9 files changed, 86 insertions, 37 deletions
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index b610bb8..6a4f375 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -50,28 +50,6 @@ known_shlib_kwargs.update({'version' : True,
                            'name_suffix' : True,
                            'vs_module_defs' : True})
 
-backslash_explanation = \
-'''Compiler arguments have a backslash "\\" character. This is unfortunately not
-permitted. The reason for this is that backslash is a shell quoting character
-that behaves differently across different systems. Because of this is it not
-possible to make it work reliably across all the platforms Meson needs to
-support.
-
-There are several different ways of working around this issue. Most of the time
-you are using this to provide a -D define to your compiler. Try instead to
-create a config.h file and put all of your definitions in it using
-configure_file().
-
-Another approach is to move the backslashes into the source and have the other
-bits in the def. So you would have an arg -DPLAIN_TEXT="foo" and then in your
-C sources something like this:
-
-const char *fulltext = "\\\\" PLAIN_TEXT;
-
-We are fully aware that these are not really usable or pleasant ways to do
-this but it's the best we can do given the way shell quoting works.
-'''
-
 def sources_are_suffix(sources, suffix):
     for source in sources:
         if source.endswith('.' + suffix):
@@ -606,8 +584,6 @@ class BuildTarget():
         for a in args:
             if not isinstance(a, (str, File)):
                 raise InvalidArguments('A non-string passed to compiler args.')
-            if isinstance(a, str) and '\\' in a:
-                raise InvalidArguments(backslash_explanation)
         if language in self.extra_args:
             self.extra_args[language] += args
         else:
diff --git a/test cases/common/115 spaces backslash/asm output/meson.build b/test cases/common/115 spaces backslash/asm output/meson.build
new file mode 100644
index 0000000..b5f13f5
--- /dev/null
+++ b/test cases/common/115 spaces backslash/asm output/meson.build
@@ -0,0 +1,2 @@
+configure_file(output : 'blank.txt', configuration : configuration_data())
+
diff --git a/test cases/common/115 spaces backslash/comparer-end-notstring.c b/test cases/common/115 spaces backslash/comparer-end-notstring.c
new file mode 100644
index 0000000..65bf8bc
--- /dev/null
+++ b/test cases/common/115 spaces backslash/comparer-end-notstring.c
@@ -0,0 +1,20 @@
+#include "comparer.h"
+
+#ifndef COMPARER_INCLUDED
+#error "comparer.h not included"
+#endif
+
+/* This converts foo\\\\bar\\\\ to "foo\\bar\\" (string literal) */
+#define Q(x) #x
+#define QUOTE(x) Q(x)
+
+#define COMPARE_WITH "foo\\bar\\" /* This is the literal `foo\bar\` */
+
+int main(int argc, char **argv) {
+    if(strcmp(QUOTE(DEF_WITH_BACKSLASH), COMPARE_WITH)) {
+        printf("Arg string is quoted incorrectly: %s instead of %s\n",
+               QUOTE(DEF_WITH_BACKSLASH), COMPARE_WITH);
+        return 1;
+    }
+    return 0;
+}
diff --git a/test cases/common/115 spaces backslash/comparer-end.c b/test cases/common/115 spaces backslash/comparer-end.c
new file mode 100644
index 0000000..fef25a5
--- /dev/null
+++ b/test cases/common/115 spaces backslash/comparer-end.c
@@ -0,0 +1,16 @@
+#include "comparer.h"
+
+#ifndef COMPARER_INCLUDED
+#error "comparer.h not included"
+#endif
+
+#define COMPARE_WITH "foo\\bar\\" /* This is `foo\bar\` */
+
+int main (int argc, char **argv) {
+    if (strcmp (DEF_WITH_BACKSLASH, COMPARE_WITH)) {
+        printf ("Arg string is quoted incorrectly: %s vs %s\n",
+                DEF_WITH_BACKSLASH, COMPARE_WITH);
+        return 1;
+    }
+    return 0;
+}
diff --git a/test cases/common/115 spaces backslash/comparer.c b/test cases/common/115 spaces backslash/comparer.c
new file mode 100644
index 0000000..937cb47
--- /dev/null
+++ b/test cases/common/115 spaces backslash/comparer.c
@@ -0,0 +1,16 @@
+#include "comparer.h"
+
+#ifndef COMPARER_INCLUDED
+#error "comparer.h not included"
+#endif
+
+#define COMPARE_WITH "foo\\bar" /* This is the literal `foo\bar` */
+
+int main (int argc, char **argv) {
+    if (strcmp (DEF_WITH_BACKSLASH, COMPARE_WITH)) {
+        printf ("Arg string is quoted incorrectly: %s instead of %s\n",
+                DEF_WITH_BACKSLASH, COMPARE_WITH);
+        return 1;
+    }
+    return 0;
+}
diff --git a/test cases/common/115 spaces backslash/include/comparer.h b/test cases/common/115 spaces backslash/include/comparer.h
new file mode 100644
index 0000000..624d96c
--- /dev/null
+++ b/test cases/common/115 spaces backslash/include/comparer.h
@@ -0,0 +1,4 @@
+#include <string.h>
+#include <stdio.h>
+
+#define COMPARER_INCLUDED
diff --git a/test cases/common/115 spaces backslash/meson.build b/test cases/common/115 spaces backslash/meson.build
new file mode 100644
index 0000000..bf614e8
--- /dev/null
+++ b/test cases/common/115 spaces backslash/meson.build
@@ -0,0 +1,28 @@
+project('comparer', 'c')
+
+# Added manually as a c_arg to test handling of include paths with backslashes
+# and spaces. This is especially useful on Windows in vcxproj files since it
+# stores include directories in a separate element that has its own
+# context-specific escaping/quoting.
+include_dir = meson.current_source_dir() + '/include'
+default_c_args = ['-I' + include_dir]
+
+if meson.get_compiler('c').get_id() == 'msvc'
+  default_c_args += ['/Faasm output\\']
+  # Hack to create the 'asm output' directory in the builddir
+  subdir('asm output')
+endif
+
+# Path can contain \. Here we're sending `"foo\bar"`.
+test('backslash quoting',
+     executable('comparer', 'comparer.c',
+                c_args : default_c_args + ['-DDEF_WITH_BACKSLASH="foo\\bar"']))
+# Path can end in \ without any special quoting. Here we send `"foo\bar\"`.
+test('backslash end quoting',
+     executable('comparer-end', 'comparer-end.c',
+                c_args : default_c_args + ['-DDEF_WITH_BACKSLASH="foo\\bar\\"']))
+# Path can (really) end in \ if we're not passing a string literal without any
+# special quoting. Here we're sending `foo\bar\`.
+test('backslash end quoting when not a string literal',
+     executable('comparer-end-notstring', 'comparer-end-notstring.c',
+                c_args : default_c_args + ['-DDEF_WITH_BACKSLASH=foo\\bar\\']))
diff --git a/test cases/failing/24 backslash/comparer.c b/test cases/failing/24 backslash/comparer.c
deleted file mode 100644
index f562f5e..0000000
--- a/test cases/failing/24 backslash/comparer.c
+++ /dev/null
@@ -1,10 +0,0 @@
-#include<string.h>
-#include<stdio.h>
-
-int main(int argc, char **argv) {
-    if(strcmp(DEF_WITH_BACKSLASH, "foo\\bar")) {
-        printf("Arg string is quoted incorrectly: %s\n", DEF_WITH_BACKSLASH);
-        return 1;
-    }
-    return 0;
-}
diff --git a/test cases/failing/24 backslash/meson.build b/test cases/failing/24 backslash/meson.build
deleted file mode 100644
index dba891e..0000000
--- a/test cases/failing/24 backslash/meson.build
+++ /dev/null
@@ -1,3 +0,0 @@
-project('comparer', 'c')
-
-test('backslash quoting', executable('comparer', 'comparer.c', c_args : '-DDEF_WITH_BACKSLASH="foo\\bar"'))