[PATCH v3 05/15] gdb: Get correct mod variable value

[Glenn Washburn <development@efficientek.com>]

For some reason, GDB is breaking on grub_dl_add() before the function
has setup its stack frame, but GDB thinks it has. So the value of mod
is bogus. To get the correct value, create a one-time break on
grub_dl_get(), which is the first line of grub_dl_add(). When this break
point hits, grub_dl_add() will have finished setting up it stack frame.
But at this point we will be in grub_dl_get()'s stack frame. So go one
frame up, which will be grub_dl_add(), to get mod's value.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/gdb_grub.in | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/grub-core/gdb_grub.in b/grub-core/gdb_grub.in
index 61dc4644fb..78219ea36e 100644
--- a/grub-core/gdb_grub.in
+++ b/grub-core/gdb_grub.in
@@ -74,7 +74,17 @@ define runtime_load_module
 	break grub_dl_add
 	commands
 		silent
-		load_module mod
+		# GDB has stopped before the call frame is setup, so mod does
+		# not have the correct value. Create a one-time break on the
+		# next function call and then go one frame up, back to the
+		# grub_dl_add frame, to get the correct value for mod.
+		tbreak grub_dl_get
+		commands
+			silent
+			fr 1
+			load_module mod
+			cont
+		end
 		cont
 	end
 end
-- 
2.34.1