From 4de60a709d3af497781b7467f2c6fe7e09b39595 Mon Sep 17 00:00:00 2001
From: Matthew Sotoudeh <matthew@masot.net>
Date: Sun, 30 Jul 2023 14:38:43 -0700
Subject: basic libdietc for writing passes in C

---
 c/examples/zero_init/.gitignore |  2 ++
 c/examples/zero_init/Makefile   | 14 ++++++++++++++
 c/examples/zero_init/dietpass.c | 25 +++++++++++++++++++++++++
 c/examples/zero_init/test.c     | 20 ++++++++++++++++++++
 4 files changed, 61 insertions(+)
 create mode 100644 c/examples/zero_init/.gitignore
 create mode 100644 c/examples/zero_init/Makefile
 create mode 100644 c/examples/zero_init/dietpass.c
 create mode 100644 c/examples/zero_init/test.c

(limited to 'c/examples')

diff --git a/c/examples/zero_init/.gitignore b/c/examples/zero_init/.gitignore
new file mode 100644
index 0000000..b74bd7f
--- /dev/null
+++ b/c/examples/zero_init/.gitignore
@@ -0,0 +1,2 @@
+default
+instrumented
diff --git a/c/examples/zero_init/Makefile b/c/examples/zero_init/Makefile
new file mode 100644
index 0000000..79b5692
--- /dev/null
+++ b/c/examples/zero_init/Makefile
@@ -0,0 +1,14 @@
+all: default instrumented
+
+default: test.c
+	gcc -O0 $^ -o $@
+
+instrumented: test.c dietpass
+	dietcc -O0 test.c -o $@ --dietc-pass $(PWD)/dietpass
+
+dietpass: dietpass.c ../../libdietc.l ../../libdietc.h
+	make -C ../..
+	gcc -O3 dietpass.c ../../libdietc.o -I../../ -lfl -o $@
+
+clean:
+	rm -f default instrumented dietpass
diff --git a/c/examples/zero_init/dietpass.c b/c/examples/zero_init/dietpass.c
new file mode 100644
index 0000000..e145a91
--- /dev/null
+++ b/c/examples/zero_init/dietpass.c
@@ -0,0 +1,25 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libdietc.h>
+
+int main(int argc, char **argv) {
+    assert(argc == 2);
+    struct program program = libdietc_parse(argv[1]);
+
+    for (struct function *f = program.functions; f; f = f->next) {
+        for (struct instruction *i = f->instructions; i; i = i->next) {
+            if (strncmp(i->line, "\tType_", strlen("\tType_"))) continue;
+            char *name = libdietc_tokdup(strchrnul(i->line, ' ') + 1);
+            struct instruction *n = calloc(1, sizeof(*n));
+            n->line = malloc(strlen(name) + 512);
+            sprintf(n->line, "memset(&%s, 0, sizeof(%s));", name, name);
+            n->next = i->next;
+            i->next = n;
+            i = n;
+        }
+    }
+    libdietc_print(program);
+    return 0;
+}
diff --git a/c/examples/zero_init/test.c b/c/examples/zero_init/test.c
new file mode 100644
index 0000000..5db109a
--- /dev/null
+++ b/c/examples/zero_init/test.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+int set_xyz() {
+    int xyz = 1;
+    return xyz;
+}
+
+int foo() {
+    int xyz;
+    return xyz;
+}
+
+int main() {
+    printf("Foo return value: %d\n", foo());
+    set_xyz();
+    printf("Foo return value: %d\n", foo());
+    set_xyz();
+    printf("Foo return value: %d\n", foo());
+    return 0;
+}
-- 
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