diff options
Diffstat (limited to 'tools/add-cfi.i386.awk')
| -rw-r--r-- | tools/add-cfi.i386.awk | 209 |
1 files changed, 0 insertions, 209 deletions
diff --git a/tools/add-cfi.i386.awk b/tools/add-cfi.i386.awk deleted file mode 100644 index d05037de..00000000 --- a/tools/add-cfi.i386.awk +++ /dev/null @@ -1,209 +0,0 @@ -# Insert GAS CFI directives ("control frame information") into x86-32 asm input -# -# CFI directives tell the assembler how to generate "stack frame" debug info -# This information can tell a debugger (like gdb) how to find the current stack -# frame at any point in the program code, and how to find the values which -# various registers had at higher points in the call stack -# With this information, the debugger can show a backtrace, and you can move up -# and down the call stack and examine the values of local variables - -BEGIN { - # don't put CFI data in the .eh_frame ELF section (which we don't keep) - print ".cfi_sections .debug_frame" - - # only emit CFI directives inside a function - in_function = 0 - - # emit .loc directives with line numbers from original source - printf ".file 1 \"%s\"\n", ARGV[1] - line_number = 0 - - # used to detect "call label; label:" trick - called = "" -} - -function get_const1() { - # for instructions with 2 operands, get 1st operand (assuming it is constant) - match($0, /-?(0x[0-9a-fA-F]+|[0-9]+),/) - return parse_const(substr($0, RSTART, RLENGTH-1)) -} - -function canonicalize_reg(register) { - if (match(register, /^e/)) - return register - else if (match(register, /[hl]$/)) # AH, AL, BH, BL, etc - return "e" substr(register, 1, 1) "x" - else # AX, BX, CX, etc - return "e" register -} -function get_reg() { - # only use if you already know there is 1 and only 1 register - match($0, /%e?([abcd][hlx]|si|di|bp)/) - return canonicalize_reg(substr($0, RSTART+1, RLENGTH-1)) -} -function get_reg1() { - # for instructions with 2 operands, get 1st operand (assuming it is register) - match($0, /%e?([abcd][hlx]|si|di|bp),/) - return canonicalize_reg(substr($0, RSTART+1, RLENGTH-2)) -} -function get_reg2() { - # for instructions with 2 operands, get 2nd operand (assuming it is register) - match($0, /,%e?([abcd][hlx]|si|di|bp)/) - return canonicalize_reg(substr($0, RSTART+2, RLENGTH-2)) -} - -function adjust_sp_offset(delta) { - if (in_function) - printf ".cfi_adjust_cfa_offset %d\n", delta -} - -{ - line_number = line_number + 1 - - # clean the input up before doing anything else - # delete comments - gsub(/(#|\/\/).*/, "") - - # canonicalize whitespace - gsub(/[ \t]+/, " ") # mawk doesn't understand \s - gsub(/ *, */, ",") - gsub(/ *: */, ": ") - gsub(/ $/, "") - gsub(/^ /, "") -} - -# check for assembler directives which we care about -/^\.(section|data|text)/ { - # a .cfi_startproc/.cfi_endproc pair should be within the same section - # otherwise, clang will choke when generating ELF output - if (in_function) { - print ".cfi_endproc" - in_function = 0 - } -} -/^\.type [a-zA-Z0-9_]+,@function/ { - functions[substr($2, 1, length($2)-10)] = 1 -} -# not interested in assembler directives beyond this, just pass them through -/^\./ { - print - next -} - -/^[a-zA-Z0-9_]+:/ { - label = substr($1, 1, length($1)-1) # drop trailing : - - if (called == label) { - # note adjustment of stack pointer from "call label; label:" - adjust_sp_offset(4) - } - - if (functions[label]) { - if (in_function) - print ".cfi_endproc" - - in_function = 1 - print ".cfi_startproc" - - for (register in saved) - delete saved[register] - for (register in dirty) - delete dirty[register] - } - - # an instruction may follow on the same line, so continue processing -} - -/^$/ { next } - -{ - called = "" - printf ".loc 1 %d\n", line_number - print -} - -# KEEPING UP WITH THE STACK POINTER -# We do NOT attempt to understand foolish and ridiculous tricks like stashing -# the stack pointer and then using %esp as a scratch register, or bitshifting -# it or taking its square root or anything stupid like that. -# %esp should only be adjusted by pushing/popping or adding/subtracting constants -# -/pushl?/ { - if (match($0, / %(ax|bx|cx|dx|di|si|bp|sp)/)) - adjust_sp_offset(2) - else - adjust_sp_offset(4) -} -/popl?/ { - if (match($0, / %(ax|bx|cx|dx|di|si|bp|sp)/)) - adjust_sp_offset(-2) - else - adjust_sp_offset(-4) -} -/addl? \$-?(0x[0-9a-fA-F]+|[0-9]+),%esp/ { adjust_sp_offset(-get_const1()) } -/subl? \$-?(0x[0-9a-fA-F]+|[0-9]+),%esp/ { adjust_sp_offset(get_const1()) } - -/call/ { - if (match($0, /call [0-9]+f/)) # "forward" label - called = substr($0, RSTART+5, RLENGTH-6) - else if (match($0, /call [0-9a-zA-Z_]+/)) - called = substr($0, RSTART+5, RLENGTH-5) -} - -# TRACKING REGISTER VALUES FROM THE PREVIOUS STACK FRAME -# -/pushl? %e(ax|bx|cx|dx|si|di|bp)/ { # don't match "push (%reg)" - # if a register is being pushed, and its value has not changed since the - # beginning of this function, the pushed value can be used when printing - # local variables at the next level up the stack - # emit '.cfi_rel_offset' for that - - if (in_function) { - register = get_reg() - if (!saved[register] && !dirty[register]) { - printf ".cfi_rel_offset %s,0\n", register - saved[register] = 1 - } - } -} - -/movl? %e(ax|bx|cx|dx|si|di|bp),-?(0x[0-9a-fA-F]+|[0-9]+)?\(%esp\)/ { - if (in_function) { - register = get_reg() - if (match($0, /-?(0x[0-9a-fA-F]+|[0-9]+)\(%esp\)/)) { - offset = parse_const(substr($0, RSTART, RLENGTH-6)) - } else { - offset = 0 - } - if (!saved[register] && !dirty[register]) { - printf ".cfi_rel_offset %s,%d\n", register, offset - saved[register] = 1 - } - } -} - -# IF REGISTER VALUES ARE UNCEREMONIOUSLY TRASHED -# ...then we want to know about it. -# -function trashed(register) { - if (in_function && !saved[register] && !dirty[register]) { - printf ".cfi_undefined %s\n", register - } - dirty[register] = 1 -} -# this does NOT exhaustively check for all possible instructions which could -# overwrite a register value inherited from the caller (just the common ones) -/mov.*,%e?([abcd][hlx]|si|di|bp)$/ { trashed(get_reg2()) } -/(add|addl|sub|subl|and|or|xor|lea|sal|sar|shl|shr).*,%e?([abcd][hlx]|si|di|bp)$/ { - trashed(get_reg2()) -} -/^i?mul [^,]*$/ { trashed("eax"); trashed("edx") } -/^i?mul.*,%e?([abcd][hlx]|si|di|bp)$/ { trashed(get_reg2()) } -/^i?div/ { trashed("eax"); trashed("edx") } -/(dec|inc|not|neg|pop) %e?([abcd][hlx]|si|di|bp)/ { trashed(get_reg()) } -/cpuid/ { trashed("eax"); trashed("ebx"); trashed("ecx"); trashed("edx") } - -END { - if (in_function) - print ".cfi_endproc" -} |