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Read version of rustc that compiled proc macro

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With Jay Somedon <jay.somedon@outlook.com>
This commit is contained in:
Jay Somedon 2020-12-11 22:14:42 +08:00 committed by Edwin Cheng
parent 7275750e42
commit 6608acef71
3 changed files with 100 additions and 12 deletions
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28
Cargo.lock generated
View file

@ -80,7 +80,7 @@ dependencies = [
"cfg-if",
"libc",
"miniz_oxide",
"object",
"object 0.23.0",
"rustc-demangle",
]
@ -1008,6 +1008,16 @@ dependencies = [
"libc",
]
[[package]]
name = "object"
version = "0.22.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8d3b63360ec3cb337817c2dbd47ab4a0f170d285d8e5a2064600f3def1402397"
dependencies = [
"flate2",
"wasmparser",
]
[[package]]
name = "object"
version = "0.23.0"
@ -1154,8 +1164,10 @@ dependencies = [
"crossbeam-channel",
"jod-thread",
"log",
"object 0.22.0",
"serde",
"serde_json",
"snap",
"stdx",
"tt",
]
@ -1168,7 +1180,7 @@ dependencies = [
"libloading",
"mbe",
"memmap2",
"object",
"object 0.23.0",
"proc_macro_api",
"proc_macro_test",
"serde_derive",
@ -1540,6 +1552,12 @@ dependencies = [
"serde",
]
[[package]]
name = "snap"
version = "1.0.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "dc725476a1398f0480d56cd0ad381f6f32acf2642704456f8f59a35df464b59a"
[[package]]
name = "socket2"
version = "0.3.19"
@ -1880,6 +1898,12 @@ dependencies = [
"winapi-util",
]
[[package]]
name = "wasmparser"
version = "0.57.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "32fddd575d477c6e9702484139cf9f23dcd554b06d185ed0f56c857dd3a47aa6"
[[package]]
name = "winapi"
version = "0.3.9"

2
crates/proc_macro_api/Cargo.toml
View file

@ -19,3 +19,5 @@ jod-thread = "0.1.1"
tt = { path = "../tt", version = "0.0.0" }
base_db = { path = "../base_db", version = "0.0.0" }
stdx = { path = "../stdx", version = "0.0.0" }
snap = "1"
object = "0.22.0"

82
crates/proc_macro_api/src/lib.rs
View file

@ -5,16 +5,11 @@
//! is used to provide basic infrastructure for communication between two
//! processes: Client (RA itself), Server (the external program)
mod rpc;
mod process;
pub mod msg;
mod process;
mod rpc;
use std::{
ffi::OsStr,
io,
path::{Path, PathBuf},
sync::Arc,
};
use std::{ffi::OsStr, fs::read as fsread, io::{self, Read}, path::{Path, PathBuf}, sync::Arc};
use base_db::{Env, ProcMacro};
use tt::{SmolStr, Subtree};
@ -23,6 +18,9 @@ use crate::process::{ProcMacroProcessSrv, ProcMacroProcessThread};
pub use rpc::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask, ProcMacroKind};
use object::read::{File as BinaryFile, Object, ObjectSection};
use snap::read::FrameDecoder as SnapDecoder;
#[derive(Debug, Clone)]
struct ProcMacroProcessExpander {
process: Arc<ProcMacroProcessSrv>,
@ -71,7 +69,10 @@ impl ProcMacroClient {
args: impl IntoIterator<Item = impl AsRef<OsStr>>,
) -> io::Result<ProcMacroClient> {
let (thread, process) = ProcMacroProcessSrv::run(process_path, args)?;
Ok(ProcMacroClient { process: Arc::new(process), thread })
Ok(ProcMacroClient {
process: Arc::new(process),
thread,
})
}
pub fn by_dylib_path(&self, dylib_path: &Path) -> Vec<ProcMacro> {
@ -98,8 +99,69 @@ impl ProcMacroClient {
dylib_path: dylib_path.into(),
});
ProcMacro { name, kind, expander }
ProcMacro {
name,
kind,
expander,
}
})
.collect()
}
// This is used inside self.read_version() to locate the ".rustc" section
// from a proc macro crate's binary file.
fn read_section<'a>(&self, dylib_binary: &'a [u8], section_name: &str) -> &'a [u8] {
BinaryFile::parse(dylib_binary)
.unwrap()
.section_by_name(section_name)
.unwrap()
.data()
.unwrap()
}
// Check the version of rustc that was used to compile a proc macro crate's
// binary file.
// A proc macro crate binary's ".rustc" section has following byte layout:
// * [b'r',b'u',b's',b't',0,0,0,5] is the first 8 bytes
// * ff060000 734e6150 is followed, it's the snappy format magic bytes,
// means bytes from here(including this sequence) are compressed in
// snappy compression format. Version info is here inside, so decompress
// this.
// The bytes you get after decompressing the snappy format portion has
// following layout:
// * [b'r',b'u',b's',b't',0,0,0,5] is the first 8 bytes(again)
// * [crate root bytes] next 4 bytes is to store crate root position,
// according to rustc's source code comment
// * [length byte] next 1 byte tells us how many bytes we should read next
// for the version string's utf8 bytes
// * [version string bytes encoded in utf8] <- GET THIS BOI
// * [some more bytes that we don really care but still there] :-)
// Check this issue for more about the bytes layout:
// https://github.com/rust-analyzer/rust-analyzer/issues/6174
fn read_version(&self, dylib_path: &Path) -> String {
let dylib_binary = fsread(dylib_path).unwrap();
let dot_rustc = self.read_section(&dylib_binary, ".rustc");
let snappy_portion = &dot_rustc[8..];
let mut snappy_decoder = SnapDecoder::new(snappy_portion);
// the bytes before version string bytes, so this basically is:
// 8 bytes for [b'r',b'u',b's',b't',0,0,0,5]
// 4 bytes for [crate root bytes]
// 1 byte for length of version string
// so 13 bytes in total, and we should check the 13th byte
// to know the length
let mut bytes_before_version = [0u8; 13];
snappy_decoder
.read_exact(&mut bytes_before_version)
.unwrap();
let length = bytes_before_version[12]; // what? can't use -1 indexing?
let mut version_string_utf8 = vec![0u8; length as usize];
snappy_decoder.read_exact(&mut version_string_utf8).unwrap();
let version_string = String::from_utf8(version_string_utf8).unwrap();
version_string
}
}