GH-111485: Separate out parsing, analysis and code-gen phases of tier 1 code generator (GH-112299)

Tools/cases_generator/stack.py

@@ -0,0 +1,81 @@
+import sys
+from analyzer import StackItem
+from dataclasses import dataclass
+from formatting import maybe_parenthesize
+
+
+def var_size(var: StackItem) -> str:
+    if var.condition:
+        # Special case simplification
+        if var.condition == "oparg & 1" and var.size == "1":
+            return f"({var.condition})"
+        else:
+            return f"(({var.condition}) ? {var.size} : 0)"
+    else:
+        return var.size
+
+
+class StackOffset:
+    "The stack offset of the virtual base of the stack from the physical stack pointer"
+
+    def __init__(self) -> None:
+        self.popped: list[str] = []
+        self.pushed: list[str] = []
+
+    def pop(self, item: StackItem) -> None:
+        self.popped.append(var_size(item))
+
+    def push(self, item: StackItem) -> None:
+        self.pushed.append(var_size(item))
+
+    def simplify(self) -> None:
+        "Remove matching values from both the popped and pushed list"
+        if not self.popped or not self.pushed:
+            return
+        # Sort the list so the lexically largest element is last.
+        popped = sorted(self.popped)
+        pushed = sorted(self.pushed)
+        self.popped = []
+        self.pushed = []
+        while popped and pushed:
+            pop = popped.pop()
+            push = pushed.pop()
+            if pop == push:
+                pass
+            elif pop > push:
+                # if pop > push, there can be no element in pushed matching pop.
+                self.popped.append(pop)
+                pushed.append(push)
+            else:
+                self.pushed.append(push)
+                popped.append(pop)
+        self.popped.extend(popped)
+        self.pushed.extend(pushed)
+
+    def to_c(self) -> str:
+        self.simplify()
+        int_offset = 0
+        symbol_offset = ""
+        for item in self.popped:
+            try:
+                int_offset -= int(item)
+            except ValueError:
+                symbol_offset += f" - {maybe_parenthesize(item)}"
+        for item in self.pushed:
+            try:
+                int_offset += int(item)
+            except ValueError:
+                symbol_offset += f" + {maybe_parenthesize(item)}"
+        if symbol_offset and not int_offset:
+            res = symbol_offset
+        else:
+            res = f"{int_offset}{symbol_offset}"
+        if res.startswith(" + "):
+            res = res[3:]
+        if res.startswith(" - "):
+            res = "-" + res[3:]
+        return res
+
+    def clear(self) -> None:
+        self.popped = []
+        self.pushed = []