1 files changed, 89 insertions, 0 deletions
diff --git a/clang/test/Preprocessor/embed_parameter_offset.c b/clang/test/Preprocessor/embed_parameter_offset.c
new file mode 100644
index 0000000..ab1bd3f
--- /dev/null
+++ b/clang/test/Preprocessor/embed_parameter_offset.c
@@ -0,0 +1,89 @@
+// RUN: %clang_cc1 -std=c23 %s --embed-dir=%S/Inputs -fsyntax-only -verify
+
+const char data[] = {
+#embed <jk.txt>
+};
+const char offset_data[] = {
+#embed <jk.txt> clang::offset(1)
+};
+static_assert(sizeof(data) == 2);
+static_assert('j' == data[0]);
+static_assert('k' == data[1]);
+static_assert(sizeof(offset_data) == 1);
+static_assert('k' == offset_data[0]);
+static_assert(offset_data[0] == data[1]);
+
+// Cannot have a negative offset.
+#embed <jk.txt> clang::offset(-1)
+// expected-error@-1 {{invalid value '-1'; must be positive}}
+
+// If the offset is past the end of the file, the file should be considered
+// empty.
+#if __has_embed(<jk.txt> clang::offset(3)) != __STDC_EMBED_EMPTY__
+#error "__has_embed should return false when there's no data"
+#endif
+
+// When the offset is past the end of the file, the resource is empty, so if_empty kicks in.
+const unsigned char buffer[] = {
+#embed <jk.txt> clang::offset(3) if_empty(1)
+};
+static_assert(sizeof(buffer) == 1);
+static_assert(buffer[0] == 1);
+
+// However, prefix and suffix do not kick in.
+const unsigned char other_buffer[] = {
+  1,
+#embed <jk.txt> clang::offset(3) prefix(2,) suffix(3)
+};
+static_assert(sizeof(other_buffer) == 1);
+static_assert(other_buffer[0] == 1);
+
+// Ensure we can offset to zero (that's the default behavior)
+const unsigned char third_buffer[] = {
+#embed <jk.txt> clang::offset(0)
+};
+static_assert(sizeof(third_buffer) == 2);
+static_assert('j' == third_buffer[0]);
+static_assert('k' == third_buffer[1]);
+
+// Test the offsets of a file with more than one character in it.
+const unsigned char fourth_buffer[] = {
+#embed <media/art.txt> clang::offset(24) limit(4)
+};
+static_assert(sizeof(fourth_buffer) == 4);
+static_assert('.' == fourth_buffer[0]);
+static_assert('-' == fourth_buffer[1]);
+static_assert('.' == fourth_buffer[2]);
+static_assert('\'' == fourth_buffer[3]);
+
+// Ensure that an offset larger than what can fit into a 64-bit value is
+// rejected. This offset is fine because it fits in a 64-bit value.
+const unsigned char fifth_buffer[] = {
+  1,
+#embed <jk.txt> clang::offset(0xFFFF'FFFF'FFFF'FFFF)
+};
+static_assert(sizeof(fifth_buffer) == 1);
+static_assert(1 == fifth_buffer[0]);
+
+// But this one is not fine because it does not fit into a 64-bit value.
+const unsigned char sixth_buffer[] = {
+#embed <jk.txt> clang::offset(0xFFFF'FFFF'FFFF'FFFF'1)
+};
+// expected-error@-2 {{integer literal is too large to be represented in any integer type}}
+
+// Ensure we diagnose duplicate parameters even if they're the same value.
+const unsigned char a[] = {
+#embed <jk.txt> clang::offset(1) prefix() clang::offset(1)
+// expected-error@-1 {{cannot specify parameter 'clang::offset' twice in the same '#embed' directive}}
+,
+#embed <jk.txt> clang::offset(1) if_empty() clang::offset(2)
+// expected-error@-1 {{cannot specify parameter 'clang::offset' twice in the same '#embed' directive}}
+};
+
+// Matches with C23 6.10.3.2p2, is documented as part of our extension.
+static_assert(
+#embed <jk.txt> clang::offset(defined(FOO))
+  == 0); // expected-error {{expected expression}}
+ /* expected-error@-2 {{'defined' cannot appear within this context}}
+    pedantic-warning@-2 {{'clang::offset' is a Clang extension}}
+  */