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[lld][WebAssembly] Use writePtrConst helper function #166228

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Merged
merged 1 commit into from
Nov 3, 2025
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[lld][WebAssembly] Use writePtrConst helper function #166228

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60 changes: 60 additions & 0 deletions lld/test/wasm/runtime-relocations-himem.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
## Verifies runtime relocation code for addresses over 2gb works correctly.
## We have had issues with LEB encoding of address over 2gb in i32.const
## instruction leading to invalid binaries.

# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown -o %t.o %s
# RUN: wasm-ld --global-base=2147483648 --experimental-pic --unresolved-symbols=import-dynamic -no-gc-sections --shared-memory --no-entry -o %t.wasm %t.o
# XUN: obj2yaml %t.wasm | FileCheck %s
# RUN: llvm-objdump -d --no-show-raw-insn --no-leading-addr %t.wasm | FileCheck %s --

.globl tls_sym
.globl data_sym
.globl _start
.globaltype __tls_base, i32

_start:
.functype _start () -> ()
global.get __tls_base
i32.const tls_sym@TLSREL
i32.add
drop
i32.const data_sym
drop
end_function

.section tls_sec,"T",@
.p2align 2
tls_sym:
.int32 0
.int32 extern_sym
.size tls_sym, 8

.section data_sec,"",@
.p2align 2
data_sym:
.int32 0
.int32 extern_sym
.size data_sym, 8

.section .custom_section.target_features,"",@
.int8 2
.int8 43
.int8 7
.ascii "atomics"
.int8 43
.int8 11
.ascii "bulk-memory"

# CHECK: <__wasm_apply_data_relocs>:
# CHECK-EMPTY:
# CHECK-NEXT: i32.const -2147483636
# CHECK-NEXT: global.get 0
# CHECK-NEXT: i32.store 0
# CHECK-NEXT: end

# CHECK: <__wasm_apply_tls_relocs>:
# CHECK-EMPTY:
# CHECK-NEXT: i32.const -2147483644
# CHECK-NEXT: global.get 0
# CHECK-NEXT: i32.store 0
# CHECK-NEXT: end
14 changes: 4 additions & 10 deletions lld/wasm/InputChunks.cpp
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Expand Up @@ -423,8 +423,6 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {

bool is64 = ctx.arg.is64.value_or(false);
bool generated = false;
unsigned opcode_ptr_const = is64 ? WASM_OPCODE_I64_CONST
: WASM_OPCODE_I32_CONST;
unsigned opcode_ptr_add = is64 ? WASM_OPCODE_I64_ADD
: WASM_OPCODE_I32_ADD;

Expand All @@ -451,8 +449,7 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {
<< " output offset=" << offset << "\n");

// Calculate the address at which to apply the relocation
writeU8(os, opcode_ptr_const, "CONST");
writeSleb128(os, offset, "offset");
writePtrConst(os, offset, is64, "offset");

// In PIC mode we need to add the __memory_base
if (ctx.isPic) {
Expand All @@ -466,8 +463,6 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {

// Now figure out what we want to store at this location
bool is64 = relocIs64(rel.Type);
unsigned opcode_reloc_const =
is64 ? WASM_OPCODE_I64_CONST : WASM_OPCODE_I32_CONST;
unsigned opcode_reloc_add =
is64 ? WASM_OPCODE_I64_ADD : WASM_OPCODE_I32_ADD;
unsigned opcode_reloc_store =
Expand All @@ -477,8 +472,7 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {
writeU8(os, WASM_OPCODE_GLOBAL_GET, "GLOBAL_GET");
writeUleb128(os, sym->getGOTIndex(), "global index");
if (rel.Addend) {
writeU8(os, opcode_reloc_const, "CONST");
writeSleb128(os, rel.Addend, "addend");
writePtrConst(os, rel.Addend, is64, "addend");
writeU8(os, opcode_reloc_add, "ADD");
}
} else {
Expand All @@ -491,8 +485,8 @@ bool InputChunk::generateRelocationCode(raw_ostream &os) const {
baseSymbol = ctx.sym.tlsBase;
writeU8(os, WASM_OPCODE_GLOBAL_GET, "GLOBAL_GET");
writeUleb128(os, baseSymbol->getGlobalIndex(), "base");
writeU8(os, opcode_reloc_const, "CONST");
writeSleb128(os, file->calcNewValue(rel, tombstone, this), "offset");
writePtrConst(os, file->calcNewValue(rel, tombstone, this), is64,
"offset");
writeU8(os, opcode_reloc_add, "ADD");
}

Expand Down
8 changes: 2 additions & 6 deletions lld/wasm/SyntheticSections.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -434,8 +434,6 @@ void GlobalSection::addInternalGOTEntry(Symbol *sym) {
void GlobalSection::generateRelocationCode(raw_ostream &os, bool TLS) const {
assert(!ctx.arg.extendedConst);
bool is64 = ctx.arg.is64.value_or(false);
unsigned opcode_ptr_const = is64 ? WASM_OPCODE_I64_CONST
: WASM_OPCODE_I32_CONST;
unsigned opcode_ptr_add = is64 ? WASM_OPCODE_I64_ADD
: WASM_OPCODE_I32_ADD;

Expand All @@ -452,8 +450,7 @@ void GlobalSection::generateRelocationCode(raw_ostream &os, bool TLS) const {
writeUleb128(os, ctx.sym.memoryBase->getGlobalIndex(), "__memory_base");

// Add the virtual address of the data symbol
writeU8(os, opcode_ptr_const, "CONST");
writeSleb128(os, d->getVA(), "offset");
writePtrConst(os, d->getVA(), is64, "offset");
} else if (auto *f = dyn_cast<FunctionSymbol>(sym)) {
if (f->isStub)
continue;
Expand All @@ -462,8 +459,7 @@ void GlobalSection::generateRelocationCode(raw_ostream &os, bool TLS) const {
writeUleb128(os, ctx.sym.tableBase->getGlobalIndex(), "__table_base");

// Add the table index to __table_base
writeU8(os, opcode_ptr_const, "CONST");
writeSleb128(os, f->getTableIndex(), "offset");
writePtrConst(os, f->getTableIndex(), is64, "offset");
} else {
assert(isa<UndefinedData>(sym) || isa<SharedData>(sym));
continue;
Expand Down
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