On 08/19/2012 05:28 AM, Pekka Enberg wrote:
Jonathan Neuschäfer reports:
A simple function like this will compile to the following llvm
bitcode:
/* C */
void func(void) {
return;
}
/* LLVM */
define i8 @func() {
L0:
ret void
}
The return type of the function and the type in the return instruction
don't match.
I found this inconsistency by running LLVM's bitcode validation on the
bitcode produced by sparse-llvm.
Move 'void *' special-casing from sym_basetype_type() to sym_ptr_type()
to fix the issue.
Reported by: Jonathan Neuschäfer <j.neuschaefer@xxxxxxx>
Cc: Christopher Li <sparse@xxxxxxxxxxx>
Cc: Jeff Garzik <jgarzik@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
sparse-llvm.c | 12 ++++++++++--
validation/backend/void-return-type.c | 13 +++++++++++++
2 files changed, 23 insertions(+), 2 deletions(-)
create mode 100644 validation/backend/void-return-type.c
diff --git a/sparse-llvm.c b/sparse-llvm.c
index e02e212..213d42d 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -150,7 +150,13 @@ static LLVMTypeRef sym_union_type(LLVMModuleRef module, struct symbol *sym)
static LLVMTypeRef sym_ptr_type(LLVMModuleRef module, struct symbol *sym)
{
- LLVMTypeRef type = symbol_type(module, sym->ctype.base_type);
+ LLVMTypeRef type;
+
+ /* 'void *' is treated like 'char *' */
+ if (is_void_type(sym->ctype.base_type))
+ type = LLVMInt8Type();
+ else
+ type = symbol_type(module, sym->ctype.base_type);
return LLVMPointerType(type, 0);
}
@@ -176,10 +182,12 @@ static LLVMTypeRef sym_basetype_type(struct symbol *sym)
}
} else {
switch (sym->bit_size) {
+ case -1:
+ ret = LLVMVoidType();
+ break;
case 1:
ret = LLVMInt1Type();
break;
- case -1: /* 'void *' is treated like 'char *' */
case 8:
ret = LLVMInt8Type();
break;
diff --git a/validation/backend/void-return-type.c b/validation/backend/void-return-type.c
new file mode 100644
index 0000000..b282fde
--- /dev/null
+++ b/validation/backend/void-return-type.c
@@ -0,0 +1,13 @@
+static void foo(void)
+{
+}
+
+static void *bar(void *p)
+{
+ return p;
+}
+
ACK the code... would prefer that the first testcase included a
"return;" just to be certain we get that right.
Jeff
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