fix(ast): strip stack canary boilerplate from decompiled C output

include/patchestry/AST/FunctionBuilder.hpp

@@ -120,6 +120,8 @@ namespace patchestry::ast {
         std::reference_wrapper< std::unordered_map< std::string, clang::VarDecl * > >
             global_var_list;
 
+        bool is_stack_canary_operation(const Operation &op) const;
+
         std::unordered_map< std::string, clang::VarDecl * > local_variables;
         std::unordered_map< std::string, clang::LabelDecl * > labels_declaration;
         std::unordered_map< std::string, clang::Stmt * > operation_stmts;

lib/patchestry/AST/FunctionBuilder.cpp

@@ -696,6 +696,36 @@ namespace patchestry::ast {
         return stmt_vec;
     }
 
+    /**
+     * @brief Detects whether an operation is part of compiler-inserted stack canary
+     * boilerplate (__stack_chk_guard load/compare, __stack_chk_fail call).
+     */
+    bool FunctionBuilder::is_stack_canary_operation(const Operation &op) const {
+        auto is_canary_global = [this](const std::optional< std::string > &key) -> bool {
+            if (!key.has_value()) return false;
+            auto it = global_var_list.get().find(*key);
+            if (it == global_var_list.get().end()) return false;
+            const auto &name = it->second->getNameAsString();
+            return name == "__stack_chk_guard" || name == "___stack_chk_guard";
+        };
+
+        for (const auto &input : op.inputs) {
+            if (is_canary_global(input.global)) return true;
+        }
+
+        if (op.output.has_value() && is_canary_global(op.output->global)) return true;
+
+        if (op.target.has_value() && op.target->function.has_value()) {
+            auto it = function_list.get().find(*op.target->function);
+            if (it != function_list.get().end()) {
+                const auto &name = it->second->getNameAsString();
+                if (name == "__stack_chk_fail" || name == "___stack_chk_fail") return true;
+            }
+        }
+
+        return false;
+    }
+
     /**
      * @brief Generates a vector of `clang::Stmt*` representing the operations in a basic block.
      *
@@ -727,6 +757,11 @@ namespace patchestry::ast {
 
             const auto &operation = block.operations.at(operation_key);
 
+            // Skip compiler-inserted stack canary boilerplate
+            if (is_stack_canary_operation(operation)) {
+                continue;
+            }
+
             // Save pending_materialized in case create_operation re-enters
             // (e.g., create_temporary resolving a forward reference triggers
             // nested operation building that appends to the same vector).

test/patchir-decomp/bl_device__process_entry.json

@@ -3,6 +3,9 @@
 // RUN: test -e %t.c
 // RUN: %patchir-decomp -input %t.json -emit-cir -emit-mlir -emit-llvm -print-tu -output %t >> /dev/null 2>&1
 // RUN: test -e %t.c
+// RUN: %file-check -vv -check-prefix=CGEN %s --input-file %t.c
+// CGEN: bl_device__process_entry
+// CGEN-NOT: __stack_chk_fail
 // RUN: %file-check -vv -check-prefix=CIR %s --input-file %t.cir
 // CIR: cir.func @bl_device__process_entry
 // RUN: %file-check -vv -check-prefix=MLIR %s --input-file %t.mlir