GH-129715: Don't project traces that return to an unknown caller (GH-130024)

brandtbucher · web-flow · commit 11bb08e4ec7b · 2025-02-12T10:16:43.000-08:00
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-02-11-22-20-21.gh-issue-129715.mopO8n.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-02-11-22-20-21.gh-issue-129715.mopO8n.rst
@@ -0,0 +1 @@
+Improve the experimental JIT's handling of returns to unknown callers.
diff --git a/Python/instrumentation.c b/Python/instrumentation.c
@@ -185,8 +185,7 @@ is_instrumented(int opcode)
 {
     assert(opcode != 0);
     assert(opcode != RESERVED);
-    assert(opcode != ENTER_EXECUTOR);
-    return opcode >= MIN_INSTRUMENTED_OPCODE;
+    return opcode != ENTER_EXECUTOR && opcode >= MIN_INSTRUMENTED_OPCODE;
 }
 
 #ifndef NDEBUG
diff --git a/Python/optimizer.c b/Python/optimizer.c
@@ -671,7 +671,7 @@ translate_bytecode_to_trace(
                         if (trace_stack_depth == 0) {
                             DPRINTF(2, "Trace stack underflow\n");
                             OPT_STAT_INC(trace_stack_underflow);
-                            goto done;
+                            return 0;
                         }
                     }
                     uint32_t orig_oparg = oparg;  // For OPARG_TOP/BOTTOM

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Improve the experimental JIT's handling of returns to unknown callers.`
Original file line number	Diff line number	Diff line change
`@@ -185,8 +185,7 @@ is_instrumented(int opcode)`
`185`	`185`	`{`
`186`	`186`	`assert(opcode != 0);`
`187`	`187`	`assert(opcode != RESERVED);`
`188`		`- assert(opcode != ENTER_EXECUTOR);`
`189`		`- return opcode >= MIN_INSTRUMENTED_OPCODE;`
	`188`	`+ return opcode != ENTER_EXECUTOR && opcode >= MIN_INSTRUMENTED_OPCODE;`
`190`	`189`	`}`
`191`	`190`
`192`	`191`	`#ifndef NDEBUG`
Original file line number	Diff line number	Diff line change
`@@ -671,7 +671,7 @@ translate_bytecode_to_trace(`
`671`	`671`	`if (trace_stack_depth == 0) {`
`672`	`672`	`DPRINTF(2, "Trace stack underflow\n");`
`673`	`673`	`OPT_STAT_INC(trace_stack_underflow);`
`674`		`- goto done;`
	`674`	`+ return 0;`
`675`	`675`	`}`
`676`	`676`	`}`
`677`	`677`	`uint32_t orig_oparg = oparg; // For OPARG_TOP/BOTTOM`