fn to_llvm_relocation_model(relocation_model: RelocModel) -> llvm::RelocModel {
match relocation_model {
RelocModel::Static => llvm::RelocModel::Static,
- RelocModel::Pic => llvm::RelocModel::PIC,
+ // LLVM doesn't have a PIE relocation model, it represents PIE as PIC with an extra attribute.
+ RelocModel::Pic | RelocModel::Pie => llvm::RelocModel::PIC,
RelocModel::DynamicNoPic => llvm::RelocModel::DynamicNoPic,
RelocModel::Ropi => llvm::RelocModel::ROPI,
RelocModel::Rwpi => llvm::RelocModel::RWPI,
let llvm_target = SmallCStr::new(&sess.target.llvm_target);
llvm::LLVMRustSetNormalizedTarget(llmod, llvm_target.as_ptr());
- if sess.relocation_model() == RelocModel::Pic {
+ let reloc_model = sess.relocation_model();
+ if matches!(reloc_model, RelocModel::Pic | RelocModel::Pie) {
llvm::LLVMRustSetModulePICLevel(llmod);
// PIE is potentially more effective than PIC, but can only be used in executables.
// If all our outputs are executables, then we can relax PIC to PIE.
- if sess.crate_types().iter().all(|ty| *ty == CrateType::Executable) {
+ if reloc_model == RelocModel::Pie
+ || sess.crate_types().iter().all(|ty| *ty == CrateType::Executable)
+ {
llvm::LLVMRustSetModulePIELevel(llmod);
}
}
match req {
PrintRequest::RelocationModels => {
println!("Available relocation models:");
- for name in
- &["static", "pic", "dynamic-no-pic", "ropi", "rwpi", "ropi-rwpi", "default"]
- {
+ for name in &[
+ "static",
+ "pic",
+ "pie",
+ "dynamic-no-pic",
+ "ropi",
+ "rwpi",
+ "ropi-rwpi",
+ "default",
+ ] {
println!(" {}", name);
}
println!();
return true;
}
+ // With pie relocation model calls of functions defined in the translation
+ // unit can use copy relocations.
+ if self.tcx.sess.relocation_model() == RelocModel::Pie && !is_declaration {
+ return true;
+ }
+
return false;
}
}
fn link_output_kind(sess: &Session, crate_type: CrateType) -> LinkOutputKind {
let kind = match (crate_type, sess.crt_static(Some(crate_type)), sess.relocation_model()) {
(CrateType::Executable, _, _) if sess.is_wasi_reactor() => LinkOutputKind::WasiReactorExe,
- (CrateType::Executable, false, RelocModel::Pic) => LinkOutputKind::DynamicPicExe,
+ (CrateType::Executable, false, RelocModel::Pic | RelocModel::Pie) => {
+ LinkOutputKind::DynamicPicExe
+ }
(CrateType::Executable, false, _) => LinkOutputKind::DynamicNoPicExe,
- (CrateType::Executable, true, RelocModel::Pic) => LinkOutputKind::StaticPicExe,
+ (CrateType::Executable, true, RelocModel::Pic | RelocModel::Pie) => {
+ LinkOutputKind::StaticPicExe
+ }
(CrateType::Executable, true, _) => LinkOutputKind::StaticNoPicExe,
(_, true, _) => LinkOutputKind::StaticDylib,
(_, false, _) => LinkOutputKind::DynamicDylib,
pub enum RelocModel {
Static,
Pic,
+ Pie,
DynamicNoPic,
Ropi,
Rwpi,
Ok(match s {
"static" => RelocModel::Static,
"pic" => RelocModel::Pic,
+ "pie" => RelocModel::Pie,
"dynamic-no-pic" => RelocModel::DynamicNoPic,
"ropi" => RelocModel::Ropi,
"rwpi" => RelocModel::Rwpi,
match *self {
RelocModel::Static => "static",
RelocModel::Pic => "pic",
+ RelocModel::Pie => "pie",
RelocModel::DynamicNoPic => "dynamic-no-pic",
RelocModel::Ropi => "ropi",
RelocModel::Rwpi => "rwpi",
depending on the produced crate types. \
This is the default model for majority of supported targets.
+- `pie` - position independent executable, relocatable code but without support for symbol
+interpositioning (replacing symbols by name using `LD_PRELOAD` and similar). Equivalent to the "uppercase" `-fPIE` option in other compilers. `pie`
+code cannot be linked into shared libraries (you'll get a linking error on attempt to do this).
+
#### Special relocation models
- `dynamic-no-pic` - relocatable external references, non-relocatable code. \
--- /dev/null
+// revisions: x64
+// assembly-output: emit-asm
+// [x64] compile-flags: --target x86_64-unknown-linux-gnu -Crelocation-model=pic
+// [x64] needs-llvm-components: x86
+
+
+#![feature(no_core, lang_items)]
+#![no_core]
+#![crate_type="rlib"]
+
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+
+// CHECK-LABEL: call_other_fn:
+// CHECK: {{(jmpq|callq)}} *other_fn@GOTPCREL(%rip)
+#[no_mangle]
+pub fn call_other_fn() -> u8 {
+ unsafe {
+ other_fn()
+ }
+}
+
+// CHECK-LABEL: other_fn:
+// CHECK: callq *foreign_fn@GOTPCREL(%rip)
+#[no_mangle]
+#[inline(never)]
+pub fn other_fn() -> u8 {
+ unsafe {
+ foreign_fn()
+ }
+}
+
+extern "C" {fn foreign_fn() -> u8;}
--- /dev/null
+// revisions: x64
+// assembly-output: emit-asm
+// [x64] compile-flags: --target x86_64-unknown-linux-gnu -Crelocation-model=pie
+// [x64] needs-llvm-components: x86
+
+
+#![feature(no_core, lang_items)]
+#![no_core]
+#![crate_type="rlib"]
+
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+
+// CHECK-LABEL: call_other_fn:
+// With PIE local functions are called "directly".
+// CHECK: {{(jmp|callq)}} other_fn
+#[no_mangle]
+pub fn call_other_fn() -> u8 {
+ unsafe {
+ other_fn()
+ }
+}
+
+// CHECK-LABEL: other_fn:
+// External functions are still called through GOT, since we don't know if the symbol
+// is defined in the binary or in the shared library.
+// CHECK: callq *foreign_fn@GOTPCREL(%rip)
+#[no_mangle]
+#[inline(never)]
+pub fn other_fn() -> u8 {
+ unsafe {
+ foreign_fn()
+ }
+}
+
+extern "C" {fn foreign_fn() -> u8;}
--- /dev/null
+// compile-flags: -C relocation-model=pic
+
+#![crate_type = "rlib"]
+
+// CHECK: define i8 @call_foreign_fn()
+#[no_mangle]
+pub fn call_foreign_fn() -> u8 {
+ unsafe {
+ foreign_fn()
+ }
+}
+
+// CHECK: declare zeroext i8 @foreign_fn()
+extern "C" {fn foreign_fn() -> u8;}
+
+// CHECK: !{i32 7, !"PIC Level", i32 2}
--- /dev/null
+// compile-flags: -C relocation-model=pie
+// only-x86_64-unknown-linux-gnu
+
+#![crate_type = "rlib"]
+
+// With PIE we know local functions cannot be interpositioned, we can mark them
+// as dso_local.
+// CHECK: define dso_local i8 @call_foreign_fn()
+#[no_mangle]
+pub fn call_foreign_fn() -> u8 {
+ unsafe {
+ foreign_fn()
+ }
+}
+
+// External functions are still marked as non-dso_local, since we don't know if the symbol
+// is defined in the binary or in the shared library.
+// CHECK: declare zeroext i8 @foreign_fn()
+extern "C" {fn foreign_fn() -> u8;}
+
+// CHECK: !{i32 7, !"PIC Level", i32 2}
+// CHECK: !{i32 7, !"PIE Level", i32 2}