diff --git a/gcc/Makefile.in b/gcc/Makefile.in index 571e9c28e29..a4344d67f44 100644 --- a/gcc/Makefile.in +++ b/gcc/Makefile.in @@ -1420,6 +1420,7 @@ OBJS = \ gimple-streamer-in.o \ gimple-streamer-out.o \ gimple-walk.o \ + gimple-warn-recursion.o \ gimplify.o \ gimplify-me.o \ godump.o \ diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index 3976fc368db..4b8a094b206 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -738,6 +738,10 @@ Wincompatible-pointer-types C ObjC Var(warn_incompatible_pointer_types) Init(1) Warning Warn when there is a conversion between pointers that have incompatible types. +Winfinite-recursion +C ObjC C++ LTO ObjC++ Var(warn_infinite_recursion) Warning LangEnabledBy(C ObjC C++ LTO ObjC++, Wall) +Warn for infinitely recursive calls. + Waddress-of-packed-member C ObjC C++ ObjC++ Var(warn_address_of_packed_member) Init(1) Warning Warn when the address of packed member of struct or union is taken. diff --git a/gcc/common.opt b/gcc/common.opt index db6010e4e20..755e1a233b7 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -636,6 +636,10 @@ Wimplicit-fallthrough= Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5) Warn when a switch case falls through. +Winfinite-recursion +Var(warn_infinite_recursion) Warning +Warn for infinitely recursive calls. + Winline Common Var(warn_inline) Warning Optimization Warn when an inlined function cannot be inlined. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 57675a476e3..36fe96b441b 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -359,6 +359,7 @@ Objective-C and Objective-C++ Dialects}. -Wignored-qualifiers -Wno-incompatible-pointer-types @gol -Wimplicit -Wimplicit-fallthrough -Wimplicit-fallthrough=@var{n} @gol -Wno-implicit-function-declaration -Wno-implicit-int @gol +-Winfinite-recursion @gol -Winit-self -Winline -Wno-int-conversion -Wint-in-bool-context @gol -Wno-int-to-pointer-cast -Wno-invalid-memory-model @gol -Winvalid-pch -Wjump-misses-init -Wlarger-than=@var{byte-size} @gol @@ -6194,6 +6195,14 @@ is only active when @option{-fdelete-null-pointer-checks} is active, which is enabled by optimizations in most targets. The precision of the warnings depends on the optimization options used. +@item -Winfinite-recursion +@opindex Winfinite-recursion +@opindex Wno-infinite-recursion +Warn about infinitely recursive calls. The warning is effective at all +optimization levels but requires optimization in order to detect infinite +recursion in calls between two or more functions. +@option{-Winfinite-recursion} is included in @option{-Wall}. + @item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)} @opindex Winit-self @opindex Wno-init-self diff --git a/gcc/gimple-warn-recursion.c b/gcc/gimple-warn-recursion.c new file mode 100644 index 00000000000..4dc61b08c50 --- /dev/null +++ b/gcc/gimple-warn-recursion.c @@ -0,0 +1,202 @@ +/* -Winfinite-recursion support. + Copyright (C) 2021 Free Software Foundation, Inc. + Contributed by Martin Sebor + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + GCC is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING3. If not see + . */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "backend.h" +#include "tree.h" +#include "gimple.h" +#include "tree-pass.h" +#include "ssa.h" +#include "diagnostic-core.h" +// #include "tree-dfa.h" +#include "attribs.h" +#include "gimple-iterator.h" + +namespace { + +const pass_data warn_recursion_data = +{ + GIMPLE_PASS, /* type */ + "*infinite-recursion", /* name */ + OPTGROUP_NONE, /* optinfo_flags */ + TV_NONE, /* tv_id */ + PROP_ssa, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ +}; + +class pass_warn_recursion : public gimple_opt_pass +{ +public: + pass_warn_recursion (gcc::context *); + +private: + virtual bool gate (function *) { return warn_infinite_recursion; } + + virtual unsigned int execute (function *); + + bool find_function_exit (basic_block); + + /* Recursive calls found in M_FUNC. */ + vec *m_calls; + /* Basic blocks already visited in the current function. */ + bitmap m_visited; + /* The current function. */ + function *m_func; + /* The current function code if it's (also) a built-in. */ + built_in_function m_built_in; + /* True if M_FUNC is a noreturn function. */ + bool noreturn_p; +}; + +/* Initialize the pass and its members. */ + +pass_warn_recursion::pass_warn_recursion (gcc::context *ctxt) + : gimple_opt_pass (warn_recursion_data, ctxt), + m_calls (), m_visited (), m_func (), m_built_in (), noreturn_p () +{ +} + +/* Return true if there is path from BB to M_FUNC exit point along which + there is no (recursive) call to M_FUNC. */ + +bool +pass_warn_recursion::find_function_exit (basic_block bb) +{ + if (!bitmap_set_bit (m_visited, bb->index)) + return false; + + if (bb == EXIT_BLOCK_PTR_FOR_FN (m_func)) + return true; + + /* Iterate over statements in BB, looking for a call to FNDECL. */ + for (auto si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next_nondebug (&si)) + { + gimple *stmt = gsi_stmt (si); + if (!is_gimple_call (stmt)) + continue; + + if (gimple_call_builtin_p (stmt, BUILT_IN_LONGJMP)) + /* A longjmp breaks infinite recursion. */ + return true; + + if (tree fndecl = gimple_call_fndecl (stmt)) + { + /* A throw statement breaks infinite recursion. */ + tree id = DECL_NAME (fndecl); + const char *name = IDENTIFIER_POINTER (id); + if (startswith (name, "__cxa_throw")) + return true; + /* As does a call to POSIX siglongjmp. */ + if (!strcmp (name, "siglongjmp")) + return true; + + if (m_built_in && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL) + && m_built_in == DECL_FUNCTION_CODE (fndecl)) + { + /* The call is being made from the definition of a built-in + (e.g., in a replacement of one) to itself. */ + m_calls->safe_push (stmt); + return false; + } + } + + if (noreturn_p) + { + /* A noreturn call breaks infinite recursion. */ + int flags = gimple_call_flags (stmt); + if (flags & ECF_NORETURN) + return true; + } + + tree callee = gimple_call_fndecl (stmt); + if (!callee || m_func->decl != callee) + continue; + + /* Add the recursive call to the vector and return false. */ + m_calls->safe_push (stmt); + return false; + } + + /* If no call to FNDECL has been found search all BB's successors. */ + edge e; + edge_iterator ei; + FOR_EACH_EDGE (e, ei, bb->succs) + if (find_function_exit (e->dest)) + return true; + + return false; +} + + +/* Search FUNC for unconditionally infinitely recursive calls to self + and issue a warning if it is such a function. */ + +unsigned int +pass_warn_recursion::execute (function *func) +{ + auto_bitmap visited; + auto_vec calls; + + m_visited = visited; + m_calls = &calls; + m_func = func; + + /* Avoid diagnosing an apparently infinitely recursive function that + doesn't return where the infinite recursion might be avoided by + a call to another noreturn function. */ + noreturn_p = lookup_attribute ("noreturn", DECL_ATTRIBUTES (m_func->decl)); + + if (fndecl_built_in_p (m_func->decl, BUILT_IN_NORMAL)) + m_built_in = DECL_FUNCTION_CODE (m_func->decl); + else + m_built_in = BUILT_IN_NONE; + + basic_block entry_bb = ENTRY_BLOCK_PTR_FOR_FN (func); + + if (find_function_exit (entry_bb) || m_calls->length () == 0) + return 0; + + if (warning_at (DECL_SOURCE_LOCATION (func->decl), + OPT_Winfinite_recursion, + "infinite recursion detected")) + for (auto stmt: *m_calls) + { + location_t loc = gimple_location (stmt); + if (loc == UNKNOWN_LOCATION) + continue; + + inform (loc, "recursive call"); + } + + return 0; +} + +} // namespace + +gimple_opt_pass * +make_pass_warn_recursion (gcc::context *ctxt) +{ + return new pass_warn_recursion (ctxt); +} diff --git a/gcc/passes.def b/gcc/passes.def index b583d17c86f..37ea0d318d1 100644 --- a/gcc/passes.def +++ b/gcc/passes.def @@ -71,6 +71,7 @@ along with GCC; see the file COPYING3. If not see NEXT_PASS (pass_rebuild_cgraph_edges); NEXT_PASS (pass_local_fn_summary); NEXT_PASS (pass_early_inline); + NEXT_PASS (pass_warn_recursion); NEXT_PASS (pass_all_early_optimizations); PUSH_INSERT_PASSES_WITHIN (pass_all_early_optimizations) NEXT_PASS (pass_remove_cgraph_callee_edges); diff --git a/gcc/testsuite/c-c++-common/attr-used-5.c b/gcc/testsuite/c-c++-common/attr-used-5.c index 448e19f6f0e..7ba5a455706 100644 --- a/gcc/testsuite/c-c++-common/attr-used-5.c +++ b/gcc/testsuite/c-c++-common/attr-used-5.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-skip-if "non-ELF target" { *-*-darwin* } } */ -/* { dg-options "-Wall -O2" } */ +/* { dg-options "-Wall -Wno-infinite-recursion -O2" } */ struct dtv_slotinfo_list { diff --git a/gcc/testsuite/c-c++-common/attr-used-6.c b/gcc/testsuite/c-c++-common/attr-used-6.c index b9974e2a4f2..00b128205b6 100644 --- a/gcc/testsuite/c-c++-common/attr-used-6.c +++ b/gcc/testsuite/c-c++-common/attr-used-6.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-skip-if "non-ELF target" { *-*-darwin* } } */ -/* { dg-options "-Wall -O2" } */ +/* { dg-options "-Wall -Wno-infinite-recursion -O2" } */ struct dtv_slotinfo_list { diff --git a/gcc/testsuite/c-c++-common/attr-used-9.c b/gcc/testsuite/c-c++-common/attr-used-9.c index 049c0beb1ee..c4d86c19bc5 100644 --- a/gcc/testsuite/c-c++-common/attr-used-9.c +++ b/gcc/testsuite/c-c++-common/attr-used-9.c @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-skip-if "non-ELF target" { *-*-darwin* } } */ -/* { dg-options "-Wall -O2" } */ +/* { dg-options "-Wall -Wno-infinite-recursion -O2" } */ struct dtv_slotinfo_list { diff --git a/gcc/testsuite/g++.dg/warn/Winfinite-recursion-2.C b/gcc/testsuite/g++.dg/warn/Winfinite-recursion-2.C new file mode 100644 index 00000000000..b3102836664 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Winfinite-recursion-2.C @@ -0,0 +1,75 @@ +/* PR middle-end/88232 - Please implement -Winfinite-recursion + Test case from PR 87742 (see PR 88232, comment 2. + { dg-do compile { target c++11 } } + { dg-options "-Wall -Winfinite-recursion" } */ + +namespace std +{ +class type_info { +public: + void k() const; +}; + +} // namespace std + +using std::type_info; + +template struct f { static constexpr int c = a; }; +struct h { + typedef int e; +}; + +template struct m; +template +struct m : m {}; +template +struct m : f {}; +template struct n; +template +struct n : n {}; +template struct n<0, j, ac...> : h {}; +template class F { + template struct I : m<0, i, l...> {}; + template struct s : n {}; + static const type_info *const b[]; + struct G { + template + operator ag() const // { dg-warning "-Winfinite-recursion" } + { + return *this; + } + }; + unsigned o; + G ah; + +public: + F(); + long t() const { return o; } + const type_info &m_fn3() const { return *b[o]; } + template typename s::e *m_fn4() const { + if (o != ab) + return nullptr; + return ah; + } + template void m_fn5() const { + m_fn4(); + const type_info &r = m_fn3(); + r.k(); + } + template void u() const { m_fn5::c>(); } +}; +template const type_info *const F::b[] {&typeid(l)...}; +using am = unsigned char; +class H { + enum bd : am { be = 2 }; + using bf = F; + bf ah; + template void v() const { ah.u(); } + void w() const; +}; +void H::w() const { + bd d = bd(ah.t()); + switch (d) + case be: + v(); +} diff --git a/gcc/testsuite/g++.dg/warn/Winfinite-recursion-3.C b/gcc/testsuite/g++.dg/warn/Winfinite-recursion-3.C new file mode 100644 index 00000000000..166e6d5790d --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Winfinite-recursion-3.C @@ -0,0 +1,77 @@ +/* PR middle-end/88232 - Please implement -Winfinite-recursion + { dg-do compile } + { dg-options "-Wall -Winfinite-recursion" } */ + +typedef __SIZE_TYPE__ size_t; + +/* Might throw. */ +void f (); + +/* Verify a warning is issued even though a call to f() might throw, + breaking the infinite recursion. */ + +void warn_f_call_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + if (n > 7) + f (); + warn_f_call_r (n - 1); // { dg-message "recursive call" } +} + +void warn_f_do_while_call_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + f (); + do + { + f (); + warn_f_do_while_call_r (n - 1); // { dg-message "recursive call" } + } + while (1); +} + + +struct X +{ + X (int); + ~X (); +}; + +/* Verify a warning even though the X ctor might throw, breaking + the recursion. Using possible throwing to suppress the warning + would make it pretty much useless in C++. */ + +int warn_class_with_ctor (int n) // { dg-warning "-Winfinite-recursion" } +{ + X x (n); + return n + warn_class_with_ctor (n - 1); +} + + +int nowarn_throw (int n) +{ + if (n > 7) + throw "argument too big"; + + return n + nowarn_throw (n - 1); +} + + +/* Verify call operator new doesn't suppress the warning even though + it might throw. */ + +extern int* eipa[]; + +void warn_call_new (int i) // { dg-warning "-Winfinite-recursion" } +{ + eipa[i] = new int; + + warn_call_new (i - 1); +} + +/* Verify a recursive call to operator new. */ + +void* operator new[] (size_t n) // { dg-warning "-Winfinite-recursion" } +{ + char *p = new char[n + sizeof (n)]; // { dg-message "recursive call" } + *(size_t*)p = n; + return p + sizeof n; +} diff --git a/gcc/testsuite/g++.dg/warn/Winfinite-recursion.C b/gcc/testsuite/g++.dg/warn/Winfinite-recursion.C new file mode 100644 index 00000000000..faf0984eeb4 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Winfinite-recursion.C @@ -0,0 +1,34 @@ +/* PR middle-end/88232 - Please implement -Winfinite-recursion + { dg-do compile } + { dg-options "-Wall -Winfinite-recursion" } */ + +template +struct C +{ + void foo () // { dg-warning "-Winfinite-recursion" } + { + static_cast(this)->foo (); + } +}; + +struct D : C +{ + // this is missing: + // void foo() {} +}; + +void f (D *d) +{ + d->foo (); +} + + +struct E : C +{ + void foo() {} +}; + +void g (E *e) +{ + e->foo (); +} diff --git a/gcc/testsuite/gcc.dg/Winfinite-recursion-2.c b/gcc/testsuite/gcc.dg/Winfinite-recursion-2.c new file mode 100644 index 00000000000..23483122a6b --- /dev/null +++ b/gcc/testsuite/gcc.dg/Winfinite-recursion-2.c @@ -0,0 +1,252 @@ +/* PR middle-end/88232 - Please implement -Winfinite-recursion + Exercise warning with optimization. Same as -Winfinite-recursion.c + plus mutually recursive calls that depend on inlining. + { dg-do compile } + { dg-options "-O2 -Wall -Winfinite-recursion" } */ + +#define NORETURN __attribute__ ((noreturn)) + +typedef __SIZE_TYPE__ size_t; + +extern void abort (void); +extern void exit (int); + +extern int ei; +int (*pfi_v)(void); + + +/* Make sure the warning doesn't assume every call has a DECL. */ + +int nowarn_pfi_v (void) +{ + return pfi_v (); +} + + +int warn_fi_v (void) // { dg-warning "-Winfinite-recursion" } +{ + return warn_fi_v (); // { dg-message "recursive call" } +} + +/* Verify #pragma suppression works. */ + +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Winfinite-recursion" + +int suppress_warn_fi_v (void) +{ + return warn_fi_v (); +} + +#pragma GCC diagnostic pop + +int nowarn_fi_v (void) +{ + if (ei++ == 0) + return nowarn_fi_v (); + return 0; +} + + +int warn_if_i (int i) // { dg-warning "-Winfinite-recursion" } +{ + if (i > 0) + return warn_if_i (--i); // { dg-message "recursive call" } + else if (i < 0) + return warn_if_i (-i); // { dg-message "recursive call" } + else + return warn_if_i (7); // { dg-message "recursive call" } +} + + +int nowarn_if_i (int i) +{ + if (i > 0) + return nowarn_if_i (--i); + else if (i < 0) + return nowarn_if_i (-i); + else + return -1; +} + +int nowarn_switch (int i, int a[]) +{ + switch (i) + { + case 0: return nowarn_switch (a[3], a + 1); + case 1: return nowarn_switch (a[5], a + 2); + case 2: return nowarn_switch (a[7], a + 3); + case 3: return nowarn_switch (a[9], a + 4); + } + return 77; +} + +int warn_switch (int i, int a[]) // { dg-warning "-Winfinite-recursion" } +{ + switch (i) + { + case 0: return warn_switch (a[3], a + 1); + case 1: return warn_switch (a[5], a + 2); + case 2: return warn_switch (a[7], a + 3); + case 3: return warn_switch (a[9], a + 4); + default: return warn_switch (a[1], a + 5); + } +} + +NORETURN void fnoreturn (void); + +/* Verify there's no warning for a function that doesn't return. */ +int nowarn_call_noret (void) +{ + fnoreturn (); +} + +int warn_call_noret_r (void) // { dg-warning "-Winfinite-recursion" } +{ + warn_call_noret_r (); // { dg-message "recursive call" } + fnoreturn (); +} + +/* Verify a warning even though the abort() call would prevent the infinite + recursion. There's no good way to tell the two cases apart and letting + a simple abort prevent the warning would make it ineffective in cases + where it's the result of assert() expansion and not meant to actually + prevent recursion. */ + +int +warn_noret_call_abort_r (char *s, int n) // { dg-warning "-Winfinite-recursion" } +{ + if (!s) + abort (); + + if (n > 7) + abort (); + + return n + warn_noret_call_abort_r (s, n - 1); // { dg-message "recursive call" } +} + +/* Verify that a warning is not issued for an apparently infinitely + recursive function like the one above where the recursion would be + prevented by a call to a noreturn function if the recursive function + is itself declared noreturn. */ + +NORETURN void nowarn_noret_call_abort_r (int n) +{ + if (n > 7) + abort (); + + nowarn_noret_call_abort_r (n - 1); +} + +int warn_call_abort_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_abort_r (n - 1); // { dg-message "recursive call" } + if (n > 7) // unreachable + abort (); + return n; +} + + +/* And again with exit() for good measure. */ + +int warn_call_exit_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_exit_r (n - 1); // { dg-message "recursive call" } + if (n > 7) + exit (0); + return n; +} + +struct __jmp_buf_tag { }; +typedef struct __jmp_buf_tag jmp_buf[1]; + +extern jmp_buf jmpbuf; + +/* A call to longjmp() breaks infinite recursion. Verify it suppresses + the warning. */ + +int nowarn_call_longjmp_r (int n) +{ + if (n > 7) + __builtin_longjmp (jmpbuf, 1); + return n + nowarn_call_longjmp_r (n - 1); +} + +int warn_call_longjmp_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_longjmp_r (n - 1); // { dg-message "recursive call" } + if (n > 7) + __builtin_longjmp (jmpbuf, 1); + return n; +} + + +struct __sigjmp_buf_tag { }; +typedef struct __sigjmp_buf_tag sigjmp_buf[1]; + +extern sigjmp_buf sigjmpbuf; + +/* GCC has no __builtin_siglongjmp(). */ +extern void siglongjmp (sigjmp_buf, int); + +/* A call to longjmp() breaks infinite recursion. Verify it suppresses + the warning. */ + +int nowarn_call_siglongjmp_r (int n) +{ + if (n > 7) + siglongjmp (sigjmpbuf, 1); + return n + nowarn_call_siglongjmp_r (n - 1); +} + + +int nowarn_while_do_call_r (int n) +{ + int z = 0; + while (n) + z += nowarn_while_do_call_r (n--); + return z; +} + +int warn_do_while_call_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + int z = 0; + do + z += warn_do_while_call_r (n); // { dg-message "recursive call" } + while (--n); + return z; +} + + +/* Verify warnings for a naive replacement of a built-in fucntion. */ + +void* malloc (size_t n) // { dg-warning "-Winfinite-recursion" } +{ + size_t *p = + (size_t*)__builtin_malloc (n + sizeof n); // { dg-message "recursive call" } + *p = n; + return p + 1; +} + + +int nowarn_fact (int n) +{ + return n ? n * nowarn_fact (n - 1) : 1; +} + + +static int fi_v (void); + +/* It would seem preferable to issue the warning for the extern function + but as it happens it's the static function that's inlined into a recursive + call to itself and warn_call_fi_v() expands to a call to it. */ + +int warn_call_fi_v (void) // { dg-warning "-Winfinite-recursion" "" { xfail *-*-* } } +{ + return fi_v (); // { dg-message "recursive call" } +} + +static int fi_v (void) // { dg-warning "-Winfinite-recursion" } +{ + return warn_call_fi_v (); +} diff --git a/gcc/testsuite/gcc.dg/Winfinite-recursion.c b/gcc/testsuite/gcc.dg/Winfinite-recursion.c new file mode 100644 index 00000000000..e3253567d34 --- /dev/null +++ b/gcc/testsuite/gcc.dg/Winfinite-recursion.c @@ -0,0 +1,227 @@ +/* PR middle-end/88232 - Please implement -Winfinite-recursion + Verify simple cases without optimization. + { dg-do compile } + { dg-options "-Wall -Winfinite-recursion" } */ + +#define NORETURN __attribute__ ((noreturn)) + +typedef __SIZE_TYPE__ size_t; + +extern void abort (void); +extern void exit (int); + +extern int ei; +int (*pfi_v)(void); + + +/* Make sure the warning doesn't assume every call has a DECL. */ + +int nowarn_pfi_v (void) +{ + return pfi_v (); +} + + +int warn_fi_v (void) // { dg-warning "-Winfinite-recursion" } +{ + return warn_fi_v (); // { dg-message "recursive call" } +} + +/* Verify #pragma suppression works. */ + +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Winfinite-recursion" + +int suppress_warn_fi_v (void) +{ + return warn_fi_v (); +} + +#pragma GCC diagnostic pop + + +int nowarn_fi_v (void) +{ + if (ei++ == 0) + return nowarn_fi_v (); + return 0; +} + +int warn_if_i (int i) // { dg-warning "-Winfinite-recursion" } +{ + if (i > 0) + return warn_if_i (--i); // { dg-message "recursive call" } + else if (i < 0) + return warn_if_i (-i); // { dg-message "recursive call" } + else + return warn_if_i (7); // { dg-message "recursive call" } +} + + +int nowarn_if_i (int i) +{ + if (i > 0) + return nowarn_if_i (--i); + else if (i < 0) + return nowarn_if_i (-i); + else + return -1; +} + +int nowarn_switch (int i, int a[]) +{ + switch (i) + { + case 0: return nowarn_switch (a[3], a + 1); + case 1: return nowarn_switch (a[5], a + 2); + case 2: return nowarn_switch (a[7], a + 3); + case 3: return nowarn_switch (a[9], a + 4); + } + return 77; +} + +int warn_switch (int i, int a[]) // { dg-warning "-Winfinite-recursion" } +{ + switch (i) + { + case 0: return warn_switch (a[3], a + 1); + case 1: return warn_switch (a[5], a + 2); + case 2: return warn_switch (a[7], a + 3); + case 3: return warn_switch (a[9], a + 4); + default: return warn_switch (a[1], a + 5); + } +} + +NORETURN void fnoreturn (void); + +/* Verify there's no warning for a function that doesn't return. */ +int nowarn_call_noret (void) +{ + fnoreturn (); +} + +int warn_call_noret_r (void) // { dg-warning "-Winfinite-recursion" } +{ + warn_call_noret_r (); // { dg-message "recursive call" } + fnoreturn (); +} + +/* Verify a warning even though the abort() call would prevent the infinite + recursion. There's no good way to tell the two cases apart and letting + a simple abort prevent the warning would make it ineffective in cases + where it's the result of assert() expansion and not meant to actually + prevent recursion. */ + +int +warn_noret_call_abort_r (char *s, int n) // { dg-warning "-Winfinite-recursion" } +{ + if (!s) + abort (); + + if (n > 7) + abort (); + + return n + warn_noret_call_abort_r (s, n - 1); // { dg-message "recursive call" } +} + +/* Verify that a warning is not issued for an apparently infinitely + recursive function like the one above where the recursion would be + prevented by a call to a noreturn function if the recursive function + is itself declared noreturn. */ + +NORETURN void nowarn_noret_call_abort_r (int n) +{ + if (n > 7) + abort (); + + nowarn_noret_call_abort_r (n - 1); +} + +int warn_call_abort_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_abort_r (n - 1); // { dg-message "recursive call" } + if (n > 7) // unreachable + abort (); + return n; +} + + +/* And again with exit() for good measure. */ + +int warn_call_exit_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_exit_r (n - 1); // { dg-message "recursive call" } + if (n > 7) + exit (0); + return n; +} + +struct __jmp_buf_tag { }; +typedef struct __jmp_buf_tag jmp_buf[1]; + +extern jmp_buf jmpbuf; + +/* A call to longjmp() breaks infinite recursion. Verify it suppresses + the warning. */ + +int nowarn_call_longjmp_r (int n) +{ + if (n > 7) + __builtin_longjmp (jmpbuf, 1); + return n + nowarn_call_longjmp_r (n - 1); +} + +int warn_call_longjmp_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + n += warn_call_longjmp_r (n - 1); // { dg-message "recursive call" } + if (n > 7) + __builtin_longjmp (jmpbuf, 1); + return n; +} + + +struct __sigjmp_buf_tag { }; +typedef struct __sigjmp_buf_tag sigjmp_buf[1]; + +extern sigjmp_buf sigjmpbuf; + +/* GCC has no __builtin_siglongjmp(). */ +extern void siglongjmp (sigjmp_buf, int); + +/* A call to longjmp() breaks infinite recursion. Verify it suppresses + the warning. */ + +int nowarn_call_siglongjmp_r (int n) +{ + if (n > 7) + siglongjmp (sigjmpbuf, 1); + return n + nowarn_call_siglongjmp_r (n - 1); +} + + +int nowarn_while_do_call_r (int n) +{ + int z = 0; + while (n) + z += nowarn_while_do_call_r (n--); + return z; +} + +int warn_do_while_call_r (int n) // { dg-warning "-Winfinite-recursion" } +{ + int z = 0; + do + z += warn_do_while_call_r (n); // { dg-message "recursive call" } + while (--n); + return z; +} + +/* Verify warnings for a naive replacement of a built-in fucntion. */ + +void* malloc (size_t n) // { dg-warning "-Winfinite-recursion" } +{ + size_t *p = + (size_t*)__builtin_malloc (n + sizeof n); // { dg-message "recursive call" } + *p = n; + return p + 1; +} diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h index d494aff1c4c..3559c3c9f1b 100644 --- a/gcc/tree-pass.h +++ b/gcc/tree-pass.h @@ -435,6 +435,7 @@ extern gimple_opt_pass *make_pass_object_sizes (gcc::context *ctxt); extern gimple_opt_pass *make_pass_early_object_sizes (gcc::context *ctxt); extern gimple_opt_pass *make_pass_warn_access (gcc::context *ctxt); extern gimple_opt_pass *make_pass_warn_printf (gcc::context *ctxt); +extern gimple_opt_pass *make_pass_warn_recursion (gcc::context *ctxt); extern gimple_opt_pass *make_pass_strlen (gcc::context *ctxt); extern gimple_opt_pass *make_pass_fold_builtins (gcc::context *ctxt); extern gimple_opt_pass *make_pass_post_ipa_warn (gcc::context *ctxt);