From dd63b74836d5a80adb61da935b6990e9f58c4a3e Mon Sep 17 00:00:00 2001 From: Zalathar Date: Sun, 5 Jan 2025 12:29:37 +1100 Subject: [PATCH] Use constants for DWARF opcodes, instead of FFI calls --- .../src/debuginfo/dwarf_const.rs | 8 ++++++++ .../rustc_codegen_llvm/src/debuginfo/mod.rs | 15 ++++++--------- compiler/rustc_codegen_llvm/src/llvm/ffi.rs | 3 --- .../rustc_llvm/llvm-wrapper/RustWrapper.cpp | 18 ++++++------------ 4 files changed, 20 insertions(+), 24 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs b/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs index 53dc5308fb2d2..84f3654663b66 100644 --- a/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs +++ b/compiler/rustc_codegen_llvm/src/debuginfo/dwarf_const.rs @@ -18,3 +18,11 @@ pub(crate) const DW_ATE_float: c_uint = 0x04; pub(crate) const DW_ATE_signed: c_uint = 0x05; pub(crate) const DW_ATE_unsigned: c_uint = 0x07; pub(crate) const DW_ATE_UTF: c_uint = 0x10; + +// DWARF expression operators + +pub(crate) const DW_OP_deref: u64 = 0x06; +pub(crate) const DW_OP_plus_uconst: u64 = 0x23; +/// Defined by LLVM in `llvm/include/llvm/BinaryFormat/Dwarf.h`. +/// Double-checked by a static assertion in `RustWrapper.cpp`. +pub(crate) const DW_OP_LLVM_fragment: u64 = 0x1000; diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs index 1c941cd92dcb5..cb18f3cd78bf8 100644 --- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs @@ -153,29 +153,26 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> { indirect_offsets: &[Size], fragment: Option>, ) { + use dwarf_const::{DW_OP_LLVM_fragment, DW_OP_deref, DW_OP_plus_uconst}; + // Convert the direct and indirect offsets and fragment byte range to address ops. - // FIXME(eddyb) use `const`s instead of getting the values via FFI, - // the values should match the ones in the DWARF standard anyway. - let op_deref = || unsafe { llvm::LLVMRustDIBuilderCreateOpDeref() }; - let op_plus_uconst = || unsafe { llvm::LLVMRustDIBuilderCreateOpPlusUconst() }; - let op_llvm_fragment = || unsafe { llvm::LLVMRustDIBuilderCreateOpLLVMFragment() }; let mut addr_ops = SmallVec::<[u64; 8]>::new(); if direct_offset.bytes() > 0 { - addr_ops.push(op_plus_uconst()); + addr_ops.push(DW_OP_plus_uconst); addr_ops.push(direct_offset.bytes() as u64); } for &offset in indirect_offsets { - addr_ops.push(op_deref()); + addr_ops.push(DW_OP_deref); if offset.bytes() > 0 { - addr_ops.push(op_plus_uconst()); + addr_ops.push(DW_OP_plus_uconst); addr_ops.push(offset.bytes() as u64); } } if let Some(fragment) = fragment { // `DW_OP_LLVM_fragment` takes as arguments the fragment's // offset and size, both of them in bits. - addr_ops.push(op_llvm_fragment()); + addr_ops.push(DW_OP_LLVM_fragment); addr_ops.push(fragment.start.bits() as u64); addr_ops.push((fragment.end - fragment.start).bits() as u64); } diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs index 21be66cb29b69..bb324ee682cdb 100644 --- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs +++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs @@ -2177,9 +2177,6 @@ unsafe extern "C" { Location: &'a DILocation, BD: c_uint, ) -> Option<&'a DILocation>; - pub fn LLVMRustDIBuilderCreateOpDeref() -> u64; - pub fn LLVMRustDIBuilderCreateOpPlusUconst() -> u64; - pub fn LLVMRustDIBuilderCreateOpLLVMFragment() -> u64; pub fn LLVMRustWriteTypeToString(Type: &Type, s: &RustString); pub fn LLVMRustWriteValueToString(value_ref: &Value, s: &RustString); diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp index ca62483b0aa2b..1236622fecec1 100644 --- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp +++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp @@ -54,6 +54,12 @@ using namespace llvm; using namespace llvm::sys; using namespace llvm::object; +// This opcode is an LLVM detail that could hypothetically change, so verify +// that the hard-coded value in `dwarf_const.rs` still agrees with LLVM. +static_assert( + dwarf::DW_OP_LLVM_fragment == 0x1000, + "DW_OP_LLVM_fragment has changed from the value used by Rust-side code"); + // LLVMAtomicOrdering is already an enum - don't create another // one. static AtomicOrdering fromRust(LLVMAtomicOrdering Ordering) { @@ -1397,18 +1403,6 @@ LLVMRustDILocationCloneWithBaseDiscriminator(LLVMMetadataRef Location, return wrap(NewLoc.has_value() ? NewLoc.value() : nullptr); } -extern "C" uint64_t LLVMRustDIBuilderCreateOpDeref() { - return dwarf::DW_OP_deref; -} - -extern "C" uint64_t LLVMRustDIBuilderCreateOpPlusUconst() { - return dwarf::DW_OP_plus_uconst; -} - -extern "C" uint64_t LLVMRustDIBuilderCreateOpLLVMFragment() { - return dwarf::DW_OP_LLVM_fragment; -} - extern "C" void LLVMRustWriteTypeToString(LLVMTypeRef Ty, RustStringRef Str) { auto OS = RawRustStringOstream(Str); unwrap(Ty)->print(OS);