown printf format\n");
+				break;
+		}
+		i++;
+	}
+	fChained->Print(format, args);
+}
+#endif
+
+static const char *kdebug_demangle(const char *sym)
+{
+	char *demangled;
+	size_t length = DEMANGLE_BUFFER_SIZE;
+	int status;
+
+	demangled = abi::__cxa_demangle(sym, sDemangleBuffer, &length, &status);
+	if (status == 0)
+		return demangled;
+	// something bad happened
+	return sym;
+}
+
+static void
+exit_debugger()
+{
+}
+
+
+static status_t
+std_ops(int32 op, ...)
+{
+	if (op == B_MODULE_INIT) {
+#if 0
+		DebugOutputFilter *old;
+		DemangleDebugOutputFilter *filter = new(std::nothrow) DemangleDebugOutputFilter;
+		old = set_debug_output_filter(filter);
+		filter->SetChain(old);
+#endif
+		debug_set_demangle_hook(kdebug_demangle);
+
+		return B_OK;
+	} else if (op == B_MODULE_UNINIT) {
+		return B_OK;
+	}
+
+	return B_BAD_VALUE;
+}
+
+
+static struct debugger_module_info sModuleInfo = {
+	{
+		"debugger/demangle/v1",
+		B_KEEP_LOADED,
+		&std_ops
+	},
+
+	NULL,
+	exit_debugger,
+	NULL,
+	NULL
+};
+
+module_info *modules[] = { 
+	(module_info *)&sModuleInfo,
+	NULL
+};
+

src/system/kernel/arch/x86/arch_debug.cpp

@@ -98,6 +98,10 @@ lookup_symbol(struct thread* thread, addr_t address, addr_t *_baseAddress,
 		}
 	}
 
+	if (status == B_OK) {
+		*_symbolName = debug_demangle(*_symbolName);
+	}
+
 	return status;
 }
 

src/system/kernel/debug/debug.cpp

@@ -89,6 +89,8 @@ static const uint32 kMaxDebuggerModules = sizeof(sDebuggerModules)
 static char sLineBuffer[HISTORY_SIZE][LINE_BUFFER_SIZE] = { "", };
 static int32 sCurrentLine = 0;
 
+static const char *(*sDemangleHook)(const char *) = NULL;
+
 #define distance(a, b) ((a) < (b) ? (b) - (a) : (a) - (b))
 
 
@@ -1383,3 +1385,20 @@ dump_block(const char *buffer, int size, const char *prefix)
 		dprintf("\n");
 	}
 }
+
+
+extern void
+debug_set_demangle_hook(const char *(*hook)(const char *))
+{
+	sDemangleHook = hook;
+}
+
+
+extern const char *
+debug_demangle(const char *sym)
+{
+	if (sDemangleHook)
+		return sDemangleHook(sym);
+	return sym;
+}
+