From fb26be33a11999e0ba6a0dfde0cc271890792fa7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Wed, 10 Oct 2018 23:31:52 +0300
Subject: [PATCH] Correct the escaping of arguments passed through on windows

---
 wrappers/clang-target-wrapper.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/wrappers/clang-target-wrapper.c b/wrappers/clang-target-wrapper.c
index 7097786..d432c07 100644
--- a/wrappers/clang-target-wrapper.c
+++ b/wrappers/clang-target-wrapper.c
@@ -53,10 +53,22 @@ static TCHAR *escape(const TCHAR *str) {
     int i;
     *ptr++ = '"';
     for (i = 0; str[i]; i++) {
-        if (str[i] == '"')
+        if (str[i] == '"') {
+            int j = i - 1;
+            // Before all double quotes, backslashes need to be escaped, but
+            // not elsewhere.
+            while (j >= 0 && str[j--] == '\\')
+                *ptr++ = '\\';
+            // Escape the next double quote.
             *ptr++ = '\\';
+        }
         *ptr++ = str[i];
     }
+    // Any final backslashes, before the quote around the whole argument,
+    // need to be doubled.
+    int j = i - 1;
+    while (j >= 0 && str[j--] == '\\')
+        *ptr++ = '\\';
     *ptr++ = '"';
     *ptr++ = '\0';
     return out;