Add test of a backslash in a file path on Linux and Mac OS X.

While I'm here, fix a typo in the name of json_formating.c and add `--`
to its `3c` command lines.

Author: mattmccutchen-cci

clang/test/3C/json_formating.c renamed to clang/test/3C/json_formatting.c

@@ -1,9 +1,9 @@
 // RUN: rm -rf %t*
 // RUN: mkdir %t.alltypes && cd %t.alltypes
-// RUN: 3c -base-dir=%S -alltypes -dump-stats -dump-intermediate -debug-solver %s
+// RUN: 3c -base-dir=%S -alltypes -dump-stats -dump-intermediate -debug-solver %s --
 // RUN: python -c "import json, glob; [json.load(open(f)) for f in glob.glob('*.json')]"
 // RUN: mkdir %t.noalltypes && cd %t.noalltypes
-// RUN: 3c -base-dir=%S -dump-stats -dump-intermediate -debug-solver %s
+// RUN: 3c -base-dir=%S -dump-stats -dump-intermediate -debug-solver %s --
 // RUN: python -c "import json, glob; [json.load(open(f)) for f in glob.glob('*.json')]"
 
 // Testing that json files output for statistics logging are well formed

clang/test/3C/json_formatting_backslash.c

@@ -0,0 +1,36 @@
+// Regression test for a bug in which 3C didn't escape backslashes in file paths
+// in its JSON output
+// (https://github.com/correctcomputation/checkedc-clang/issues/619). On
+// Windows, file paths contain backslashes as the directory separator, so the
+// main json_formatting.c test would catch the bug. This test catches the bug on
+// Linux and Mac OS X by manually creating a file with a backslash in the name
+// (which is an ordinary filename character on these OSes).
+
+// UNSUPPORTED: system-windows
+
+// We reuse json_formatting.c to ensure that we test all the same code
+// constructs, but we `#include` it instead of running 3c on it directly because
+// some code used by 3c seems to be messing with backslashes in file names on
+// the command line. The `#include` seems to preserve the backslash. (This is an
+// unusual case, so it wouldn't be surprising if 3c's behavior changes at some
+// point and this test breaks and we have to redesign it.)
+
+// RUN: rm -rf %t*
+
+// RUN: mkdir %t.alltypes && cd %t.alltypes
+// RUN: cp %s .
+// RUN: cp %S/json_formatting.c 'json\_formatting.h'
+// RUN: 3c -alltypes -dump-stats -dump-intermediate -debug-solver -output-dir=out.checked json_formatting_backslash.c --
+// RUN: python -c "import json, glob; [json.load(open(f)) for f in glob.glob('*.json')]"
+
+// RUN: mkdir %t.noalltypes && cd %t.noalltypes
+// RUN: cp %s .
+// RUN: cp %S/json_formatting.c 'json\_formatting.h'
+// RUN: 3c -dump-stats -dump-intermediate -debug-solver -output-dir=out.checked json_formatting_backslash.c --
+// RUN: python -c "import json, glob; [json.load(open(f)) for f in glob.glob('*.json')]"
+
+// Even though this looks like a double-quoted string, the Checked C compiler
+// seems to require the backslash to _not_ be escaped. We choose `\_` because it
+// is not a valid escape sequence in a JSON string literal (see
+// https://www.json.org/).
+#include "json\_formatting.h"