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.
This commit is contained in:
James Lyon
@ -15,11 +15,16 @@ add_test(NAME abitest-cc WORKING_DIRECTORY ${CMAKE_BINARY_DIR} COMMAND abitest-c
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set(ABITEST_TCC abitest-tcc${CMAKE_EXECUTABLE_SUFFIX})
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get_property(LIBTCC_LIB TARGET libtcc PROPERTY LOCATION)
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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)
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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)
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add_custom_target(abitest-tcc-exe ALL DEPENDS ${ABITEST_TCC})
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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)
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set(VLA_TEST vla_test${CMAKE_EXECUTABLE_SUFFIX})
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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)
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add_custom_target(vla_test-exe ALL DEPENDS ${VLA_TEST})
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add_test(vla_test vla_test)
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add_executable(tcctest-cc tcctest.c)
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target_link_libraries(tcctest-cc libtcc)
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set_target_properties(tcctest-cc PROPERTIES COMPILE_FLAGS -std=gnu99)
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@ -41,21 +46,21 @@ if(PYTHONINTERP_FOUND)
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# Object + link output
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set(TEST4 test4${CMAKE_EXECUTABLE_SUFFIX})
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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)
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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)
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add_custom_command(OUTPUT ${TEST4} COMMAND tcc ${TCC_TEST_CFLAGS} test4.o -o ${TEST4} DEPENDS tcc test4.o)
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add_custom_target(test4-exe ALL DEPENDS ${TEST4})
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add_test(test4 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST4})
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# Dynamic output
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set(TEST5 test5${CMAKE_EXECUTABLE_SUFFIX})
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add_custom_command(OUTPUT ${TEST5} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -o ${TEST5} DEPENDS tcc tcctest.c)
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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)
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add_custom_target(test5-exe ALL DEPENDS ${TEST5})
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add_test(test5 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST5})
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if(TCC_BCHECK)
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# Dynamic output + bound check
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set(TEST6 test6${CMAKE_EXECUTABLE_SUFFIX})
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add_custom_command(OUTPUT ${TEST5} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -b -o ${TEST6} DEPENDS tcc tcctest.c)
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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)
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add_custom_target(test6-exe ALL DEPENDS ${TEST6})
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add_test(test6 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST6})
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endif()
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@ -63,7 +68,7 @@ if(PYTHONINTERP_FOUND)
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if(0)
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# Static output
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set(TEST7 test7${CMAKE_EXECUTABLE_SUFFIX})
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add_custom_command(OUTPUT ${TEST7} COMMAND tcc ${TCC_TEST_CFLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/tcctest.c -static -o ${TEST7} DEPENDS tcc tcctest.c)
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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)
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add_custom_target(test7-exe ALL DEPENDS ${TEST7})
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add_test(test7 ${TCCTEST_PY} ${CMAKE_CURRENT_BINARY_DIR}/${TEST7})
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endif()
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@ -14,6 +14,7 @@ TESTS = \
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libtest \
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test3 \
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abitest \
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vla_test-run \
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moretests
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# test4 -- problem with -static
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@ -31,6 +32,10 @@ endif
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ifeq ($(TARGETOS),Darwin)
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TESTS := $(filter-out hello-exe test3 btest,$(TESTS))
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endif
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ifeq ($(ARCH),i386)
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else ifneq ($(ARCH),x86-64)
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TESTS := $(filter-out vla_test-run,$(TESTS))
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endif
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ifdef DISABLE_STATIC
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export LD_LIBRARY_PATH:=$(CURDIR)/..
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@ -190,6 +195,12 @@ abitest: abitest-cc$(EXESUF) abitest-tcc$(EXESUF)
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./abitest-cc$(EXESUF) lib_path=.. include="$(top_srcdir)/include"
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./abitest-tcc$(EXESUF) lib_path=.. include="$(top_srcdir)/include"
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vla_test$(EXESUF): vla_test.c
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$(TCC) -o $@ $^ $(CPPFLAGS) $(CFLAGS)
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vla_test-run: vla_test$(EXESUF)
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@echo ------------ $@ ------------
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./vla_test$(EXESUF)
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# targets for development
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%.bin: %.c tcc
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$(TCC) -g -o $@ $<
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84
tests/vla_test.c
Normal file
84
tests/vla_test.c
Normal file
@ -0,0 +1,84 @@
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/*
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* Test that allocating a variable length array in a loop
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* does not use up a linear amount of memory
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#define LOOP_COUNT 1000
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#define ARRAY_SIZE 100
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/* Overwrite a VLA. This will overwrite the return address if SP is incorrect */
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void smash(char *p, int n) {
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memset(p, 0, n);
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}
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int test1(int n) {
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int i;
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char *array_ptrs[LOOP_COUNT];
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for (i = 0; i < LOOP_COUNT; ++i) {
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char test[n];
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smash(test, n);
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array_ptrs[i] = test;
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}
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return (array_ptrs[0]-array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1;
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}
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/* ensure goto does not circumvent array free */
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int test2(int n) {
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char *array_ptrs[LOOP_COUNT];
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int i = 0;
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loop:;
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char test[n];
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smash(test, n);
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if (i >= LOOP_COUNT)
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goto end;
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array_ptrs[i] = test;
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++i;
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goto loop;
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end:
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smash(test, n);
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char test2[n];
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smash(test2, n);
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return (array_ptrs[0] - array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1;
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}
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int test3(int n) {
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char test[n];
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smash(test, n);
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goto label;
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label:
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smash(test, n);
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char test2[n];
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smash(test2, n);
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return (test-test2 >= n) ? 0 : 1;
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}
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#define RUN_TEST(t) \
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if (!testname || (strcmp(#t, testname) == 0)) { \
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fputs(#t "... ", stdout); \
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fflush(stdout); \
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if (t(ARRAY_SIZE) == 0) { \
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fputs("success\n", stdout); \
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} else { \
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fputs("failure\n", stdout); \
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retval = EXIT_FAILURE; \
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} \
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}
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int main(int argc, char **argv) {
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const char *testname = NULL;
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int retval = EXIT_SUCCESS;
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if (argc > 1)
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testname = argv[1];
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RUN_TEST(test1)
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RUN_TEST(test2)
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RUN_TEST(test3)
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return retval;
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}
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