From a8a47a309c08de3dc6e10b64404db78fe070db3f Mon Sep 17 00:00:00 2001
From: Timur Safin <tsafin@tarantool.org>
Date: Mon, 30 May 2022 19:40:40 +0300
Subject: [PATCH] debugger: correct step_over for unbalanced calls/returns
Number of 'call' hook invocations is always greater than
number of 'return' hook events. (i.e. ffi functions does use
`call` but there is no `return`. Same is for builtin functions
like `assert` or `error`).
We count number of stack frames available, and stop once
level is once again less or equal to the necessary one.
Math.huge is used to stop on each line (trace mode).
NO_CHANGELOG=internal
NO_DOC=internal
NO_TEST=internal
---
third_party/lua/luadebug.lua | 102 ++++++++++++++++++++++++-----------
1 file changed, 72 insertions(+), 30 deletions(-)
diff --git a/third_party/lua/luadebug.lua b/third_party/lua/luadebug.lua
index 11bc3c959c..842e37df74 100644
--- a/third_party/lua/luadebug.lua
+++ b/third_party/lua/luadebug.lua
@@ -25,6 +25,7 @@
]]
local dbg
+local fio = require('fio')
local DEBUGGER = 'luadebug.lua'
-- Use ANSI color codes in the prompt by default.
@@ -70,6 +71,17 @@ local function pretty(obj, max_depth)
return recurse(obj, 0)
end
+local function get_stack_length(offset)
+ local index = offset + 1
+ while true do
+ if not debug.getinfo(index) then
+ break
+ end
+ index = index + 1
+ end
+ return index - offset - 1
+end
+
-- The stack level that cmd_* functions use to access locals or info
-- The structure of the code very carefully ensures this.
local CMD_STACK_LEVEL = 6
@@ -136,39 +148,68 @@ local function format_stack_frame_info(info)
return format_loc(source, info.currentline) .. " in " .. namewhat .. " " .. name
end
+local function normalize_path(file)
+ -- If the name doesn't start with `@`, assume it's a file name if it's all
+ -- on one line.
+ if string.find(file, "^@") or not string.find(file, "[\r\n]") then
+ file = string.gsub(string.gsub(file, "^@", ""), "\\", "/")
+
+ file = fio.basename(file)
+
+ -- some file systems allow newlines in file names; remove these.
+ file = string.gsub(file, "\n", ' ')
+ end
+ return file
+end
+
+local myself = normalize_path(debug.getinfo(1,'S').source)
+
local repl
-- Return false for stack frames without source,
-- which includes C frames, Lua bytecode, and `loadstring` functions
local function frame_has_line(info) return info.currentline >= 0 end
-local function hook_factory(repl_threshold)
- return function(offset, reason)
+local dbg_hook_ofs = 2
+
+local function hook_factory(level)
+ local stop_level = level or -1
+ return function(reason)
return function(event, _)
-- Skip events that don't have line information.
- if not frame_has_line(debug.getinfo(2)) then return end
-
- -- Tail calls are specifically ignored since they also will have tail returns to balance out.
- if event == "call" then
- offset = offset + 1
- elseif event == "return" and offset > repl_threshold then
- offset = offset - 1
- elseif event == "line" and offset <= repl_threshold then
- repl(reason)
+ local info = debug.getinfo(2, "Snl")
+ local file = normalize_path(info.source)
+
+ if not frame_has_line(info) or file == myself then
+ return
+ end
+
+ -- [Correction logics borrowed from mobdebug.lua]
+ -- This is needed to check if the stack got shorter or longer.
+ -- Unfortunately counting call/return calls is not reliable.
+ -- The discrepancy may happen when "pcall(load, '')" call is made
+ -- or when "error()" is called in a function.
+ -- Start from one level higher just in case we need to grow the
+ -- stack. This may happen after coroutine.resume call to a function
+ -- that doesn't have any other instructions to execute. It triggers
+ -- three returns: "return, tail return, return", which needs to be
+ -- accounted for.
+ local offset = get_stack_length(dbg_hook_ofs)
+
+ if event == "line" then
+ if offset <= stop_level then
+ repl(reason)
+ end
end
end
end
end
-local hook_step = hook_factory(1)
-local hook_next = hook_factory(0)
-local hook_finish = hook_factory(-1)
-
-- Create a table of all the locally accessible variables.
-- Globals are not included when running the locals command, but are when running the print command.
local function local_bindings(offset, include_globals)
local level = offset + stack_inspect_offset + CMD_STACK_LEVEL
- local func = debug.getinfo(level).func
+ local func = debug.getinfo(level, "f").func
local bindings = {}
-- Retrieve the upvalues
@@ -316,20 +357,18 @@ end
local unpack = unpack or table.unpack
local pack = function(...) return { n = select("#", ...), ... } end
+local current_stack_level = function() return get_stack_length(stack_top) end
+
local function cmd_step()
- stack_inspect_offset = stack_top
- return true, hook_step
+ return true, hook_factory(math.huge)
end
local function cmd_next()
- stack_inspect_offset = stack_top
- return true, hook_next
+ return true, hook_factory(current_stack_level() - CMD_STACK_LEVEL)
end
local function cmd_finish()
- local offset = stack_top - stack_inspect_offset
- stack_inspect_offset = stack_top
- return true, offset < 0 and hook_factory(offset - 1) or hook_finish
+ return true, hook_factory(current_stack_level() - CMD_STACK_LEVEL - 1)
end
-- simply continue execution
@@ -386,7 +425,7 @@ local function cmd_down()
repeat -- Find the next frame with a file.
offset = offset + 1
- info = debug.getinfo(offset + CMD_STACK_LEVEL)
+ info = debug.getinfo(offset + CMD_STACK_LEVEL, "Snl")
until not info or frame_has_line(info)
if info then
@@ -426,13 +465,13 @@ local function cmd_up()
end
local function cmd_where(context_lines)
- local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL)
+ local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL, "Snl")
return (info and where(info, tonumber(context_lines) or 5))
end
local function cmd_listing(context_lines)
local offset = stack_inspect_offset + CMD_STACK_LEVEL - 2
- local info = debug.getinfo(offset)
+ local info = debug.getinfo(offset, "Snl")
return (info and where(info, tonumber(context_lines) or 5))
end
@@ -440,7 +479,7 @@ local function cmd_trace()
dbg_writeln("Inspecting frame %d", stack_inspect_offset - stack_top)
local i = 0;
while true do
- local info = debug.getinfo(stack_top + CMD_STACK_LEVEL + i)
+ local info = debug.getinfo(stack_top + CMD_STACK_LEVEL + i, "Snl")
if not info then break end
local is_current_frame = (i + stack_top == stack_inspect_offset)
@@ -635,11 +674,13 @@ end
repl = function(reason)
start_repl()
-- Skip frames without source info.
- while not frame_has_line(debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL - 3)) do
+ while not frame_has_line(debug.getinfo(stack_inspect_offset +
+ CMD_STACK_LEVEL - 3, "Snl")) do
stack_inspect_offset = stack_inspect_offset + 1
end
- local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL - 3)
+ local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL - 3,
+ "Snl")
reason = reason and (color_yellow("break via ") .. color_red(reason) ..
GREEN_CARET) or ""
dbg_writeln(reason .. format_stack_frame_info(info))
@@ -693,7 +734,8 @@ dbg = setmetatable({
stack_inspect_offset = top_offset
stack_top = top_offset
- debug.sethook(hook_next(1, source or "dbg()"), "crl")
+ local hook_next = hook_factory(current_stack_level())
+ debug.sethook(hook_next(source or "dbg()"), "l")
return
end,
})
--
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