glcpp: error on multiple #else/#elif directives

The preprocessor currently accepts multiple else/elif-groups
per if-section. The GLSL-preprocessor is defined by the C++
specification, which defines the following parse-rule:

if-section:
	if-group elif-groups(opt) else-group(opt) endif-line

This clearly only allows a single else-group, that has to come
after any elif-groups.

So let's modify the code to follow the specification. Add test
to prevent regressions.

Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Carl Worth <[email protected]>

Cc: 10.0 <[email protected]>

4 files changed, 28 insertions, 0 deletions

diff --git a/src/glsl/glcpp/tests/118-multiple-else.c b/src/glsl/glcpp/tests/118-multiple-else.c
new file mode 100644
index 00000000000..62ad49cf7bb
--- /dev/null
+++ b/src/glsl/glcpp/tests/118-multiple-else.c
@@ -0,0 +1,6 @@
+#if 0
+#else
+int foo;
+#else
+int bar;
+#endif
diff --git a/src/glsl/glcpp/tests/118-multiple-else.c.expected b/src/glsl/glcpp/tests/118-multiple-else.c.expected
new file mode 100644
index 00000000000..eaec4815076
--- /dev/null
+++ b/src/glsl/glcpp/tests/118-multiple-else.c.expected
@@ -0,0 +1,8 @@
+0:4(1): preprocessor error: multiple #else
+
+
+int foo;
+
+int bar;
+
+
diff --git a/src/glsl/glcpp/tests/119-elif-after-else.c b/src/glsl/glcpp/tests/119-elif-after-else.c
new file mode 100644
index 00000000000..9b9e9233bcb
--- /dev/null
+++ b/src/glsl/glcpp/tests/119-elif-after-else.c
@@ -0,0 +1,6 @@
+#if 0
+#else
+int foo;
+#elif 0
+int bar;
+#endif
diff --git a/src/glsl/glcpp/tests/119-elif-after-else.c.expected b/src/glsl/glcpp/tests/119-elif-after-else.c.expected
new file mode 100644
index 00000000000..33f05136158
--- /dev/null
+++ b/src/glsl/glcpp/tests/119-elif-after-else.c.expected
@@ -0,0 +1,8 @@
+0:4(1): preprocessor error: #elif after #else
+
+
+int foo;
+
+int bar;
+
+