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Add a compilation section to disable address maps (#3598)

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* Add a compilation section to disable address maps

This commit adds a new `Config::generate_address_map` compilation
setting which is used to disable emission of the `.wasmtime.addrmap`
section of compiled artifacts. This section is currently around the size
of the entire `.text` section itself unfortunately and for size reasons
may wish to be omitted. Functionality-wise all that is lost is knowing
the precise wasm module offset address of a faulting instruction or in a
backtrace of instructions. This also means that if the module has DWARF
debugging information available with it Wasmtime isn't able to produce a
filename and line number in the backtrace.

This option remains enabled by default. This option may not be needed in
the future with #3547 perhaps, but in the meantime it seems reasonable
enough to support a configuration mode where the section is entirely
omitted if the smallest module possible is desired.

* Fix some CI issues

* Update tests/all/traps.rs

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>

* Do less work in compilation for address maps

But only when disabled

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>
This commit is contained in:
Alex Crichton
2021-12-13 13:48:05 -06:00
committed by GitHub
parent c1c4c59670
commit f1225dfd93
12 changed files with 147 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
crates/cranelift/src/compiler.rs
View File

@@ -63,6 +63,7 @@ impl Compiler {
context: &Context,
data: &FunctionBodyData<'_>,
body_len: u32,
tunables: &Tunables,
) -> FunctionAddressMap {
// Generate artificial srcloc for function start/end to identify boundary
// within module.
@@ -75,17 +76,21 @@ impl Compiler {
// New-style backend: we have a `MachCompileResult` that will give us `MachSrcLoc` mapping
// tuples.
let instructions = collect_address_maps(
body_len,
context
.mach_compile_result
.as_ref()
.unwrap()
.buffer
.get_srclocs_sorted()
.into_iter()
.map(|&MachSrcLoc { start, end, loc }| (loc, start, (end - start))),
);
let instructions = if tunables.generate_address_map {
collect_address_maps(
body_len,
context
.mach_compile_result
.as_ref()
.unwrap()
.buffer
.get_srclocs_sorted()
.into_iter()
.map(|&MachSrcLoc { start, end, loc }| (loc, start, (end - start))),
)
} else {
Vec::new()
};
FunctionAddressMap {
instructions: instructions.into(),
@@ -179,7 +184,7 @@ impl wasmtime_environ::Compiler for Compiler {
.map_err(|error| CompileError::Codegen(pretty_error(&context.func, error)))?;
let address_transform =
self.get_function_address_map(&context, &input, code_buf.len() as u32);
self.get_function_address_map(&context, &input, code_buf.len() as u32, tunables);
let ranges = if tunables.generate_native_debuginfo {
Some(
@@ -221,7 +226,7 @@ impl wasmtime_environ::Compiler for Compiler {
translation: &ModuleTranslation,
types: &TypeTables,
funcs: PrimaryMap<DefinedFuncIndex, Box<dyn Any + Send>>,
emit_dwarf: bool,
tunables: &Tunables,
obj: &mut Object<'static>,
) -> Result<(PrimaryMap<DefinedFuncIndex, FunctionInfo>, Vec<Trampoline>)> {
let funcs: crate::CompiledFunctions = funcs
@@ -244,7 +249,9 @@ impl wasmtime_environ::Compiler for Compiler {
let mut func_starts = Vec::with_capacity(funcs.len());
for (i, func) in funcs.iter() {
let range = builder.func(i, func);
addrs.push(range.clone(), &func.address_map.instructions);
if tunables.generate_address_map {
addrs.push(range.clone(), &func.address_map.instructions);
}
traps.push(range.clone(), &func.traps);
func_starts.push(range.start);
if self.linkopts.padding_between_functions > 0 {
@@ -266,7 +273,7 @@ impl wasmtime_environ::Compiler for Compiler {
builder.unwind_info();
if emit_dwarf && funcs.len() > 0 {
if tunables.generate_native_debuginfo && funcs.len() > 0 {
let ofs = VMOffsets::new(
self.isa
.triple()
@@ -297,7 +304,10 @@ impl wasmtime_environ::Compiler for Compiler {
}
builder.finish()?;
addrs.append_to(obj);
if tunables.generate_address_map {
addrs.append_to(obj);
}
traps.append_to(obj);
Ok((