This series includes changes to the x86 TCG decoder that switch the 1-byte opcodes to the table-driven decoder (except for x87). A few easy 2-byte opcodes are also converted (BSWAP, SETcc, CMOVcc, MOVZX/MOVSX and those that are extensions of 1-byte opcodes like PUSH/POP FS/GS, LFS/LGS/LSS).
After optimization, the generated code is generally similar to what is produced by the old decoder, with some differences for 32-bit multiplications and rotate operations (RCL/RCR, and ROL/ROR less so). This reaches a point where prefix decoding is done entirely in the new decoder; when the opcode is loaded, if needed it will defer to translate.c for the actual translation of the instruction. Quite surprisingly, even without removing this duplicate code the patch remove more lines than it adds, even though the table-driven translator is theoretically more verbose (1 line per entry in the tables plus all the function declarations for group decoders and emitters). This shows how operand decoding is spread all over the place in translate.c. These have been ready for a few months; now that it seems clearer that issue 2092 is a generic problem with vhost-user, it is time to get this upstream. Paolo Based-on: <20240406223248.502699-1-richard.hender...@linaro.org> Paolo Bonzini (19): target/i386: use TSTEQ/TSTNE to test low bits target/i386: use TSTEQ/TSTNE to check flags target/i386: remove mask from CCPrepare target/i386: do not use s->tmp0 and s->tmp4 to compute flags target/i386: reintroduce debugging mechanism target/i386: move 00-5F opcodes to new decoder target/i386: extract gen_far_call/jmp, reordering temporaries target/i386: allow instructions with more than one immediate target/i386: move 60-BF opcodes to new decoder target/i386: generalize gen_movl_seg_T0 target/i386: move C0-FF opcodes to new decoder (except for x87) target/i386: merge and enlarge a few ranges for call to disas_insn_new target/i386: move remaining conditional operations to new decoder target/i386: move BSWAP to new decoder target/i386: port extensions of one-byte opcodes to new decoder target/i386: remove now-converted opcodes from old decoder target/i386: decode x87 instructions in a separate function target/i386: split legacy decoder into a separate function target/i386: remove duplicate prefix decoding include/tcg/tcg.h | 6 + target/i386/helper.h | 11 - target/i386/tcg/decode-new.h | 23 +- target/i386/tcg/shift_helper_template.h.inc | 108 - target/i386/tcg/int_helper.c | 34 - target/i386/tcg/translate.c | 3717 ++++--------------- target/i386/tcg/decode-new.c.inc | 602 ++- target/i386/tcg/emit.c.inc | 1560 +++++++- 8 files changed, 2914 insertions(+), 3147 deletions(-) delete mode 100644 target/i386/tcg/shift_helper_template.h.inc -- 2.44.0