gh-98831: Modernize FORMAT_VALUE (#101628)

Generator update: support balanced parentheses and brackets in conditions and size expressions.

3 files changed, 12 insertions, 30 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index c6c00a7..d0f0513 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -3054,18 +3054,10 @@ dummy_func(
             ERROR_IF(slice == NULL, error);
         }
 
-        // error: FORMAT_VALUE has irregular stack effect
-        inst(FORMAT_VALUE) {
+        inst(FORMAT_VALUE, (value, fmt_spec if ((oparg & FVS_MASK) == FVS_HAVE_SPEC) -- result)) {
             /* Handles f-string value formatting. */
-            PyObject *result;
-            PyObject *fmt_spec;
-            PyObject *value;
             PyObject *(*conv_fn)(PyObject *);
             int which_conversion = oparg & FVC_MASK;
-            int have_fmt_spec = (oparg & FVS_MASK) == FVS_HAVE_SPEC;
-
-            fmt_spec = have_fmt_spec ? POP() : NULL;
-            value = POP();
 
             /* See if any conversion is specified. */
             switch (which_conversion) {
@@ -3088,7 +3080,7 @@ dummy_func(
                 Py_DECREF(value);
                 if (result == NULL) {
                     Py_XDECREF(fmt_spec);
-                    goto error;
+                    ERROR_IF(true, error);
                 }
                 value = result;
             }
@@ -3106,12 +3098,8 @@ dummy_func(
                 result = PyObject_Format(value, fmt_spec);
                 Py_DECREF(value);
                 Py_XDECREF(fmt_spec);
-                if (result == NULL) {
-                    goto error;
-                }
+                ERROR_IF(result == NULL, error);
             }
-
-            PUSH(result);
         }
 
         inst(COPY, (bottom, unused[oparg-1] -- bottom, unused[oparg-1], top)) {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index ded68d0..3ef8086 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -3703,16 +3703,12 @@
         }
 
         TARGET(FORMAT_VALUE) {
-            /* Handles f-string value formatting. */
+            PyObject *fmt_spec = ((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? PEEK((((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0)) : NULL;
+            PyObject *value = PEEK(1 + (((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0));
             PyObject *result;
-            PyObject *fmt_spec;
-            PyObject *value;
+            /* Handles f-string value formatting. */
             PyObject *(*conv_fn)(PyObject *);
             int which_conversion = oparg & FVC_MASK;
-            int have_fmt_spec = (oparg & FVS_MASK) == FVS_HAVE_SPEC;
-
-            fmt_spec = have_fmt_spec ? POP() : NULL;
-            value = POP();
 
             /* See if any conversion is specified. */
             switch (which_conversion) {
@@ -3735,7 +3731,7 @@
                 Py_DECREF(value);
                 if (result == NULL) {
                     Py_XDECREF(fmt_spec);
-                    goto error;
+                    if (true) { STACK_SHRINK((((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0)); goto pop_1_error; }
                 }
                 value = result;
             }
@@ -3753,12 +3749,10 @@
                 result = PyObject_Format(value, fmt_spec);
                 Py_DECREF(value);
                 Py_XDECREF(fmt_spec);
-                if (result == NULL) {
-                    goto error;
-                }
+                if (result == NULL) { STACK_SHRINK((((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0)); goto pop_1_error; }
             }
-
-            PUSH(result);
+            STACK_SHRINK((((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0));
+            POKE(1, result);
             DISPATCH();
         }
 
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index c1e12a4..52bab1c 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -333,7 +333,7 @@ _PyOpcode_num_popped(int opcode, int oparg, bool jump) {
         case BUILD_SLICE:
             return ((oparg == 3) ? 1 : 0) + 2;
         case FORMAT_VALUE:
-            return -1;
+            return (((oparg & FVS_MASK) == FVS_HAVE_SPEC) ? 1 : 0) + 1;
         case COPY:
             return (oparg-1) + 1;
         case BINARY_OP:
@@ -681,7 +681,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
         case BUILD_SLICE:
             return 1;
         case FORMAT_VALUE:
-            return -1;
+            return 1;
         case COPY:
             return (oparg-1) + 2;
         case BINARY_OP: