From: Ken Jin <kenjin@python.org>
Date: Wed, 20 Aug 2025 14:53:54 +0000 (+0800)
Subject: gh-137728 gh-137762: Fix bugs in the JIT with many local variables (GH-137764)
X-Git-Tag: v3.15.0a1~632
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7fda8b66debb24e0520b94c3769b648c7305f84e;p=thirdparty%2FPython%2Fcpython.git

gh-137728 gh-137762: Fix bugs in the JIT with many local variables (GH-137764)
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-08-14-14-18-29.gh-issue-137728.HdYS9R.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-08-14-14-18-29.gh-issue-137728.HdYS9R.rst
new file mode 100644
index 000000000000..cc4a55ddf383
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-08-14-14-18-29.gh-issue-137728.HdYS9R.rst
@@ -0,0 +1 @@
+Fix the JIT's handling of many local variables. This previously caused a segfault.
diff --git a/Python/optimizer_analysis.c b/Python/optimizer_analysis.c
index dd3e49b83d99..533d70580e4c 100644
--- a/Python/optimizer_analysis.c
+++ b/Python/optimizer_analysis.c
@@ -484,13 +484,10 @@ optimize_uops(
     _Py_uop_abstractcontext_init(ctx);
     _Py_UOpsAbstractFrame *frame = _Py_uop_frame_new(ctx, co, curr_stacklen, NULL, 0);
     if (frame == NULL) {
-        return -1;
+        return 0;
     }
     ctx->curr_frame_depth++;
     ctx->frame = frame;
-    ctx->done = false;
-    ctx->out_of_space = false;
-    ctx->contradiction = false;
 
     _PyUOpInstruction *this_instr = NULL;
     for (int i = 0; !ctx->done; i++) {
diff --git a/Python/optimizer_symbols.c b/Python/optimizer_symbols.c
index 8a3df236c806..8169ce9df5aa 100644
--- a/Python/optimizer_symbols.c
+++ b/Python/optimizer_symbols.c
@@ -888,6 +888,13 @@ _Py_uop_abstractcontext_init(JitOptContext *ctx)
 
     // Frame setup
     ctx->curr_frame_depth = 0;
+
+    // Ctx signals.
+    // Note: this must happen before frame_new, as it might override
+    // the result should frame_new set things to bottom.
+    ctx->done = false;
+    ctx->out_of_space = false;
+    ctx->contradiction = false;
 }
 
 int