Fix false positive with embedded gcc -print-* commands

[blhc/blhc.git] / bin / blhc

diff --git a/bin/blhc b/bin/blhc
index 8c1d1fb7acc9b27cbec5a8b98662ae2cd0452a80..81d3b1237aee9eb6a961c050ec2b6a3a95c522bc 100755 (executable)
--- a/bin/blhc
+++ b/bin/blhc
@@ -750,6 +750,7 @@ foreach my $flags (@flag_refs_all) {
 }
 
 # Precompile ignore line regexps, also anchor at beginning and end of line.
+# Additional entries are also extracted from the build log, see below.
 foreach my $ignore (@option_ignore_line) {
     $ignore = qr/^$ignore$/;
 }
@@ -954,6 +955,15 @@ foreach my $file (@ARGV) {
             }
         }
 
+        # Permit dynamic excludes from within the build log to ignore false
+        # positives. Cannot use a separate config file as we often only have
+        # the build log itself.
+        if (index($line, 'blhc: ignore-line-regexp: ') == 0) {
+            my $ignore = substr $line, 26, -1; # -1 to ignore '\n' at the end
+            push @option_ignore_line, qr/^$ignore$/;
+            next;
+        }
+
         next if $line =~ /^\s*#/;
         # Ignore compiler warnings for now.
         next if $line =~ /$warning_regex/o;
@@ -1066,6 +1076,10 @@ foreach my $file (@ARGV) {
             next if $line =~ m{$cc_regex_normal\s*>\s*\S+}o;
             # Hex output may contain "cc".
             next if $line =~ m#(?:\b[0-9a-fA-F]{2,}\b\s*){5}#;
+            # Meson build output
+            next if $line =~ /^C\+\+ linker for the host machine: /;
+            # Embedded `gcc -print-*` commands
+            next if $line =~ /`$cc_regex_normal\s*[^`]*-print-\S+`/;
 
             # Check if additional hardening options were used. Used to ensure
             # they are used for the complete build.
@@ -1514,6 +1528,22 @@ If there's no output, no flags are missing and the build log is fine.
 See F<README> for details about performed checks, auto-detection and
 limitations.
 
+=head1 FALSE POSITIVES
+
+To suppress false positives you can embed the following string in the build
+log:
+
+    blhc: ignore-line-regexp: REGEXP
+
+All lines fully matching REGEXP (see B<--ignore-line> for details) will be
+ignored.
+
+Please use this feature sparingly so that missing flags are not overlooked. If
+you find false positives which affect more packages please report a bug.
+
+To generate this string simply use echo in C<debian/rules>; make sure to use @
+to suppress the echo command itself as it could also trigger a false positive.
+
 =head1 OPTIONS
 
 =over 8