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Write .debug_frame information (#53)

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* Write .debug_frame information

* mv map_reg
This commit is contained in:
Yury Delendik
2020-03-11 10:22:51 -05:00
committed by GitHub
parent 2ead747f48
commit f76b36f737
16 changed files with 403 additions and 112 deletions
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140
crates/debug/src/frame.rs Normal file
View File

@@ -0,0 +1,140 @@
use crate::transform::map_reg;
use std::collections::HashMap;
use wasmtime_environ::entity::EntityRef;
use wasmtime_environ::isa::{CallConv, TargetIsa};
use wasmtime_environ::wasm::DefinedFuncIndex;
use wasmtime_environ::{FrameLayoutChange, FrameLayouts};
use gimli::write::{
Address, CallFrameInstruction, CommonInformationEntry as CIEEntry, Error,
FrameDescriptionEntry as FDEEntry, FrameTable,
};
use gimli::{Encoding, Format, Register, X86_64};
fn to_cfi(
isa: &dyn TargetIsa,
change: &FrameLayoutChange,
cfa_def_reg: &mut Register,
cfa_def_offset: &mut i32,
) -> Option<CallFrameInstruction> {
Some(match change {
FrameLayoutChange::CallFrameAddressAt { reg, offset } => {
let mapped = match map_reg(isa, *reg) {
Ok(r) => r,
Err(_) => return None,
};
let offset = (*offset) as i32;
if mapped != *cfa_def_reg && offset != *cfa_def_offset {
*cfa_def_reg = mapped;
*cfa_def_offset = offset;
CallFrameInstruction::Cfa(mapped, offset)
} else if offset != *cfa_def_offset {
*cfa_def_offset = offset;
CallFrameInstruction::CfaOffset(offset)
} else if mapped != *cfa_def_reg {
*cfa_def_reg = mapped;
CallFrameInstruction::CfaRegister(mapped)
} else {
return None;
}
}
FrameLayoutChange::RegAt { reg, cfa_offset } => {
assert!(cfa_offset % -8 == 0);
let cfa_offset = *cfa_offset as i32;
let mapped = match map_reg(isa, *reg) {
Ok(r) => r,
Err(_) => return None,
};
CallFrameInstruction::Offset(mapped, cfa_offset)
}
FrameLayoutChange::ReturnAddressAt { cfa_offset } => {
assert!(cfa_offset % -8 == 0);
let cfa_offset = *cfa_offset as i32;
CallFrameInstruction::Offset(X86_64::RA, cfa_offset)
}
FrameLayoutChange::Preserve => CallFrameInstruction::RememberState,
FrameLayoutChange::Restore => CallFrameInstruction::RestoreState,
})
}
pub fn get_debug_frame_bytes(
funcs: &[(*const u8, usize)],
isa: &dyn TargetIsa,
layouts: &FrameLayouts,
) -> Result<Option<FrameTable>, Error> {
// FIXME Only x86-64 at this moment.
if isa.name() != "x86" || isa.pointer_bits() != 64 {
return Ok(None);
}
let address_size = isa.pointer_bytes();
let encoding = Encoding {
format: Format::Dwarf64,
version: 4,
address_size,
};
let mut frames = FrameTable::default();
let mut cached_cies = HashMap::new();
for (i, f) in funcs.into_iter().enumerate() {
let layout = &layouts[DefinedFuncIndex::new(i)];
// FIXME Can only process functions with SystemV-like prologue.
if layout.call_conv != CallConv::Fast
&& layout.call_conv != CallConv::Cold
&& layout.call_conv != CallConv::SystemV
{
continue;
}
// Caching CIE with similar initial_commands.
let (cie_id, mut cfa_def_reg, mut cfa_def_offset) = {
use std::collections::hash_map::Entry;
match cached_cies.entry(&layout.initial_commands) {
Entry::Occupied(o) => *o.get(),
Entry::Vacant(v) => {
// cfa_def_reg and cfa_def_offset initialized with some random values.
let mut cfa_def_reg = X86_64::RA;
let mut cfa_def_offset = 0i32;
// TODO adjust code_alignment_factor and data_alignment_factor based on ISA.
let mut cie = CIEEntry::new(
encoding,
/* code_alignment_factor = */ 1,
/* data_alignment_factor = */ -8,
/* return_address_register = */ X86_64::RA,
);
for cmd in layout.initial_commands.iter() {
if let Some(instr) = to_cfi(isa, cmd, &mut cfa_def_reg, &mut cfa_def_offset)
{
cie.add_instruction(instr);
}
}
let cie_id = frames.add_cie(cie);
*v.insert((cie_id, cfa_def_reg, cfa_def_offset))
}
}
};
let f_len = f.1 as u32;
let mut fde = FDEEntry::new(
Address::Symbol {
symbol: i,
addend: 0,
},
f_len,
);
for (offset, cmd) in layout.commands.into_iter() {
if let Some(instr) = to_cfi(isa, cmd, &mut cfa_def_reg, &mut cfa_def_offset) {
fde.add_instruction(*offset as u32, instr);
}
}
frames.add_fde(cie_id, fde);
}
Ok(Some(frames))
}

21
crates/debug/src/lib.rs
View File

@@ -2,17 +2,19 @@
#![allow(clippy::cast_ptr_alignment)]
use crate::frame::get_debug_frame_bytes;
use anyhow::Error;
use faerie::{Artifact, Decl};
use more_asserts::assert_gt;
use target_lexicon::BinaryFormat;
use wasmtime_environ::isa::TargetIsa;
use wasmtime_environ::{ModuleAddressMap, ModuleVmctxInfo, ValueLabelsRanges};
use wasmtime_environ::{FrameLayouts, ModuleAddressMap, ModuleVmctxInfo, ValueLabelsRanges};
pub use crate::read_debuginfo::{read_debuginfo, DebugInfoData, WasmFileInfo};
pub use crate::transform::transform_dwarf;
pub use crate::write_debuginfo::{emit_dwarf, ResolvedSymbol, SymbolResolver};
mod frame;
mod gc;
mod read_debuginfo;
mod transform;
@@ -33,10 +35,21 @@ pub fn emit_debugsections(
debuginfo_data: &DebugInfoData,
at: &ModuleAddressMap,
ranges: &ValueLabelsRanges,
frame_layouts: &FrameLayouts,
) -> Result<(), Error> {
let resolver = FunctionRelocResolver {};
let dwarf = transform_dwarf(isa, debuginfo_data, at, vmctx_info, ranges)?;
emit_dwarf(obj, dwarf, &resolver)?;
let max = at.values().map(|v| v.body_len).fold(0, usize::max);
let mut funcs_bodies = Vec::with_capacity(max as usize);
funcs_bodies.resize(max as usize, 0);
let funcs = at
.values()
.map(|v| (::std::ptr::null(), v.body_len))
.collect::<Vec<(*const u8, usize)>>();
let frames = get_debug_frame_bytes(&funcs, isa, frame_layouts)?;
emit_dwarf(obj, dwarf, &resolver, frames)?;
Ok(())
}
@@ -57,6 +70,7 @@ pub fn emit_debugsections_image(
vmctx_info: &ModuleVmctxInfo,
at: &ModuleAddressMap,
ranges: &ValueLabelsRanges,
frame_layouts: &FrameLayouts,
funcs: &[(*const u8, usize)],
) -> Result<Vec<u8>, Error> {
let func_offsets = &funcs
@@ -79,7 +93,8 @@ pub fn emit_debugsections_image(
let body = unsafe { std::slice::from_raw_parts(segment_body.0, segment_body.1) };
obj.declare_with("all", Decl::function(), body.to_vec())?;
emit_dwarf(&mut obj, dwarf, &resolver)?;
let frames = get_debug_frame_bytes(funcs, isa, frame_layouts)?;
emit_dwarf(&mut obj, dwarf, &resolver, frames)?;
// LLDB is too "magical" about mach-o, generating elf
let mut bytes = obj.emit_as(BinaryFormat::Elf)?;

62
crates/debug/src/transform/expression.rs
View File

@@ -1,11 +1,12 @@
use super::address_transform::AddressTransform;
use anyhow::{bail, Context, Error, Result};
use gimli::{self, write, Expression, Operation, Reader, ReaderOffset, Register, X86_64};
use super::map_reg::map_reg;
use anyhow::{Context, Error, Result};
use gimli::{self, write, Expression, Operation, Reader, ReaderOffset, X86_64};
use more_asserts::{assert_le, assert_lt};
use std::collections::{HashMap, HashSet};
use wasmtime_environ::entity::EntityRef;
use wasmtime_environ::ir::{StackSlots, ValueLabel, ValueLabelsRanges, ValueLoc};
use wasmtime_environ::isa::{RegUnit, TargetIsa};
use wasmtime_environ::isa::TargetIsa;
use wasmtime_environ::wasm::{get_vmctx_value_label, DefinedFuncIndex};
use wasmtime_environ::ModuleMemoryOffset;
@@ -70,61 +71,6 @@ impl<'a> CompiledExpression<'a> {
}
}
fn map_reg(isa: &dyn TargetIsa, reg: RegUnit) -> Result<Register> {
// TODO avoid duplication with fde.rs
assert!(isa.name() == "x86" && isa.pointer_bits() == 64);
// Mapping from https://github.com/bytecodealliance/cranelift/pull/902 by @iximeow
const X86_GP_REG_MAP: [gimli::Register; 16] = [
X86_64::RAX,
X86_64::RCX,
X86_64::RDX,
X86_64::RBX,
X86_64::RSP,
X86_64::RBP,
X86_64::RSI,
X86_64::RDI,
X86_64::R8,
X86_64::R9,
X86_64::R10,
X86_64::R11,
X86_64::R12,
X86_64::R13,
X86_64::R14,
X86_64::R15,
];
const X86_XMM_REG_MAP: [gimli::Register; 16] = [
X86_64::XMM0,
X86_64::XMM1,
X86_64::XMM2,
X86_64::XMM3,
X86_64::XMM4,
X86_64::XMM5,
X86_64::XMM6,
X86_64::XMM7,
X86_64::XMM8,
X86_64::XMM9,
X86_64::XMM10,
X86_64::XMM11,
X86_64::XMM12,
X86_64::XMM13,
X86_64::XMM14,
X86_64::XMM15,
];
let reg_info = isa.register_info();
let bank = reg_info.bank_containing_regunit(reg).unwrap();
match bank.name {
"IntRegs" => {
// x86 GP registers have a weird mapping to DWARF registers, so we use a
// lookup table.
Ok(X86_GP_REG_MAP[(reg - bank.first_unit) as usize])
}
"FloatRegs" => Ok(X86_XMM_REG_MAP[(reg - bank.first_unit) as usize]),
bank_name => {
bail!("unsupported register bank: {}", bank_name);
}
}
}
fn translate_loc(
loc: ValueLoc,
frame_info: Option<&FunctionFrameInfo>,

58
crates/debug/src/transform/map_reg.rs Normal file
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@@ -0,0 +1,58 @@
use anyhow::{bail, Result};
use gimli::{Register, X86_64};
use wasmtime_environ::isa::{RegUnit, TargetIsa};
pub(crate) fn map_reg(isa: &dyn TargetIsa, reg: RegUnit) -> Result<Register> {
// TODO avoid duplication with fde.rs
assert!(isa.name() == "x86" && isa.pointer_bits() == 64);
// Mapping from https://github.com/bytecodealliance/cranelift/pull/902 by @iximeow
const X86_GP_REG_MAP: [Register; 16] = [
X86_64::RAX,
X86_64::RCX,
X86_64::RDX,
X86_64::RBX,
X86_64::RSP,
X86_64::RBP,
X86_64::RSI,
X86_64::RDI,
X86_64::R8,
X86_64::R9,
X86_64::R10,
X86_64::R11,
X86_64::R12,
X86_64::R13,
X86_64::R14,
X86_64::R15,
];
const X86_XMM_REG_MAP: [Register; 16] = [
X86_64::XMM0,
X86_64::XMM1,
X86_64::XMM2,
X86_64::XMM3,
X86_64::XMM4,
X86_64::XMM5,
X86_64::XMM6,
X86_64::XMM7,
X86_64::XMM8,
X86_64::XMM9,
X86_64::XMM10,
X86_64::XMM11,
X86_64::XMM12,
X86_64::XMM13,
X86_64::XMM14,
X86_64::XMM15,
];
let reg_info = isa.register_info();
let bank = reg_info.bank_containing_regunit(reg).unwrap();
match bank.name {
"IntRegs" => {
// x86 GP registers have a weird mapping to DWARF registers, so we use a
// lookup table.
Ok(X86_GP_REG_MAP[(reg - bank.first_unit) as usize])
}
"FloatRegs" => Ok(X86_XMM_REG_MAP[(reg - bank.first_unit) as usize]),
bank_name => {
bail!("unsupported register bank: {}", bank_name);
}
}
}

2
crates/debug/src/transform/mod.rs
View File

@@ -14,11 +14,13 @@ use wasmtime_environ::isa::TargetIsa;
use wasmtime_environ::{ModuleAddressMap, ModuleVmctxInfo, ValueLabelsRanges};
pub use address_transform::AddressTransform;
pub(crate) use map_reg::map_reg;
mod address_transform;
mod attr;
mod expression;
mod line_program;
mod map_reg;
mod range_info_builder;
mod refs;
mod simulate;

27
crates/debug/src/write_debuginfo.rs
View File

@@ -1,6 +1,6 @@
use faerie::artifact::{Decl, SectionKind};
use faerie::*;
use gimli::write::{Address, Dwarf, EndianVec, Result, Sections, Writer};
use gimli::write::{Address, DebugFrame, Dwarf, EndianVec, FrameTable, Result, Sections, Writer};
use gimli::{RunTimeEndian, SectionId};
#[derive(Clone)]
@@ -24,6 +24,7 @@ pub fn emit_dwarf(
artifact: &mut Artifact,
mut dwarf: Dwarf,
symbol_resolver: &dyn SymbolResolver,
frames: Option<FrameTable>,
) -> anyhow::Result<()> {
let endian = RunTimeEndian::Little;
@@ -52,6 +53,30 @@ pub fn emit_dwarf(
}
Ok(())
})?;
if let Some(frames) = frames {
let mut debug_frame = DebugFrame::from(WriterRelocate::new(endian, symbol_resolver));
frames.write_debug_frame(&mut debug_frame).unwrap();
artifact.declare_with(
SectionId::DebugFrame.name(),
Decl::section(SectionKind::Debug),
debug_frame.writer.take(),
)?;
for reloc in &debug_frame.relocs {
artifact.link_with(
faerie::Link {
from: SectionId::DebugFrame.name(),
to: &reloc.name,
at: u64::from(reloc.offset),
},
faerie::Reloc::Debug {
size: reloc.size,
addend: reloc.addend as i32,
},
)?;
}
}
Ok(())
}