[jdk17u-dev] RFR: 8291550: RISC-V: jdk uses misaligned memory access when AvoidUnalignedAccess enabled

[Vladimir Kempik]

On Fri, 6 Oct 2023 12:22:20 GMT, Olga Mikhaltsova <omikhaltcova at openjdk.org> wrote:

> I'd like to backport JDK-8291550 to jdk17u.
> 
> The patch applies not cleanly. It differs from the original one in the following:
> 
> **1.** **src/hotspot/cpu/riscv/c2_MacroAssembler_riscv.cpp**
> 
> `#undef VFCVT_SAFE` was removed because there is no `#define VFCVT_SAFE(VFLOATCVT)` (JDK-8306966)
> 
> **2.** **src/hotspot/cpu/riscv/gc/shared/barrierSetNMethod_riscv.cpp**
> 
> The difference is in context due to method signature change by JDK-8299229
> `void NativeNMethodBarrier::verify() const {..`
> `bool NativeNMethodBarrier::check_barrier(err_msg& msg) const {..`
> 
> `msg.print(..)` was replaced with `tty->print_cr(..)`
> 
> **3.** **src/hotspot/cpu/riscv/interp_masm_riscv.cpp**
> 
> The changes were not applied to 
> `void InterpreterMacroAssembler::load_resolved_indy_entry(Register cache, Register index) {`
> This method doesn't exist, it was added by JDK-8301995.
> 
> **4.** **src/hotspot/cpu/riscv/macroAssembler_riscv.cpp**
> 
> The difference is in context due to the method signature change by JDK-8298075
> `address MacroAssembler::get_target_of_li32(address insn_addr) {`
> `static address get_target_of_li32(address insn_addr) `{
> 
> `NULL` was replaced with `nullptr` by JDK-8301496.
> 
> **5.** **src/hotspot/cpu/riscv/nativeInst_riscv.cpp**
>          **src/hotspot/cpu/riscv/nativeInst_riscv.hpp**
>  
> `NULL` was replaced with `nullptr` by JDK-8301496

Changes requested by vkempik (Reviewer).

Marked as reviewed by vkempik (Reviewer).

Marked as reviewed by vkempik (Reviewer).

src/hotspot/cpu/riscv/macroAssembler_riscv.cpp line 4102:

> 4100: // base:  Address of a buffer to be zeroed, 8 bytes aligned.
> 4101: // cnt:   Immediate count in HeapWords.
> 4102: void MacroAssembler::zero_words(Register base, u_int64_t cnt) {

looks like this edit was accidentially added to the backport, other than that - looks good

-------------

PR Review: https://git.openjdk.org/jdk17u-dev/pull/1852#pullrequestreview-1661913601
PR Review: https://git.openjdk.org/jdk17u-dev/pull/1852#pullrequestreview-1661991845
PR Review: https://git.openjdk.org/jdk17u-dev/pull/1852#pullrequestreview-1662018309
PR Review Comment: https://git.openjdk.org/jdk17u-dev/pull/1852#discussion_r1348751842