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Merged
alexcrichton merged 2 commits into from
Jan 8, 2025
Merged

pulley: Add some macro-instructions related to bounds-checks #9943

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862f09c
pulley: Add some macro-instructions related to bounds-checks
alexcrichton Dec 15, 2024
ef6fb75
Remove incorrect lowering rule
alexcrichton Jan 7, 2025
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27 changes: 27 additions & 0 deletions cranelift/codegen/src/isa/pulley_shared/lower.isle
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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,33 @@
(rule (lower (trapnz cond code))
(side_effect (pulley_trap_if (lower_cond cond) code)))

;; Special-cases for bounds-checks-related traps emitted for wasm loads/stores.
;; Each of these translates to a single "xbc" (x-register bounds check)
;; instruction
(rule 1 (lower (trapnz (icmp (IntCC.UnsignedGreaterThan)
a
b @ (value_type $I32))
code))
(side_effect (pulley_xbc32_bound32_trap a b 0 code)))

(rule 1 (lower (trapnz (icmp (IntCC.UnsignedGreaterThan)
(uextend a @ (value_type $I32))
b @ (value_type $I64))
code))
(side_effect (pulley_xbc32_bound64_trap a b 0 code)))

(rule 2 (lower (trapnz (icmp (IntCC.UnsignedGreaterThan)
a
(isub b @ (value_type $I32) (u8_from_iconst c)))
code))
(side_effect (pulley_xbc32_bound32_trap a b c code)))

(rule 2 (lower (trapnz (icmp (IntCC.UnsignedGreaterThan)
(uextend a @ (value_type $I32))
(isub b @ (value_type $I64) (u8_from_iconst c)))
code))
(side_effect (pulley_xbc32_bound64_trap a b c code)))

;;;; Rules for `get_stack_pointer` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(rule (lower (get_stack_pointer))
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20 changes: 20 additions & 0 deletions pulley/src/interp.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2371,6 +2371,26 @@ impl OpVisitor for Interpreter<'_> {
self.state[dst].set_i64(a.wrapping_abs());
ControlFlow::Continue(())
}

fn xbc32_bound64_trap(&mut self, addr: XReg, bound: XReg, off: u8) -> ControlFlow<Done> {
let bound = self.state[bound].get_u64();
let addr = u64::from(self.state[addr].get_u32());
if addr > bound.wrapping_sub(u64::from(off)) {
self.done_trap::<crate::XBc32Bound64Trap>()
} else {
ControlFlow::Continue(())
}
}

fn xbc32_bound32_trap(&mut self, addr: XReg, bound: XReg, off: u8) -> ControlFlow<Done> {
let bound = self.state[bound].get_u32();
let addr = self.state[addr].get_u32();
if addr > bound.wrapping_sub(u32::from(off)) {
self.done_trap::<crate::XBc32Bound32Trap>()
} else {
ControlFlow::Continue(())
}
}
}

impl ExtendedOpVisitor for Interpreter<'_> {
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6 changes: 6 additions & 0 deletions pulley/src/lib.rs
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Expand Up @@ -580,6 +580,12 @@ macro_rules! for_each_op {
xselect32 = XSelect32 { dst: XReg, cond: XReg, if_nonzero: XReg, if_zero: XReg };
/// `dst = low32(cond) ? if_nonzero : if_zero`
xselect64 = XSelect64 { dst: XReg, cond: XReg, if_nonzero: XReg, if_zero: XReg };

/// `trapif(zext(low32(addr)) > bound - off)` (unsigned)
xbc32_bound64_trap = XBc32Bound64Trap { addr: XReg, bound: XReg, off: u8 };

/// `trapif(zext(low32(addr)) > low32(bound) - off)` (unsigned)
xbc32_bound32_trap = XBc32Bound32Trap { addr: XReg, bound: XReg, off: u8 };
}
};
}
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110 changes: 110 additions & 0 deletions tests/disas/pulley/pulley32_memory32.wat
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@@ -0,0 +1,110 @@
;;! target = "pulley32"
;;! test = "compile"

(module
(memory 1)

(func $load8 (param i32) (result i32)
(i32.load8_u (local.get 0)))

(func $load16 (param i32) (result i32)
(i32.load16_u (local.get 0)))

(func $load32 (param i32) (result i32)
(i32.load (local.get 0)))

(func $load64 (param i32) (result i64)
(i64.load (local.get 0)))

(func $load8_offset (param i32) (result i32)
(i32.load8_u offset=32 (local.get 0)))

(func $load16_offset (param i32) (result i32)
(i32.load16_u offset=32 (local.get 0)))

(func $load32_offset (param i32) (result i32)
(i32.load offset=32 (local.get 0)))

(func $load64_offset (param i32) (result i64)
(i64.load offset=32 (local.get 0)))
)
;; wasm[0]::function[0]::load8:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; br_if_xulteq32 x6, x2, 0x14 // target = 0x19

@abrown abrown Jan 8, 2025

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We don't want this one to use the new xbc macro-op?

@alexcrichton alexcrichton Jan 8, 2025

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No we probably do but I wanted to add this here for complete-ness to show that it's not currently using the new op. One-byte loads/stores are generated a bit differently with bounds checks and use a >= condition instead of > + arithmetic to test whether something is out of bounds. That made it so it doesn't fall into the patterns I added and would need a specific opcode just for the one-byte access. I figured it's probably fine to leave that off for now and add in the future if necessary

;; c: xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload8_u32_offset8 x0, x7, 0
;; pop_frame
;; ret
;; 19: trap
;;
;; wasm[0]::function[1]::load16:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 2
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload16le_u32_offset8 x0, x7, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[2]::load32:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 4
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload32le_offset8 x0, x7, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[3]::load64:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 8
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload64le_offset8 x0, x7, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[4]::load8_offset:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 33
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload8_u32_offset8 x0, x7, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[5]::load16_offset:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 34
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload16le_u32_offset8 x0, x7, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[6]::load32_offset:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 36
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload32le_offset8 x0, x7, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[7]::load64_offset:
;; push_frame
;; xload32le_offset8 x6, x0, 52
;; xbc32_bound32_trap x2, x6, 40
;; xload32le_offset8 x7, x0, 48
;; xadd32 x7, x7, x2
;; xload64le_offset8 x0, x7, 32
;; pop_frame
;; ret
118 changes: 118 additions & 0 deletions tests/disas/pulley/pulley64_memory32.wat
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Original file line number Diff line number Diff line change
@@ -0,0 +1,118 @@
;;! target = "pulley64"
;;! test = "compile"

(module
(memory 1)

(func $load8 (param i32) (result i32)
(i32.load8_u (local.get 0)))

(func $load16 (param i32) (result i32)
(i32.load16_u (local.get 0)))

(func $load32 (param i32) (result i32)
(i32.load (local.get 0)))

(func $load64 (param i32) (result i64)
(i64.load (local.get 0)))

(func $load8_offset (param i32) (result i32)
(i32.load8_u offset=32 (local.get 0)))

(func $load16_offset (param i32) (result i32)
(i32.load16_u offset=32 (local.get 0)))

(func $load32_offset (param i32) (result i32)
(i32.load offset=32 (local.get 0)))

(func $load64_offset (param i32) (result i64)
(i64.load offset=32 (local.get 0)))
)
;; wasm[0]::function[0]::load8:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; br_if_xulteq64 x8, x7, 0x14 // target = 0x1c
;; f: xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload8_u32_offset8 x0, x8, 0
;; pop_frame
;; ret
;; 1c: trap
;;
;; wasm[0]::function[1]::load16:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 2
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload16le_u32_offset8 x0, x8, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[2]::load32:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 4
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload32le_offset8 x0, x8, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[3]::load64:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 8
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload64le_offset8 x0, x8, 0
;; pop_frame
;; ret
;;
;; wasm[0]::function[4]::load8_offset:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 33
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload8_u32_offset8 x0, x8, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[5]::load16_offset:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 34
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload16le_u32_offset8 x0, x8, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[6]::load32_offset:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 36
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload32le_offset8 x0, x8, 32
;; pop_frame
;; ret
;;
;; wasm[0]::function[7]::load64_offset:
;; push_frame
;; xload64le_offset8 x8, x0, 104
;; zext32 x7, x2
;; xbc32_bound64_trap x2, x8, 40
;; xload64le_offset8 x8, x0, 96
;; xadd64 x8, x8, x7
;; xload64le_offset8 x0, x8, 32
;; pop_frame
;; ret