From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2209) id 62A4C3857C62; Fri, 22 Jul 2022 23:52:58 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 62A4C3857C62 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: David Malcolm To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-1807] analyzer: fix state explosion on va_arg [PR106413] X-Act-Checkin: gcc X-Git-Author: David Malcolm X-Git-Refname: refs/heads/master X-Git-Oldrev: 0fb35a45a28c674d5d420528f7dec629e42b4850 X-Git-Newrev: 6d5194a10dc103031b9c8a03091ca70f6db33c8b Message-Id: <20220722235258.62A4C3857C62@sourceware.org> Date: Fri, 22 Jul 2022 23:52:58 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Jul 2022 23:52:58 -0000 https://gcc.gnu.org/g:6d5194a10dc103031b9c8a03091ca70f6db33c8b commit r13-1807-g6d5194a10dc103031b9c8a03091ca70f6db33c8b Author: David Malcolm Date: Fri Jul 22 19:50:54 2022 -0400 analyzer: fix state explosion on va_arg [PR106413] Fix state explosion on va_arg when the call to va_start is in the top-level function of the analysis. gcc/analyzer/ChangeLog: PR analyzer/106413 * varargs.cc (region_model::impl_call_va_start): Avoid iterating through non-existant variadic arguments by initializing the impl_region to "UNKNOWN" if the va_start occurs in the top-level function to the analysis. gcc/testsuite/ChangeLog: PR analyzer/106413 * gcc.dg/analyzer/torture/stdarg-4.c: New test. Signed-off-by: David Malcolm Diff: --- gcc/analyzer/varargs.cc | 26 +- gcc/testsuite/gcc.dg/analyzer/torture/stdarg-4.c | 329 +++++++++++++++++++++++ 2 files changed, 350 insertions(+), 5 deletions(-) diff --git a/gcc/analyzer/varargs.cc b/gcc/analyzer/varargs.cc index c45585ce457..9400086b10e 100644 --- a/gcc/analyzer/varargs.cc +++ b/gcc/analyzer/varargs.cc @@ -667,11 +667,27 @@ region_model::impl_call_va_start (const call_details &cd) const svalue *ptr_to_impl_reg = m_mgr->get_ptr_svalue (NULL_TREE, impl_reg); set_value (out_reg, ptr_to_impl_reg, cd.get_ctxt ()); - /* "*(&IMPL_REGION) = VA_LIST_VAL (0);". */ - const region *init_var_arg_reg - = m_mgr->get_var_arg_region (get_current_frame (), 0); - const svalue *ap_sval = m_mgr->get_ptr_svalue (NULL_TREE, init_var_arg_reg); - set_value (impl_reg, ap_sval, cd.get_ctxt ()); + if (get_stack_depth () > 1) + { + /* The interprocedural case: the frame containing the va_start call + will have been populated with any variadic aruguments. + Initialize IMPL_REGION with a ptr to var_arg_region 0. */ + const region *init_var_arg_reg + = m_mgr->get_var_arg_region (get_current_frame (), 0); + const svalue *ap_sval + = m_mgr->get_ptr_svalue (NULL_TREE, init_var_arg_reg); + set_value (impl_reg, ap_sval, cd.get_ctxt ()); + } + else + { + /* The frame containing va_start is an entry-point to the analysis, + so there won't be any specific var_arg_regions populated within it. + Initialize IMPL_REGION as the UNKNOWN_SVALUE to avoid state + explosions on repeated calls to va_arg. */ + const svalue *unknown_sval + = m_mgr->get_or_create_unknown_svalue (NULL_TREE); + set_value (impl_reg, unknown_sval, cd.get_ctxt ()); + } } /* Handle the on_call_pre part of "__builtin_va_copy". */ diff --git a/gcc/testsuite/gcc.dg/analyzer/torture/stdarg-4.c b/gcc/testsuite/gcc.dg/analyzer/torture/stdarg-4.c new file mode 100644 index 00000000000..8275b0fa9ba --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/torture/stdarg-4.c @@ -0,0 +1,329 @@ +/* { dg-skip-if "" { *-*-* } { "-fno-fat-lto-objects" } { "" } } */ + +#include "../analyzer-decls.h" + +/* va_arg in loop, with no caller to function containing va_start. */ + +int test_1a (const char *fmt, ...) +{ + __builtin_va_list args; + int sum = 0; + char ch; + + __builtin_va_start(args, fmt); + + while (ch = *fmt++) + if (ch == '%') + sum += __builtin_va_arg(args, int); + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with no caller to function containing va_start. */ + +static int test_1b_callee (const char *fmt, __builtin_va_list args) +{ + int sum = 0; + char ch; + + while (ch = *fmt++) + if (ch == '%') + sum += __builtin_va_arg(args, int); + + return sum; +} + +int test_1b_caller (const char *fmt, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, fmt); + + sum = test_1b_callee (fmt, args); + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with a caller to the function containing va_start, + with specific args. */ + +static int +test_1c_inner (const char *fmt, __builtin_va_list args) +{ + int sum = 0; + char ch; + + while (ch = *fmt++) + if (ch == '%') + sum += __builtin_va_arg(args, int); + + return sum; +} + +static int +test_1c_middle (const char *fmt, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, fmt); + + sum = test_1c_inner (fmt, args); + + __builtin_va_end(args); + + return sum; +} + +void test_1c_outer (void) +{ + int sum = test_1c_middle ("%%", 42, 17); + + __analyzer_describe (0, sum); /* { dg-message "'\\(int\\)59'" } */ +} + +/* va_arg in loop, with no caller to function containing va_start. */ + +int test_2a (int count, ...) +{ + __builtin_va_list args; + int sum = 0; + char ch; + + __builtin_va_start(args, count); + + while (count-- > 0) + sum += __builtin_va_arg(args, int); + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with no caller to function containing va_start. */ + +static int test_2b_callee (int count, __builtin_va_list args) +{ + int sum = 0; + + while (count-- > 0) + sum += __builtin_va_arg(args, int); + + return sum; +} + +int test_2b_caller (int count, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, count); + + sum = test_2b_callee (count, args); + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with a caller to the function containing va_start, + with specific args. */ + +static int test_2c_inner (int count, __builtin_va_list args) +{ + int sum = 0; + + while (count-- > 0) + sum += __builtin_va_arg(args, int); + + return sum; +} + +int test_2c_middle (int count, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, count); + + sum = test_2c_inner (count, args); + + __builtin_va_end(args); + + return sum; +} + +void test_2c_outer (void) +{ + int sum = test_2c_middle (2, 50, 42); + + __analyzer_describe (0, sum); /* { dg-message "'\\(int\\)92'" } */ +} + +/* va_arg in loop, with no caller to function containing va_start. */ + +int test_3a (int placeholder, ...) +{ + __builtin_va_list args; + int sum = 0; + int val; + + __builtin_va_start(args, placeholder); + + while (val = __builtin_va_arg(args, int)) + sum += val; + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with no caller to function containing va_start. */ + +static int test_3b_callee (__builtin_va_list args) +{ + int sum = 0; + int val; + while (val = __builtin_va_arg(args, int)) + sum += val; + return sum; +} + +int test_3b_caller (int placeholder, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, placeholder); + + sum = test_3b_callee (args); + + __builtin_va_end(args); + + return sum; +} + +/* va_arg in loop, with a caller to the function containing va_start, + with specific args. */ + +static int test_3c_inner (__builtin_va_list args) +{ + int sum = 0; + int val; + while (val = __builtin_va_arg(args, int)) + sum += val; + return sum; +} + +int test_3c_middle (int placeholder, ...) +{ + __builtin_va_list args; + int sum = 0; + + __builtin_va_start(args, placeholder); + + sum = test_3c_inner (args); + + __builtin_va_end(args); + + return sum; +} + +void test_3c_outer (void) +{ + int sum = test_3c_middle (0, 5, 12, 0); + __analyzer_describe (0, sum); /* { dg-message "'\\(int\\)17'" } */ +} + +/* va_arg in loop, with no caller to function containing va_start, + with a va_copy. */ + +static int test_3d_callee (__builtin_va_list args) +{ + int sum = 0; + int val; + while (val = __builtin_va_arg(args, int)) + sum += val; + return sum; +} + +int test_3d_caller (int placeholder, ...) +{ + __builtin_va_list args1, args2; + int sum = 0; + + __builtin_va_start(args1, placeholder); + __builtin_va_copy (args2, args1); + + sum = test_3d_callee (args1); + __builtin_va_end(args1); + + sum += test_3d_callee (args2); + __builtin_va_end(args2); + + return sum; +} + +/* va_arg in loop, with a caller to the function containing va_start, + with specific args, with a va_copy. */ + +static int test_3e_inner (__builtin_va_list args) +{ + int sum = 0; + int val; + while (val = __builtin_va_arg(args, int)) + sum += val; + return sum; +} + +int test_3e_middle (int placeholder, ...) +{ + __builtin_va_list args1, args2; + int sum = 0; + + __builtin_va_start(args1, placeholder); + __builtin_va_copy (args2, args1); + + sum = test_3e_inner (args1); + __builtin_va_end(args1); + + sum += test_3e_inner (args2); + __builtin_va_end(args2); + + return sum; +} + +void test_3e_outer (void) +{ + int sum = test_3e_middle (0, 5, 6, 0); + __analyzer_describe (0, sum); /* { dg-message "'\\(int\\)22'" } */ +} + +/* va_arg in loop, with specific symbolic args. */ + +static int test_3f_callee (int placeholder, ...) +{ + __builtin_va_list args; + int sum = 0; + int val; + + __builtin_va_start(args, placeholder); + + while (val = __builtin_va_arg(args, int)) + sum += val; + + __builtin_va_end(args); + + return sum; +} + +void test_3f_caller (int x, int y, int z) +{ + int sum = test_3f_callee (0, x, y, z, 0); + __analyzer_describe (0, sum); /* { dg-message "'UNKNOWN\\(int\\)'" } */ +}