LibreOffice Module bridges (master) 1
gcc3_linux_intel/callvirtualmethod.cxx
Go to the documentation of this file.
1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2/*
3 * This file is part of the LibreOffice project.
4 *
5 * This Source Code Form is subject to the terms of the Mozilla Public
6 * License, v. 2.0. If a copy of the MPL was not distributed with this
7 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 *
9 * This file incorporates work covered by the following license notice:
10 *
11 * Licensed to the Apache Software Foundation (ASF) under one or more
12 * contributor license agreements. See the NOTICE file distributed
13 * with this work for additional information regarding copyright
14 * ownership. The ASF licenses this file to you under the Apache
15 * License, Version 2.0 (the "License"); you may not use this file
16 * except in compliance with the License. You may obtain a copy of
17 * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 */
19
20#include <sal/config.h>
21
22#include <cassert>
23
24#include <cppu/macros.hxx>
25#include <sal/types.h>
26#include <typelib/typeclass.h>
27#include <typelib/typedescription.h>
28
29#include "callvirtualmethod.hxx"
30#include "share.hxx"
31
32// The call instruction within the asm block of callVirtualMethod may throw
33// exceptions. At least GCC 4.7.0 with -O0 would create (unnecessary)
34// .gcc_exception_table call-site table entries around all other calls in this
35// function that can throw, leading to std::terminate if the asm call throws an
36// exception and the unwinding C++ personality routine finds the unexpected hole
37// in the .gcc_exception_table. Therefore, make sure this function explicitly
38// only calls nothrow-functions (so GCC 4.7.0 with -O0 happens to not create a
39// .gcc_exception_table section at all for this function). For some reason,
40// this also needs to be in a source file of its own.
41//
42// Also, this file should be compiled with -fnon-call-exceptions, and ideally
43// there would be a way to tell the compiler that the asm block contains calls
44// to functions that can potentially throw; see the mail thread starting at
45// <http://gcc.gnu.org/ml/gcc/2012-03/msg00454.html> "C++: Letting compiler know
46// asm block can call function that can throw?"
47
49 void * pAdjustedThisPtr, sal_Int32 nVtableIndex, void * pRegisterReturn,
50 typelib_TypeDescription * pReturnTypeDescr, bool bSimpleReturn,
51 sal_Int32 * pStackLongs, sal_Int32 nStackLongs)
52{
53 // parameter list is mixed list of * and values
54 // reference parameters are pointers
55
56 assert(pStackLongs && pAdjustedThisPtr);
57 assert(sizeof (void *) == 4 && sizeof (sal_Int32) == 4);
58 // unexpected size of int
59 assert(nStackLongs && pStackLongs); // no stack
60
61#if defined __clang__
62 if (! pAdjustedThisPtr) CPPU_CURRENT_NAMESPACE::dummy_can_throw_anything("xxx"); // address something
63#endif
64
65 long edx, eax; // for register returns
66 void * stackptr;
67 asm volatile (
68 "mov %%esp, %2\n\t"
69 // preserve potential 128bit stack alignment
70 "and $0xfffffff0, %%esp\n\t"
71 "mov %3, %%eax\n\t"
72 "lea -4(,%%eax,4), %%eax\n\t"
73 "and $0xf, %%eax\n\t"
74 "sub $0xc, %%eax\n\t"
75 "add %%eax, %%esp\n\t"
76 // copy values
77 "mov %3, %%eax\n\t"
78 "mov %%eax, %%edx\n\t"
79 "dec %%edx\n\t"
80 "shl $2, %%edx\n\t"
81 "add %4, %%edx\n"
82 "Lcopy:\n\t"
83 "pushl 0(%%edx)\n\t"
84 "sub $4, %%edx\n\t"
85 "dec %%eax\n\t"
86 "jne Lcopy\n\t"
87 // do the actual call
88 "mov %5, %%edx\n\t"
89 "mov 0(%%edx), %%edx\n\t"
90 "mov %6, %%eax\n\t"
91 "shl $2, %%eax\n\t"
92 "add %%eax, %%edx\n\t"
93 "mov 0(%%edx), %%edx\n\t"
94 "call *%%edx\n\t"
95 // save return registers
96 "mov %%eax, %0\n\t"
97 "mov %%edx, %1\n\t"
98 // cleanup stack
99 "mov %2, %%esp\n\t"
100 : "=m"(eax), "=m"(edx), "=m"(stackptr)
101 : "m"(nStackLongs), "m"(pStackLongs), "m"(pAdjustedThisPtr), "m"(nVtableIndex)
102 : "eax", "ecx", "edx" );
103 switch( pReturnTypeDescr->eTypeClass )
104 {
105 case typelib_TypeClass_VOID:
106 break;
107 case typelib_TypeClass_HYPER:
108 case typelib_TypeClass_UNSIGNED_HYPER:
109 static_cast<long*>(pRegisterReturn)[1] = edx;
110 [[fallthrough]];
111 case typelib_TypeClass_LONG:
112 case typelib_TypeClass_UNSIGNED_LONG:
113 case typelib_TypeClass_CHAR:
114 case typelib_TypeClass_ENUM:
115 static_cast<long*>(pRegisterReturn)[0] = eax;
116 break;
117 case typelib_TypeClass_SHORT:
118 case typelib_TypeClass_UNSIGNED_SHORT:
119 *static_cast<unsigned short*>(pRegisterReturn) = eax;
120 break;
121 case typelib_TypeClass_BOOLEAN:
122 case typelib_TypeClass_BYTE:
123 *static_cast<unsigned char*>(pRegisterReturn) = eax;
124 break;
125 case typelib_TypeClass_FLOAT:
126 asm ( "fstps %0" : : "m"(*static_cast<char *>(pRegisterReturn)) );
127 break;
128 case typelib_TypeClass_DOUBLE:
129 asm ( "fstpl %0\n\t" : : "m"(*static_cast<char *>(pRegisterReturn)) );
130 break;
131 default:
132 {
133#if defined (FREEBSD) || defined(NETBSD) || defined(OPENBSD) || defined(MACOSX) || \
134 defined(DRAGONFLY)
135 sal_Int32 const nRetSize = pReturnTypeDescr->nSize;
136 if (bSimpleReturn && nRetSize <= 8 && nRetSize > 0)
137 {
138 if (nRetSize > 4)
139 static_cast<long *>(pRegisterReturn)[1] = edx;
140 static_cast<long *>(pRegisterReturn)[0] = eax;
141 }
142#else
143 (void)bSimpleReturn;
144#endif
145 break;
146 }
147 }
148}
149
150/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
struct _typelib_TypeDescription typelib_TypeDescription
Definition: msvc/except.hxx:52
void dummy_can_throw_anything(char const *)
void callVirtualMethod(void *pAdjustedThisPtr, sal_Int32 nVtableIndex, void *pRegisterReturn, typelib_TypeDescription *pReturnTypeDescr, bool bSimpleReturn, sal_Int32 *pStackLongs, sal_Int32 nStackLongs)