1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129

use crate::error::LinkError;
use loupe::MemoryUsage;
use std::ptr::NonNull;
use std::sync::Arc;
use wasmer_types::entity::{EntityRef, PrimaryMap};
use wasmer_types::{
    GlobalType, LocalGlobalIndex, LocalMemoryIndex, LocalTableIndex, MemoryIndex, MemoryType,
    TableIndex, TableType,
};
use wasmer_vm::MemoryError;
use wasmer_vm::{Global, Memory, ModuleInfo, Table};
use wasmer_vm::{MemoryStyle, TableStyle};
use wasmer_vm::{VMMemoryDefinition, VMTableDefinition};

/// An engine delegates the creation of memories, tables, and globals
/// to a foreign implementor of this trait.
pub trait Tunables: MemoryUsage {
    /// Construct a `MemoryStyle` for the provided `MemoryType`
    fn memory_style(&self, memory: &MemoryType) -> MemoryStyle;

    /// Construct a `TableStyle` for the provided `TableType`
    fn table_style(&self, table: &TableType) -> TableStyle;

    /// Create a memory owned by the host given a [`MemoryType`] and a [`MemoryStyle`].
    fn create_host_memory(
        &self,
        ty: &MemoryType,
        style: &MemoryStyle,
    ) -> Result<Arc<dyn Memory>, MemoryError>;

    /// Create a memory owned by the VM given a [`MemoryType`] and a [`MemoryStyle`].
    ///
    /// # Safety
    /// - `vm_definition_location` must point to a valid location in VM memory.
    unsafe fn create_vm_memory(
        &self,
        ty: &MemoryType,
        style: &MemoryStyle,
        vm_definition_location: NonNull<VMMemoryDefinition>,
    ) -> Result<Arc<dyn Memory>, MemoryError>;

    /// Create a table owned by the host given a [`TableType`] and a [`TableStyle`].
    fn create_host_table(
        &self,
        ty: &TableType,
        style: &TableStyle,
    ) -> Result<Arc<dyn Table>, String>;

    /// Create a table owned by the VM given a [`TableType`] and a [`TableStyle`].
    ///
    /// # Safety
    /// - `vm_definition_location` must point to a valid location in VM memory.
    unsafe fn create_vm_table(
        &self,
        ty: &TableType,
        style: &TableStyle,
        vm_definition_location: NonNull<VMTableDefinition>,
    ) -> Result<Arc<dyn Table>, String>;

    /// Create a global with an unset value.
    fn create_global(&self, ty: GlobalType) -> Result<Arc<Global>, String> {
        Ok(Arc::new(Global::new(ty)))
    }

    /// Allocate memory for just the memories of the current module.
    unsafe fn create_memories(
        &self,
        module: &ModuleInfo,
        memory_styles: &PrimaryMap<MemoryIndex, MemoryStyle>,
        memory_definition_locations: &[NonNull<VMMemoryDefinition>],
    ) -> Result<PrimaryMap<LocalMemoryIndex, Arc<dyn Memory>>, LinkError> {
        let num_imports = module.num_imported_memories;
        let mut memories: PrimaryMap<LocalMemoryIndex, _> =
            PrimaryMap::with_capacity(module.memories.len() - num_imports);
        for index in num_imports..module.memories.len() {
            let mi = MemoryIndex::new(index);
            let ty = &module.memories[mi];
            let style = &memory_styles[mi];
            let mdl = memory_definition_locations[index];
            memories.push(
                self.create_vm_memory(ty, style, mdl)
                    .map_err(|e| LinkError::Resource(format!("Failed to create memory: {}", e)))?,
            );
        }
        Ok(memories)
    }

    /// Allocate memory for just the tables of the current module.
    unsafe fn create_tables(
        &self,
        module: &ModuleInfo,
        table_styles: &PrimaryMap<TableIndex, TableStyle>,
        table_definition_locations: &[NonNull<VMTableDefinition>],
    ) -> Result<PrimaryMap<LocalTableIndex, Arc<dyn Table>>, LinkError> {
        let num_imports = module.num_imported_tables;
        let mut tables: PrimaryMap<LocalTableIndex, _> =
            PrimaryMap::with_capacity(module.tables.len() - num_imports);
        for index in num_imports..module.tables.len() {
            let ti = TableIndex::new(index);
            let ty = &module.tables[ti];
            let style = &table_styles[ti];
            let tdl = table_definition_locations[index];
            tables.push(
                self.create_vm_table(ty, style, tdl)
                    .map_err(LinkError::Resource)?,
            );
        }
        Ok(tables)
    }

    /// Allocate memory for just the globals of the current module,
    /// with initializers applied.
    fn create_globals(
        &self,
        module: &ModuleInfo,
    ) -> Result<PrimaryMap<LocalGlobalIndex, Arc<Global>>, LinkError> {
        let num_imports = module.num_imported_globals;
        let mut vmctx_globals = PrimaryMap::with_capacity(module.globals.len() - num_imports);

        for &global_type in module.globals.values().skip(num_imports) {
            vmctx_globals.push(
                self.create_global(global_type)
                    .map_err(LinkError::Resource)?,
            );
        }

        Ok(vmctx_globals)
    }
}