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Implement jump tables (#453)

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* Add 'jump_table_entry' and 'indirect_jump' instructions.

* Update CodeSink to keep track of code size. Pretty up clif-util's disassembly output.

* Only disassemble the machine portion of output. Pretty print the read-only data after it.

* Update switch frontend code to use new br_table instruction w/ default.
This commit is contained in:
Tyler McMullen
2018-10-03 11:04:21 -06:00
committed by Dan Gohman
parent de1d82b4ba
commit 79cea5e18b
39 changed files with 627 additions and 100 deletions
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8
lib/codegen/src/isa/x86/binemit.rs
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@@ -3,7 +3,7 @@
use super::registers::RU;
use binemit::{bad_encoding, CodeSink, Reloc};
use ir::condcodes::{CondCode, FloatCC, IntCC};
use ir::{Ebb, Function, Inst, InstructionData, Opcode, TrapCode};
use ir::{Ebb, Function, Inst, InstructionData, JumpTable, Opcode, TrapCode};
use isa::{RegUnit, StackBase, StackBaseMask, StackRef};
use regalloc::RegDiversions;
@@ -249,6 +249,7 @@ fn sib_noindex<CS: CodeSink + ?Sized>(base: RegUnit, sink: &mut CS) {
sink.put1(b);
}
/// Emit a SIB byte with a scale, base, and index.
fn sib<CS: CodeSink + ?Sized>(scale: u8, index: RegUnit, base: RegUnit, sink: &mut CS) {
// SIB SS_III_BBB.
debug_assert_eq!(scale & !0x03, 0, "Scale out of range");
@@ -332,3 +333,8 @@ fn disp4<CS: CodeSink + ?Sized>(destination: Ebb, func: &Function, sink: &mut CS
let delta = func.offsets[destination].wrapping_sub(sink.offset() + 4);
sink.put4(delta);
}
fn jt_disp4<CS: CodeSink + ?Sized>(jt: JumpTable, func: &Function, sink: &mut CS) {
let delta = func.jt_offsets[jt].wrapping_sub(sink.offset() + 4);
sink.put4(delta);
}