support for a brief backtrace format

This only prints symbol+offset, or an address if the symbol isn't
known.

* runtime/runtime.h (SYM_VERBOSE_NO, SYM_VERBOSE_FULL,
  SYM_VERBOSE_BRIEF): new constants
* runtime/stack.c (_stp_stack_print): support brief format
* runtime/sym.c (_stp_func_print): ditto
* tapset/ucontext-unwind.stp (print_ubacktrace_brief): new function
* testsuite/systemtap.context/fib.c: new test program
* testsuite/systemtap.context/fib.stp: new test
* testsuite/systemtap.context/fib.exp: new test

5 files changed, 46 insertions, 14 deletions

diff --git a/runtime/runtime.h b/runtime/runtime.h
index a7ee962c..0fd2a380 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -126,6 +126,16 @@ static struct
 #endif
 #endif
 
+#ifndef SYM_VERBOSE_NO
+#define SYM_VERBOSE_NO 0
+#endif
+#ifndef SYM_VERBOSE_FULL
+#define SYM_VERBOSE_FULL 1
+#endif
+#ifndef SYM_VERBOSE_BRIEF
+#define SYM_VERBOSE_BRIEF 2
+#endif
+
 #include "alloc.c"
 #include "print.c"
 #include "string.c"
diff --git a/runtime/stack-i386.c b/runtime/stack-i386.c
index fef11871..4bd3cc53 100644
--- a/runtime/stack-i386.c
+++ b/runtime/stack-i386.c
@@ -63,6 +63,7 @@ static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels,
 
 	while (levels && (tsk || !arch_unw_user_mode(&info))) {
 		int ret = unwind(&info, tsk);
+#if UPROBES_API_VERSION > 1
                 unsigned long maybe_pc = 0;                
                 if (ri) {
                         maybe_pc = uprobe_get_pc(ri, UNW_PC(&info),
@@ -72,6 +73,7 @@ static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels,
                         else
                                 UNW_PC(&info) = maybe_pc;
                 }
+#endif
 		dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
 		if (ret == 0) {
 			_stp_func_print(UNW_PC(&info), verbose, 1, tsk);
diff --git a/runtime/stack-x86_64.c b/runtime/stack-x86_64.c
index 3fc203f7..80ebd3e7 100644
--- a/runtime/stack-x86_64.c
+++ b/runtime/stack-x86_64.c
@@ -38,6 +38,7 @@ static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels,
 
 	while (levels && (tsk || !arch_unw_user_mode(&info))) {
 		int ret = unwind(&info, tsk);
+#if UPROBES_API_VERSION > 1
                 unsigned long maybe_pc = 0;
                 if (ri) {
                         maybe_pc = uprobe_get_pc(ri, UNW_PC(&info),
@@ -47,6 +48,7 @@ static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels,
                         else
                                 UNW_PC(&info) = maybe_pc;
                 }
+#endif
 		dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
 		if (ret == 0) {
 			_stp_func_print(UNW_PC(&info), verbose, 1, tsk);
diff --git a/runtime/stack.c b/runtime/stack.c
index 27abee7e..3d907a7f 100644
--- a/runtime/stack.c
+++ b/runtime/stack.c
@@ -112,15 +112,20 @@ static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe
 	if (verbose) {
 		/* print the current address */
 		if (pi) {
-			_stp_print("Returning from: ");
-			_stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
-			_stp_print("\nReturning to  : ");
+			if (verbose == SYM_VERBOSE_FULL) {
+				_stp_print("Returning from: ");
+				_stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
+				_stp_print("\nReturning to  : ");
+			}
 			_stp_symbol_print((unsigned long)_stp_ret_addr_r(pi));
                 } else if (ri) {
-                        _stp_print("Returning from: ");
-                        _stp_usymbol_print(ri->rp->u.vaddr, tsk);
-			_stp_print("\nReturning to  : ");
-                        _stp_usymbol_print(ri->ret_addr, tsk);
+			if (verbose == SYM_VERBOSE_FULL) {
+				_stp_print("Returning from: ");
+				_stp_usymbol_print(ri->rp->u.vaddr, tsk);
+				_stp_print("\nReturning to  : ");
+				_stp_usymbol_print(ri->ret_addr, tsk);
+			} else
+				_stp_func_print(ri->ret_addr, verbose, 0, tsk);
 		} else {
 			_stp_print_char(' ');
 			if (tsk)
@@ -128,7 +133,8 @@ static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe
 			else
 			  _stp_symbol_print(REG_IP(regs));
 		}
-		_stp_print_char('\n');
+		if (verbose != SYM_VERBOSE_BRIEF)
+			_stp_print_char('\n');
 	} else if (pi)
 		_stp_printf("%p %p ", (int64_t)(long)_stp_ret_addr_r(pi), (int64_t) REG_IP(regs));
 	else 
diff --git a/runtime/sym.c b/runtime/sym.c
index 953161bc..cd0c8a71 100644
--- a/runtime/sym.c
+++ b/runtime/sym.c
@@ -374,19 +374,31 @@ static int _stp_func_print(unsigned long address, int verbose, int exact,
 	else
 		exstr = " (inexact)";
 
-	name = _stp_kallsyms_lookup(address, &size, &offset, &modname, NULL, task);
+	name = _stp_kallsyms_lookup(address, &size, &offset, &modname, NULL,
+				task);
 
 	if (name) {
-		if (verbose) {
+		switch (verbose) {
+		case SYM_VERBOSE_FULL:
 			if (modname && *modname)
 				_stp_printf(" %p : %s+%#lx/%#lx [%s]%s\n",
-					    (int64_t) address, name, offset, size, modname, exstr);
+					(int64_t) address, name, offset,
+					size, modname, exstr);
 			else
-				_stp_printf(" %p : %s+%#lx/%#lx%s\n", (int64_t) address, name, offset, size, exstr);
-		} else
+				_stp_printf(" %p : %s+%#lx/%#lx%s\n",
+					(int64_t) address, name, offset, size,
+					exstr);
+			break;
+		case SYM_VERBOSE_BRIEF:
+			_stp_printf("%s+%#lx\n", name, offset);
+			break;
+		case SYM_VERBOSE_NO:
+		default:
 			_stp_printf("%p ", (int64_t) address);
+		}
 		return 1;
-	}
+	} else if (verbose == SYM_VERBOSE_BRIEF)
+		_stp_printf("%p\n", (int64_t) address);
 	return 0;
 }