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Fix LLVM IR generated for C-variadic arguments

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It is possible to create malformed LLVM IR given variadic arguments that
are aggregate types. This occurs due to improper tracking of the current
argument in the functions list of arguments.
This commit is contained in:
Dan Robertson 2019-03-27 13:00:37 +00:00
parent b0fcfa7d61
commit a9d62be557
No known key found for this signature in database
GPG Key ID: 45C4A652C47E42A5
2 changed files with 23 additions and 13 deletions
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15
src/librustc_codegen_ssa/mir/block.rs
View File

@ -20,7 +20,7 @@
use super::{FunctionCx, LocalRef};
use super::place::PlaceRef;
use super::operand::{OperandValue, OperandRef};
use super::operand::OperandRef;
use super::operand::OperandValue::{Pair, Ref, Immediate};
/// Used by `FunctionCx::codegen_terminator` for emitting common patterns
@ -695,18 +695,7 @@ fn codegen_call_terminator<'b>(
// an "spoofed" `VaList`. This argument is ignored, but we need to
// populate it with a dummy operand so that the users real arguments
// are not overwritten.
let i = if sig.c_variadic && last_arg_idx.map(|x| x == i).unwrap_or(false) {
let layout = match self.cx.tcx().lang_items().va_list() {
Some(did) => bx.cx().layout_of(bx.tcx().type_of(did)),
None => bug!("`va_list` language item required for C-variadics"),
};
let op = OperandRef {
val: OperandValue::Immediate(
bx.cx().const_undef(bx.cx().immediate_backend_type(layout)
)),
layout: layout,
};
self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]);
let i = if sig.c_variadic && last_arg_idx.map(|x| i >= x).unwrap_or(false) {
if i + 1 < fn_ty.args.len() {
i + 1
} else {

21
src/test/codegen/issue-58881.rs Normal file
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@ -0,0 +1,21 @@
// compile-flags: -C no-prepopulate-passes
//
// only-x86_64
// ignore-windows
#![crate_type = "lib"]
extern "C" {
fn variadic_fn(_: i32, ...);
}
#[repr(C)]
struct Foo(u8);
#[repr(C)]
struct Bar(u64, u64, u64);
// Ensure that emit arguments of the correct type.
pub unsafe fn test_call_variadic() {
// CHECK: call void (i32, ...) @variadic_fn(i32 0, i8 {{.*}}, %Bar* {{.*}})
variadic_fn(0, Foo(0), Bar(0, 0, 0))
}