The __LINE__ macro creates challenges for binary diffing. When a .patch file adds or removes lines, it shifts the line numbers for all code below it. This can cause the code generation of functions using __LINE__ to change due to the line number constant being embedded in a MOV instruction, despite there being no semantic difference. Avoid such false positives by adding a fix-patch-lines script which can be used to insert a #line directive in each patch hunk affecting the line numbering. This script will be used by klp-build, which will be introduced in a subsequent patch.
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| @@ -0,0 +1,79 @@ | ||
| 1 | +#!/usr/bin/awk -f | |
| 2 | +# SPDX-License-Identifier: GPL-2.0 | |
| 3 | +# | |
| 4 | +# Use #line directives to preserve original __LINE__ numbers across patches to | |
| 5 | +# avoid unwanted compilation changes. | |
| 6 | + | |
| 7 | +BEGIN { | |
| 8 | + in_hunk = 0 | |
| 9 | + skip = 0 | |
| 10 | +} | |
| 11 | + | |
| 12 | +/^--- / { | |
| 13 | + skip = $2 !~ /\.(c|h)$/ | |
| 14 | ||
| 15 | + next | |
| 16 | +} | |
| 17 | + | |
| 18 | +/^@@/ { | |
| 19 | + if (skip) { | |
| 20 | ||
| 21 | + next | |
| 22 | + } | |
| 23 | + | |
| 24 | + in_hunk = 1 | |
| 25 | + | |
| 26 | + # for @@ -1,3 +1,4 @@: | |
| 27 | + # 1: line number in old file | |
| 28 | + # 3: how many lines the hunk covers in old file | |
| 29 | + # 1: line number in new file | |
| 30 | + # 4: how many lines the hunk covers in new file | |
| 31 | + | |
| 32 | + match($0, /^@@ -([0-9]+)(,([0-9]+))? \+([0-9]+)(,([0-9]+))? @@/, m) | |
| 33 | + | |
| 34 | + # Set 'cur' to the old file's line number at the start of the hunk. It | |
| 35 | + # gets incremented for every context line and every line removal, so | |
| 36 | + # that it always represents the old file's current line number. | |
| 37 | + cur = m[1] | |
| 38 | + | |
| 39 | + # last = last line number of current hunk | |
| 40 | + last = cur + (m[3] ? m[3] : 1) - 1 | |
| 41 | + | |
| 42 | + need_line_directive = 0 | |
| 43 | + | |
| 44 | ||
| 45 | + next | |
| 46 | +} | |
| 47 | + | |
| 48 | +{ | |
| 49 | + if (skip || !in_hunk || $0 ~ /^\\ No newline at end of file/) { | |
| 50 | ||
| 51 | + next | |
| 52 | + } | |
| 53 | + | |
| 54 | + # change line | |
| 55 | + if ($0 ~ /^[+-]/) { | |
| 56 | + # inject #line after this group of changes | |
| 57 | + need_line_directive = 1 | |
| 58 | + | |
| 59 | + if ($0 ~ /^-/) | |
| 60 | + cur++ | |
| 61 | + | |
| 62 | ||
| 63 | + next | |
| 64 | + } | |
| 65 | + | |
| 66 | + # If this is the first context line after a group of changes, inject | |
| 67 | + # the #line directive to force the compiler to correct the line | |
| 68 | + # numbering to match the original file. | |
| 69 | + if (need_line_directive) { | |
| 70 | + print "+#line " cur | |
| 71 | + need_line_directive = 0 | |
| 72 | + } | |
| 73 | + | |
| 74 | + if (cur == last) | |
| 75 | + in_hunk = 0 | |
| 76 | + | |
| 77 | + cur++ | |
| 78 | ||
| 79 | +} | |