Rollup merge of rust-lang#32732 - dotdash:ext_arg, r=eddyb

Handle integer-extending for C ABI We need to supply sext/zext attributes to LLVM to ensure that arguments are extended to the appropriate width in the correct way. Most platforms extend integers less than 32 bits, though not all.
Manishearth · Apr 6, 2016 · 81d3d71 · 81d3d71
2 parents ef39a8d + 4815f7e
commit 81d3d71
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Showing 11 changed files with 102 additions and 21 deletions.
diff --git a/src/librustc_trans/abi.rs b/src/librustc_trans/abi.rs
@@ -80,6 +80,8 @@ pub struct ArgType {
  /// Only later will `original_ty` aka `%Foo` be used in the LLVM function
  /// pointer type, without ever having introspected it.
  pub ty: Type,
+ /// Signedness for integer types, None for other types
+ pub signedness: Option<bool>,
  /// Coerced LLVM Type
  pub cast: Option<Type>,
  /// Dummy argument, which is emitted before the real argument
@@ -94,6 +96,7 @@ impl ArgType {
  kind: ArgKind::Direct,
  original_ty: original_ty,
  ty: ty,
+ signedness: None,
  cast: None,
  pad: None,
  attrs: llvm::Attributes::default()
@@ -123,6 +126,19 @@ impl ArgType {
  self.kind = ArgKind::Ignore;
  }
 
+ pub fn extend_integer_width_to(&mut self, bits: u64) {
+ // Only integers have signedness
+ if let Some(signed) = self.signedness {
+ if self.ty.int_width() < bits {
+ self.attrs.set(if signed {
+ llvm::Attribute::SExt
+ } else {
+ llvm::Attribute::ZExt
+ });
+ }
+ }
+ }
+
  pub fn is_indirect(&self) -> bool {
  self.kind == ArgKind::Indirect
  }
@@ -268,6 +284,9 @@ impl FnType {
  } else {
  let mut arg = ArgType::new(type_of::type_of(ccx, ty),
  type_of::sizing_type_of(ccx, ty));
+ if ty.is_integral() {
+ arg.signedness = Some(ty.is_signed());
+ }
  if llsize_of_real(ccx, arg.ty) == 0 {
  // For some forsaken reason, x86_64-pc-windows-gnu
  // doesn't ignore zero-sized struct arguments.

diff --git a/src/librustc_trans/cabi_aarch64.rs b/src/librustc_trans/cabi_aarch64.rs
@@ -163,6 +163,7 @@ fn is_homogenous_aggregate_ty(ty: Type) -> Option<(Type, u64)> {
 
 fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
  if is_reg_ty(ret.ty) {
+ ret.extend_integer_width_to(32);
  return;
  }
  if let Some((base_ty, members)) = is_homogenous_aggregate_ty(ret.ty) {
@@ -190,6 +191,7 @@ fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
 
 fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType) {
  if is_reg_ty(arg.ty) {
+ arg.extend_integer_width_to(32);
  return;
  }
  if let Some((base_ty, members)) = is_homogenous_aggregate_ty(arg.ty) {

diff --git a/src/librustc_trans/cabi_arm.rs b/src/librustc_trans/cabi_arm.rs
@@ -131,6 +131,7 @@ fn ty_size(ty: Type, align_fn: TyAlignFn) -> usize {
 
 fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType, align_fn: TyAlignFn) {
  if is_reg_ty(ret.ty) {
+ ret.extend_integer_width_to(32);
  return;
  }
  let size = ty_size(ret.ty, align_fn);
@@ -150,6 +151,7 @@ fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType, align_fn: TyAlignFn) {
 
 fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType, align_fn: TyAlignFn) {
  if is_reg_ty(arg.ty) {
+ arg.extend_integer_width_to(32);
  return;
  }
  let align = align_fn(arg.ty);

diff --git a/src/librustc_trans/cabi_mips.rs b/src/librustc_trans/cabi_mips.rs
@@ -86,6 +86,14 @@ fn ty_size(ty: Type) -> usize {
  }
 }
 
+fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
+ if is_reg_ty(ret.ty) {
+ ret.extend_integer_width_to(32);
+ } else {
+ ret.make_indirect(ccx);
+ }
+}
+
 fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType, offset: &mut usize) {
  let orig_offset = *offset;
  let size = ty_size(arg.ty) * 8;
@@ -98,6 +106,8 @@ fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType, offset: &mut usize) {
  if !is_reg_ty(arg.ty) {
  arg.cast = Some(struct_ty(ccx, arg.ty));
  arg.pad = padding_ty(ccx, align, orig_offset);
+ } else {
+ arg.extend_integer_width_to(32);
  }
 }
 
@@ -146,8 +156,8 @@ fn struct_ty(ccx: &CrateContext, ty: Type) -> Type {
 }
 
 pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
- if !fty.ret.is_ignore() && !is_reg_ty(fty.ret.ty) {
- fty.ret.make_indirect(ccx);
+ if !fty.ret.is_ignore() {
+ classify_ret_ty(ccx, &mut fty.ret);
  }
 
  let mut offset = if fty.ret.is_indirect() { 4 } else { 0 };

diff --git a/src/librustc_trans/cabi_powerpc.rs b/src/librustc_trans/cabi_powerpc.rs
@@ -82,6 +82,14 @@ fn ty_size(ty: Type) -> usize {
  }
 }
 
+fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
+ if is_reg_ty(ret.ty) {
+ ret.extend_integer_width_to(32);
+ } else {
+ ret.make_indirect(ccx);
+ }
+}
+
 fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType, offset: &mut usize) {
  let orig_offset = *offset;
  let size = ty_size(arg.ty) * 8;
@@ -94,6 +102,8 @@ fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType, offset: &mut usize) {
  if !is_reg_ty(arg.ty) {
  arg.cast = Some(struct_ty(ccx, arg.ty));
  arg.pad = padding_ty(ccx, align, orig_offset);
+ } else {
+ arg.extend_integer_width_to(32);
  }
 }
 
@@ -141,8 +151,8 @@ fn struct_ty(ccx: &CrateContext, ty: Type) -> Type {
 }
 
 pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
- if !fty.ret.is_ignore() && !is_reg_ty(fty.ret.ty) {
- fty.ret.make_indirect(ccx);
+ if !fty.ret.is_ignore() {
+ classify_ret_ty(ccx, &mut fty.ret);
  }
 
  let mut offset = if fty.ret.is_indirect() { 4 } else { 0 };

diff --git a/src/librustc_trans/cabi_powerpc64.rs b/src/librustc_trans/cabi_powerpc64.rs
@@ -153,6 +153,7 @@ fn is_homogenous_aggregate_ty(ty: Type) -> Option<(Type, u64)> {
 
 fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
  if is_reg_ty(ret.ty) {
+ ret.extend_integer_width_to(64);
  return;
  }
 
@@ -187,6 +188,7 @@ fn classify_ret_ty(ccx: &CrateContext, ret: &mut ArgType) {
 
 fn classify_arg_ty(ccx: &CrateContext, arg: &mut ArgType) {
  if is_reg_ty(arg.ty) {
+ arg.extend_integer_width_to(64);
  return;
  }
 

diff --git a/src/librustc_trans/cabi_x86.rs b/src/librustc_trans/cabi_x86.rs
@@ -15,25 +15,29 @@ use super::common::*;
 use super::machine::*;
 
 pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
- if !fty.ret.is_ignore() && fty.ret.ty.kind() == Struct {
- // Returning a structure. Most often, this will use
- // a hidden first argument. On some platforms, though,
- // small structs are returned as integers.
- //
- // Some links:
- // http://www.angelcode.com/dev/callconv/callconv.html
- // Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp
- let t = &ccx.sess().target.target;
- if t.options.is_like_osx || t.options.is_like_windows {
- match llsize_of_alloc(ccx, fty.ret.ty) {
- 1 => fty.ret.cast = Some(Type::i8(ccx)),
- 2 => fty.ret.cast = Some(Type::i16(ccx)),
- 4 => fty.ret.cast = Some(Type::i32(ccx)),
- 8 => fty.ret.cast = Some(Type::i64(ccx)),
- _ => fty.ret.make_indirect(ccx)
+ if !fty.ret.is_ignore() {
+ if fty.ret.ty.kind() == Struct {
+ // Returning a structure. Most often, this will use
+ // a hidden first argument. On some platforms, though,
+ // small structs are returned as integers.
+ //
+ // Some links:
+ // http://www.angelcode.com/dev/callconv/callconv.html
+ // Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp
+ let t = &ccx.sess().target.target;
+ if t.options.is_like_osx || t.options.is_like_windows {
+ match llsize_of_alloc(ccx, fty.ret.ty) {
+ 1 => fty.ret.cast = Some(Type::i8(ccx)),
+ 2 => fty.ret.cast = Some(Type::i16(ccx)),
+ 4 => fty.ret.cast = Some(Type::i32(ccx)),
+ 8 => fty.ret.cast = Some(Type::i64(ccx)),
+ _ => fty.ret.make_indirect(ccx)
+ }
+ } else {
+ fty.ret.make_indirect(ccx);
  }
  } else {
- fty.ret.make_indirect(ccx);
+ fty.ret.extend_integer_width_to(32);
  }
  }
 
@@ -42,6 +46,8 @@ pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
  if arg.ty.kind() == Struct {
  arg.make_indirect(ccx);
  arg.attrs.set(Attribute::ByVal);
+ } else {
+ arg.extend_integer_width_to(32);
  }
  }
 }
diff --git a/src/librustc_trans/cabi_x86_64.rs b/src/librustc_trans/cabi_x86_64.rs
@@ -400,6 +400,8 @@ pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
  } else {
  arg.cast = Some(llreg_ty(ccx, &cls));
  }
+ } else {
+ arg.extend_integer_width_to(32);
  }
  }
 

diff --git a/src/librustc_trans/cabi_x86_win64.rs b/src/librustc_trans/cabi_x86_win64.rs
@@ -26,6 +26,8 @@ pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType) {
  8 => a.cast = Some(Type::i64(ccx)),
  _ => a.make_indirect(ccx)
  }
+ } else {
+ a.extend_integer_width_to(32);
  }
  };
 

diff --git a/src/rt/rust_test_helpers.c b/src/rt/rust_test_helpers.c
@@ -243,3 +243,7 @@ double rust_interesting_average(uint64_t n, ...) {
  va_end(pairs);
  return sum / n;
 }
+
+int32_t rust_int8_to_int32(int8_t x) {
+ return (int32_t)x;
+}
diff --git a/src/test/run-pass/cabi-int-widening.rs b/src/test/run-pass/cabi-int-widening.rs
@@ -0,0 +1,22 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[link(name = "rust_test_helpers")]
+extern {
+ fn rust_int8_to_int32(_: i8) -> i32;
+}
+
+fn main() {
+ let x = unsafe {
+ rust_int8_to_int32(-1)
+ };
+
+ assert!(x == -1);
+}