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wasm2c: Alter how segments are loaded #2555

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f1c33fa
Alter how segments are loaded
squk Mar 5, 2025
8127bef
Add tests
squk Mar 6, 2025
4897602
testing stuf
squk Mar 14, 2025
355d46e
Remove comments
squk Mar 17, 2025
f6e78d5
Update test
squk Mar 17, 2025
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71 changes: 53 additions & 18 deletions src/c-writer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2242,6 +2242,46 @@ void CWriter::WriteDataInitializers() {
Write(CloseBrace(), ";", Newline());
}

Write(Newline(),
"static const u8* active_data_segment_data_ptrs[] = ", OpenBrace());
for (const DataSegment* data_segment : module_->data_segments) {
if (data_segment->kind != SegmentKind::Active ||
data_segment->data.empty()) {
continue;
}
Write("data_segment_data_",
GlobalName(ModuleFieldType::DataSegment, data_segment->name), ",",
Newline());
}
Write(CloseBrace(), ";", Newline());

Write(Newline(),
"static const size_t active_data_segment_sizes[] = ", OpenBrace());
for (const DataSegment* data_segment : module_->data_segments) {
if (data_segment->kind != SegmentKind::Active ||
data_segment->data.empty()) {
continue;
}
Write(data_segment->data.size(), ", // data_segment_data_",
GlobalName(ModuleFieldType::DataSegment, data_segment->name),
Newline());
}
Write(CloseBrace(), ";", Newline());

Write(Newline(),
"static const u32 active_data_segment_offsets[] = ", OpenBrace());
for (const DataSegment* data_segment : module_->data_segments) {
if (data_segment->kind != SegmentKind::Active ||
data_segment->data.empty()) {
continue;
}
WriteInitExpr(data_segment->offset);
Write(", // data_segment_data_",
GlobalName(ModuleFieldType::DataSegment, data_segment->name),
Newline());
}
Write(CloseBrace(), ";", Newline());

Write(Newline(), "static void init_memories(", ModuleInstanceTypeName(),
"* instance) ", OpenBrace());
if (module_->memories.size() > module_->num_memory_imports) {
Expand All @@ -2262,24 +2302,19 @@ void CWriter::WriteDataInitializers() {
}
}

for (const DataSegment* data_segment : module_->data_segments) {
if (data_segment->kind != SegmentKind::Active) {
continue;
}
const Memory* memory =
module_->memories[module_->GetMemoryIndex(data_segment->memory_var)];
Write("LOAD_DATA(",
ExternalInstanceRef(ModuleFieldType::Memory, memory->name), ", ");
WriteInitExpr(data_segment->offset);
if (data_segment->data.empty()) {
Write(", NULL, 0");
} else {
Write(", data_segment_data_",
GlobalName(ModuleFieldType::DataSegment, data_segment->name), ", ",
data_segment->data.size());
}
Write(");", Newline());
}
Write(
"for (int i = 0; i < sizeof(active_data_segment_data_ptrs) / "
"sizeof(active_data_segment_data_ptrs[0]); i++) ",
OpenBrace(), Newline());

const Memory* memory = module_->memories[0];

Write("LOAD_DATA(",
ExternalInstanceRef(ModuleFieldType::Memory, memory->name),
", active_data_segment_offsets[i], active_data_segment_data_ptrs[i], "
"active_data_segment_sizes[i]);",
Newline());
Write(CloseBrace(), Newline());

Write(CloseBrace(), Newline());

Expand Down
13 changes: 13 additions & 0 deletions test/wasm2c/check-imports.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -834,7 +834,20 @@ static u32 wrap_w2c_test_f1(void *instance) {
return w2c_test_f1(instance);
}

static const u8* active_data_segment_data_ptrs[] = {
};

static const size_t active_data_segment_sizes[] = {
};

static const u32 active_data_segment_offsets[] = {
};

static void init_memories(w2c_test* instance) {
for (int i = 0; i < sizeof(active_data_segment_data_ptrs) / sizeof(active_data_segment_data_ptrs[0]); i++) {

LOAD_DATA((*instance->w2c_env_0x5F_linear_memory), active_data_segment_offsets[i], active_data_segment_data_ptrs[i], active_data_segment_sizes[i]);
}
}

static const wasm_elem_segment_expr_t elem_segment_exprs_w2c_test_e0[] = {
Expand Down
13 changes: 13 additions & 0 deletions test/wasm2c/export-names.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -826,7 +826,20 @@ static void w2c_test__0(w2c_test*);

FUNC_TYPE_T(w2c_test_t0) = "\x36\xa9\xe7\xf1\xc9\x5b\x82\xff\xb9\x97\x43\xe0\xc5\xc4\xce\x95\xd8\x3c\x9a\x43\x0a\xac\x59\xf8\x4e\xf3\xcb\xfa\xb6\x14\x50\x68";

static const u8* active_data_segment_data_ptrs[] = {
};

static const size_t active_data_segment_sizes[] = {
};

static const u32 active_data_segment_offsets[] = {
};

static void init_memories(w2c_test* instance) {
for (int i = 0; i < sizeof(active_data_segment_data_ptrs) / sizeof(active_data_segment_data_ptrs[0]); i++) {

LOAD_DATA((*instance->w2c_0x5Cmodule_import0x200x2A0x2F), active_data_segment_offsets[i], active_data_segment_data_ptrs[i], active_data_segment_sizes[i]);
}
}

/* export: '' */
Expand Down
17 changes: 16 additions & 1 deletion test/wasm2c/hello.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -844,9 +844,24 @@ static const u8 data_segment_data_w2c_test_d0[] = {
0x2e, 0x0a,
};

static const u8* active_data_segment_data_ptrs[] = {
data_segment_data_w2c_test_d0,
};

static const size_t active_data_segment_sizes[] = {
14, // data_segment_data_w2c_test_d0
};

static const u32 active_data_segment_offsets[] = {
8u, // data_segment_data_w2c_test_d0
};

static void init_memories(w2c_test* instance) {
wasm_rt_allocate_memory(&instance->w2c_memory, 1, 65536, 0, 65536);
LOAD_DATA(instance->w2c_memory, 8u, data_segment_data_w2c_test_d0, 14);
for (int i = 0; i < sizeof(active_data_segment_data_ptrs) / sizeof(active_data_segment_data_ptrs[0]); i++) {

LOAD_DATA(instance->w2c_memory, active_data_segment_offsets[i], active_data_segment_data_ptrs[i], active_data_segment_sizes[i]);
}
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@sbc100 sbc100 Mar 17, 2025

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Do you know why the compiler was using more memory in the old form? Is it because of inlining somehow?

That amount of static data here is the same right? Does the program you are having trouble with contains a huge about of segments?

}

static void init_data_instances(w2c_test *instance) {
Expand Down
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