| author |  Andrew Kelley <andrew@ziglang.org> 2025-01-09 20:55:39-08:00 |
| committer | Andrew Kelley <andrew@ziglang.org> 2025-01-15 15:11:36-08:00 |
| log | 788b7f8f115e8510176ca7fbfdc04fb48d69ecb1 |
| tree | 91208c95559c3d9ddb00ea97c6a7a64ca70292c2 |
| parent | 1c4b4fb51604f388bb4355e566aac4ea9fda8960 |
wasm linker: don't call init functions unless object included
3 files changed, 14 insertions(+), 5 deletions(-)
src- link
src/link/Wasm.zig+10-2
| ... | ... | @@ -117,7 +117,7 @@ object_memories: std.ArrayListUnmanaged(ObjectMemory) = .empty, |
| 117 | 117 | object_relocations: std.MultiArrayList(ObjectRelocation) = .empty, |
| 118 | 118 | |
| 119 | 119 | /// List of initialization functions. These must be called in order of priority |
| 120 | /// by the (synthetic) __wasm_call_ctors function. | |
| 120 | /// by the (synthetic) `__wasm_call_ctors` function. | |
| 121 | 121 | object_init_funcs: std.ArrayListUnmanaged(InitFunc) = .empty, |
| 122 | 122 | |
| 123 | 123 | /// The data section of an object has many segments. Each segment corresponds |
| ... | ... | @@ -3308,7 +3308,10 @@ pub fn prelink(wasm: *Wasm, prog_node: std.Progress.Node) link.File.FlushError!v |
| 3308 | 3308 | } |
| 3309 | 3309 | // Also treat init functions as roots. |
| 3310 | 3310 | for (wasm.object_init_funcs.items) |init_func| { |
| 3311 | try markFunction(wasm, init_func.function_index); | |
| 3311 | const func = init_func.function_index.ptr(wasm); | |
| 3312 | if (func.object_index.ptr(wasm).is_included) { | |
| 3313 | try markFunction(wasm, init_func.function_index); | |
| 3314 | } | |
| 3312 | 3315 | } |
| 3313 | 3316 | wasm.functions_end_prelink = @intCast(wasm.functions.entries.len); |
| 3314 | 3317 | wasm.function_exports_len = @intCast(wasm.function_exports.items.len); |
| ... | ... | @@ -3383,6 +3386,7 @@ fn markFunction(wasm: *Wasm, i: ObjectFunctionIndex) link.File.FlushError!void { |
| 3383 | 3386 | const rdynamic = comp.config.rdynamic; |
| 3384 | 3387 | const is_obj = comp.config.output_mode == .Obj; |
| 3385 | 3388 | const function = i.ptr(wasm); |
| 3389 | markObject(wasm, function.object_index); | |
| 3386 | 3390 | |
| 3387 | 3391 | if (!is_obj and function.flags.isExported(rdynamic)) try wasm.function_exports.append(gpa, .{ |
| 3388 | 3392 | .name = function.name.unwrap().?, |
| ... | ... | @@ -3392,6 +3396,10 @@ fn markFunction(wasm: *Wasm, i: ObjectFunctionIndex) link.File.FlushError!void { |
| 3392 | 3396 | try wasm.markRelocations(function.relocations(wasm)); |
| 3393 | 3397 | } |
| 3394 | 3398 | |
| 3399 | fn markObject(wasm: *Wasm, i: ObjectIndex) void { | |
| 3400 | i.ptr(wasm).is_included = true; | |
| 3401 | } | |
| 3402 | ||
| 3395 | 3403 | /// Recursively mark alive everything referenced by the global. |
| 3396 | 3404 | fn markGlobalImport( |
| 3397 | 3405 | wasm: *Wasm, |
src/link/Wasm/Flush.zig+2-3
| ... | ... | @@ -188,8 +188,6 @@ pub fn finish(f: *Flush, wasm: *Wasm) !void { |
| 188 | 188 | for (wasm.object_indirect_function_set.keys()) |object_function_index| |
| 189 | 189 | f.indirect_function_table.putAssumeCapacity(.fromObjectFunction(wasm, object_function_index), {}); |
| 190 | 190 | |
| 191 | // TODO only include init functions for objects with must_link=true or | |
| 192 | // which have any alive functions inside them. | |
| 193 | 191 | if (wasm.object_init_funcs.items.len > 0) { |
| 194 | 192 | // Zig has no constructors so these are only for object file inputs. |
| 195 | 193 | mem.sortUnstable(Wasm.InitFunc, wasm.object_init_funcs.items, {}, Wasm.InitFunc.lessThan); |
| ... | ... | @@ -692,7 +690,7 @@ pub fn finish(f: *Flush, wasm: *Wasm) !void { |
| 692 | 690 | } |
| 693 | 691 | |
| 694 | 692 | // When the shared-memory option is enabled, we *must* emit the 'data count' section. |
| 695 | if (f.data_segment_groups.items.len > 0 and shared_memory) { | |
| 693 | { | |
| 696 | 694 | const header_offset = try reserveVecSectionHeader(gpa, binary_bytes); |
| 697 | 695 | replaceVecSectionHeader(binary_bytes, header_offset, .data_count, @intCast(f.data_segment_groups.items.len)); |
| 698 | 696 | } |
| ... | ... | @@ -1644,6 +1642,7 @@ fn emitCallCtorsFunction(wasm: *const Wasm, binary_bytes: *std.ArrayListUnmanage |
| 1644 | 1642 | |
| 1645 | 1643 | for (wasm.object_init_funcs.items) |init_func| { |
| 1646 | 1644 | const func = init_func.function_index.ptr(wasm); |
| 1645 | if (!func.object_index.ptr(wasm).is_included) continue; | |
| 1647 | 1646 | const ty = func.type_index.ptr(wasm); |
| 1648 | 1647 | const n_returns = ty.returns.slice(wasm).len; |
| 1649 | 1648 |
src/link/Wasm/Object.zig+2
| ... | ... | @@ -48,6 +48,7 @@ code_section_index: ?Wasm.ObjectSectionIndex, |
| 48 | 48 | global_section_index: ?Wasm.ObjectSectionIndex, |
| 49 | 49 | /// Guaranteed to be non-null when data segments has nonzero length. |
| 50 | 50 | data_section_index: ?Wasm.ObjectSectionIndex, |
| 51 | is_included: bool, | |
| 51 | 52 | |
| 52 | 53 | pub const RelativeSlice = struct { |
| 53 | 54 | off: u32, |
| ... | ... | @@ -1414,6 +1415,7 @@ pub fn parse( |
| 1414 | 1415 | .code_section_index = code_section_index, |
| 1415 | 1416 | .global_section_index = global_section_index, |
| 1416 | 1417 | .data_section_index = data_section_index, |
| 1418 | .is_included = must_link, | |
| 1417 | 1419 | }; |
| 1418 | 1420 | } |
| 1419 | 1421 |