IR JIT: too long jmp distance in ir_add_veneer, ir_aarch64.dasc:6495.

[danog]

Description

Running ./psalm --no-cache in https://github.com/vimeo/psalm/tree/preload_all_classes_tmp on aarch64 (mac OS 15.3.1, not reproducible on linux aarch64 on a KVM in the same machine) triggers the following assertion:

Assertion failed: (0 && "too long jmp distance"), function ir_add_veneer, file ir_aarch64.dasc, line 6495.

On 3b23de3, the following assertion is triggered instead:

Assertion failed: (_blocks[use] == b || use_insn->op == IR_PARAM), function ir_schedule, file ir_gcm.c, line 948.

The issue is triggered by the large number of class_exists statements in src/Psalm/Internal/Preloader.php, reducing the number to < ~1020 fixes the issue.

PHP Version

PHP 8.4.4 or 3b23de3

Operating System

Mac OS 15.3.1

[danog]

Ping @dstogov

[dstogov]

Thanks for the report.
Can you reproduce the issue running php -d opcache.jit=1205 Preloader.php
The second assertion looks unrelated.

[dstogov]

@danog could you please check the patch.
It should fix only the first problem, I need a reproduction case for the second one.

diff --git a/ext/opcache/jit/ir/ir_aarch64.dasc b/ext/opcache/jit/ir/ir_aarch64.dasc
index 772eea7a5d7..67bb0cdaea1 100644
--- a/ext/opcache/jit/ir/ir_aarch64.dasc
+++ b/ext/opcache/jit/ir/ir_aarch64.dasc
@@ -6441,6 +6441,8 @@ static int ir_add_veneer(dasm_State *Dst, void *buffer, uint32_t ins, int *b, ui
 		if (ctx->get_veneer) {
 			veneer = ctx->get_veneer(ctx, addr);
 		}
+	} else if ((ins >> 16) == DASM_REL_PC) {
+		addr = (char*)cp - 4 + offset;
 	} else {
 		IR_ASSERT(0 && "too long jmp distance");
 		return 0;
@@ -6525,7 +6527,9 @@ static int ir_add_veneer(dasm_State *Dst, void *buffer, uint32_t ins, int *b, ui
 		return 0;
 	}
 
-	if (!ctx->set_veneer || !ctx->set_veneer(ctx, addr, veneer)) {
+	if ((ins >> 16) == DASM_REL_PC) {
+	  *DASM_POS2PTR(Dst, *(b - 1)) = (int)((char*)addr - (char*)buffer);
+	} else if (!ctx->set_veneer || !ctx->set_veneer(ctx, addr, veneer)) {
 		IR_ASSERT(0 && "too long jmp distance");
 		return 0;
 	}
'''

[danog]

@dstogov The second can be easily reproduced by running ./psalm --no-cache on 3b23de3, with the opcache extension loaded via php.ini.

Trying with the patch applied on top of PHP-8.4 now...

[danog]

@dstogov your patch doesn't fix the issue when applied on PHP-8.4:

daniil@MBP-di-Daniil php-src % git diff
diff --git a/ext/opcache/jit/ir/ir_aarch64.dasc b/ext/opcache/jit/ir/ir_aarch64.dasc
index 772eea7a5d..67bb0cdaea 100644
--- a/ext/opcache/jit/ir/ir_aarch64.dasc
+++ b/ext/opcache/jit/ir/ir_aarch64.dasc
@@ -6441,6 +6441,8 @@ static int ir_add_veneer(dasm_State *Dst, void *buffer, uint32_t ins, int *b, ui
                if (ctx->get_veneer) {
                        veneer = ctx->get_veneer(ctx, addr);
                }
+       } else if ((ins >> 16) == DASM_REL_PC) {
+               addr = (char*)cp - 4 + offset;
        } else {
                IR_ASSERT(0 && "too long jmp distance");
                return 0;
@@ -6525,7 +6527,9 @@ static int ir_add_veneer(dasm_State *Dst, void *buffer, uint32_t ins, int *b, ui
                return 0;
        }

-       if (!ctx->set_veneer || !ctx->set_veneer(ctx, addr, veneer)) {
+       if ((ins >> 16) == DASM_REL_PC) {
+         *DASM_POS2PTR(Dst, *(b - 1)) = (int)((char*)addr - (char*)buffer);
+       } else if (!ctx->set_veneer || !ctx->set_veneer(ctx, addr, veneer)) {
                IR_ASSERT(0 && "too long jmp distance");
                return 0;
        }

daniil@MBP-di-Daniil psalm % git diff
diff --git a/src/Psalm/Internal/Fork/PsalmRestarter.php b/src/Psalm/Internal/Fork/PsalmRestarter.php
index 5a702e137..01808ffd7 100644
--- a/src/Psalm/Internal/Fork/PsalmRestarter.php
+++ b/src/Psalm/Internal/Fork/PsalmRestarter.php
@@ -166,7 +166,7 @@ final class PsalmRestarter extends XdebugHandler
         // executed in the parent process (before restart)
         // if it wasn't loaded then we apparently don't have opcache installed and there's no point trying
         // to tweak it
-        $additional_options = $opcache_loaded ? [] : ['-dzend_extension=opcache'];
+        $additional_options = $opcache_loaded ? [] : ['-dzend_extension=/Users/daniil/repos/php-src/./ext/opcache/.libs/opcache.so'];
         foreach (self::REQUIRED_OPCACHE_SETTINGS as $key => $value) {
             $additional_options []= "-dopcache.{$key}={$value}";
         }
daniil@MBP-di-Daniil psalm % ~/repos/php-src/sapi/cli/php ./psalm --no-cache
php(75602,0x1fa134840) malloc: nano zone abandoned due to inability to reserve vm space.
php(75605,0x1fa134840) malloc: nano zone abandoned due to inability to reserve vm space.

JIT acceleration: ON

JIT compilation in progress... Assertion failed: (0 && "too long jmp distance"), function ir_add_veneer, file ir_aarch64.dasc, line 6497.

[dstogov]

It seems you have a different problem, that I can't reproduce (I don't have Mac).

[danog]

https://github.com/sickcodes/Docker-OSX might help

[iluuu1994]

@danog FWIW I tried that in the past and couldn't get it working.