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[Liftoff][x64] Assert that 32-bit values are zero extended

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On x64, the upper 32 bit of a register holding a 32-bit value are
always zero. Add several assertions to check that. This is particularly
important for memory accesses, where the whole 64-bit register is used
as offset for the memory access.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: Ifd3c6e90bb0056dbc2b8c66de919f35c7787965b
Reviewed-on: https://chromium-review.googlesource.com/963321
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51947}
This commit is contained in:
Clemens Hammacher 2018-03-14 20:48:28 +01:00 committed by Commit Bot
parent ad6c11f2df
commit 410893e9a9
1 changed files with 7 additions and 1 deletions
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8
src/wasm/baseline/x64/liftoff-assembler-x64.h
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@ -160,6 +160,9 @@ void LiftoffAssembler::Load(LiftoffRegister dst, Register src_addr,
Register offset_reg, uint32_t offset_imm,
LoadType type, LiftoffRegList pinned,
uint32_t* protected_load_pc) {
if (emit_debug_code() && offset_reg != no_reg) {
AssertZeroExtended(offset_reg);
}
Operand src_op =
liftoff::GetMemOp(this, src_addr, offset_reg, offset_imm, pinned);
if (protected_load_pc) *protected_load_pc = pc_offset();
@ -209,6 +212,9 @@ void LiftoffAssembler::Store(Register dst_addr, Register offset_reg,
uint32_t offset_imm, LiftoffRegister src,
StoreType type, LiftoffRegList pinned,
uint32_t* protected_store_pc) {
if (emit_debug_code() && offset_reg != no_reg) {
AssertZeroExtended(offset_reg);
}
Operand dst_op =
liftoff::GetMemOp(this, dst_addr, offset_reg, offset_imm, pinned);
if (protected_store_pc) *protected_store_pc = pc_offset();
@ -653,8 +659,8 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
movsxlq(dst.gp(), src.gp());
return true;
case kExprI64UConvertI32:
AssertZeroExtended(src.gp());
if (dst.gp() != src.gp()) movl(dst.gp(), src.gp());
// TODO(clemensh): Add assertion that the upper 32 bit are zero.
return true;
case kExprI64ReinterpretF64:
Movq(dst.gp(), src.fp());