Minor fixes to write barriers#75478

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Merged
VSadov merged 2 commits into from
Apr 11, 2023
Merged

Minor fixes to write barriers #75478

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cb1509d
Minor fixes to write barriers
AntonLapounov Sep 12, 2022
da811d6
use the same predicated compare as on Unix when checking ephemeral lo…
VSadov Apr 10, 2023
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2 changes: 1 addition & 1 deletion src/coreclr/vm/amd64/JitHelpers_Fast.asm
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
; Check that our adjusted destination is somewhere in the shadow gc
add r10, [g_GCShadow]
cmp r10, [g_GCShadowEnd]
ja NoShadow
Comment thread
VSadov marked this conversation as resolved.
jnb NoShadow

; Write ref into real GC
mov [rdi], rcx
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/vm/amd64/JitHelpers_Slow.asm
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
; Check that our adjusted destination is somewhere in the shadow gc
add r10, [g_GCShadow]
cmp r10, [g_GCShadowEnd]
ja NoShadow
jnb NoShadow

; Write ref into real GC; see comment below about possibility of AV
mov [rcx], rdx
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/vm/amd64/jithelpers_fast.S
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
add r10, [rax]
PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
cmp r10, [rax]
ja NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

// Write ref into real GC
mov [rdi], rcx
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/vm/amd64/jithelpers_slow.S
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
add r10, [rax]
PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
cmp r10, [r11]
ja NoShadow
jnb NoShadow

// Write ref into real GC// see comment below about possibility of AV
mov [rdi], rsi
Expand Down
2 changes: 1 addition & 1 deletion src/coreclr/vm/arm64/asmhelpers.S
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
// branch to exit is taken.
ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
// Check if we need to update the card table
Expand Down
16 changes: 10 additions & 6 deletions src/coreclr/vm/arm64/asmhelpers.asm
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
; Branch to Exit if the reference is not in the Gen0 heap
;
adr x12, wbs_ephemeral_low
ldp x12, x16, [x12]
ldr x12, wbs_ephemeral_low
cbz x12, SkipEphemeralCheck

cmp x15, x12
blo Exit

cmp x15, x16
bhi Exit
ldr x12, wbs_ephemeral_high

; Compare against the upper bound if the previous comparison indicated
; that the destination address is greater than or equal to the lower
; bound. Otherwise, set the C flag (specified by the 0x2) so that the
; branch to exit is taken.
ccmp x15, x12, #0x2, hs

bhs Exit

@VSadovVSadovSep 14, 2022

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The .S version is using ccmp here. I think we should use the same pattern in both cases.

I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.

On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.

@VSadovVSadovSep 14, 2022

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And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S


SkipEphemeralCheck
; Check if we need to update the card table
Expand Down
4 changes: 2 additions & 2 deletions src/coreclr/vm/i386/jithelp.S
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
mov [edx], edx
cmp ecx, [edx]
pop edx
ja LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

// TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
// mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
mov eax, [eax]
cmp edx, [eax]
pop eax
ja LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

// TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
// mfence barriers on either side of these two writes to make sure that
Expand Down
4 changes: 2 additions & 2 deletions src/coreclr/vm/i386/jithelp.asm
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
jb WriteBarrier_NoShadow_&rg
add ecx, [g_GCShadow]
cmp ecx, [g_GCShadowEnd]
ja WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
jb ByRefWriteBarrier_NoShadow
add edx, [g_GCShadow]
cmp edx, [g_GCShadowEnd]
ja ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
; mfence barriers on either side of these two writes to make sure that
Expand Down
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Minor fixes to write barriers#75478

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 Merged

VSadov
merged 2 commits into

from

Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

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Choose a reason for hiding this comment

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And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Minor fixes to write barriers#75478

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to your account

 Merged

VSadov
merged 2 commits into

from

Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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2 commits


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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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Choose a reason for hiding this comment

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

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Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Minor fixes to write barriers#75478

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 Merged

VSadov
merged 2 commits into

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Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

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And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
Minor fixes to write barriers#75478

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to your account

 Merged

VSadov
merged 2 commits into

from

Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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Copy Markdown

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Choose a reason for hiding this comment

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Minor fixes to write barriers#75478

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
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to your account

 Merged

VSadov
merged 2 commits into

from

Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
Show file tree
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2 commits


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Hold shift + click to select a range
cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

File filter

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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Choose a reason for hiding this comment

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Minor fixes to write barriers#75478

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 Merged

VSadov
merged 2 commits into

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Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

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And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
Minor fixes to write barriers#75478

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 Merged

VSadov
merged 2 commits into

from

Apr 11, 2023
 Merged


Minor fixes to write barriers
#75478
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cb1509d

Minor fixes to write barriers


AntonLapounov Sep 12, 2022
da811d6

use the same predicated compare as on Unix when checking ephemeral lo…


VSadov Apr 10, 2023

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2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Fast.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -279,7 +279,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
Comment thread
VSadov marked this conversation as resolved.

jnb NoShadow

 ; Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/JitHelpers_Slow.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -81,7 +81,7 @@ ifdef WRITE_BARRIER_CHECK
 ; Check that our adjusted destination is somewhere in the shadow gc
 add r10, [g_GCShadow]
 cmp r10, [g_GCShadowEnd]
ja  NoShadow
jnb NoShadow

 ; Write ref into real GC; see comment below about possibility of AV
 mov [rcx], rdx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_fast.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -300,7 +300,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, rax
 cmp r10, [rax]
ja  NoShadow_ByRefWriteBarrier
jnb NoShadow_ByRefWriteBarrier

 // Write ref into real GC
 mov [rdi], rcx
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/amd64/jithelpers_slow.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -28,7 +28,7 @@ LEAF_ENTRY JIT_WriteBarrier_Debug, _TEXT
 add r10, [rax]
 PREPARE_EXTERNAL_VAR g_GCShadowEnd, r11
 cmp r10, [r11]
ja  NoShadow
jnb NoShadow

 // Write ref into real GC// see comment below about possibility of AV
 mov [rdi], rsi
Expand Down

2 changes: 1 addition & 1 deletion
src/coreclr/vm/arm64/asmhelpers.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -420,7 +420,7 @@ LOCAL_LABEL(CheckCardTable):
 // branch to exit is taken.
 ccmp x15, x12, #0x2, hs

bhi LOCAL_LABEL(Exit)
bhs LOCAL_LABEL(Exit)

LOCAL_LABEL(SkipEphemeralCheck):
 // Check if we need to update the card table
Expand Down

16 changes: 10 additions & 6 deletions
src/coreclr/vm/arm64/asmhelpers.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -473,15 +473,19 @@ ShadowUpdateDisabled
CheckCardTable
 ; Branch to Exit if the reference is not in the Gen0 heap
 ;
 adr x12, wbs_ephemeral_low
 ldp x12, x16, [x12]
 ldr x12, wbs_ephemeral_low
 cbz x12, SkipEphemeralCheck

 cmp x15, x12
 blo Exit

 cmp x15, x16
 bhi Exit
 ldr x12, wbs_ephemeral_high

 ; Compare against the upper bound if the previous comparison indicated
 ; that the destination address is greater than or equal to the lower
 ; bound. Otherwise, set the C flag (specified by the 0x2) so that the
 ; branch to exit is taken.
 ccmp x15, x12, #0x2, hs

 bhs Exit
@VSadovVSadovSep 14, 2022

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Choose a reason for hiding this comment

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The .S version is using ccmp here. I think we should use the same pattern in both cases.
I wonder which would be better though. In theory the ephemeral check should more often fail than pass, statistically. In a large heap most objects are tenured. Ephemeral set is supposed to be small.
On the other hand both patterns probably work the same on a speculative CPU, but the predicated pattern is shorter by one instruction.
@VSadovVSadovSep 14, 2022

Copy link


Copy Markdown

Member
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

And on server GC ephemeral check will always pass. I think, since we are touching this, it should be switched to the predicated form like in .S

SkipEphemeralCheck
 ; Check if we need to update the card table
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.S

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -109,7 +109,7 @@ PATCH_LABEL JIT_DebugWriteBarrier\rg
 mov [edx], edx
 cmp ecx, [edx]
 pop edx
ja  LOCAL_LABEL(WriteBarrier_NoShadow_\rg)
jae LOCAL_LABEL(WriteBarrier_NoShadow_\rg)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -281,7 +281,7 @@ LEAF_ENTRY JIT_ByRefWriteBarrier, _TEXT
 mov eax, [eax]
 cmp edx, [eax]
 pop eax
ja  LOCAL_LABEL(ByRefWriteBarrier_NoShadow)
jae LOCAL_LABEL(ByRefWriteBarrier_NoShadow)

 // TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 // mfence barriers on either side of these two writes to make sure that
Expand Down

4 changes: 2 additions & 2 deletions
src/coreclr/vm/i386/jithelp.asm

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -193,7 +193,7 @@ ifdef WRITE_BARRIER_CHECK
 jb WriteBarrier_NoShadow_&rg
 add ecx, [g_GCShadow]
 cmp ecx, [g_GCShadowEnd]
ja  WriteBarrier_NoShadow_&rg
jae WriteBarrier_NoShadow_&rg

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand DownExpand Up@@ -330,7 +330,7 @@ ifdef WRITE_BARRIER_CHECK
 jb ByRefWriteBarrier_NoShadow
 add edx, [g_GCShadow]
 cmp edx, [g_GCShadowEnd]
ja  ByRefWriteBarrier_NoShadow
jae ByRefWriteBarrier_NoShadow

 ; TODO: In Orcas timeframe if we move to P4+ only on X86 we should enable
 ; mfence barriers on either side of these two writes to make sure that
Expand Down