fc62d4ad65
* Cranelift: Make `heap_addr` return calculated `base + index + offset`
Rather than return just the `base + index`.
(Note: I've chosen to use the nomenclature "index" for the dynamic operand and
"offset" for the static immediate.)
This move the addition of the `offset` into `heap_addr`, instead of leaving it
for the subsequent memory operation, so that we can Spectre-guard the full
address, and not allow speculative execution to read the first 4GiB of memory.
Before this commit, we were effectively doing
load(spectre_guard(base + index) + offset)
Now we are effectively doing
load(spectre_guard(base + index + offset))
Finally, this also corrects `heap_addr`'s documented semantics to say that it
returns an address that will trap on access if `index + offset + access_size` is
out of bounds for the given heap, rather than saying that the `heap_addr` itself
will trap. This matches the implemented behavior for static memories, and after
https://github.com/bytecodealliance/wasmtime/pull/5190 lands (which is blocked
on this commit) will also match the implemented behavior for dynamic memories.
* Update heap_addr docs
* Factor out `offset + size` to a helper
52 lines
1.4 KiB
Rust
52 lines
1.4 KiB
Rust
//! Test command for testing the LICM pass.
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//!
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//! The `licm` test command runs each function through the LICM pass after ensuring
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//! that all instructions are legal for the target.
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//!
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//! The resulting function is sent to `filecheck`.
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use crate::subtest::{run_filecheck, Context, SubTest};
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use cranelift_codegen;
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use cranelift_codegen::ir::Function;
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use cranelift_reader::TestCommand;
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use std::borrow::Cow;
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struct TestLICM;
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pub fn subtest(parsed: &TestCommand) -> anyhow::Result<Box<dyn SubTest>> {
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assert_eq!(parsed.command, "licm");
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if !parsed.options.is_empty() {
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anyhow::bail!("No options allowed on {}", parsed);
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}
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Ok(Box::new(TestLICM))
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}
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impl SubTest for TestLICM {
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fn name(&self) -> &'static str {
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"licm"
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}
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fn needs_isa(&self) -> bool {
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true
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}
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fn is_mutating(&self) -> bool {
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true
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}
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fn run(&self, func: Cow<Function>, context: &Context) -> anyhow::Result<()> {
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let isa = context.isa.expect("LICM needs an ISA");
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let mut comp_ctx = cranelift_codegen::Context::for_function(func.into_owned());
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comp_ctx.flowgraph();
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comp_ctx.compute_loop_analysis();
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comp_ctx
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.licm(isa)
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.map_err(|e| crate::pretty_anyhow_error(&comp_ctx.func, Into::into(e)))?;
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let text = comp_ctx.func.display().to_string();
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log::debug!("Post-LICM CLIF:\n{}", text);
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run_filecheck(&text, context)
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}
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}
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