1 files changed, 123 insertions, 0 deletions
diff --git a/Tools/c-analyzer/c_parser/preprocessor/gcc.py b/Tools/c-analyzer/c_parser/preprocessor/gcc.py
new file mode 100644
index 00000000000..bb404a487b7
--- /dev/null
+++ b/Tools/c-analyzer/c_parser/preprocessor/gcc.py
@@ -0,0 +1,123 @@
+import os.path
+import re
+
+from . import common as _common
+
+
+TOOL = 'gcc'
+
+# https://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html
+LINE_MARKER_RE = re.compile(r'^# (\d+) "([^"]+)"(?: [1234])*$')
+PREPROC_DIRECTIVE_RE = re.compile(r'^\s*#\s*(\w+)\b.*')
+COMPILER_DIRECTIVE_RE = re.compile(r'''
+    ^
+    (.*?)  # <before>
+    (__\w+__)  # <directive>
+    \s*
+    [(] [(]
+    (
+        [^()]*
+        (?:
+            [(]
+            [^()]*
+            [)]
+            [^()]*
+         )*
+     )  # <args>
+    ( [)] [)] )?  # <closed>
+''', re.VERBOSE)
+
+POST_ARGS = (
+    '-pthread',
+    '-std=c99',
+    #'-g',
+    #'-Og',
+    #'-Wno-unused-result',
+    #'-Wsign-compare',
+    #'-Wall',
+    #'-Wextra',
+    '-E',
+)
+
+
+def preprocess(filename, incldirs=None, macros=None, samefiles=None):
+    text = _common.preprocess(
+        TOOL,
+        filename,
+        incldirs=incldirs,
+        macros=macros,
+        #preargs=PRE_ARGS,
+        postargs=POST_ARGS,
+        executable=['gcc'],
+        compiler='unix',
+    )
+    return _iter_lines(text, filename, samefiles)
+
+
+def _iter_lines(text, filename, samefiles, *, raw=False):
+    lines = iter(text.splitlines())
+
+    # Build the lines and filter out directives.
+    partial = 0  # depth
+    origfile = None
+    for line in lines:
+        m = LINE_MARKER_RE.match(line)
+        if m:
+            lno, origfile = m.groups()
+            lno = int(lno)
+        elif _filter_orig_file(origfile, filename, samefiles):
+            if (m := PREPROC_DIRECTIVE_RE.match(line)):
+                name, = m.groups()
+                if name != 'pragma':
+                    raise Exception(line)
+            else:
+                if not raw:
+                    line, partial = _strip_directives(line, partial=partial)
+                yield _common.SourceLine(
+                    _common.FileInfo(filename, lno),
+                    'source',
+                    line or '',
+                    None,
+                )
+            lno += 1
+
+
+def _strip_directives(line, partial=0):
+    # We assume there are no string literals with parens in directive bodies.
+    while partial > 0:
+        if not (m := re.match(r'[^{}]*([()])', line)):
+            return None, partial
+        delim, = m.groups()
+        partial += 1 if delim == '(' else -1  # opened/closed
+        line = line[m.end():]
+
+    line = re.sub(r'__extension__', '', line)
+
+    while (m := COMPILER_DIRECTIVE_RE.match(line)):
+        before, _, _, closed = m.groups()
+        if closed:
+            line = f'{before} {line[m.end():]}'
+        else:
+            after, partial = _strip_directives(line[m.end():], 2)
+            line = f'{before} {after or ""}'
+            if partial:
+                break
+
+    return line, partial
+
+
+def _filter_orig_file(origfile, current, samefiles):
+    if origfile == current:
+        return True
+    if origfile == '<stdin>':
+        return True
+    if os.path.isabs(origfile):
+        return False
+
+    for filename in samefiles or ():
+        if filename.endswith(os.path.sep):
+            filename += os.path.basename(current)
+        if origfile == filename:
+            return True
+
+    return False