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Unified Diff: src/compiler/wasm-compiler.cc

Issue 2416393002: Revert of [wasm] Fix bounds check for zero initial memory. (Closed)
Patch Set: Created 4 years, 2 months ago
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Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 484a0d9a5063c6b1baf876ea818fb9c9d998fd05..4392896c644b8796b013903a81c22a5804f71e5b 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -2859,22 +2859,25 @@
uint32_t size = module_->instance->mem_size;
byte memsize = wasm::WasmOpcodes::MemSize(memtype);
+ // Check against the effective size.
size_t effective_size;
- if (size <= offset || size < (static_cast<uint64_t>(offset) + memsize)) {
+ if (size == 0) {
+ effective_size = 0;
+ } else if (offset >= size ||
+ (static_cast<uint64_t>(offset) + memsize) > size) {
// Two checks are needed in the case where the offset is statically
// out of bounds; one check for the offset being in bounds, and the next for
// the offset + index being out of bounds for code to be patched correctly
// on relocation.
- size_t effective_offset = offset + memsize - 1;
+ effective_size = size - memsize + 1;
Node* cond = graph()->NewNode(jsgraph()->machine()->Uint32LessThan(),
- jsgraph()->IntPtrConstant(effective_offset),
+ jsgraph()->IntPtrConstant(offset),
jsgraph()->RelocatableInt32Constant(
- static_cast<uint32_t>(size),
+ static_cast<uint32_t>(effective_size),
RelocInfo::WASM_MEMORY_SIZE_REFERENCE));
trap_->AddTrapIfFalse(wasm::kTrapMemOutOfBounds, cond, position);
- // For offset > effective size, this relies on check above to fail and
- // effective size can be negative, relies on wrap around.
- effective_size = size - offset - memsize + 1;
+ DCHECK(offset >= effective_size);
+ effective_size = offset - effective_size;
} else {
effective_size = size - offset - memsize + 1;
CHECK(effective_size <= kMaxUInt32);
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