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Added a pseudo instruction 'loadAddressOf()' to load a memory address into a register (Compiler/AArch64)

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kobalicek
2022-03-27 22:33:35 +02:00
parent 21a31b8a33
commit 7342f7d78d
2 changed files with 54 additions and 0 deletions
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12
src/asmjit/arm/a64compiler.h
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@@ -169,6 +169,18 @@ public:
//! \}
//! \name Compiler specific
//! \{
//! Special pseudo-instruction that can be used to load a memory address into `o0` GP register.
//!
//! \note At the moment this instruction is only useful to load a stack allocated address into a GP register
//! for further use. It makes very little sense to use it for anything else. The semantics of this instruction
//! is the same as X86 `LEA` (load effective address) instruction.
inline Error loadAddressOf(const Gp& o0, const Mem& o1) { return _emitter()->_emitI(Inst::kIdAdr, o0, o1); }
//! \}
//! \name Function Call & Ret Intrinsics
//! \{

42
src/asmjit/arm/a64rapass.cpp
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@@ -713,6 +713,48 @@ ASMJIT_FAVOR_SPEED Error ARMRAPass::_rewrite(BaseNode* first, BaseNode* stop) no
mem.clearRegHome();
mem.addOffsetLo32(offset);
}
// Rewrite `loadAddressOf()` construct.
if (node->type() == NodeType::kInst) {
InstNode* inst = node->as<InstNode>();
if (inst->realId() == Inst::kIdAdr && inst->opCount() == 2) {
int64_t offset = mem.offset();
if (!mem.hasBase()) {
inst->setId(Inst::kIdMov);
inst->setOp(1, Imm(offset));
}
else {
InstId op = offset < 0 ? Inst::kIdSub : Inst::kIdAdd;
uint64_t val = offset < 0 ? Support::neg(uint64_t(offset)) : uint64_t(offset);
GpX base = GpX(mem.baseId());
inst->setId(op);
inst->setOpCount(3);
inst->setOp(1, base);
inst->setOp(2, Imm(val));
if (val > 0xFFFu && (val & ~uint64_t(0xFFF000u)) != 0) {
const Operand_& dst = inst->op(0);
// Use two operations if the stack address is greater than 4095.
if (val <= 0xFFFFFFu) {
cc()->_setCursor(inst->prev());
cc()->_emitI(op, dst, base, Imm(val & 0xFFFu));
inst->setOp(1, dst);
inst->setOp(2, Imm(val & 0xFFF000u));
}
else {
cc()->_setCursor(inst->prev());
cc()->_emitI(Inst::kIdMov, inst->op(0), Imm(val));
inst->setOp(1, base);
inst->setOp(2, dst);
}
}
}
}
}
}
}
}