feat: resolve include name relative to the current file name

3 files changed, 46 insertions, 11 deletions

diff --git a/src/preprocess.c b/src/preprocess.c
index e44bbf4..3ed9740 100644
--- a/src/preprocess.c
+++ b/src/preprocess.c
@@ -1220,18 +1220,22 @@ void process_ifndef_directive(Preprocessor* pp, int directive_token_pos) {
     remove_directive_tokens(pp, directive_token_pos, pp->pos);
 }
 
-const char* read_include_header_name(Preprocessor* pp) {
+Token* read_include_header_name(Preprocessor* pp) {
     Token* tok = next_pp_token(pp);
     if (tok->kind != TokenKind_header_name) {
         fatal_error("%s:%d: invalid #include", tok->loc.filename, tok->loc.line);
     }
-
-    return tok->value.string;
+    return tok;
 }
 
-const char* resolve_include_name(Preprocessor* pp, const char* include_name) {
+const char* resolve_include_name(Preprocessor* pp, const Token* include_name_token) {
+    const char* include_name = include_name_token->value.string;
     if (include_name[0] == '"') {
-        return strndup(include_name + 1, strlen(include_name) - 2);
+        char* current_filename = strdup(include_name_token->loc.filename);
+        const char* current_dir = dirname(current_filename);
+        char* buf = calloc(strlen(include_name) - 2 + 1 + strlen(current_dir) + 1, sizeof(char));
+        sprintf(buf, "%s/%.*s", current_dir, strlen(include_name) - 2, include_name + 1);
+        return buf;
     } else {
         for (int i = 0; i < pp->n_include_paths; ++i) {
             char* buf = calloc(strlen(include_name) - 2 + 1 + strlen(pp->include_paths[i]) + 1, sizeof(char));
@@ -1291,7 +1295,7 @@ void expand_include_directive(Preprocessor* pp, int directive_token_pos, const c
 void process_include_directive(Preprocessor* pp, int directive_token_pos) {
     next_pp_token(pp);
     skip_whitespaces(pp);
-    const char* include_name = read_include_header_name(pp);
+    Token* include_name = read_include_header_name(pp);
     const char* include_name_resolved = resolve_include_name(pp, include_name);
     if (include_name_resolved == NULL) {
         fatal_error("cannot resolve include file name: %s", include_name);
diff --git a/tests/055.sh b/tests/055.sh
index 6fc3608..997f12b 100644
--- a/tests/055.sh
+++ b/tests/055.sh
@@ -1,7 +1,3 @@
-cat <<'EOF' > expected
-8
-EOF
-
 cat <<'EOF' > header.h
 int add(int a, int b) {
     return a + b;
@@ -10,6 +6,9 @@ int add(int a, int b) {
 int printf(const char*, ...);
 EOF
 
+cat <<'EOF' > expected
+8
+EOF
 test_diff <<'EOF'
 #include "header.h"
 
@@ -18,3 +17,35 @@ int main() {
     return 0;
 }
 EOF
+
+mkdir -p foo
+cat <<'EOF' > bar.h
+#include "baz.h"
+EOF
+cat <<'EOF' > baz.h
+#define A 123
+EOF
+cat <<'EOF' > foo/bar.h
+#include "baz.h"
+EOF
+cat <<'EOF' > foo/baz.h
+#define A 456
+EOF
+
+cat <<'EOF' > expected
+123
+456
+EOF
+test_diff <<'EOF'
+int printf(const char*, ...);
+
+int main() {
+#include "bar.h"
+    printf("%d\n", A);
+
+#undef A
+
+#include "foo/bar.h"
+    printf("%d\n", A);
+}
+EOF
diff --git a/tests/057.sh b/tests/057.sh
index 8850e55..291030c 100644
--- a/tests/057.sh
+++ b/tests/057.sh
@@ -1,5 +1,5 @@
 cat <<'EOF' > expected
-cannot open include file: nonexistent.h
+cannot open include file: ./nonexistent.h
 EOF
 
 test_compile_error <<'EOF'