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Fix invalid store offsets in memset polyfill #1787

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Merged
merged 2 commits into from
Apr 6, 2021
Merged

Fix invalid store offsets in memset polyfill #1787

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daf3ddf
Fix invalid store offsets in memset polyfill
dcodeIO Apr 6, 2021
70b87ba
handle potentially negative offsets only
dcodeIO Apr 6, 2021
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26 changes: 13 additions & 13 deletions std/assembly/util/memory.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -201,17 +201,17 @@ export function memset(dest: usize, c: u8, n: usize): void { // see: musl/src/st
} else {
// fill head and tail with minimal branching
if (!n) return;
let dend = dest + n - 4;
let dend = dest + n;
store<u8>(dest, c);
store<u8>(dend, c, 3);
store<u8>(dend - 1, c);
if (n <= 2) return;
store<u8>(dest, c, 1);
store<u8>(dest, c, 2);
store<u8>(dend, c, 2);
store<u8>(dend, c, 1);
store<u8>(dend - 2, c);
store<u8>(dend - 3, c);
if (n <= 6) return;
store<u8>(dest, c, 3);
store<u8>(dend, c);
store<u8>(dend - 4, c);
if (n <= 8) return;

// advance pointer to align it at 4-byte boundary
Expand All @@ -223,23 +223,23 @@ export function memset(dest: usize, c: u8, n: usize): void { // see: musl/src/st
let c32: u32 = <u32>-1 / 255 * c;

// fill head/tail up to 28 bytes each in preparation
dend = dest + n - 28;
dend = dest + n;
store<u32>(dest, c32);
store<u32>(dend, c32, 24);
store<u32>(dend - 4, c32);
if (n <= 8) return;
store<u32>(dest, c32, 4);
store<u32>(dest, c32, 8);
store<u32>(dend, c32, 16);
store<u32>(dend, c32, 20);
store<u32>(dend - 12, c32);
store<u32>(dend - 8, c32);
if (n <= 24) return;
store<u32>(dest, c32, 12);
store<u32>(dest, c32, 16);
store<u32>(dest, c32, 20);
store<u32>(dest, c32, 24);
store<u32>(dend, c32);
store<u32>(dend, c32, 4);
store<u32>(dend, c32, 8);
store<u32>(dend, c32, 12);
store<u32>(dend - 28, c32);
store<u32>(dend - 24, c32);
store<u32>(dend - 20, c32);
store<u32>(dend - 16, c32);

// align to a multiple of 8
k = 24 + (dest & 4);
Expand Down
44 changes: 31 additions & 13 deletions tests/compiler/call-super.optimized.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -1449,11 +1449,11 @@
local.get $0
local.get $1
i32.add
i32.const 4
i32.sub
local.tee $2
i32.const 1
i32.sub
i32.const 0
i32.store8 offset=3
i32.store8
local.get $1
i32.const 2
i32.le_u
Expand All @@ -1465,11 +1465,15 @@
i32.const 0
i32.store8 offset=2
local.get $2
i32.const 2
i32.sub
i32.const 0
i32.store8 offset=2
i32.store8
local.get $2
i32.const 3
i32.sub
i32.const 0
i32.store8 offset=1
i32.store8
local.get $1
i32.const 6
i32.le_u
Expand All @@ -1478,6 +1482,8 @@
i32.const 0
i32.store8 offset=3
local.get $2
i32.const 4
i32.sub
i32.const 0
i32.store8
local.get $1
Expand All @@ -1503,11 +1509,11 @@
i32.and
local.tee $2
i32.add
i32.const 28
i32.sub
local.tee $1
i32.const 4
i32.sub
i32.const 0
i32.store offset=24
i32.store
local.get $2
i32.const 8
i32.le_u
Expand All @@ -1519,11 +1525,15 @@
i32.const 0
i32.store offset=8
local.get $1
i32.const 12
i32.sub
i32.const 0
i32.store offset=16
i32.store
local.get $1
i32.const 8
i32.sub
i32.const 0
i32.store offset=20
i32.store
local.get $2
i32.const 24
i32.le_u
Expand All @@ -1541,17 +1551,25 @@
i32.const 0
i32.store offset=24
local.get $1
i32.const 28
i32.sub
i32.const 0
i32.store
local.get $1
i32.const 24
i32.sub
i32.const 0
i32.store offset=4
i32.store
local.get $1
i32.const 20
i32.sub
i32.const 0
i32.store offset=8
i32.store
local.get $1
i32.const 16
i32.sub
i32.const 0
i32.store offset=12
i32.store
local.get $0
local.get $0
i32.const 4
Expand Down
44 changes: 31 additions & 13 deletions tests/compiler/call-super.untouched.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -2089,15 +2089,15 @@
local.get $5
local.get $3
i32.add
i32.const 4
i32.sub
local.set $6
local.get $5
local.get $4
i32.store8
local.get $6
i32.const 1
i32.sub
local.get $4
i32.store8 offset=3
i32.store8
local.get $3
i32.const 2
i32.le_u
Expand All @@ -2111,11 +2111,15 @@
local.get $4
i32.store8 offset=2
local.get $6
i32.const 2
i32.sub
local.get $4
i32.store8 offset=2
i32.store8
local.get $6
i32.const 3
i32.sub
local.get $4
i32.store8 offset=1
i32.store8
local.get $3
i32.const 6
i32.le_u
Expand All @@ -2126,6 +2130,8 @@
local.get $4
i32.store8 offset=3
local.get $6
i32.const 4
i32.sub
local.get $4
i32.store8
local.get $3
Expand Down Expand Up @@ -2163,15 +2169,15 @@
local.get $5
local.get $3
i32.add
i32.const 28
i32.sub
local.set $6
local.get $5
local.get $8
i32.store
local.get $6
i32.const 4
i32.sub
local.get $8
i32.store offset=24
i32.store
local.get $3
i32.const 8
i32.le_u
Expand All @@ -2185,11 +2191,15 @@
local.get $8
i32.store offset=8
local.get $6
i32.const 12
i32.sub
local.get $8
i32.store offset=16
i32.store
local.get $6
i32.const 8
i32.sub
local.get $8
i32.store offset=20
i32.store
local.get $3
i32.const 24
i32.le_u
Expand All @@ -2209,17 +2219,25 @@
local.get $8
i32.store offset=24
local.get $6
i32.const 28
i32.sub
local.get $8
i32.store
local.get $6
i32.const 24
i32.sub
local.get $8
i32.store offset=4
i32.store
local.get $6
i32.const 20
i32.sub
local.get $8
i32.store offset=8
i32.store
local.get $6
i32.const 16
i32.sub
local.get $8
i32.store offset=12
i32.store
i32.const 24
local.get $5
i32.const 4
Expand Down
44 changes: 31 additions & 13 deletions tests/compiler/class-implements.untouched.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -2099,15 +2099,15 @@
local.get $5
local.get $3
i32.add
i32.const 4
i32.sub
local.set $6
local.get $5
local.get $4
i32.store8
local.get $6
i32.const 1
i32.sub
local.get $4
i32.store8 offset=3
i32.store8
local.get $3
i32.const 2
i32.le_u
Expand All @@ -2121,11 +2121,15 @@
local.get $4
i32.store8 offset=2
local.get $6
i32.const 2
i32.sub
local.get $4
i32.store8 offset=2
i32.store8
local.get $6
i32.const 3
i32.sub
local.get $4
i32.store8 offset=1
i32.store8
local.get $3
i32.const 6
i32.le_u
Expand All @@ -2136,6 +2140,8 @@
local.get $4
i32.store8 offset=3
local.get $6
i32.const 4
i32.sub
local.get $4
i32.store8
local.get $3
Expand Down Expand Up @@ -2173,15 +2179,15 @@
local.get $5
local.get $3
i32.add
i32.const 28
i32.sub
local.set $6
local.get $5
local.get $8
i32.store
local.get $6
i32.const 4
i32.sub
local.get $8
i32.store offset=24
i32.store
local.get $3
i32.const 8
i32.le_u
Expand All @@ -2195,11 +2201,15 @@
local.get $8
i32.store offset=8
local.get $6
i32.const 12
i32.sub
local.get $8
i32.store offset=16
i32.store
local.get $6
i32.const 8
i32.sub
local.get $8
i32.store offset=20
i32.store
local.get $3
i32.const 24
i32.le_u
Expand All @@ -2219,17 +2229,25 @@
local.get $8
i32.store offset=24
local.get $6
i32.const 28
i32.sub
local.get $8
i32.store
local.get $6
i32.const 24
i32.sub
local.get $8
i32.store offset=4
i32.store
local.get $6
i32.const 20
i32.sub
local.get $8
i32.store offset=8
i32.store
local.get $6
i32.const 16
i32.sub
local.get $8
i32.store offset=12
i32.store
i32.const 24
local.get $5
i32.const 4
Expand Down
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