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authorRichard Henderson <richard.henderson@linaro.org>2020-11-04 12:43:20 -0800
committerRichard Henderson <richard.henderson@linaro.org>2021-01-07 05:09:42 -1000
commit4b6a52d01e0dd640dd15f79264b38790023e3587 (patch)
treeef9775b26775dd9a2b7a9be2b5fe8b81d2ee7b18
parent844d0442a53ca40a8d826e7549f27a8d4ac3a582 (diff)
downloadqemu-arm-4b6a52d01e0dd640dd15f79264b38790023e3587.tar.gz
tcg/riscv: Remove branch-over-branch fallback
Since 7ecd02a06f8, we are prepared to re-start code generation with a smaller TB if a relocation is out of range. We no longer need to leave a nop in the stream Just In Case. Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
-rw-r--r--tcg/riscv/tcg-target.c.inc56
1 files changed, 6 insertions, 50 deletions
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 5b4c500a4b..34bee9c5a7 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -469,43 +469,16 @@ static bool reloc_call(tcg_insn_unit *code_ptr, const tcg_insn_unit *target)
static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
intptr_t value, intptr_t addend)
{
- uint32_t insn = *code_ptr;
- intptr_t diff;
- bool short_jmp;
-
tcg_debug_assert(addend == 0);
-
switch (type) {
case R_RISCV_BRANCH:
- diff = value - (uintptr_t)code_ptr;
- short_jmp = diff == sextreg(diff, 0, 12);
- if (short_jmp) {
- return reloc_sbimm12(code_ptr, (tcg_insn_unit *)value);
- } else {
- /* Invert the condition */
- insn = insn ^ (1 << 12);
- /* Clear the offset */
- insn &= 0x01fff07f;
- /* Set the offset to the PC + 8 */
- insn |= encode_sbimm12(8);
-
- /* Move forward */
- code_ptr[0] = insn;
-
- /* Overwrite the NOP with jal x0,value */
- diff = value - (uintptr_t)(code_ptr + 1);
- insn = encode_uj(OPC_JAL, TCG_REG_ZERO, diff);
- code_ptr[1] = insn;
-
- return true;
- }
- break;
+ return reloc_sbimm12(code_ptr, (tcg_insn_unit *)value);
case R_RISCV_JAL:
return reloc_jimm20(code_ptr, (tcg_insn_unit *)value);
case R_RISCV_CALL:
return reloc_call(code_ptr, (tcg_insn_unit *)value);
default:
- tcg_abort();
+ g_assert_not_reached();
}
}
@@ -779,21 +752,8 @@ static void tcg_out_brcond(TCGContext *s, TCGCond cond, TCGReg arg1,
arg2 = t;
}
- if (l->has_value) {
- intptr_t diff = tcg_pcrel_diff(s, l->u.value_ptr);
- if (diff == sextreg(diff, 0, 12)) {
- tcg_out_opc_branch(s, op, arg1, arg2, diff);
- } else {
- /* Invert the conditional branch. */
- tcg_out_opc_branch(s, op ^ (1 << 12), arg1, arg2, 8);
- tcg_out_opc_jump(s, OPC_JAL, TCG_REG_ZERO, diff - 4);
- }
- } else {
- tcg_out_reloc(s, s->code_ptr, R_RISCV_BRANCH, l, 0);
- tcg_out_opc_branch(s, op, arg1, arg2, 0);
- /* NOP to allow patching later */
- tcg_out_opc_imm(s, OPC_ADDI, TCG_REG_ZERO, TCG_REG_ZERO, 0);
- }
+ tcg_out_reloc(s, s->code_ptr, R_RISCV_BRANCH, l, 0);
+ tcg_out_opc_branch(s, op, arg1, arg2, 0);
}
static void tcg_out_setcond(TCGContext *s, TCGCond cond, TCGReg ret,
@@ -1009,8 +969,6 @@ static void tcg_out_tlb_load(TCGContext *s, TCGReg addrl,
/* Compare masked address with the TLB entry. */
label_ptr[0] = s->code_ptr;
tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP0, TCG_REG_TMP1, 0);
- /* NOP to allow patching later */
- tcg_out_opc_imm(s, OPC_ADDI, TCG_REG_ZERO, TCG_REG_ZERO, 0);
/* TLB Hit - translate address using addend. */
if (TCG_TARGET_REG_BITS > TARGET_LONG_BITS) {
@@ -1054,8 +1012,7 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
}
/* resolve label address */
- if (!patch_reloc(l->label_ptr[0], R_RISCV_BRANCH,
- (intptr_t) s->code_ptr, 0)) {
+ if (!reloc_sbimm12(l->label_ptr[0], s->code_ptr)) {
return false;
}
@@ -1089,8 +1046,7 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
}
/* resolve label address */
- if (!patch_reloc(l->label_ptr[0], R_RISCV_BRANCH,
- (intptr_t) s->code_ptr, 0)) {
+ if (!reloc_sbimm12(l->label_ptr[0], s->code_ptr)) {
return false;
}