runtime: adjust traceback / garbage collector boundary

The garbage collection routine addframeroots is duplicating
logic in the traceback routine that calls it, sometimes correctly,
sometimes incorrectly, sometimes incompletely.
Pass necessary information to addframeroots instead of
deriving it anew.

Should make addframeroots significantly more robust.
It's certainly smaller.

Also try to standardize on uintptr for saved pc, sp values.

Will make CL 10036044 trivial.

R=golang-dev, dave, dvyukov
CC=golang-dev
https://golang.org/cl/10169045

1 files changed, 28 insertions, 9 deletions

diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 564493511b..cbaff4bb52 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -211,7 +211,7 @@ struct	Gobuf
 {
 	// The offsets of these fields are known to (hard-coded in) libmach.
 	uintptr	sp;
-	byte*	pc;
+	uintptr	pc;
 	G*	g;
 };
 struct	GCStats
@@ -234,7 +234,7 @@ struct	G
 	Gobuf	sched;
 	uintptr	gcstack;		// if status==Gsyscall, gcstack = stackbase to use during gc
 	uintptr	gcsp;		// if status==Gsyscall, gcsp = sched.sp to use during gc
-	byte*	gcpc;		// if status==Gsyscall, gcpc = sched.pc to use during gc
+	uintptr	gcpc;		// if status==Gsyscall, gcpc = sched.pc to use during gc
 	uintptr	gcguard;		// if status==Gsyscall, gcguard = stackguard to use during gc
 	uintptr	stackguard;	// same as stackguard0, but not set to StackPreempt
 	uintptr	stack0;
@@ -375,8 +375,8 @@ enum
 struct	Stktop
 {
 	// The offsets of these fields are known to (hard-coded in) libmach.
-	uint8*	stackguard;
-	uint8*	stackbase;
+	uintptr	stackguard;
+	uintptr	stackbase;
 	Gobuf	gobuf;
 	uint32	argsize;
 
@@ -646,12 +646,33 @@ struct DeferChunk
 struct Panic
 {
 	Eface	arg;		// argument to panic
-	byte*	stackbase;	// g->stackbase in panic
+	uintptr	stackbase;	// g->stackbase in panic
 	Panic*	link;		// link to earlier panic
 	bool	recovered;	// whether this panic is over
 };
 
 /*
+ * stack traces
+ */
+typedef struct Stkframe Stkframe;
+struct Stkframe
+{
+	Func*	fn;	// function being run
+	uintptr	pc;	// program counter within fn
+	uintptr	lr;	// program counter at caller aka link register
+	uintptr	sp;	// stack pointer at pc
+	uintptr	fp;	// stack pointer at caller aka frame pointer
+	byte*	argp;	// pointer to function arguments
+	uintptr	arglen;	// number of bytes at argp
+	byte*	varp;	// pointer to local variables
+	uintptr	varlen;	// number of bytes at varp
+};
+
+int32	runtime·gentraceback(uintptr, uintptr, uintptr, G*, int32, uintptr*, int32, void(*)(Stkframe*, void*), void*);
+void	runtime·traceback(uintptr pc, uintptr sp, uintptr lr, G* gp);
+void	runtime·tracebackothers(G*);
+
+/*
  * external data
  */
 extern	String	runtime·emptystring;
@@ -718,8 +739,6 @@ void	runtime·sigenable(uint32 sig);
 void	runtime·sigdisable(uint32 sig);
 int32	runtime·gotraceback(bool *crash);
 void	runtime·goroutineheader(G*);
-void	runtime·traceback(uint8 *pc, uint8 *sp, uint8 *lr, G* gp);
-void	runtime·tracebackothers(G*);
 int32	runtime·open(int8*, int32, int32);
 int32	runtime·read(int32, void*, int32);
 int32	runtime·write(int32, void*, int32);
@@ -770,7 +789,7 @@ void*	runtime·malloc(uintptr size);
 void	runtime·free(void *v);
 bool	runtime·addfinalizer(void*, FuncVal *fn, uintptr);
 void	runtime·runpanic(Panic*);
-void*	runtime·getcallersp(void*);
+uintptr	runtime·getcallersp(void*);
 int32	runtime·mcount(void);
 int32	runtime·gcount(void);
 void	runtime·mcall(void(*)(G*));
@@ -792,7 +811,6 @@ void	runtime·exitsyscall(void);
 G*	runtime·newproc1(FuncVal*, byte*, int32, int32, void*);
 bool	runtime·sigsend(int32 sig);
 int32	runtime·callers(int32, uintptr*, int32);
-int32	runtime·gentraceback(byte*, byte*, byte*, G*, int32, uintptr*, int32, void (*)(Func*, byte*, byte*, void*), void*);
 int64	runtime·nanotime(void);
 void	runtime·dopanic(int32);
 void	runtime·startpanic(void);
@@ -813,6 +831,7 @@ int32	runtime·netpollopen(uintptr, PollDesc*);
 int32   runtime·netpollclose(uintptr);
 void	runtime·netpollready(G**, PollDesc*, int32);
 void	runtime·crash(void);
+void	_rt0_go(void);
 
 #pragma	varargck	argpos	runtime·printf	1
 #pragma	varargck	type	"c"	int32