From 41b3c7a50727f715111d09af982e2e9a0deeb688 Mon Sep 17 00:00:00 2001 From: James Lyon Date: Sat, 27 Apr 2013 20:39:34 +0100 Subject: Improved variable length array support. VLA storage is now freed when it goes out of scope. This makes it possible to use a VLA inside a loop without consuming an unlimited amount of memory. Combining VLAs with alloca() should work as in GCC - when a VLA is freed, memory allocated by alloca() after the VLA was created is also freed. There are some exceptions to this rule when using goto: if a VLA is in scope at the goto, jumping to a label will reset the stack pointer to where it was immediately after the last VLA was created prior to the label, or to what it was before the first VLA was created if the label is outside the scope of any VLA. This means that in some cases combining alloca() and VLAs will free alloca() memory where GCC would not. --- tests/CMakeLists.txt | 15 ++++++---- tests/Makefile | 11 +++++++ tests/vla_test.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+), 5 deletions(-) create mode 100644 tests/vla_test.c (limited to 'tests') diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt index bcd37cd..cf5caf8 100644 --- a/tests/CMakeLists.txt +++ b/tests/CMakeLists.txt @@ -15,11 +15,16 @@ add_test(NAME abitest-cc WORKING_DIRECTORY ${CMAKE_BINARY_DIR} COMMAND abitest-c set(ABITEST_TCC abitest-tcc${CMAKE_EXECUTABLE_SUFFIX}) get_property(LIBTCC_LIB TARGET libtcc PROPERTY LOCATION) -add_custom_command(OUTPUT ${ABITEST_TCC} COMMAND tcc ${TCC_CFLAGS} -g ${CMAKE_CURRENT_SOURCE_DIR}/abitest.c ${LIBTCC_LDFLAGS} ${LIBTCC_LIB} -o ${ABITEST_TCC} DEPENDS tcc abitest.c) +add_custom_command(OUTPUT ${ABITEST_TCC} COMMAND tcc ${TCC_CFLAGS} -g ${CMAKE_CURRENT_SOURCE_DIR}/abitest.c ${LIBTCC_LDFLAGS} ${LIBTCC_LIB} -o ${ABITEST_TCC} DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/abitest.c) add_custom_target(abitest-tcc-exe ALL DEPENDS ${ABITEST_TCC}) add_test(NAME abitest-tcc WORKING_DIRECTORY ${CMAKE_BINARY_DIR} COMMAND ${CMAKE_CURRENT_BINARY_DIR}/${ABITEST_TCC} lib_path=${CMAKE_BINARY_DIR} include=${CMAKE_SOURCE_DIR}/include) +set(VLA_TEST vla_test${CMAKE_EXECUTABLE_SUFFIX}) +add_custom_command(OUTPUT ${VLA_TEST} COMMAND tcc ${TCC_CFLAGS} -g ${CMAKE_CURRENT_SOURCE_DIR}/vla_test.c -o ${VLA_TEST} DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/vla_test.c) +add_custom_target(vla_test-exe ALL DEPENDS ${VLA_TEST}) +add_test(vla_test vla_test) + add_executable(tcctest-cc tcctest.c) target_link_libraries(tcctest-cc libtcc) set_target_properties(tcctest-cc PROPERTIES COMPILE_FLAGS -std=gnu99) @@ -41,21 +46,21 @@ if(PYTHONINTERP_FOUND) # Object + link output set(TEST4 test4${CMAKE_EXECUTABLE_SUFFIX}) - add_custom_command(OUTPUT test4.o COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -c -o test4.o DEPENDS tcc tcctest.c) + add_custom_command(OUTPUT test4.o COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -c -o test4.o DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c) add_custom_command(OUTPUT ${TEST4} COMMAND tcc ${TCC_TEST_CFLAGS} test4.o -o ${TEST4} DEPENDS tcc test4.o) add_custom_target(test4-exe ALL DEPENDS ${TEST4}) add_test(test4 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST4}) # Dynamic output set(TEST5 test5${CMAKE_EXECUTABLE_SUFFIX}) - add_custom_command(OUTPUT ${TEST5} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -o ${TEST5} DEPENDS tcc tcctest.c) + add_custom_command(OUTPUT ${TEST5} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -o ${TEST5} DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c) add_custom_target(test5-exe ALL DEPENDS ${TEST5}) add_test(test5 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST5}) if(TCC_BCHECK) # Dynamic output + bound check set(TEST6 test6${CMAKE_EXECUTABLE_SUFFIX}) - add_custom_command(OUTPUT ${TEST5} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -b -o ${TEST6} DEPENDS tcc tcctest.c) + add_custom_command(OUTPUT ${TEST6} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -b -o ${TEST6} DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c) add_custom_target(test6-exe ALL DEPENDS ${TEST6}) add_test(test6 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST6}) endif() @@ -63,7 +68,7 @@ if(PYTHONINTERP_FOUND) if(0) # Static output set(TEST7 test7${CMAKE_EXECUTABLE_SUFFIX}) - add_custom_command(OUTPUT ${TEST7} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -static -o ${TEST7} DEPENDS tcc tcctest.c) + add_custom_command(OUTPUT ${TEST7} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -static -o ${TEST7} DEPENDS tcc ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c) add_custom_target(test7-exe ALL DEPENDS ${TEST7}) add_test(test7 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST7}) endif() diff --git a/tests/Makefile b/tests/Makefile index edb581c..08dfa42 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -14,6 +14,7 @@ TESTS = \ libtest \ test3 \ abitest \ + vla_test-run \ moretests # test4 -- problem with -static @@ -31,6 +32,10 @@ endif ifeq ($(TARGETOS),Darwin) TESTS := $(filter-out hello-exe test3 btest,$(TESTS)) endif +ifeq ($(ARCH),i386) +else ifneq ($(ARCH),x86-64) + TESTS := $(filter-out vla_test-run,$(TESTS)) +endif ifdef DISABLE_STATIC export LD_LIBRARY_PATH:=$(CURDIR)/.. @@ -190,6 +195,12 @@ abitest: abitest-cc$(EXESUF) abitest-tcc$(EXESUF) ./abitest-cc$(EXESUF) lib_path=.. include="$(top_srcdir)/include" ./abitest-tcc$(EXESUF) lib_path=.. include="$(top_srcdir)/include" +vla_test$(EXESUF): vla_test.c + $(TCC) -o $@ $^ $(CPPFLAGS) $(CFLAGS) +vla_test-run: vla_test$(EXESUF) + @echo ------------ $@ ------------ + ./vla_test$(EXESUF) + # targets for development %.bin: %.c tcc $(TCC) -g -o $@ $< diff --git a/tests/vla_test.c b/tests/vla_test.c new file mode 100644 index 0000000..3616c46 --- /dev/null +++ b/tests/vla_test.c @@ -0,0 +1,84 @@ +/* + * Test that allocating a variable length array in a loop + * does not use up a linear amount of memory + */ + +#include +#include +#include + +#define LOOP_COUNT 1000 +#define ARRAY_SIZE 100 + +/* Overwrite a VLA. This will overwrite the return address if SP is incorrect */ +void smash(char *p, int n) { + memset(p, 0, n); +} + +int test1(int n) { + int i; + char *array_ptrs[LOOP_COUNT]; + + for (i = 0; i < LOOP_COUNT; ++i) { + char test[n]; + smash(test, n); + array_ptrs[i] = test; + } + + return (array_ptrs[0]-array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1; +} + +/* ensure goto does not circumvent array free */ +int test2(int n) { + char *array_ptrs[LOOP_COUNT]; + + int i = 0; +loop:; + char test[n]; + smash(test, n); + if (i >= LOOP_COUNT) + goto end; + array_ptrs[i] = test; + ++i; + goto loop; + +end: + smash(test, n); + char test2[n]; + smash(test2, n); + return (array_ptrs[0] - array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1; +} + +int test3(int n) { + char test[n]; + smash(test, n); + goto label; +label: + smash(test, n); + char test2[n]; + smash(test2, n); + return (test-test2 >= n) ? 0 : 1; +} + +#define RUN_TEST(t) \ + if (!testname || (strcmp(#t, testname) == 0)) { \ + fputs(#t "... ", stdout); \ + fflush(stdout); \ + if (t(ARRAY_SIZE) == 0) { \ + fputs("success\n", stdout); \ + } else { \ + fputs("failure\n", stdout); \ + retval = EXIT_FAILURE; \ + } \ + } + +int main(int argc, char **argv) { + const char *testname = NULL; + int retval = EXIT_SUCCESS; + if (argc > 1) + testname = argv[1]; + RUN_TEST(test1) + RUN_TEST(test2) + RUN_TEST(test3) + return retval; +} -- cgit v1.3.1