Hello all ! I'm still fighting to make tinycc on ARM work properly, to test it I'm using fossil-scm as a test program because it's not a trivial program and self contained, tinycc on linux 32 and 64 bits already is capable of generate working programs form it but on ARM right now it compiles but the program do not produce the correct results.
One technique I was willing to use is to generate a callgraph of the program on linux (that is done) and then on ARM (here is the trouble). For that I'm using a translated program from bash/awk ( http://publicclu2.blogspot.co.uk/2013/05/call-graph-generation.html) to lua with some fixes (see attached), the other possibility would be to use "valgrind --tool=callgrind" but the tinycc generated programs are rejected from valgrind for several reasons: 1- "Inconsistency detected by ld.so: rtld.c: 1292: dl_main: Assertion `_rtld_local._dl_rtld_map.l_libname' failed!" for this one I found a workaround making a change on tccelf.c (it's on the mob but commented because it has a side effect of programs generated with debug information and stripped afterwards segfaults). 2- "disInstr(arm): unhandled instruction: 0xE3511000 cond=14(0xE) 27:20=53(0x35) 4:4=0 3:0=0(0x0)" on ARM the programs generated with tinycc emits a combination of instructions that confuses valgrind (note the same program compiled with gcc works fine with valgrind). 3- "Invalid read of size 4 ... Address 0x????? is just below the stack ptr." on ARM the programs generated with tinycc manage the stack in a way that confuses valgrind/gdb (note the same program compiled with gcc works fine with valgrind). With GDB and the lua script attached it also fails because the way tinycc generated programs manipulate the stack: ------ GNU gdb (GDB) 7.7 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html > This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "armv7l-unknown-linux-gnueabihf". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from check-va-tcc...done. (gdb) b main Breakpoint 1 at 0x8260: file check-va.c, line 18. (gdb) r Starting program: /home/mingo/dev/tmp/check-va-tcc Breakpoint 1, main () at check-va.c:18 18 myprintf (); (gdb) s myprintf () at check-va.c:13 13 return passdown(); (gdb) bt 2 #0 myprintf () at check-va.c:13 #1 0xbefff628 in ?? () Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) s Cannot access memory at address 0x0 passdown () at check-va.c:8 8 return db_prepare(); (gdb) bt 2 #0 passdown () at check-va.c:8 #1 0xbefff618 in ?? () Cannot access memory at address 0x0 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) s db_prepare () at check-va.c:3 3 return 2; (gdb) bt 2 #0 db_prepare () at check-va.c:3 #1 0x0000822c in passdown () at check-va.c:8 Cannot access memory at address 0x0 (More stack frames follow...) (gdb) ------ So my call for help from anyone with tinycc/ARM knowledge is how we can make tinycc generated programs on ARM to play nice with valgrind/gdb ? Mainly the stack issue (attached we have a obdump of the same sample with gcc and tcc). If we can achieve this investigate why tinycc generated programs like fossil-scm to not work properly will be a bit easier. Thanks in advance for your time, attention and any help !
Breakpoint 1 at 0x83c8: file check-va.c, line 3. Breakpoint 2 at 0x83f8: file check-va.c, line 18. Breakpoint 3 at 0x83e8: file check-va.c, line 13. Breakpoint 4 at 0x83d8: file check-va.c, line 8. Breakpoint 2, main () at check-va.c:18 18 myprintf (); #0 main () at check-va.c:18 Breakpoint 3, myprintf () at check-va.c:13 13 return passdown(); #0 myprintf () at check-va.c:13 #1 0x000083fc in main () at check-va.c:18 main myprintf () Breakpoint 4, passdown () at check-va.c:8 8 return db_prepare(); #0 passdown () at check-va.c:8 #1 0x000083ec in myprintf () at check-va.c:13 myprintf passdown () Breakpoint 1, db_prepare () at check-va.c:3 3 return 2; #0 db_prepare () at check-va.c:3 #1 0x000083dc in passdown () at check-va.c:8 passdown db_prepare () Breakpoint 1, db_prepare () at check-va.c:3 3 return 2; #0 db_prepare () at check-va.c:3 #1 0x00008400 in main () at check-va.c:19 [Inferior 1 (process 6708) exited normally] Function calls count db_prepare 2 main 1 myprintf 1 passdown 1
callgraph
Description: Binary data
-- Permission is hereby granted, free of charge, to any person -- obtaining a copy of this software and associated documentation files -- (the "Software"), to deal in the Software without restriction, -- including without limitation the rights to use, copy, modify, merge, -- publish, distribute, sublicense, and/or sell copies of the Software, -- and to permit persons to whom the Software is furnished to do so, -- subject to the following conditions: -- -- The above copyright notice and this permission notice shall be -- included in all copies or substantial portions of the Software. -- -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF -- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND -- NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS -- BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN -- ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN -- CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE -- SOFTWARE. --based on callgraph from http://publicclu2.blogspot.co.uk/2013/05/call-graph-generation.html --translated to lua by Domingo Alvarez Duarte mingodad_at_gmail_dot_com local strFormat = string.format local function capture(cmd) local f = assert(io.popen(cmd, 'r')) local s = assert(f:read('*a')) f:close() return s end local prog_name="callgraph" if #arg < 1 then print( strFormat("Usage: %s EXECUTABLE [ARGS...]", prog_name)) print( strFormat("\nExample: %s ~/bin/test-program foo 23", prog_name)) os.exit( 1 ) end -- Sanity checks. local FILE=arg[1] local fd, err = io.open(FILE) if err then print(strFormat("%s: Unable to find executable '%s'", prog_name, FILE)) os.exit( 1 ) end fd:close() local str = capture(strFormat("gdb --eval-command=quit %s 2>&1", FILE)) if str:match("(no debugging symbols found)") or str:match("(not in executable format)") then print(strFormat([==[ %s: Can't print call graph for '%s' because it's not a binary executable compiled with debugging symbols. ]==], prog_name, FILE)) os.exit( 1 ) end -- Set up temporary files. local TRACE_file_name = FILE .. ".gdb.trace" local TRACE_fd=io.open(TRACE_file_name, "w") local GETFUNCS_file_name = FILE .. ".gdb.funcs" local GETFUNCS_fd=io.open(GETFUNCS_file_name, "w") -- Take control of GDB and print call graph. GETFUNCS_fd:write([[ set height 0 info functions ]]) GETFUNCS_fd:close() str = capture(strFormat("gdb --batch --command=%s %s 2>/dev/null", GETFUNCS_file_name, FILE)) --print(str) --os.exit(1) local total = 0; TRACE_fd:write([[ set width 0 set height 0 set verbose off ]]) local functions_to_break = {} for fn in str:gmatch("([a-zA-Z_][a-zA-Z0-9_]+)%b()") do TRACE_fd:write(strFormat("break %s\n", fn)); functions_to_break[fn] = 0; total = total + 1; end for i = 1, total do TRACE_fd:write(strFormat("commands %d\n", i)); --TRACE_fd:write("info args\n"); TRACE_fd:write( "backtrace 2\ncontinue\nend\n"); end TRACE_fd:write( "run\n"); TRACE_fd:close() local cmd_args = "" for i=2, #arg do cmd_args = cmd_args .. " " .. arg[i] end --print(FILE, cmd_args) local cmd = strFormat("gdb --batch --command=%s --tty=/dev/null --args %s %s 2>/dev/null", TRACE_file_name, FILE, cmd_args) --print(cmd) local fd_cmd = assert(io.popen(cmd, 'r')) local function joinLines(s) if not s:match(":%d+$") then --parameters have embedded new lines while(true) do local new_line = fd_cmd:read('*l') if not new_line then break end s = s .. "\\n" .. new_line if new_line:match(":%d+$") then break end end end return s end local isrecord = false; local callee = ""; local caller = "*INITIAL*"; local params = ""; while(true) do local s = fd_cmd:read('*l') if not s then break end --print(s) if s:match("^Breakpoint [0-9]+,") then isrecord = true; s = joinLines(s) callee, params = s:match("^Breakpoint [0-9]+,%s*(%S+)%s*(%(.*%))%s+at%s+%S+:%d+$"); local call_count = functions_to_break[callee] if call_count then functions_to_break[callee] = call_count + 1 else print("Bad match", callee, s) end elseif s:match("^#1%s+") then if (isrecord) then s = joinLines(s) caller =s:match("^#1%s+%S+%s+%S+%s+(%S+)"); end elseif #s == 0 then if (isrecord and (caller ~= "*INITIAL*")) then print(strFormat("%s %s %s", caller, callee, params)); callee = ""; caller = ""; params = ""; end else --print("No match line", s) end end fd_cmd:close() local functions_calls = {} for fn, cnt in pairs(functions_to_break) do table.insert(functions_calls, {fn, cnt}) end --table.sort(functions_calls, function(a,b) return a[2] > b[2] end) table.sort(functions_calls, function(a,b) if a[2] == b[2] then return a[1] < b[1] end return a[2] > b[2] end) print("Function calls count") for k,v in ipairs(functions_calls) do print(v[1], v[2]) end
int db_prepare(void)
{
return 2;
}
static int passdown (void)
{
return db_prepare();
}
static int myprintf (void)
{
return passdown();
}
int main ()
{
myprintf ();
db_prepare();
return 0;
}
check-va-mk
Description: Binary data
check-va-gcc.o.dump.asm
Description: Binary data
check-va-tcc.o.dump.asm
Description: Binary data
Breakpoint 1 at 0x820c: file check-va.c, line 3. Breakpoint 2 at 0x8260: file check-va.c, line 18. Breakpoint 3 at 0x8244: file check-va.c, line 13. Breakpoint 4 at 0x8228: file check-va.c, line 8. Breakpoint 2, main () at check-va.c:18 18 myprintf (); #0 main () at check-va.c:18 Breakpoint 3, myprintf () at check-va.c:13 13 return passdown(); #0 myprintf () at check-va.c:13 #1 0xbefff628 in ?? () 8 return db_prepare(); #0 passdown () at check-va.c:8 #1 0xbefff618 in ?? () 3 return 2; #0 db_prepare () at check-va.c:3 #1 0x0000822c in passdown () at check-va.c:8 passdown myprintf () Breakpoint 1, db_prepare () at check-va.c:3 3 return 2; #0 db_prepare () at check-va.c:3 #1 0x00008268 in main () at check-va.c:19 [Inferior 1 (process 6694) exited normally] Function calls count db_prepare 1 main 1 myprintf 1 passdown 0
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