lcompilers · czgdp1807 · Nov 29, 2022 · Dec 5, 2022
diff --git a/.gitignore b/.gitignore
@@ -217,3 +217,10 @@ integration_tests/array_02_decl
 integration_tests/array_02_decl.c
 integration_tests/expr_12
 integration_tests/expr_12.c
+integration_tests/expr_07_generated.c
+integration_tests/expr_07.c
+expr_07.c
+tests/c_interop1.c
+tests/expr7.c
+tests/loop1.c
+tests/loop2.c
diff --git a/integration_tests/CMakeLists.txt b/integration_tests/CMakeLists.txt
@@ -46,12 +46,13 @@ message("LPYTHON_RTLIB_LIBRARY: ${LPYTHON_RTLIB_LIBRARY}")
 
 macro(RUN)
     set(options FAIL)
-    set(oneValueArgs NAME IMPORT_PATH)
+    set(oneValueArgs NAME IMPORT_PATH CUSTOM_C_POSTPROCESSOR)
     set(multiValueArgs LABELS EXTRAFILES)
     cmake_parse_arguments(RUN "${options}" "${oneValueArgs}"
                           "${multiValueArgs}" ${ARGN} )
     set(name ${RUN_NAME})
     set(import_path ${RUN_IMPORT_PATH})
+    set(custom_c_postprocessor ${RUN_CUSTOM_C_POSTPROCESSOR})
     if (NOT name)
         message(FATAL_ERROR "Must specify the NAME argument")
     endif()
@@ -82,11 +83,20 @@ macro(RUN)
                 set_tests_properties(${name} PROPERTIES WILL_FAIL TRUE)
             endif()
         elseif(KIND STREQUAL "c")
-            add_custom_command(
-                OUTPUT ${name}.c
-                COMMAND lpython --show-c ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py > ${name}.c
-                DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py
-                VERBATIM)
+            if (custom_c_postprocessor)
+                add_custom_command(
+                    OUTPUT ${name}.c
+                    COMMAND lpython --show-c ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py
+                            --custom-c-postprocessor ${CMAKE_CURRENT_SOURCE_DIR}/${custom_c_postprocessor} -o ${name}.c
+                    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py
+                    VERBATIM)
+            else ()
+                add_custom_command(
+                    OUTPUT ${name}.c
+                    COMMAND lpython --show-c ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py -o ${name}.c
+                    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${name}.py
+                    VERBATIM)
+            endif()
             add_executable(${name} ${name}.c ${RUN_EXTRAFILES})
             set_target_properties(${name} PROPERTIES LINKER_LANGUAGE C)
             target_link_libraries(${name} lpython_rtlib)
@@ -209,7 +219,8 @@ RUN(NAME expr_03             LABELS cpython llvm c wasm)
 RUN(NAME expr_04             LABELS cpython llvm c)
 RUN(NAME expr_05             LABELS cpython llvm c)
 RUN(NAME expr_06             LABELS cpython llvm c)
-RUN(NAME expr_07             LABELS cpython llvm c)
+RUN(NAME expr_07             CUSTOM_C_POSTPROCESSOR test_c_custom_postprocessor.py
+        LABELS cpython llvm c)
 RUN(NAME expr_08             LABELS llvm c)
 RUN(NAME expr_09             LABELS cpython llvm c)
 RUN(NAME expr_10             LABELS cpython llvm c)

diff --git a/integration_tests/test_c_custom_postprocessor.py b/integration_tests/test_c_custom_postprocessor.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+
+import sys
+
+filename = sys.argv[1]
+
+file = open(filename, "r")
+f = file.read()
+file.close()
+
+file = open(filename, "w")
+file.write(f)
+file.close()
diff --git a/src/bin/lpython.cpp b/src/bin/lpython.cpp
@@ -60,6 +60,12 @@ std::string remove_extension(const std::string& filename) {
     return filename.substr(0, lastdot);
 }
 
+std::string extract_extension(const std::string& filename) {
+    size_t lastdot = filename.find_last_of(".");
+    if (lastdot == std::string::npos) return "";
+    return filename.substr(lastdot);
+}
+
 std::string remove_path(const std::string& filename) {
     size_t lastslash = filename.find_last_of("/");
     if (lastslash == std::string::npos) return filename;
@@ -289,7 +295,35 @@ int emit_c(const std::string &infile,
         LFORTRAN_ASSERT(diagnostics.has_error())
         return 3;
     }
-    std::cout << res.result;
+
+    std::string output_file;
+    bool print_to_std = true;
+    if( !compiler_options.arg_o.empty() ) {
+        output_file = compiler_options.arg_o;
+        print_to_std = false;
+    } else {
+        output_file = remove_extension(infile) + ".c";
+    }
+    std::string ccode_file = output_file;
+    std::ofstream ccode_out(ccode_file);
+    ccode_out << res.result;
+    ccode_out.close();
+    if( !compiler_options.c_postprocessor_script.empty() ) {
+        std::string command = "python " + compiler_options.c_postprocessor_script + " " + ccode_file;
+        system(command.c_str());
+        if( print_to_std ) {
+            std::ifstream ccode_in(ccode_file);
+            std::string modified_result = "";
+            while( std::getline(ccode_in, modified_result) ) {
+                std::cout << modified_result << "\n";
+            }
+            ccode_in.close();
+        }
+    } else {
+        if( print_to_std ) {
+            std::cout << res.result;
+        }
+    }
     return 0;
 }
 
@@ -1297,6 +1331,7 @@ int main(int argc, char *argv[])
         bool show_errors = false;
         bool with_intrinsic_modules = false;
         std::string arg_pass;
+        std::string script_path;
         bool arg_no_color = false;
         bool show_llvm = false;
         bool show_asm = false;
@@ -1363,6 +1398,7 @@ int main(int argc, char *argv[])
         app.add_flag("--indent", compiler_options.indent, "Indented print ASR/AST");
         app.add_flag("--tree", compiler_options.tree, "Tree structure print ASR/AST");
         app.add_option("--pass", arg_pass, "Apply the ASR pass and show ASR (implies --show-asr)");
+        app.add_option("--custom-c-postprocessor", script_path, "The script for processing the C code generated by --show-c command.");
         app.add_flag("--disable-main", compiler_options.disable_main, "Do not generate any code for the `main` function");
         app.add_flag("--symtab-only", compiler_options.symtab_only, "Only create symbol tables in ASR (skip executable stmt)");
         app.add_flag("--time-report", time_report, "Show compilation time report");
@@ -1485,6 +1521,17 @@ int main(int argc, char *argv[])
             return 1;
         }
 
+        if( !script_path.empty() && extract_extension(script_path) != ".py" ) {
+            std::cerr << "Only a Python script is supported as a postprocessor for generated C code." << std::endl;
+            return 1;
+        }
+
+        if( !script_path.empty() && !LFortran::path_exists(script_path) ) {
+            std::cerr << script_path << " is inaccessible or doesn't exist on your system." << std::endl;
+            return 1;
+        }
+
+        compiler_options.c_postprocessor_script = script_path;
         if (arg_backend == "llvm") {
             backend = Backend::llvm;
         } else if (arg_backend == "cpp") {

diff --git a/src/libasr/utils.h b/src/libasr/utils.h
@@ -52,6 +52,7 @@ struct CompilerOptions {
     bool emit_debug_info = false;
     bool emit_debug_line_column = false;
     std::string import_path = "";
+    std::string c_postprocessor_script = "";
     Platform platform;
 
     CompilerOptions () : platform{get_platform()} {};