aboutsummaryrefslogtreecommitdiff
path: root/amd64
diff options
context:
space:
mode:
authorQuentin Carbonneaux <[email protected]>2022-11-24 11:08:33 +0100
committerQuentin Carbonneaux <[email protected]>2022-11-27 21:48:21 +0100
commit9126afa2da0e1635d78429075cc44ca576f68169 (patch)
tree0836f3da0fdfee9af24ca5dabb8244af61e5283e /amd64
parentb5da3f3d64c857baf808220e202dc37c5c039eb8 (diff)
new hlt block terminator
It is handy to express when the end of a block cannot be reached. If a hlt terminator is executed, it traps the program. We don't go the llvm way and specify execution semantics as undefined behavior.
Diffstat (limited to 'amd64')
-rw-r--r--amd64/emit.c3
-rw-r--r--amd64/isel.c4
2 files changed, 6 insertions, 1 deletions
diff --git a/amd64/emit.c b/amd64/emit.c
index a034a66..9e5996b 100644
--- a/amd64/emit.c
+++ b/amd64/emit.c
@@ -582,6 +582,9 @@ amd64_emitfn(Fn *fn, FILE *f)
emitins(*i, fn, f);
lbl = 1;
switch (b->jmp.type) {
+ case Jhlt:
+ fprintf(f, "\tud2\n");
+ break;
case Jret0:
if (fn->dynalloc)
fprintf(f,
diff --git a/amd64/isel.c b/amd64/isel.c
index 63c304a..6d62275 100644
--- a/amd64/isel.c
+++ b/amd64/isel.c
@@ -465,7 +465,9 @@ seljmp(Blk *b, Fn *fn)
Ins *fi;
Tmp *t;
- if (b->jmp.type == Jret0 || b->jmp.type == Jjmp)
+ if (b->jmp.type == Jret0
+ || b->jmp.type == Jjmp
+ || b->jmp.type == Jhlt)
return;
assert(b->jmp.type == Jjnz);
r = b->jmp.arg;