feat: support -MMD flag

9 files changed, 90 insertions, 17 deletions

diff --git a/src/cli.c b/src/cli.c
index ccc64b9..d4297aa 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -5,6 +5,7 @@ CliArgs* parse_cli_args(int argc, char** argv) {
     const char* output_filename = NULL;
     int positional_arguments_start = -1;
     BOOL only_compile = FALSE;
+    BOOL generate_deps = FALSE;
 
     for (int i = 1; i < argc; ++i) {
         if (argv[i][0] != '-') {
@@ -16,8 +17,8 @@ CliArgs* parse_cli_args(int argc, char** argv) {
             // ignore
         } else if (c == 'O') {
             // ignore
-        } else if (c == 'M') {
-            // ignore
+        } else if (c == 'M' && argv[i][2] == '\0') {
+            // ignore -M
         } else if (c == 'o') {
             if (argc <= i + 1) {
                 fatal_error("-o requires filename");
@@ -26,6 +27,8 @@ CliArgs* parse_cli_args(int argc, char** argv) {
             ++i;
         } else if (c == 'c') {
             only_compile = TRUE;
+        } else if (strcmp(argv[i], "-MMD") == 0) {
+            generate_deps = TRUE;
         } else {
             fatal_error("unknown option: %s", argv[i]);
         }
@@ -41,6 +44,7 @@ CliArgs* parse_cli_args(int argc, char** argv) {
     a->only_compile = only_compile;
     a->totally_deligate_to_gcc = FALSE;
     a->gcc_command = NULL;
+    a->generate_deps = generate_deps;
 
     if (!a->only_compile && str_ends_with(a->input_filename, ".o")) {
         a->totally_deligate_to_gcc = TRUE;
diff --git a/src/cli.h b/src/cli.h
index 3288c10..398ecaf 100644
--- a/src/cli.h
+++ b/src/cli.h
@@ -8,6 +8,7 @@ struct CliArgs {
     const char* output_filename;
     BOOL output_assembly;
     BOOL only_compile;
+    BOOL generate_deps;
     BOOL totally_deligate_to_gcc;
     const char* gcc_command;
 };
diff --git a/src/fs.c b/src/fs.c
new file mode 100644
index 0000000..a299ef9
--- /dev/null
+++ b/src/fs.c
@@ -0,0 +1,26 @@
+#include "fs.h"
+#include "std.h"
+
+// 'ext' must include '.'.
+char* replace_extension(const char* file_name, const char* ext) {
+    size_t len = strlen(file_name);
+    const char* last_slash = strrchr(file_name, '/');
+    const char* last_dot = strrchr(file_name, '.');
+
+    size_t ext_len = strlen(ext);
+    size_t base_len;
+    // !last_slash: foo.c
+    // last_slash < last_dot: ./bar/foo.c
+    if (last_dot && (!last_slash || last_slash < last_dot)) {
+        base_len = last_dot - file_name;
+    } else {
+        base_len = len;
+    }
+
+    char* result = calloc(base_len + ext_len + 1, sizeof(char));
+    memcpy(result, file_name, base_len);
+    memcpy(result + base_len, ext, ext_len);
+    result[base_len + ext_len] = '\0';
+
+    return result;
+}
diff --git a/src/fs.h b/src/fs.h
new file mode 100644
index 0000000..b71889f
--- /dev/null
+++ b/src/fs.h
@@ -0,0 +1,7 @@
+#ifndef DUCC_FS_H
+#define DUCC_FS_H
+
+// 'ext' must include '.'.
+char* replace_extension(const char* file_name, const char* ext);
+
+#endif
diff --git a/src/io.c b/src/io.c
index 5530ab7..ecbb0c9 100644
--- a/src/io.c
+++ b/src/io.c
@@ -14,12 +14,7 @@ void sourcelocation_build_json(JsonBuilder* builder, SourceLocation* loc) {
 }
 
 InFile* infile_open(const char* filename) {
-    FILE* in;
-    if (strcmp(filename, "-") == 0) {
-        in = stdin;
-    } else {
-        in = fopen(filename, "rb");
-    }
+    FILE* in = fopen(filename, "rb");
     if (!in) {
         return NULL;
     }
diff --git a/src/main.c b/src/main.c
index 5704367..b064f39 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2,6 +2,7 @@
 #include "cli.h"
 #include "codegen.h"
 #include "common.h"
+#include "fs.h"
 #include "io.h"
 #include "parse.h"
 #include "preprocess.h"
@@ -16,7 +17,11 @@ int main(int argc, char** argv) {
     }
 
     InFile* source = infile_open(cli_args->input_filename);
-    TokenArray* pp_tokens = preprocess(source);
+
+    StrArray included_files;
+    strings_init(&included_files);
+
+    TokenArray* pp_tokens = preprocess(source, &included_files);
     TokenArray* tokens = tokenize(pp_tokens);
     Program* prog = parse(tokens);
 
@@ -45,4 +50,18 @@ int main(int argc, char** argv) {
             fatal_error("gcc failed: %d", result);
         }
     }
+
+    if (cli_args->generate_deps && cli_args->only_compile && cli_args->output_filename) {
+        const char* dep_filename = replace_extension(cli_args->output_filename, ".d");
+
+        FILE* dep_file = fopen(dep_filename, "w");
+        if (!dep_file) {
+            fatal_error("Cannot open dependency file: %s", dep_filename);
+        }
+        fprintf(dep_file, "%s:", cli_args->output_filename);
+        for (size_t i = 0; i < included_files.len; ++i) {
+            fprintf(dep_file, " \\\n    %s", included_files.data[i]);
+        }
+        fprintf(dep_file, "\n");
+    }
 }
diff --git a/src/preprocess.c b/src/preprocess.c
index 284a633..03a2121 100644
--- a/src/preprocess.c
+++ b/src/preprocess.c
@@ -559,12 +559,14 @@ struct Preprocessor {
     int include_depth;
     char** include_paths;
     int n_include_paths;
+    StrArray* included_files;
 };
 typedef struct Preprocessor Preprocessor;
 
-static TokenArray* do_preprocess(InFile* src, int depth, MacroArray* macros);
+static TokenArray* do_preprocess(InFile* src, int depth, MacroArray* macros, StrArray* included_files);
 
-static Preprocessor* preprocessor_new(TokenArray* pp_tokens, int include_depth, MacroArray* macros) {
+static Preprocessor* preprocessor_new(TokenArray* pp_tokens, int include_depth, MacroArray* macros,
+                                      StrArray* included_files) {
     if (include_depth >= 32) {
         fatal_error("include depth limit exceeded");
     }
@@ -574,6 +576,7 @@ static Preprocessor* preprocessor_new(TokenArray* pp_tokens, int include_depth,
     pp->macros = macros;
     pp->include_depth = include_depth;
     pp->include_paths = calloc(16, sizeof(char*));
+    pp->included_files = included_files;
 
     return pp;
 }
@@ -745,7 +748,8 @@ static void expand_include_directive(Preprocessor* pp, const char* include_name,
                     original_include_name_tok->loc.line, token_stringify(original_include_name_tok));
     }
 
-    TokenArray* include_pp_tokens = do_preprocess(include_source, pp->include_depth + 1, pp->macros);
+    TokenArray* include_pp_tokens =
+        do_preprocess(include_source, pp->include_depth + 1, pp->macros, pp->included_files);
     tokens_pop(include_pp_tokens); // pop EOF token
     pp->pos = insert_pp_tokens(pp, pp->pos, include_pp_tokens);
 }
@@ -1119,6 +1123,20 @@ static void preprocess_include_directive(Preprocessor* pp) {
         fatal_error("%s:%d: cannot resolve include file name: %s", include_name->loc.filename, include_name->loc.line,
                     token_stringify(include_name));
     }
+
+    if (include_name->value.string[0] == '"') {
+        BOOL already_included = FALSE;
+        for (size_t i = 0; i < pp->included_files->len; ++i) {
+            if (strcmp(pp->included_files->data[i], include_name_resolved) == 0) {
+                already_included = TRUE;
+                break;
+            }
+        }
+        if (!already_included) {
+            strings_push(pp->included_files, include_name_resolved);
+        }
+    }
+
     skip_whitespaces(pp);
     expect_pp_token(pp, TokenKind_newline);
     expand_include_directive(pp, include_name_resolved, include_name);
@@ -1379,9 +1397,9 @@ static char* get_ducc_include_path() {
     return buf;
 }
 
-static TokenArray* do_preprocess(InFile* src, int depth, MacroArray* macros) {
+static TokenArray* do_preprocess(InFile* src, int depth, MacroArray* macros, StrArray* included_files) {
     TokenArray* pp_tokens = pp_tokenize(src);
-    Preprocessor* pp = preprocessor_new(pp_tokens, depth, macros);
+    Preprocessor* pp = preprocessor_new(pp_tokens, depth, macros, included_files);
     add_include_path(pp, get_ducc_include_path());
     add_include_path(pp, "/usr/include/x86_64-linux-gnu");
     add_include_path(pp, "/usr/include");
@@ -1390,8 +1408,9 @@ static TokenArray* do_preprocess(InFile* src, int depth, MacroArray* macros) {
     return pp->pp_tokens;
 }
 
-TokenArray* preprocess(InFile* src) {
+TokenArray* preprocess(InFile* src, StrArray* included_files) {
     MacroArray* macros = macros_new();
     add_predefined_macros(macros);
-    return do_preprocess(src, 0, macros);
+    strings_push(included_files, src->loc.filename);
+    return do_preprocess(src, 0, macros, included_files);
 }
diff --git a/src/preprocess.h b/src/preprocess.h
index b43ec4c..81007c3 100644
--- a/src/preprocess.h
+++ b/src/preprocess.h
@@ -1,9 +1,10 @@
 #ifndef DUCC_PREPROCESS_H
 #define DUCC_PREPROCESS_H
 
+#include "common.h"
 #include "io.h"
 #include "token.h"
 
-TokenArray* preprocess(InFile* src);
+TokenArray* preprocess(InFile* src, StrArray* included_files);
 
 #endif
diff --git a/src/std.h b/src/std.h
index 2353026..2b1ad4a 100644
--- a/src/std.h
+++ b/src/std.h
@@ -34,6 +34,7 @@ int strncmp(const char*, const char*, size_t);
 char* strdup(const char*);
 char* strndup(const char*, size_t);
 char* strstr(const char*, const char*);
+char* strrchr(const char*, int);
 long strtol(const char*, char**, int);
 int system(const char*);