add sys.caller

R=r
DELTA=139  (101 added, 38 deleted, 0 changed)
OCL=22462
CL=22466

3 files changed, 101 insertions, 38 deletions

diff --git a/src/cmd/gc/sys.go b/src/cmd/gc/sys.go
index ba74fae61..b61536a2e 100644
--- a/src/cmd/gc/sys.go
+++ b/src/cmd/gc/sys.go
@@ -5,8 +5,9 @@
 
 package PACKAGE
 
+// emitted by compiler, not referred to by go programs
+
 export func	mal(int32) *any;
-export func	breakpoint();
 export func	throwindex();
 export func	throwreturn();
 export func	panicl(int32);
@@ -35,25 +36,6 @@ export func	ifaceI2T2(sigt *byte, iface any) (ret any, ok bool);
 export func	ifaceI2I(sigi *byte, iface any) (ret any);
 export func	ifaceI2I2(sigi *byte, iface any) (ret any, ok bool);
 export func	ifaceeq(i1 any, i2 any) (ret bool);
-export func	reflect(i interface { }) (uint64, string, bool);
-export func	unreflect(uint64, string, bool) (ret interface { });
-
-export func	argc() int;
-export func	envc() int;
-export func	argv(int) string;
-export func	envv(int) string;
-
-export func	frexp(float64) (float64, int);		// break fp into exp,fract
-export func	ldexp(float64, int) float64;		// make fp from exp,fract
-export func	modf(float64) (float64, float64);	// break fp into double.double
-export func	isInf(float64, int) bool;		// test for infinity
-export func	isNaN(float64) bool;			// test for not-a-number
-export func	Inf(int) float64;			// return signed Inf
-export func	NaN() float64;				// return a NaN
-export func	float32bits(float32) uint32;		// raw bits
-export func	float64bits(float64) uint64;		// raw bits
-export func	float32frombits(uint32) float32;	// raw bits
-export func	float64frombits(uint64) float64;	// raw bits
 
 export func	newmap(keysize int, valsize int,
 			keyalg int, valalg int,
@@ -85,6 +67,30 @@ export func	arraysliced(old []any, lb int, hb int, width int) (ary []any);
 export func	arrayslices(old *any, nel int, lb int, hb int, width int) (ary []any);
 export func	arrays2d(old *any, nel int) (ary []any);
 
+// used by go programs
+
+export func	breakpoint();
+
+export func	reflect(i interface { }) (uint64, string, bool);
+export func	unreflect(uint64, string, bool) (ret interface { });
+
+export func	argc() int;
+export func	envc() int;
+export func	argv(int) string;
+export func	envv(int) string;
+
+export func	frexp(float64) (float64, int);		// break fp into exp,fract
+export func	ldexp(float64, int) float64;		// make fp from exp,fract
+export func	modf(float64) (float64, float64);	// break fp into double.double
+export func	isInf(float64, int) bool;		// test for infinity
+export func	isNaN(float64) bool;			// test for not-a-number
+export func	Inf(int) float64;			// return signed Inf
+export func	NaN() float64;				// return a NaN
+export func	float32bits(float32) uint32;		// raw bits
+export func	float64bits(float64) uint64;		// raw bits
+export func	float32frombits(uint32) float32;	// raw bits
+export func	float64frombits(uint64) float64;	// raw bits
+
 export func	gosched();
 export func	goexit();
 
@@ -96,6 +102,7 @@ export func	stringtorune(string, int) (int, int);	// convert bytes to runes
 export func	exit(int);
 
 export func	symdat() (symtab []byte, pclntab []byte);
+export func	caller(n int) (pc uint64, file string, line int, ok bool);
 
 export func	semacquire(sema *int32);
 export func	semrelease(sema *int32);
diff --git a/src/cmd/gc/sysimport.c b/src/cmd/gc/sysimport.c
index 00251018e..5436e2418 100644
--- a/src/cmd/gc/sysimport.c
+++ b/src/cmd/gc/sysimport.c
@@ -1,7 +1,6 @@
 char *sysimport =
 	"package sys\n"
 	"export func sys.mal (? int32) (? *any)\n"
-	"export func sys.breakpoint ()\n"
 	"export func sys.throwindex ()\n"
 	"export func sys.throwreturn ()\n"
 	"export func sys.panicl (? int32)\n"
@@ -27,23 +26,6 @@ char *sysimport =
 	"export func sys.ifaceI2I (sigi *uint8, iface any) (ret any)\n"
 	"export func sys.ifaceI2I2 (sigi *uint8, iface any) (ret any, ok bool)\n"
 	"export func sys.ifaceeq (i1 any, i2 any) (ret bool)\n"
-	"export func sys.reflect (i interface { }) (? uint64, ? string, ? bool)\n"
-	"export func sys.unreflect (? uint64, ? string, ? bool) (ret interface { })\n"
-	"export func sys.argc () (? int)\n"
-	"export func sys.envc () (? int)\n"
-	"export func sys.argv (? int) (? string)\n"
-	"export func sys.envv (? int) (? string)\n"
-	"export func sys.frexp (? float64) (? float64, ? int)\n"
-	"export func sys.ldexp (? float64, ? int) (? float64)\n"
-	"export func sys.modf (? float64) (? float64, ? float64)\n"
-	"export func sys.isInf (? float64, ? int) (? bool)\n"
-	"export func sys.isNaN (? float64) (? bool)\n"
-	"export func sys.Inf (? int) (? float64)\n"
-	"export func sys.NaN () (? float64)\n"
-	"export func sys.float32bits (? float32) (? uint32)\n"
-	"export func sys.float64bits (? float64) (? uint64)\n"
-	"export func sys.float32frombits (? uint32) (? float32)\n"
-	"export func sys.float64frombits (? uint64) (? float64)\n"
 	"export func sys.newmap (keysize int, valsize int, keyalg int, valalg int, hint int) (hmap map[any] any)\n"
 	"export func sys.mapaccess1 (hmap map[any] any, key any) (val any)\n"
 	"export func sys.mapaccess2 (hmap map[any] any, key any) (val any, pres bool)\n"
@@ -68,6 +50,24 @@ char *sysimport =
 	"export func sys.arraysliced (old []any, lb int, hb int, width int) (ary []any)\n"
 	"export func sys.arrayslices (old *any, nel int, lb int, hb int, width int) (ary []any)\n"
 	"export func sys.arrays2d (old *any, nel int) (ary []any)\n"
+	"export func sys.breakpoint ()\n"
+	"export func sys.reflect (i interface { }) (? uint64, ? string, ? bool)\n"
+	"export func sys.unreflect (? uint64, ? string, ? bool) (ret interface { })\n"
+	"export func sys.argc () (? int)\n"
+	"export func sys.envc () (? int)\n"
+	"export func sys.argv (? int) (? string)\n"
+	"export func sys.envv (? int) (? string)\n"
+	"export func sys.frexp (? float64) (? float64, ? int)\n"
+	"export func sys.ldexp (? float64, ? int) (? float64)\n"
+	"export func sys.modf (? float64) (? float64, ? float64)\n"
+	"export func sys.isInf (? float64, ? int) (? bool)\n"
+	"export func sys.isNaN (? float64) (? bool)\n"
+	"export func sys.Inf (? int) (? float64)\n"
+	"export func sys.NaN () (? float64)\n"
+	"export func sys.float32bits (? float32) (? uint32)\n"
+	"export func sys.float64bits (? float64) (? uint64)\n"
+	"export func sys.float32frombits (? uint32) (? float32)\n"
+	"export func sys.float64frombits (? uint64) (? float64)\n"
 	"export func sys.gosched ()\n"
 	"export func sys.goexit ()\n"
 	"export func sys.readfile (? string) (? string, ? bool)\n"
@@ -76,6 +76,7 @@ char *sysimport =
 	"export func sys.stringtorune (? string, ? int) (? int, ? int)\n"
 	"export func sys.exit (? int)\n"
 	"export func sys.symdat () (symtab []uint8, pclntab []uint8)\n"
+	"export func sys.caller (n int) (pc uint64, file string, line int, ok bool)\n"
 	"export func sys.semacquire (sema *int32)\n"
 	"export func sys.semrelease (sema *int32)\n"
 	"\n"
diff --git a/src/runtime/rt2_amd64.c b/src/runtime/rt2_amd64.c
index 9c8436f17..62c74bf51 100644
--- a/src/runtime/rt2_amd64.c
+++ b/src/runtime/rt2_amd64.c
@@ -69,3 +69,58 @@ traceback(byte *pc0, byte *sp, G *g)
 	}
 	prints("...\n");
 }
+
+// func caller(n int) (pc uint64, file string, line int, ok bool)
+void
+sys·caller(int32 n, uint64 retpc, string retfile, int32 retline, bool retbool)
+{
+	uint64 pc;
+	byte *sp;
+	Stktop *stk;
+	Func *f;
+
+	// our caller's pc, sp.
+	sp = (byte*)&n;
+	pc = *(uint64*)(sp-8);
+	if((f = findfunc(pc)) == nil) {
+	error:
+		retpc = 0;
+		retline = 0;
+		retfile = nil;
+		retbool = false;
+		FLUSH(&retpc);
+		FLUSH(&retfile);
+		FLUSH(&retline);
+		FLUSH(&retbool);
+		return;
+	}
+
+	// now unwind n levels
+	stk = (Stktop*)g->stackbase;
+	while(n-- > 0) {
+		while(pc == (uint64)retfromnewstack) {
+			sp = stk->oldsp;
+			stk = (Stktop*)stk->oldbase;
+			pc = *(uint64*)(sp+8);
+			sp += 16;
+		}
+
+		if(f->frame < 8)	// assembly functions lie
+			sp += 8;
+		else
+			sp += f->frame;
+
+		pc = *(uint64*)(sp-8);
+		if(pc <= 0x1000 || (f = findfunc(pc)) == nil)
+			goto error;
+	}
+
+	retpc = pc;
+	retfile = f->src;
+	retline = funcline(f, pc-1);
+	retbool = true;
+	FLUSH(&retpc);
+	FLUSH(&retfile);
+	FLUSH(&retline);
+	FLUSH(&retbool);
+}