From fb093e29d013ce0ce8e9181bd10635d14a48bcd2 Mon Sep 17 00:00:00 2001 From: Martin Liska Date: Thu, 9 Apr 2020 15:50:58 +0200 Subject: [PATCH] List valid pairs for new and delete operators. gcc/ChangeLog: 2020-04-09 Martin Liska Jakub Jelinek PR c++/94314 * cgraphclones.c (set_new_clone_decl_and_node_flags): Drop DECL_IS_REPLACEABLE_OPERATOR during cloning. * tree-ssa-dce.c (valid_new_delete_pair_p): New function. (propagate_necessity): Check operator names. gcc/testsuite/ChangeLog: 2020-04-09 Martin Liska Jakub Jelinek PR c++/94314 * g++.dg/pr94314-4.C: New test. --- gcc/cgraphclones.c | 2 + gcc/testsuite/g++.dg/pr94314-4.C | 33 +++++++++++ gcc/tree-ssa-dce.c | 98 ++++++++++++++++++++++++++++---- 3 files changed, 123 insertions(+), 10 deletions(-) create mode 100644 gcc/testsuite/g++.dg/pr94314-4.C diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c index c73b8f810f0..8f541a28b6e 100644 --- a/gcc/cgraphclones.c +++ b/gcc/cgraphclones.c @@ -165,6 +165,7 @@ set_new_clone_decl_and_node_flags (cgraph_node *new_node) DECL_STATIC_DESTRUCTOR (new_node->decl) = 0; DECL_SET_IS_OPERATOR_NEW (new_node->decl, 0); DECL_SET_IS_OPERATOR_DELETE (new_node->decl, 0); + DECL_IS_REPLACEABLE_OPERATOR (new_node->decl) = 0; new_node->externally_visible = 0; new_node->local = 1; @@ -1030,6 +1031,7 @@ cgraph_node::create_version_clone_with_body DECL_STATIC_DESTRUCTOR (new_decl) = 0; DECL_SET_IS_OPERATOR_NEW (new_decl, 0); DECL_SET_IS_OPERATOR_DELETE (new_decl, 0); + DECL_IS_REPLACEABLE_OPERATOR (new_decl) = 0; /* Create the new version's call-graph node. and update the edges of the new node. */ diff --git a/gcc/testsuite/g++.dg/pr94314-4.C b/gcc/testsuite/g++.dg/pr94314-4.C new file mode 100644 index 00000000000..afa2a443dc4 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr94314-4.C @@ -0,0 +1,33 @@ +/* PR c++/94314. */ +/* { dg-do run } */ +/* { dg-options "-O2 -fdump-tree-cddce-details -std=c++14" } */ +/* { dg-additional-options "-fdelete-null-pointer-checks" } */ + +#include + +int count = 0; + +__attribute__((malloc, noinline)) void* operator new[](__SIZE_TYPE__ sz) { + ++count; + return ::operator new(sz); +} + +void operator delete[](void* ptr) noexcept { + --count; + ::operator delete(ptr); +} + +void operator delete[](void* ptr, __SIZE_TYPE__ sz) noexcept { + --count; + ::operator delete(ptr, sz); +} + +int main() { + delete[] new int[1]; + if (count != 0) + __builtin_abort (); + + return 0; +} + +/* { dg-final { scan-tree-dump-not "Deleting : operator delete" "cddce1"} } */ diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c index fd5f24c746c..757cfad5b5e 100644 --- a/gcc/tree-ssa-dce.c +++ b/gcc/tree-ssa-dce.c @@ -646,6 +646,77 @@ degenerate_phi_p (gimple *phi) return true; } +/* Return that NEW_CALL and DELETE_CALL are a valid pair of new + and delete operators. */ + +static bool +valid_new_delete_pair_p (gimple *new_call, gimple *delete_call) +{ + tree new_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (new_call)); + tree delete_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (delete_call)); + const char *new_name = IDENTIFIER_POINTER (new_asm); + const char *delete_name = IDENTIFIER_POINTER (delete_asm); + unsigned int new_len = IDENTIFIER_LENGTH (new_asm); + unsigned int delete_len = IDENTIFIER_LENGTH (delete_asm); + + if (new_len < 5 || delete_len < 6) + return false; + if (new_name[0] == '_') + ++new_name, --new_len; + if (new_name[0] == '_') + ++new_name, --new_len; + if (delete_name[0] == '_') + ++delete_name, --delete_len; + if (delete_name[0] == '_') + ++delete_name, --delete_len; + if (new_len < 4 || delete_len < 5) + return false; + /* *_len is now just the length after initial underscores. */ + if (new_name[0] != 'Z' || new_name[1] != 'n') + return false; + if (delete_name[0] != 'Z' || delete_name[1] != 'd') + return false; + /* _Znw must match _Zdl, _Zna must match _Zda. */ + if ((new_name[2] != 'w' || delete_name[2] != 'l') + && (new_name[2] != 'a' || delete_name[2] != 'a')) + return false; + /* 'j', 'm' and 'y' correspond to size_t. */ + if (new_name[3] != 'j' && new_name[3] != 'm' && new_name[3] != 'y') + return false; + if (delete_name[3] != 'P' || delete_name[4] != 'v') + return false; + if (new_len == 4 + || (new_len == 18 && !memcmp (new_name + 4, "RKSt9nothrow_t", 14))) + { + /* _ZnXY or _ZnXYRKSt9nothrow_t matches + _ZdXPv, _ZdXPvY and _ZdXPvRKSt9nothrow_t. */ + if (delete_len == 5) + return true; + if (delete_len == 6 && delete_name[5] == new_name[3]) + return true; + if (delete_len == 19 && !memcmp (delete_name + 5, "RKSt9nothrow_t", 14)) + return true; + } + else if ((new_len == 19 && !memcmp (new_name + 4, "St11align_val_t", 15)) + || (new_len == 33 + && !memcmp (new_name + 4, "St11align_val_tRKSt9nothrow_t", 29))) + { + /* _ZnXYSt11align_val_t or _ZnXYSt11align_val_tRKSt9nothrow_t matches + _ZdXPvSt11align_val_t or _ZdXPvYSt11align_val_t or or + _ZdXPvSt11align_val_tRKSt9nothrow_t. */ + if (delete_len == 20 && !memcmp (delete_name + 5, "St11align_val_t", 15)) + return true; + if (delete_len == 21 + && delete_name[5] == new_name[3] + && !memcmp (delete_name + 6, "St11align_val_t", 15)) + return true; + if (delete_len == 34 + && !memcmp (delete_name + 5, "St11align_val_tRKSt9nothrow_t", 29)) + return true; + } + return false; +} + /* Propagate necessity using the operands of necessary statements. Process the uses on each statement in the worklist, and add all feeding statements which contribute to the calculation of this @@ -824,16 +895,23 @@ propagate_necessity (bool aggressive) || DECL_FUNCTION_CODE (def_callee) == BUILT_IN_CALLOC)) || DECL_IS_REPLACEABLE_OPERATOR_NEW_P (def_callee))) { - /* Delete operators can have alignment and (or) size as next - arguments. When being a SSA_NAME, they must be marked - as necessary. */ - if (is_delete_operator && gimple_call_num_args (stmt) >= 2) - for (unsigned i = 1; i < gimple_call_num_args (stmt); i++) - { - tree arg = gimple_call_arg (stmt, i); - if (TREE_CODE (arg) == SSA_NAME) - mark_operand_necessary (arg); - } + if (is_delete_operator) + { + if (!valid_new_delete_pair_p (def_stmt, stmt)) + mark_operand_necessary (gimple_call_arg (stmt, 0)); + + /* Delete operators can have alignment and (or) size + as next arguments. When being a SSA_NAME, they + must be marked as necessary. */ + if (gimple_call_num_args (stmt) >= 2) + for (unsigned i = 1; i < gimple_call_num_args (stmt); + i++) + { + tree arg = gimple_call_arg (stmt, i); + if (TREE_CODE (arg) == SSA_NAME) + mark_operand_necessary (arg); + } + } continue; } -- 2.26.0