codegen: patch method calls on-demand via traps

[mate.git] / trap.c

diff --git a/trap.c b/trap.c
index a1e5ddc8696df244d61b3628aee5631cb04d63f6..73b4256da5933fd094405d9bda8b853e03a05380 100644 (file)
--- a/trap.c
+++ b/trap.c
@@ -1,17 +1,50 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <asm/ucontext.h>
 
-void callertrap(void)
+unsigned int patchme = 0;
+void print_foo(unsigned int addr)
 {
-       char buf[5];
-       unsigned int *ptr = (unsigned int) (buf + 1);
+       // printf("\n\nprint foo: 0x%08x\n", addr);
+       patchme = addr;
+}
+
+void callertrap(int nSignal, siginfo_t *info, void *ctx)
+{
+       struct ucontext *uctx = (struct ucontext *) ctx;
+
+       printf("callertrap(mctx)  by 0x%08x\n", uctx->uc_mcontext.eip);
+       // printf("callertrap(addr)  by 0x%08x\n", info->si_addr);
+       // printf("callertrap(*esp)  by 0x%08x\n", * (unsigned int *) uctx->uc_mcontext.esp);
 
-       printf("callertrap by 0x%08x\n", *(ptr + 4));
-       /* TODO:
-        * call magic haskell function
-        * with environment information */
+       unsigned int *to_patch = (unsigned int *) (uctx->uc_mcontext.eip + 2);
+       unsigned char *insn = (unsigned int *) (uctx->uc_mcontext.eip);
+       *insn = 0x90; // nop
+       insn++;
+       *insn = 0xe8; // call
+       printf(" to_patch: 0x%08x\n", to_patch);
+       printf("*to_patch: 0x%08x\n", *to_patch);
+       if (*to_patch != 0x00000000) {
+               printf("something is wrong here. abort\n");
+               exit(0);
+       }
+       *to_patch = (unsigned int) patchme - ((unsigned int) insn + 5);
+       printf("*to_patch: 0x%08x\n", *to_patch);
+       uctx->uc_mcontext.eip = insn;
+       // while (1) ;
+}
+
+void register_signal(void)
+{
+       struct sigaction segvaction;
+       segvaction.sa_sigaction = callertrap;
+       sigemptyset(&segvaction.sa_mask);
+       segvaction.sa_flags = SA_SIGINFO | SA_RESTART;
+       sigaction(SIGSEGV, &segvaction, NULL);
 }
 
 unsigned int getaddr(void)
 {
-       return (unsigned int) callertrap;
+       return (unsigned int) print_foo;
 }