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Use trampolines for all libcalls in engine-universal and engine-dylib #2748

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merged 1 commit into from Jan 20, 2022
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5 changes: 0 additions & 5 deletions .cargo/config.toml

This file was deleted.

1 change: 1 addition & 0 deletions .github/workflows/test-sys.yaml
Expand Up @@ -166,6 +166,7 @@ jobs:
shell: bash
- name: Setup Rust target
run: |
mkdir -p .cargo
cat << EOF > .cargo/config.toml
[build]
target = "${{ matrix.target }}"
Expand Down
40 changes: 37 additions & 3 deletions Cargo.lock

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

9 changes: 4 additions & 5 deletions Makefile
Expand Up @@ -211,14 +211,13 @@ compilers_engines :=
ifeq ($(ENABLE_CRANELIFT), 1)
compilers_engines += cranelift-universal

ifneq (, $(filter 1, $(IS_DARWIN) $(IS_LINUX)))
ifneq (, $(filter 1, $(IS_WINDOWS) $(IS_DARWIN) $(IS_LINUX)))
ifeq ($(IS_AMD64), 1)
ifneq ($(LIBC), musl)
compilers_engines += cranelift-dylib
endif
else ifeq ($(IS_AARCH64), 1)
# The object crate doesn't support yet Darwin + Aarch64 relocations
ifneq ($(IS_DARWIN), 1)
ifneq ($(LIBC), musl)
compilers_engines += cranelift-dylib
endif
endif
Expand All @@ -230,7 +229,7 @@ endif
##

ifeq ($(ENABLE_LLVM), 1)
ifneq (, $(filter 1, $(IS_DARWIN) $(IS_LINUX)))
ifneq (, $(filter 1, $(IS_WINDOWS) $(IS_DARWIN) $(IS_LINUX)))
ifeq ($(IS_AMD64), 1)
compilers_engines += llvm-universal
compilers_engines += llvm-dylib
Expand All @@ -246,7 +245,7 @@ endif
##

ifeq ($(ENABLE_SINGLEPASS), 1)
ifneq (, $(filter 1, $(IS_DARWIN) $(IS_LINUX)))
ifneq (, $(filter 1, $(IS_WINDOWS) $(IS_DARWIN) $(IS_LINUX)))
ifeq ($(IS_AMD64), 1)
compilers_engines += singlepass-universal
endif
Expand Down
1 change: 1 addition & 0 deletions deny.toml
Expand Up @@ -179,6 +179,7 @@ skip = [
{ name = "semver-parser", version = "=0.7.0" },
{ name = "rustc_version", version = "=0.2.3" },
{ name = "itoa", version = "=0.4.8" },
{ name = "object", version = "=0.27.1" },
]
# Similarly to `skip` allows you to skip certain crates during duplicate
# detection. Unlike skip, it also includes the entire tree of transitive
Expand Down
1 change: 0 additions & 1 deletion lib/compiler-cranelift/src/compiler.rs
Expand Up @@ -295,7 +295,6 @@ impl Compiler for CraneliftCompiler {
function_call_trampolines,
dynamic_function_trampolines,
dwarf,
None,
))
}
}
6 changes: 6 additions & 0 deletions lib/compiler-cranelift/src/config.rs
Expand Up @@ -135,6 +135,12 @@ impl Cranelift {
flags.enable("is_pic").expect("should be a valid flag");
}

// We set up libcall trampolines in engine-dylib and engine-universal.
// These trampolines are always reachable through short jumps.
flags
.enable("use_colocated_libcalls")
.expect("should be a valid flag");

// Invert cranelift's default-on verification to instead default off.
let enable_verifier = if self.enable_verifier {
"true"
Expand Down
4 changes: 1 addition & 3 deletions lib/compiler-cranelift/src/func_environ.rs
Expand Up @@ -1132,9 +1132,7 @@ impl<'module_environment> BaseFuncEnvironment for FuncEnvironment<'module_enviro
Ok(func.import_function(ir::ExtFuncData {
name,
signature,
// We currently allocate all code segments independently, so nothing
// is colocated.
colocated: false,
colocated: true,
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I might be missing some context on what colocated means. Why is this necessary?

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This is necessary to avoid text relocations. It means that all libcalls are reachable through normal call instructions (+/- 2G on x86, +/- 128M on aarch64) so it doesn't need to load the target from memory and do an indirect call. This is true since we generate trampolines that are near the compiled code.

The text relocations are due to the way Cranelift generates indirect calls: it places the target as a pointer in the .text section (since it puts everything in .text) and marks it with a relocation so the linker fills in the libcall address at load time.

}))
}

Expand Down
1 change: 1 addition & 0 deletions lib/compiler-cranelift/src/translator/translation_utils.rs
Expand Up @@ -90,6 +90,7 @@ pub fn irreloc_to_relocationkind(reloc: Reloc) -> RelocationKind {
Reloc::X86CallPCRel4 => RelocationKind::X86CallPCRel4,
Reloc::X86CallPLTRel4 => RelocationKind::X86CallPLTRel4,
Reloc::X86GOTPCRel4 => RelocationKind::X86GOTPCRel4,
Reloc::Arm64Call => RelocationKind::Arm64Call,
_ => panic!("The relocation {} is not yet supported.", reloc),
}
}
Expand Down
6 changes: 4 additions & 2 deletions lib/compiler-llvm/Cargo.toml
Expand Up @@ -12,12 +12,14 @@ readme = "README.md"
edition = "2018"

[dependencies]
wasmer-compiler = { path = "../compiler", version = "=2.1.1", features = ["translator"] }
wasmer-compiler = { path = "../compiler", version = "=2.1.1", features = [
"translator",
] }
wasmer-vm = { path = "../vm", version = "=2.1.1" }
wasmer-types = { path = "../types", version = "=2.1.1" }
target-lexicon = { version = "0.12.2", default-features = false }
smallvec = "1.6"
object = { version = "0.27", default-features = false, features = ["read"] }
object = { version = "0.28.3", default-features = false, features = ["read"] }
libc = { version = "^0.2", default-features = false }
byteorder = "1"
itertools = "0.10"
Expand Down
39 changes: 3 additions & 36 deletions lib/compiler-llvm/src/compiler.rs
Expand Up @@ -12,10 +12,9 @@ use rayon::iter::ParallelBridge;
use rayon::prelude::{IntoParallelIterator, IntoParallelRefIterator, ParallelIterator};
use std::sync::Arc;
use wasmer_compiler::{
Architecture, Compilation, CompileError, CompileModuleInfo, Compiler, CustomSection,
CustomSectionProtection, Dwarf, FunctionBodyData, ModuleMiddleware, ModuleTranslationState,
RelocationTarget, SectionBody, SectionIndex, Symbol, SymbolRegistry, Target,
TrampolinesSection,
Compilation, CompileError, CompileModuleInfo, Compiler, CustomSection, CustomSectionProtection,
Dwarf, FunctionBodyData, ModuleMiddleware, ModuleTranslationState, RelocationTarget,
SectionBody, SectionIndex, Symbol, SymbolRegistry, Target,
};
use wasmer_types::entity::{EntityRef, PrimaryMap};
use wasmer_types::{FunctionIndex, LocalFunctionIndex, SignatureIndex};
Expand Down Expand Up @@ -305,37 +304,6 @@ impl Compiler for LLVMCompiler {
})
.collect::<PrimaryMap<LocalFunctionIndex, _>>();

let trampolines = match target.triple().architecture {
Architecture::Aarch64(_) => {
let nj = 16;
// We create a jump to an absolute 64bits address
// using x17 as a scratch register, SystemV declare both x16 and x17 as Intra-Procedural scratch register
// but Apple ask to just not use x16
// LDR x17, #8 51 00 00 58
// BR x17 20 02 1f d6
// JMPADDR 00 00 00 00 00 00 00 00
let onejump = [
0x51, 0x00, 0x00, 0x58, 0x20, 0x02, 0x1f, 0xd6, 0, 0, 0, 0, 0, 0, 0, 0,
];
let trampolines = Some(TrampolinesSection::new(
SectionIndex::from_u32(module_custom_sections.len() as u32),
nj,
onejump.len(),
));
let mut alljmps = vec![];
for _ in 0..nj {
alljmps.extend(onejump.iter().copied());
}
module_custom_sections.push(CustomSection {
protection: CustomSectionProtection::ReadExecute,
bytes: SectionBody::new_with_vec(alljmps),
relocations: vec![],
});
trampolines
}
_ => None,
};

let dwarf = if !frame_section_bytes.is_empty() {
let dwarf = Some(Dwarf::new(SectionIndex::from_u32(
module_custom_sections.len() as u32,
Expand Down Expand Up @@ -400,7 +368,6 @@ impl Compiler for LLVMCompiler {
function_call_trampolines,
dynamic_function_trampolines,
dwarf,
trampolines,
))
}
}
1 change: 0 additions & 1 deletion lib/compiler-singlepass/src/compiler.rs
Expand Up @@ -187,7 +187,6 @@ impl Compiler for SinglepassCompiler {
function_call_trampolines,
dynamic_function_trampolines,
None,
None,
))
}
}
Expand Down
37 changes: 0 additions & 37 deletions lib/compiler/src/function.rs
Expand Up @@ -109,33 +109,6 @@ impl Dwarf {
}
}

/// Trampolines section used by ARM short jump (26bits)
#[cfg_attr(feature = "enable-serde", derive(Deserialize, Serialize))]
#[cfg_attr(
feature = "enable-rkyv",
derive(RkyvSerialize, RkyvDeserialize, Archive)
)]
#[derive(Debug, PartialEq, Eq, Clone, MemoryUsage)]
pub struct TrampolinesSection {
/// SectionIndex for the actual Trampolines code
pub section_index: SectionIndex,
/// Number of jump slots in the section
pub slots: usize,
/// Slot size
pub size: usize,
}

impl TrampolinesSection {
/// Creates a `Trampolines` struct with the indice for its section, and number of slots and size of slot
pub fn new(section_index: SectionIndex, slots: usize, size: usize) -> Self {
Self {
section_index,
slots,
size,
}
}
}

/// The result of compiling a WebAssembly module's functions.
#[cfg_attr(feature = "enable-serde", derive(Deserialize, Serialize))]
#[derive(Debug, PartialEq, Eq)]
Expand Down Expand Up @@ -182,9 +155,6 @@ pub struct Compilation {

/// Section ids corresponding to the Dwarf debug info
debug: Option<Dwarf>,

/// Trampolines for the arch that needs it
trampolines: Option<TrampolinesSection>,
}

impl Compilation {
Expand All @@ -195,15 +165,13 @@ impl Compilation {
function_call_trampolines: PrimaryMap<SignatureIndex, FunctionBody>,
dynamic_function_trampolines: PrimaryMap<FunctionIndex, FunctionBody>,
debug: Option<Dwarf>,
trampolines: Option<TrampolinesSection>,
) -> Self {
Self {
functions,
custom_sections,
function_call_trampolines,
dynamic_function_trampolines,
debug,
trampolines,
}
}

Expand Down Expand Up @@ -281,11 +249,6 @@ impl Compilation {
pub fn get_debug(&self) -> Option<Dwarf> {
self.debug.clone()
}

/// Returns the Trampilines info.
pub fn get_trampolines(&self) -> Option<TrampolinesSection> {
self.trampolines.clone()
}
}

impl<'a> IntoIterator for &'a Compilation {
Expand Down
2 changes: 1 addition & 1 deletion lib/compiler/src/lib.rs
Expand Up @@ -74,7 +74,7 @@ pub use crate::error::{
};
pub use crate::function::{
Compilation, CompiledFunction, CompiledFunctionFrameInfo, CustomSections, Dwarf, FunctionBody,
Functions, TrampolinesSection,
Functions,
};
pub use crate::jump_table::{JumpTable, JumpTableOffsets};
pub use crate::module::CompileModuleInfo;
Expand Down
2 changes: 2 additions & 0 deletions lib/engine-dylib/Cargo.toml
Expand Up @@ -26,6 +26,8 @@ which = "4.0"
rkyv = "0.7.20"
loupe = "0.1"
enumset = "1.0"
enum-iterator = "0.7.0"
object = { version = "0.28.3", default-features = false, features = ["write"] }

[features]
# Enable the `compiler` feature if you want the engine to compile
Expand Down