Record module base and use it for adjusting start locations in dwarf unwinder.

5 files changed, 38 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index c122f409..8ce62fb6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2008-09-10  Mark Wielaard  <mjw@redhat.com>
 
+	* translate.cxx (dump_unwindsyms): Output module_base.
+
+2008-09-10  Mark Wielaard  <mjw@redhat.com>
+
 	* translate.cxx (get_unwind_data): New function.
 	(dump_unwindsyms): Output unwind data.
 
diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index 7502bf34..d794b4a1 100644
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -1,5 +1,12 @@
 2008-09-10  Mark Wielaard  <mjw@redhat.com>
 
+	* sym.h (_stp_module): Add module_base field.
+	* unwind.c (adjustStartLoc): New function.
+	(_stp_search_unwind_hdr): Use adjustStartLoc.
+	(unwind): Likewise.
+
+2008-09-10  Mark Wielaard  <mjw@redhat.com>
+
 	* unwind.c (unwind): Use _stp_mod_sec_lookup to get module and
 	unwind tables.
 	* runtime.h (STP_USE_FRAME_BUFFER): Disable by default for now.
diff --git a/runtime/sym.h b/runtime/sym.h
index b2fb8ee9..564f4eb2 100644
--- a/runtime/sym.h
+++ b/runtime/sym.h
@@ -34,6 +34,8 @@ struct _stp_module {
 	/* is unloading. */
   	unsigned long module; /* XXX: why not struct module * ? */
 	
+  	unsigned long module_base;
+
 	/* the stack unwind data for this module */
 	void *unwind_data;
 	void *unwind_hdr;	
diff --git a/runtime/unwind.c b/runtime/unwind.c
index 7b19573d..db8ae664 100644
--- a/runtime/unwind.c
+++ b/runtime/unwind.c
@@ -550,10 +550,27 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, s
 	return result && ptr.p8 == end && (targetLoc == 0 || state->label == NULL);
 }
 
+// This is an address inside a module, adjust.
+static unsigned long
+adjustStartLoc (unsigned long startLoc,
+		struct _stp_module *m,
+		struct _stp_section *s)
+{
+  if (startLoc && (strcmp (m->name, "kernel") != 0))
+    {
+      startLoc = _stp_module_relocate (m->name, s->name,
+				       startLoc);
+      startLoc -= m->module_base;
+    }
+  return startLoc;
+}
+
 /* If we previously created an unwind header, then use it now to binary search */
 /* for the FDE corresponding to pc. */
 
-static u32 *_stp_search_unwind_hdr(unsigned long pc, struct _stp_module *m)
+static u32 *_stp_search_unwind_hdr(unsigned long pc,
+				   struct _stp_module *m,
+				   struct _stp_section *s)
 {
 	const u8 *ptr, *end, *hdr = m->unwind_hdr;
 	unsigned long startLoc;
@@ -600,6 +617,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc, struct _stp_module *m)
 	do {
 		const u8 *cur = ptr + (num / 2) * (2 * tableSize);
 		startLoc = read_pointer(&cur, cur + tableSize, hdr[3]);
+		startLoc = adjustStartLoc(startLoc, m, s);
 		if (pc < startLoc)
 			num /= 2;
 		else {
@@ -608,7 +626,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc, struct _stp_module *m)
 		}
 	} while (startLoc && num > 1);
 
-	if (num == 1 && (startLoc = read_pointer(&ptr, ptr + tableSize, hdr[3])) != 0 && pc >= startLoc)
+	if (num == 1 && (startLoc = adjustStartLoc(read_pointer(&ptr, ptr + tableSize, hdr[3]), m, s)) != 0 && pc >= startLoc)
 		fde = (void *)read_pointer(&ptr, ptr + tableSize, hdr[3]);
 
 	dbug_unwind(1, "returning fde=%lx startLoc=%lx", fde, startLoc);
@@ -695,7 +713,7 @@ int unwind(struct unwind_frame_info *frame)
 		goto err;
 	}
 
-	fde = _stp_search_unwind_hdr(pc, m);
+	fde = _stp_search_unwind_hdr(pc, m, s);
 	dbug_unwind(1, "%s: fde=%lx\n", m->name, fde);
 
 	/* found the fde, now set startLoc and endLoc */
@@ -705,6 +723,8 @@ int unwind(struct unwind_frame_info *frame)
 			ptr = (const u8 *)(fde + 2);
 			ptrType = fde_pointer_type(cie);
 			startLoc = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType);
+			startLoc = adjustStartLoc(startLoc, m, s);
+
 			dbug_unwind(2, "startLoc=%lx, ptrType=%s", startLoc, _stp_eh_enc_name(ptrType));
 			if (!(ptrType & DW_EH_PE_indirect))
 				ptrType &= DW_EH_PE_FORM | DW_EH_PE_signed;
@@ -734,6 +754,7 @@ int unwind(struct unwind_frame_info *frame)
 
 			ptr = (const u8 *)(fde + 2);
 			startLoc = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType);
+			startLoc = adjustStartLoc(startLoc, m, s);
 			dbug_unwind(2, "startLoc=%lx, ptrType=%s", startLoc, _stp_eh_enc_name(ptrType));
 			if (!startLoc)
 				continue;
diff --git a/translate.cxx b/translate.cxx
index d4507a1f..7c1469df 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -4551,6 +4551,7 @@ dump_unwindsyms (Dwfl_Module *m,
 
   c->output << "struct _stp_module _stp_module_" << stpmod_idx << " = {" << endl;
   c->output << ".name = " << lex_cast_qstring (modname) << ", " << endl;
+  c->output << ".module_base = 0x" << hex << base << dec << ", " << endl;
 
   if (unwind != NULL)
     {