1 files changed, 332 insertions, 0 deletions
diff --git a/src/pkg/runtime/symtab.goc b/src/pkg/runtime/symtab.goc
new file mode 100644
index 000000000..15e1d28fa
--- /dev/null
+++ b/src/pkg/runtime/symtab.goc
@@ -0,0 +1,332 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Runtime symbol table parsing.
+// See http://golang.org/s/go12symtab for an overview.
+
+package runtime
+#include "runtime.h"
+#include "defs_GOOS_GOARCH.h"
+#include "os_GOOS.h"
+#include "arch_GOARCH.h"
+#include "malloc.h"
+#include "funcdata.h"
+
+typedef struct Ftab Ftab;
+struct Ftab
+{
+	uintptr	entry;
+	uintptr	funcoff;
+};
+
+extern byte pclntab[];
+
+static Ftab *ftab;
+static uintptr nftab;
+static uint32 *filetab;
+static uint32 nfiletab;
+
+static String end = { (uint8*)"end", 3 };
+
+void
+runtime·symtabinit(void)
+{
+	int32 i, j;
+	Func *f1, *f2;
+	
+	// See golang.org/s/go12symtab for header: 0xfffffffb,
+	// two zero bytes, a byte giving the PC quantum,
+	// and a byte giving the pointer width in bytes.
+	if(*(uint32*)pclntab != 0xfffffffb || pclntab[4] != 0 || pclntab[5] != 0 || pclntab[6] != PCQuantum || pclntab[7] != sizeof(void*)) {
+		runtime·printf("runtime: function symbol table header: %x %x\n", *(uint32*)pclntab, *(uint32*)(pclntab+4));
+		runtime·throw("invalid function symbol table\n");
+	}
+
+	nftab = *(uintptr*)(pclntab+8);
+	ftab = (Ftab*)(pclntab+8+sizeof(void*));
+	for(i=0; i<nftab; i++) {
+		// NOTE: ftab[nftab].entry is legal; it is the address beyond the final function.
+		if(ftab[i].entry > ftab[i+1].entry) {
+			f1 = (Func*)(pclntab + ftab[i].funcoff);
+			f2 = (Func*)(pclntab + ftab[i+1].funcoff);
+			runtime·printf("function symbol table not sorted by program counter: %p %s > %p %s", ftab[i].entry, runtime·funcname(f1), ftab[i+1].entry, i+1 == nftab ? "end" : runtime·funcname(f2));
+			for(j=0; j<=i; j++)
+				runtime·printf("\t%p %s\n", ftab[j].entry, runtime·funcname((Func*)(pclntab + ftab[j].funcoff)));
+			runtime·throw("invalid runtime symbol table");
+		}
+	}
+	
+	filetab = (uint32*)(pclntab + *(uint32*)&ftab[nftab].funcoff);
+	nfiletab = filetab[0];
+}
+
+static uint32
+readvarint(byte **pp)
+{
+	byte *p;
+	uint32 v;
+	int32 shift;
+	
+	v = 0;
+	p = *pp;
+	for(shift = 0;; shift += 7) {
+		v |= (*p & 0x7F) << shift;
+		if(!(*p++ & 0x80))
+			break;
+	}
+	*pp = p;
+	return v;
+}
+
+void*
+runtime·funcdata(Func *f, int32 i)
+{
+	byte *p;
+
+	if(i < 0 || i >= f->nfuncdata)
+		return nil;
+	p = (byte*)&f->nfuncdata + 4 + f->npcdata*4;
+	if(sizeof(void*) == 8 && ((uintptr)p & 4)) {
+		if(((uintptr)f & 4))
+			runtime·printf("misaligned func %p\n", f);
+		p += 4;
+	}
+	return ((void**)p)[i];
+}
+
+static bool
+step(byte **pp, uintptr *pc, int32 *value, bool first)
+{
+	uint32 uvdelta, pcdelta;
+	int32 vdelta;
+
+	uvdelta = readvarint(pp);
+	if(uvdelta == 0 && !first)
+		return 0;
+	if(uvdelta&1)
+		uvdelta = ~(uvdelta>>1);
+	else
+		uvdelta >>= 1;
+	vdelta = (int32)uvdelta;
+	pcdelta = readvarint(pp) * PCQuantum;
+	*value += vdelta;
+	*pc += pcdelta;
+	return 1;
+}
+
+// Return associated data value for targetpc in func f.
+// (Source file is f->src.)
+static int32
+pcvalue(Func *f, int32 off, uintptr targetpc, bool strict)
+{
+	byte *p;
+	uintptr pc;
+	int32 value;
+
+	enum {
+		debug = 0
+	};
+
+	// The table is a delta-encoded sequence of (value, pc) pairs.
+	// Each pair states the given value is in effect up to pc.
+	// The value deltas are signed, zig-zag encoded.
+	// The pc deltas are unsigned.
+	// The starting value is -1, the starting pc is the function entry.
+	// The table ends at a value delta of 0 except in the first pair.
+	if(off == 0)
+		return -1;
+	p = pclntab + off;
+	pc = f->entry;
+	value = -1;
+
+	if(debug && !runtime·panicking)
+		runtime·printf("pcvalue start f=%s [%p] pc=%p targetpc=%p value=%d tab=%p\n",
+			runtime·funcname(f), f, pc, targetpc, value, p);
+	
+	while(step(&p, &pc, &value, pc == f->entry)) {
+		if(debug)
+			runtime·printf("\tvalue=%d until pc=%p\n", value, pc);
+		if(targetpc < pc)
+			return value;
+	}
+	
+	// If there was a table, it should have covered all program counters.
+	// If not, something is wrong.
+	if(runtime·panicking || !strict)
+		return -1;
+	runtime·printf("runtime: invalid pc-encoded table f=%s pc=%p targetpc=%p tab=%p\n",
+		runtime·funcname(f), pc, targetpc, p);
+	p = (byte*)f + off;
+	pc = f->entry;
+	value = -1;
+	
+	while(step(&p, &pc, &value, pc == f->entry))
+		runtime·printf("\tvalue=%d until pc=%p\n", value, pc);
+	
+	runtime·throw("invalid runtime symbol table");
+	return -1;
+}
+
+static String unknown = { (uint8*)"?", 1 };
+
+int8*
+runtime·funcname(Func *f)
+{
+	if(f == nil || f->nameoff == 0)
+		return nil;
+	return (int8*)(pclntab + f->nameoff);
+}
+
+static int32
+funcline(Func *f, uintptr targetpc, String *file, bool strict)
+{
+	int32 line;
+	int32 fileno;
+
+	*file = unknown;
+	fileno = pcvalue(f, f->pcfile, targetpc, strict);
+	line = pcvalue(f, f->pcln, targetpc, strict);
+	if(fileno == -1 || line == -1 || fileno >= nfiletab) {
+		// runtime·printf("looking for %p in %S got file=%d line=%d\n", targetpc, *f->name, fileno, line);
+		return 0;
+	}
+	*file = runtime·gostringnocopy(pclntab + filetab[fileno]);
+	return line;
+}
+
+int32
+runtime·funcline(Func *f, uintptr targetpc, String *file)
+{
+	return funcline(f, targetpc, file, true);
+}
+
+int32
+runtime·funcspdelta(Func *f, uintptr targetpc)
+{
+	int32 x;
+	
+	x = pcvalue(f, f->pcsp, targetpc, true);
+	if(x&(sizeof(void*)-1))
+		runtime·printf("invalid spdelta %d %d\n", f->pcsp, x);
+	return x;
+}
+
+int32
+runtime·pcdatavalue(Func *f, int32 table, uintptr targetpc)
+{
+	if(table < 0 || table >= f->npcdata)
+		return -1;
+	return pcvalue(f, (&f->nfuncdata)[1+table], targetpc, true);
+}
+
+int32
+runtime·funcarglen(Func *f, uintptr targetpc)
+{
+	if(targetpc == f->entry)
+		return 0;
+	return runtime·pcdatavalue(f, PCDATA_ArgSize, targetpc-PCQuantum);
+}
+
+func funcline_go(f *Func, targetpc uintptr) (retfile String, retline int) {
+	// Pass strict=false here, because anyone can call this function,
+	// and they might just be wrong about targetpc belonging to f.
+	retline = funcline(f, targetpc, &retfile, false);
+}
+
+func funcname_go(f *Func) (ret String) {
+	ret = runtime·gostringnocopy((uint8*)runtime·funcname(f));
+}
+
+func funcentry_go(f *Func) (ret uintptr) {
+	ret = f->entry;
+}
+
+Func*
+runtime·findfunc(uintptr addr)
+{
+	Ftab *f;
+	int32 nf, n;
+
+	if(nftab == 0)
+		return nil;
+	if(addr < ftab[0].entry || addr >= ftab[nftab].entry)
+		return nil;
+
+	// binary search to find func with entry <= addr.
+	f = ftab;
+	nf = nftab;
+	while(nf > 0) {
+		n = nf/2;
+		if(f[n].entry <= addr && addr < f[n+1].entry)
+			return (Func*)(pclntab + f[n].funcoff);
+		else if(addr < f[n].entry)
+			nf = n;
+		else {
+			f += n+1;
+			nf -= n+1;
+		}
+	}
+
+	// can't get here -- we already checked above
+	// that the address was in the table bounds.
+	// this can only happen if the table isn't sorted
+	// by address or if the binary search above is buggy.
+	runtime·prints("findfunc unreachable\n");
+	return nil;
+}
+
+func FuncForPC(pc uintptr) (ret *Func) {
+	ret = runtime·findfunc(pc);
+}
+
+static bool
+hasprefix(String s, int8 *p)
+{
+	int32 i;
+
+	for(i=0; i<s.len; i++) {
+		if(p[i] == 0)
+			return 1;
+		if(p[i] != s.str[i])
+			return 0;
+	}
+	return p[i] == 0;
+}
+
+static bool
+contains(String s, int8 *p)
+{
+	int32 i;
+
+	if(p[0] == 0)
+		return 1;
+	for(i=0; i<s.len; i++) {
+		if(s.str[i] != p[0])
+			continue;
+		if(hasprefix((String){s.str + i, s.len - i}, p))
+			return 1;
+	}
+	return 0;
+}
+
+bool
+runtime·showframe(Func *f, G *gp)
+{
+	static int32 traceback = -1;
+	String name;
+
+	if(m->throwing > 0 && gp != nil && (gp == m->curg || gp == m->caughtsig))
+		return 1;
+	if(traceback < 0)
+		traceback = runtime·gotraceback(nil);
+	name = runtime·gostringnocopy((uint8*)runtime·funcname(f));
+
+	// Special case: always show runtime.panic frame, so that we can
+	// see where a panic started in the middle of a stack trace.
+	// See golang.org/issue/5832.
+	if(name.len == 7+1+5 && hasprefix(name, "runtime.panic"))
+		return 1;
+
+	return traceback > 1 || f != nil && contains(name, ".") && !hasprefix(name, "runtime.");
+}