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Refactor some internal accessors of Instance (#3021)

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This commit removes some one-use methods to inline them at their use
site, and otherwise adds bounds checks to other functions like
`imported_function` where previously the `FuncIndex` may have been
accidentally out of bounds, which would cause memory unsafety. There's
no actual bug this was fixing, just trying to improve the safety of the
code internally a little.
This commit is contained in:
Alex Crichton
2021-06-23 12:12:38 -05:00
committed by GitHub
parent 83007b79e3
commit 324d80729a
2 changed files with 41 additions and 110 deletions
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20
crates/runtime/src/instance/allocator.rs
View File

@@ -4,8 +4,8 @@ use crate::memory::{DefaultMemoryCreator, Memory};
use crate::table::Table;
use crate::traphandlers::Trap;
use crate::vmcontext::{
VMBuiltinFunctionsArray, VMCallerCheckedAnyfunc, VMContext, VMFunctionBody, VMFunctionImport,
VMGlobalDefinition, VMGlobalImport, VMMemoryImport, VMSharedSignatureIndex, VMTableImport,
VMBuiltinFunctionsArray, VMCallerCheckedAnyfunc, VMContext, VMFunctionBody, VMGlobalDefinition,
VMSharedSignatureIndex,
};
use crate::Store;
use anyhow::Result;
@@ -422,7 +422,7 @@ unsafe fn initialize_vmcontext(instance: &mut Instance, req: InstanceAllocationR
let module = &instance.module;
// Initialize shared signatures
let mut ptr = instance.signature_ids_ptr();
let mut ptr = instance.vmctx_plus_offset(instance.offsets.vmctx_signature_ids_begin());
for sig in module.types.values() {
*ptr = match sig {
ModuleType::Function(sig) => req.shared_signatures.lookup(*sig),
@@ -433,7 +433,7 @@ unsafe fn initialize_vmcontext(instance: &mut Instance, req: InstanceAllocationR
// Initialize the built-in functions
ptr::write(
instance.builtin_functions_ptr() as *mut VMBuiltinFunctionsArray,
instance.vmctx_plus_offset(instance.offsets.vmctx_builtin_functions_begin()),
VMBuiltinFunctionsArray::initialized(),
);
@@ -441,25 +441,25 @@ unsafe fn initialize_vmcontext(instance: &mut Instance, req: InstanceAllocationR
debug_assert_eq!(req.imports.functions.len(), module.num_imported_funcs);
ptr::copy(
req.imports.functions.as_ptr(),
instance.imported_functions_ptr() as *mut VMFunctionImport,
instance.vmctx_plus_offset(instance.offsets.vmctx_imported_functions_begin()),
req.imports.functions.len(),
);
debug_assert_eq!(req.imports.tables.len(), module.num_imported_tables);
ptr::copy(
req.imports.tables.as_ptr(),
instance.imported_tables_ptr() as *mut VMTableImport,
instance.vmctx_plus_offset(instance.offsets.vmctx_imported_tables_begin()),
req.imports.tables.len(),
);
debug_assert_eq!(req.imports.memories.len(), module.num_imported_memories);
ptr::copy(
req.imports.memories.as_ptr(),
instance.imported_memories_ptr() as *mut VMMemoryImport,
instance.vmctx_plus_offset(instance.offsets.vmctx_imported_memories_begin()),
req.imports.memories.len(),
);
debug_assert_eq!(req.imports.globals.len(), module.num_imported_globals);
ptr::copy(
req.imports.globals.as_ptr(),
instance.imported_globals_ptr() as *mut VMGlobalImport,
instance.vmctx_plus_offset(instance.offsets.vmctx_imported_globals_begin()),
req.imports.globals.len(),
);
@@ -490,14 +490,14 @@ unsafe fn initialize_vmcontext(instance: &mut Instance, req: InstanceAllocationR
}
// Initialize the defined tables
let mut ptr = instance.tables_ptr();
let mut ptr = instance.vmctx_plus_offset(instance.offsets.vmctx_tables_begin());
for i in 0..module.table_plans.len() - module.num_imported_tables {
ptr::write(ptr, instance.tables[DefinedTableIndex::new(i)].vmtable());
ptr = ptr.add(1);
}
// Initialize the defined memories
let mut ptr = instance.memories_ptr();
let mut ptr = instance.vmctx_plus_offset(instance.offsets.vmctx_memories_begin());
for i in 0..module.memory_plans.len() - module.num_imported_memories {
ptr::write(
ptr,