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Work around invalid DWARF bugs for fat LTO

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Signed-off-by: Yilin Chen <sticnarf@gmail.com>
This commit is contained in:
Yilin Chen 2021-09-17 20:21:33 +08:00
parent 1c03f0d0ba
commit d5de680e20
3 changed files with 20 additions and 10 deletions
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18
compiler/rustc_codegen_llvm/src/back/lto.rs
View file

@ -325,6 +325,20 @@ fn fat_lto(
drop(linker);
save_temp_bitcode(&cgcx, &module, "lto.input");
// Fat LTO also suffers from the invalid DWARF issue similar to Thin LTO.
// Here we rewrite all `DICompileUnit` pointers if there is only one `DICompileUnit`.
// This only works around the problem when codegen-units = 1.
// Refer to the comments in the `optimize_thin_module` function for more details.
let mut cu1 = ptr::null_mut();
let mut cu2 = ptr::null_mut();
unsafe { llvm::LLVMRustLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2) };
if !cu2.is_null() {
let _timer =
cgcx.prof.generic_activity_with_arg("LLVM_fat_lto_patch_debuginfo", &*module.name);
unsafe { llvm::LLVMRustLTOPatchDICompileUnit(llmod, cu1) };
save_temp_bitcode(cgcx, &module, "fat-lto-after-patch");
}
// Internalize everything below threshold to help strip out more modules and such.
unsafe {
let ptr = symbols_below_threshold.as_ptr();
@ -748,7 +762,7 @@ pub unsafe fn optimize_thin_module(
// an error.
let mut cu1 = ptr::null_mut();
let mut cu2 = ptr::null_mut();
llvm::LLVMRustThinLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2);
llvm::LLVMRustLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2);
if !cu2.is_null() {
let msg = "multiple source DICompileUnits found";
return Err(write::llvm_err(&diag_handler, msg));
@ -847,7 +861,7 @@ pub unsafe fn optimize_thin_module(
let _timer = cgcx
.prof
.generic_activity_with_arg("LLVM_thin_lto_patch_debuginfo", thin_module.name());
llvm::LLVMRustThinLTOPatchDICompileUnit(llmod, cu1);
llvm::LLVMRustLTOPatchDICompileUnit(llmod, cu1);
save_temp_bitcode(cgcx, &module, "thin-lto-after-patch");
}

8
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
View file

@ -2377,12 +2377,8 @@ extern "C" {
len: usize,
out_len: &mut usize,
) -> *const u8;
pub fn LLVMRustThinLTOGetDICompileUnit(
M: &Module,
CU1: &mut *mut c_void,
CU2: &mut *mut c_void,
);
pub fn LLVMRustThinLTOPatchDICompileUnit(M: &Module, CU: *mut c_void);
pub fn LLVMRustLTOGetDICompileUnit(M: &Module, CU1: &mut *mut c_void, CU2: &mut *mut c_void);
pub fn LLVMRustLTOPatchDICompileUnit(M: &Module, CU: *mut c_void);
pub fn LLVMRustLinkerNew(M: &'a Module) -> &'a mut Linker<'a>;
pub fn LLVMRustLinkerAdd(