mirror of
https://github.com/odin-lang/Odin.git
synced 2026-06-19 16:42:33 +00:00
94 lines
2.8 KiB
Odin
94 lines
2.8 KiB
Odin
package rexcode_wasm_module
|
|
|
|
import "base:runtime"
|
|
import "core:strings"
|
|
import wasm "core:rexcode/wasm"
|
|
|
|
Reloc_Group :: struct {
|
|
target_section: Section_Id, // index of the section these apply to
|
|
relocs: []wasm.Relocation,
|
|
}
|
|
|
|
@(require_results)
|
|
parse_relocations :: proc(m: Module, allocator: runtime.Allocator) -> (reloc_groups: []Reloc_Group, err: Reader_Error) {
|
|
groups: [dynamic]Reloc_Group
|
|
groups.allocator = m.allocator
|
|
for sec in m.sections {
|
|
if !(sec.id == .CUSTOM && strings.has_prefix(sec.name, "reloc.")) {
|
|
continue
|
|
}
|
|
|
|
r := reader(m.data[sec.offset:][:sec.size], 0)
|
|
_ = rd_name(&r) or_return // step past the custom-section name
|
|
target := Section_Id(rd_u32(&r) or_return)
|
|
count := rd_u32(&r) or_return
|
|
|
|
out := make([]wasm.Relocation, int(count), m.allocator)
|
|
w := 0
|
|
for _ in 0..<count {
|
|
code := rd_byte(&r) or_return
|
|
offset := rd_u32(&r) or_return // offset of the field within target_section
|
|
index := rd_u32(&r) or_return // symbol / target index
|
|
addend: i32 = 0
|
|
if reloc_has_addend(code) {
|
|
addend = i32(rd_sleb(&r) or_return)
|
|
}
|
|
|
|
t := reloc_type_from_wire(code) or_continue
|
|
|
|
out[w] = wasm.Relocation{
|
|
offset = offset,
|
|
label_id = index,
|
|
addend = addend,
|
|
type = t,
|
|
size = reloc_field_size(t),
|
|
}
|
|
w += 1
|
|
}
|
|
append(&groups, Reloc_Group{target_section = target, relocs = out[:w]}) or_return
|
|
}
|
|
reloc_groups = groups[:]
|
|
return
|
|
}
|
|
|
|
relocations_destroy :: proc(groups: []Reloc_Group, allocator: runtime.Allocator) {
|
|
context.allocator = allocator
|
|
for g in groups { delete(g.relocs) }
|
|
delete(groups)
|
|
}
|
|
|
|
@(require_results)
|
|
reloc_type_from_wire :: proc(code: u8) -> (wasm.Relocation_Type, bool) {
|
|
switch code {
|
|
case 0: return .FUNCTION_INDEX_LEB, true // R_WASM_FUNCTION_INDEX_LEB
|
|
case 1: return .TABLE_INDEX_SLEB, true // R_WASM_TABLE_INDEX_SLEB
|
|
case 2: return .TABLE_INDEX_I32, true // R_WASM_TABLE_INDEX_I32
|
|
case 3: return .MEMORY_ADDR_LEB, true // R_WASM_MEMORY_ADDR_LEB
|
|
case 4: return .MEMORY_ADDR_SLEB, true // R_WASM_MEMORY_ADDR_SLEB
|
|
case 5: return .MEMORY_ADDR_I32, true // R_WASM_MEMORY_ADDR_I32
|
|
case 6: return .TYPE_INDEX_LEB, true // R_WASM_TYPE_INDEX_LEB
|
|
case 7: return .GLOBAL_INDEX_LEB, true // R_WASM_GLOBAL_INDEX_LEB
|
|
case 20: return .TABLE_NUMBER_LEB, true // R_WASM_TABLE_NUMBER_LEB
|
|
}
|
|
return .NONE, false
|
|
}
|
|
|
|
// MEMORY_ADDR_* (3,4,5) and the *_OFFSET_I32 (8,9) forms carry a trailing
|
|
// signed-LEB addend; the index-type relocations do not.
|
|
@(require_results)
|
|
reloc_has_addend :: proc(code: u8) -> bool {
|
|
switch code {
|
|
case 3, 4, 5, 8, 9: return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
@(require_results)
|
|
reloc_field_size :: proc(t: wasm.Relocation_Type) -> u8 {
|
|
#partial switch t {
|
|
case .TABLE_INDEX_I32, .MEMORY_ADDR_I32:
|
|
return 4 // 4-byte LE field
|
|
}
|
|
return 5 // 5-byte padded (S)LEB field
|
|
}
|