The "graph" binary segfaults on this input:
asm("");
with gdb saying (edited for clarity):
Program received signal SIGSEGV, Segmentation fault.
in graph_ep (ep=0x7ffff7f62010) at graph.c:52
(gdb) p ep->entry
$1 = (struct instruction *) 0x0
Sadly, the commit that introduced this crash:
15fa4d60e ("topasm: top-level asm is special")
was (part of a bigger series) meant to fix crashes because
of such toplevel asm statements.
Fix this by partially reversing this commit, adding a few
checks in some others places (for tools not using the entrypoint)
and disabling output in test-parsing.c
Fixes: 15fa4d60ebba3025495bb34f0718764336d3dfe0
Reported-by: Vegard Nossum <vegard.nossum@xxxxxxxxx>
Analyzed-by: Vegard Nossum <vegard.nossum@xxxxxxxxx>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
dissect.c | 2 ++
graph.c | 2 ++
linearize.c | 8 ++++----
sparse-llvm.c | 3 +++
test-inspect.c | 2 ++
test-parsing.c | 4 +++-
6 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/dissect.c b/dissect.c
index 14d57bf5b..70d67ccbd 100644
--- a/dissect.c
+++ b/dissect.c
@@ -575,6 +575,8 @@ static inline struct symbol *do_symbol(struct symbol *sym)
type = base_type(sym);
+ if (!sym->ident) // toplevel asm
+ return type;
if (reporter->r_symdef)
reporter->r_symdef(sym);
diff --git a/graph.c b/graph.c
index be4cf282c..d8a276e11 100644
--- a/graph.c
+++ b/graph.c
@@ -182,6 +182,8 @@ int main(int argc, char **argv)
concat_symbol_list(fsyms, &all_syms);
FOR_EACH_PTR(fsyms, sym) {
+ if (!sym->ident) // toplevel asm
+ continue;
expand_symbol(sym);
linearize_symbol(sym);
} END_FOR_EACH_PTR(sym);
diff --git a/linearize.c b/linearize.c
index 30ed2a302..3d21bafab 100644
--- a/linearize.c
+++ b/linearize.c
@@ -2471,15 +2471,15 @@ static struct entrypoint *linearize_fn(struct symbol *sym, struct symbol *base_t
bb = alloc_basic_block(ep, sym->pos);
set_activeblock(ep, bb);
+ entry = alloc_instruction(OP_ENTRY, 0);
+ add_one_insn(ep, entry);
+ ep->entry = entry;
+
if (stmt->type == STMT_ASM) { // top-level asm
linearize_asm_statement(ep, stmt);
return ep;
}
- entry = alloc_instruction(OP_ENTRY, 0);
- add_one_insn(ep, entry);
- ep->entry = entry;
-
concat_symbol_list(base_type->arguments, &ep->syms);
/* FIXME!! We should do something else about varargs.. */
diff --git a/sparse-llvm.c b/sparse-llvm.c
index c7a9fbb7e..69da8d4e8 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -1139,6 +1139,9 @@ static void output_fn(LLVMModuleRef module, struct entrypoint *ep)
int nr_args = 0;
int i;
+ if (!sym->ident) // toplevel asm
+ return;
+
function.fn = get_sym_value(module, sym);
LLVMSetFunctionCallConv(function.fn, LLVMCCallConv);
LLVMSetLinkage(function.fn, function_linkage(sym));
diff --git a/test-inspect.c b/test-inspect.c
index 63754cb3c..d9bbebf0e 100644
--- a/test-inspect.c
+++ b/test-inspect.c
@@ -20,6 +20,8 @@ static void expand_symbols(struct symbol_list *list)
{
struct symbol *sym;
FOR_EACH_PTR(list, sym) {
+ if (!sym->ident) // toplevel asm
+ continue;
expand_symbol(sym);
} END_FOR_EACH_PTR(sym);
}
diff --git a/test-parsing.c b/test-parsing.c
index c5bc42e19..d18342f5f 100644
--- a/test-parsing.c
+++ b/test-parsing.c
@@ -44,6 +44,8 @@ static void clean_up_symbols(struct symbol_list *list)
struct symbol *sym;
FOR_EACH_PTR(list, sym) {
+ if (!sym->ident) // toplevel asm
+ continue;
expand_symbol(sym);
} END_FOR_EACH_PTR(sym);
}
@@ -70,7 +72,7 @@ int main(int argc, char **argv)
// Simplification
clean_up_symbols(list);
-#if 1
+#if 0
// Show the end result.
show_symbol_list(list, "\n\n");
printf("\n\n");
--
2.23.0
