From 8b8c593bf6fc3dea6af8546c33493a28366389d9 Mon Sep 17 00:00:00 2001
From: FosterProgramming <jamiefosterandco@gmail.com>
Date: Wed, 5 Nov 2025 10:04:30 +0100
Subject: [PATCH] Fix preproc not correctly reading skipped lines symbols
 inside enum (#2197)

---
 tools/preproc/asm_file.cpp | 50 +++++++++++++++++++++++++++++++++++++-
 tools/preproc/asm_file.h   |  1 +
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/tools/preproc/asm_file.cpp b/tools/preproc/asm_file.cpp
index 69b412b24e..fcc996d66d 100644
--- a/tools/preproc/asm_file.cpp
+++ b/tools/preproc/asm_file.cpp
@@ -584,7 +584,11 @@ bool AsmFile::ParseEnum()
             RaiseError("%s:%ld: empty enum is invalid", headerFilename.c_str(), currentHeaderLine);
         }
 
-        if (m_buffer[m_pos] != ',')
+        if (m_buffer[m_pos] == '#')
+        {
+            currentHeaderLine = ParseLineSkipInEnum();
+        }
+        else if (m_buffer[m_pos] != ',')
         {
             currentHeaderLine += SkipWhitespaceAndEol();
             if (m_buffer[m_pos++] == '}' && m_buffer[m_pos++] == ';')
@@ -688,6 +692,50 @@ int AsmFile::SkipWhitespaceAndEol()
     return newlines;
 }
 
+int AsmFile::ParseLineSkipInEnum(void)
+{
+    m_pos++;
+    while (m_buffer[m_pos] == ' ' || m_buffer[m_pos] == '\t')
+        m_pos++;
+
+     if (!IsAsciiDigit(m_buffer[m_pos]))
+        RaiseError("malformatted line indicator found inside `enum`, expected line number");
+
+    unsigned n = 0;
+    int digit = 0;
+    while ((digit = ConvertDigit(m_buffer[m_pos++], 10)) != -1)
+        n = 10 * n + digit;
+
+    while (m_buffer[m_pos] == ' ' || m_buffer[m_pos] == '\t')
+        m_pos++;
+
+    if (m_buffer[m_pos++] != '"')
+        RaiseError("malformatted line indicator found before `enum`, expected filename");
+
+    while (m_buffer[m_pos] != '"')
+    {
+        unsigned char c = m_buffer[m_pos++];
+
+        if (c == 0)
+        {
+            if (m_pos >= m_size)
+                RaiseError("unexpected EOF in line indicator");
+            else
+                RaiseError("unexpected null character in line indicator");
+        }
+
+        if (!IsAsciiPrintable(c))
+            RaiseError("unexpected character '\\x%02X' in line indicator", c);
+
+        if (c == '\\')
+        {
+            c = m_buffer[m_pos];
+            RaiseError("unexpected escape '\\%c' in line indicator", c);
+        }
+    }
+    return n - 1;
+}
+
 // returns the last line indicator and its corresponding file name without modifying the token index
 int AsmFile::FindLastLineNumber(std::string& filename)
 {
diff --git a/tools/preproc/asm_file.h b/tools/preproc/asm_file.h
index 33e6ce5c49..9cab32a97f 100644
--- a/tools/preproc/asm_file.h
+++ b/tools/preproc/asm_file.h
@@ -73,6 +73,7 @@ private:
     void VerifyStringLength(int length);
     int SkipWhitespaceAndEol();
     int FindLastLineNumber(std::string& filename);
+    int ParseLineSkipInEnum(void);
     std::string ReadIdentifier();
     long ReadInteger(std::string filename, long line);
 };