T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fuzz: allow generating shared memories (#4266)

Browse Source 
`wasm-smith` v0.11 has support for generating shared memories when the
`threads_enabled` configuration flag is set. This change turns on that
flag occasionally. This also upgrades `wasm-smith` to v0.11.1 to always
generate shared memory with a known maximum.
This commit is contained in:
Andrew Brown
2022-06-14 09:50:41 -07:00
committed by GitHub
parent 72f0e46fdb
commit 22e13fee1d
5 changed files with 50 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
crates/fuzzing/src/generators.rs
View File

@@ -163,6 +163,11 @@ impl<'a> Arbitrary<'a> for Config {
..
} = &config.wasmtime.strategy
{
// If the pooling allocator is used, do not allow shared memory to
// be created. FIXME: see
// https://github.com/bytecodealliance/wasmtime/issues/4244.
config.module_config.config.threads_enabled = false;
// Force the use of a normal memory config when using the pooling allocator and
// limit the static memory maximum to be the same as the pooling allocator's memory
// page limit.
@@ -296,6 +301,7 @@ impl Config {
config.reference_types_enabled = false;
config.simd_enabled = false;
config.memory64_enabled = false;
config.threads_enabled = false;
// If using the pooling allocator, update the instance limits too
if let InstanceAllocationStrategy::Pooling {
@@ -343,11 +349,11 @@ impl Config {
pub fn set_spectest_compliant(&mut self) {
let config = &mut self.module_config.config;
config.memory64_enabled = false;
config.simd_enabled = false;
config.bulk_memory_enabled = true;
config.reference_types_enabled = true;
config.multi_value_enabled = true;
config.simd_enabled = true;
config.threads_enabled = false;
config.max_memories = 1;
config.max_tables = 5;
@@ -388,6 +394,7 @@ impl Config {
.wasm_multi_memory(self.module_config.config.max_memories > 1)
.wasm_simd(self.module_config.config.simd_enabled)
.wasm_memory64(self.module_config.config.memory64_enabled)
.wasm_threads(self.module_config.config.threads_enabled)
.wasm_backtrace(self.wasmtime.wasm_backtraces)
.cranelift_nan_canonicalization(self.wasmtime.canonicalize_nans)
.cranelift_opt_level(self.wasmtime.opt_level.to_wasmtime())
@@ -434,21 +441,33 @@ impl Config {
}
}
match &self.wasmtime.memory_config {
MemoryConfig::Normal(memory_config) => {
cfg.static_memory_maximum_size(
memory_config.static_memory_maximum_size.unwrap_or(0),
)
.static_memory_guard_size(memory_config.static_memory_guard_size.unwrap_or(0))
.dynamic_memory_guard_size(memory_config.dynamic_memory_guard_size.unwrap_or(0))
.guard_before_linear_memory(memory_config.guard_before_linear_memory);
}
MemoryConfig::CustomUnaligned => {
cfg.with_host_memory(Arc::new(UnalignedMemoryCreator))
.static_memory_maximum_size(0)
.dynamic_memory_guard_size(0)
.static_memory_guard_size(0)
.guard_before_linear_memory(false);
// Vary the memory configuration, but only if threads are not enabled.
// When the threads proposal is enabled we might generate shared memory,
// which is less amenable to different memory configurations:
// - shared memories are required to be "static" so fuzzing the various
// memory configurations will mostly result in uninteresting errors.
// The interesting part about shared memories is the runtime so we
// don't fuzz non-default settings.
// - shared memories are required to be aligned which means that the
// `CustomUnaligned` variant isn't actually safe to use with a shared
// memory.
if !self.module_config.config.threads_enabled {
match &self.wasmtime.memory_config {
MemoryConfig::Normal(memory_config) => {
cfg.static_memory_maximum_size(
memory_config.static_memory_maximum_size.unwrap_or(0),
)
.static_memory_guard_size(memory_config.static_memory_guard_size.unwrap_or(0))
.dynamic_memory_guard_size(memory_config.dynamic_memory_guard_size.unwrap_or(0))
.guard_before_linear_memory(memory_config.guard_before_linear_memory);
}
MemoryConfig::CustomUnaligned => {
cfg.with_host_memory(Arc::new(UnalignedMemoryCreator))
.static_memory_maximum_size(0)
.dynamic_memory_guard_size(0)
.static_memory_guard_size(0)
.guard_before_linear_memory(false);
}
}
}
@@ -634,6 +653,11 @@ impl<'a> Arbitrary<'a> for ModuleConfig {
// `SwarmConfig::arbitrary`.
config.memory64_enabled = u.arbitrary()?;
// Allow the threads proposal if memory64 is not already enabled. FIXME:
// to allow threads and memory64 to coexist, see
// https://github.com/bytecodealliance/wasmtime/issues/4267.
config.threads_enabled = !config.memory64_enabled && u.arbitrary()?;
Ok(ModuleConfig { config })
}
}