2 files changed, 29 insertions, 0 deletions

diff --git a/src/copyjit.c b/src/copyjit.c
index 393c8e1..0de85d3 100644
--- a/src/copyjit.c
+++ b/src/copyjit.c
@@ -471,6 +471,23 @@ void compile_start(ctx_t *ctx)
 	ctx->pc = ctx->buf;
 }
 
+reloc_t compile_placeholder(ctx_t *ctx, compile_callback_t call)
+{
+	reloc_t r = {0};
+	r.addr = call(ctx, 0);
+
+	/* the immediate is the last sizeof(uintptr_t) bytes of the generated
+	 * instruction
+	 * (at least we assume, the user could've passed anything to our callback) */
+	r.imm = ((uintptr_t *)ctx->pc) - 1;
+	return r;
+}
+
+void compile_patch(reloc_t reloc, void *addr)
+{
+	*reloc.imm = (uintptr_t)addr;
+}
+
 void compile_finish(ctx_t *ctx)
 {
 	__builtin___clear_cache(ctx->buf, ctx->buf + ctx->size);
diff --git a/src/copyjit.h b/src/copyjit.h
index d752144..8170204 100644
--- a/src/copyjit.h
+++ b/src/copyjit.h
@@ -3,12 +3,21 @@
 #ifndef HMMJIT_H
 #define HMMJIT_H
 
+#include <stdint.h>
+
 typedef struct {
 	char *pc;
 	char *buf;
 	size_t size;
 } ctx_t;
 
+typedef struct {
+	void *addr;
+	uintptr_t *imm;
+} reloc_t;
+
+typedef void *(*compile_callback_t)(ctx_t *, unsigned long);
+
 #include "../lib/op_decls.h"
 #include "../lib/imm_decls.h"
 
@@ -30,6 +39,9 @@ void *compile_sly(ctx_t *ctx, unsigned long i);
 /** @todo add in placeholders (for example for load immediate but we don't know
  * what the immediate is yet) */
 
+reloc_t compile_placeholder(ctx_t *ctx, compile_callback_t call);
+void compile_patch(reloc_t reloc, void *addr);
+
 void compile_start(ctx_t *ctx);
 void compile_finish(ctx_t *ctx);
 unsigned long run(ctx_t *ctx);