fix 17868 - add pragma(crt_con-/destructor)

changelog/crt-constructor.dd

@@ -0,0 +1,33 @@
+pragma(crt_constructor) and pragma(crt_destructor) were added
+
+This allows programs to run initialization code before or cleanup code after C
+main.
+
+In particular those pragmas can be used in $(TT -betterC) code as substitutes
+for $(LINK2 $(ROOT_DIR)spec/class.html#shared_static_constructors, `shared static this()`) and
+$(LINK2 $(ROOT_DIR)spec/class.html#shared_static_destructors, `shared static ~this()`).
+
+$(RED Note:) At the time of execution druntime is not initialized.
+
+$(RED Note:) The order in which constructors are executed is unspecified.
+
+---
+import core.stdc.stdio;
+
+pragma(crt_constructor)
+void init()
+{
+    puts("init");
+}
+
+pragma(crt_destructor)
+void fini()
+{
+    puts("fini");
+}
+
+extern(C) int main()
+{
+    puts("main");
+}
+---

src/ddmd/backend/elfobj.c

@@ -1625,16 +1625,9 @@ void Obj::compiler()
  *              3:      compiler
  */
 
-void Obj::staticctor(Symbol *s,int dtor,int none)
+void Obj::staticctor(Symbol *s, int, int)
 {
-    // Static constructors and destructors
-    //dbg_printf("Obj::staticctor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    const IDXSEC seg = s->Sseg =
-        ElfObj::getsegment(".ctors", NULL, SHT_PROGBITS, SHF_ALLOC|SHF_WRITE, 4);
-    const unsigned relinfo = I64 ? R_X86_64_64 : R_386_32;
-    const size_t sz = ElfObj::writerel(seg, SegData[seg]->SDoffset, relinfo, STI_TEXT, s->Soffset);
-    SegData[seg]->SDoffset += sz;
+    setModuleCtorDtor(s, true);
 }
 
 /**************************************
@@ -1647,24 +1640,20 @@ void Obj::staticctor(Symbol *s,int dtor,int none)
 
 void Obj::staticdtor(Symbol *s)
 {
-    //dbg_printf("Obj::staticdtor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    // Why does this sequence differ from staticctor, looks like a bug?
-    const IDXSEC seg =
-        ElfObj::getsegment(".dtors", NULL, SHT_PROGBITS, SHF_ALLOC|SHF_WRITE, 4);
-    const unsigned relinfo = I64 ? R_X86_64_64 : R_386_32;
-    const size_t sz = ElfObj::writerel(seg, SegData[seg]->SDoffset, relinfo, s->Sxtrnnum, s->Soffset);
-    SegData[seg]->SDoffset += sz;
+    setModuleCtorDtor(s, false);
 }
 
 /***************************************
  * Stuff pointer to function in its own segment.
  * Used for static ctor and dtor lists.
  */
 
-void Obj::setModuleCtorDtor(Symbol *s, bool isCtor)
+void Obj::setModuleCtorDtor(Symbol *sfunc, bool isCtor)
 {
-    //dbg_printf("Obj::setModuleCtorDtor(%s) \n",s->Sident);
+    IDXSEC seg = ElfObj::getsegment(isCtor ? ".ctors" : ".dtors", NULL, SHT_PROGBITS, SHF_ALLOC|SHF_WRITE, NPTRSIZE);
+    const unsigned reltype = I64 ? R_X86_64_64 : R_386_32;
+    const size_t sz = ElfObj::writerel(seg, SegData[seg]->SDoffset, reltype, sfunc->Sxtrnnum, 0);
+    SegData[seg]->SDoffset += sz;
 }
 
 

src/ddmd/backend/machobj.c

@@ -1662,24 +1662,9 @@ void Obj::compiler()
  *              3:      compiler
  */
 
-void Obj::staticctor(Symbol *s,int dtor,int none)
+void Obj::staticctor(Symbol *s, int, int)
 {
-#if 0
-    IDXSEC seg;
-    Outbuffer *buf;
-
-    //dbg_printf("Obj::staticctor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    s->Sseg = seg =
-        ElfObj::getsegment(".ctors", NULL, SHT_PROGDEF, SHF_ALLOC|SHF_WRITE, 4);
-    buf = SegData[seg]->SDbuf;
-    if (I64)
-        buf->write64(s->Soffset);
-    else
-        buf->write32(s->Soffset);
-    MachObj::addrel(seg, SegData[seg]->SDoffset, s, RELaddr);
-    SegData[seg]->SDoffset = buf->size();
-#endif
+    setModuleCtorDtor(s, true);
 }
 
 /**************************************
@@ -1692,21 +1677,7 @@ void Obj::staticctor(Symbol *s,int dtor,int none)
 
 void Obj::staticdtor(Symbol *s)
 {
-#if 0
-    IDXSEC seg;
-    Outbuffer *buf;
-
-    //dbg_printf("Obj::staticdtor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    seg = ElfObj::getsegment(".dtors", NULL, SHT_PROGDEF, SHF_ALLOC|SHF_WRITE, 4);
-    buf = SegData[seg]->SDbuf;
-    if (I64)
-        buf->write64(s->Soffset);
-    else
-        buf->write32(s->Soffset);
-    MachObj::addrel(seg, SegData[seg]->SDoffset, s, RELaddr);
-    SegData[seg]->SDoffset = buf->size();
-#endif
+    setModuleCtorDtor(s, false);
 }
 
 
@@ -1715,9 +1686,16 @@ void Obj::staticdtor(Symbol *s)
  * Used for static ctor and dtor lists.
  */
 
-void Obj::setModuleCtorDtor(Symbol *s, bool isCtor)
+void Obj::setModuleCtorDtor(Symbol *sfunc, bool isCtor)
 {
-    //dbg_printf("Obj::setModuleCtorDtor(%s) \n",s->Sident);
+    const char *secname = isCtor ? "__mod_init_func" : "__mod_term_func";
+    const int align = I64 ? 3 : 2; // align to NPTRSIZE
+    const int flags = isCtor ? S_MOD_INIT_FUNC_POINTERS : S_MOD_TERM_FUNC_POINTERS;
+    IDXSEC seg = MachObj::getsegment(secname, "__DATA", align, flags);
+
+    const int relflags = I64 ? CFoff | CFoffset64 : CFoff;
+    const int sz = Obj::reftoident(seg, SegData[seg]->SDoffset, sfunc, 0, relflags);
+    SegData[seg]->SDoffset += sz;
 }
 
 

src/ddmd/backend/melf.h

@@ -108,6 +108,9 @@ typedef struct
         #define SHT_REL          9          /* Relocations no addends */
         #define SHT_RESTYPE      10         /* Reserved section type*/
         #define SHT_DYNTAB       11         /* Dynamic linker symbol table */
+        #define SHT_INIT_ARRAY   14         /* Array of constructors */
+        #define SHT_FINI_ARRAY   15         /* Array of destructors */
+        #define SHT_PREINIT_ARRAY 16        /* Array of pre-constructors */
         #define SHT_GROUP        17         /* Section group (COMDAT) */
         #define SHT_SYMTAB_SHNDX 18         /* Extended section indices */
   Elf32_Word   sh_flags;               /* Section attribute flags */

src/ddmd/backend/mscoffobj.c

@@ -1129,22 +1129,7 @@ void MsCoffObj::compiler()
 
 void MsCoffObj::staticctor(Symbol *s,int dtor,int none)
 {
-#if 0
-    IDXSEC seg;
-    Outbuffer *buf;
-
-    //dbg_printf("MsCoffObj::staticctor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    s->Sseg = seg =
-        MsCoffObj::getsegment(".ctors", NULL, SHT_PROGDEF, SHF_ALLOC|SHF_WRITE, 4);
-    buf = SegData[seg]->SDbuf;
-    if (I64)
-        buf->write64(s->Soffset);
-    else
-        buf->write32(s->Soffset);
-    MsCoffObj::addrel(seg, SegData[seg]->SDoffset, s, RELaddr);
-    SegData[seg]->SDoffset = buf->size();
-#endif
+    setModuleCtorDtor(s, true);
 }
 
 /**************************************
@@ -1157,21 +1142,7 @@ void MsCoffObj::staticctor(Symbol *s,int dtor,int none)
 
 void MsCoffObj::staticdtor(Symbol *s)
 {
-#if 0
-    IDXSEC seg;
-    Outbuffer *buf;
-
-    //dbg_printf("MsCoffObj::staticdtor(%s) offset %x\n",s->Sident,s->Soffset);
-    //symbol_print(s);
-    seg = MsCoffObj::getsegment(".dtors", NULL, SHT_PROGDEF, SHF_ALLOC|SHF_WRITE, 4);
-    buf = SegData[seg]->SDbuf;
-    if (I64)
-        buf->write64(s->Soffset);
-    else
-        buf->write32(s->Soffset);
-    MsCoffObj::addrel(seg, SegData[seg]->SDoffset, s, RELaddr);
-    SegData[seg]->SDoffset = buf->size();
-#endif
+    setModuleCtorDtor(s, false);
 }
 
 
@@ -1180,9 +1151,17 @@ void MsCoffObj::staticdtor(Symbol *s)
  * Used for static ctor and dtor lists.
  */
 
-void MsCoffObj::setModuleCtorDtor(Symbol *s, bool isCtor)
+void MsCoffObj::setModuleCtorDtor(Symbol *sfunc, bool isCtor)
 {
-    //dbg_printf("MsCoffObj::setModuleCtorDtor(%s) \n",s->Sident);
+    // Also see https://blogs.msdn.microsoft.com/vcblog/2006/10/20/crt-initialization/
+    // and http://www.codeguru.com/cpp/misc/misc/applicationcontrol/article.php/c6945/Running-Code-Before-and-After-Main.htm
+    const int align = I64 ? IMAGE_SCN_ALIGN_8BYTES : IMAGE_SCN_ALIGN_4BYTES;
+    const int attr = IMAGE_SCN_CNT_INITIALIZED_DATA | align | IMAGE_SCN_MEM_READ;
+    const int seg = MsCoffObj::getsegment(isCtor ? ".CRT$XCU" : ".CRT$XPU", attr);
+
+    const int relflags = I64 ? CFoff | CFoffset64 : CFoff;
+    const int sz = MsCoffObj::reftoident(seg, SegData[seg]->SDoffset, sfunc, 0, relflags);
+    SegData[seg]->SDoffset += sz;
 }
 
 

src/ddmd/dsymbolsem.d

@@ -3048,6 +3048,12 @@ extern(C++) final class DsymbolSemanticVisitor : Visitor
                 }
             }
         }
+        else if (pd.ident == Id.crt_constructor || pd.ident == Id.crt_destructor)
+        {
+            if (pd.args && pd.args.dim != 0)
+                pd.error("takes no argument");
+            goto Ldecl;
+        }
         else if (global.params.ignoreUnsupportedPragmas)
         {
             if (global.params.verbose)

src/ddmd/id.d

@@ -298,6 +298,8 @@ immutable Msgtable[] msgtable =
     { "mangle" },
     { "msg" },
     { "startaddress" },
+    { "crt_constructor" },
+    { "crt_destructor" },
 
     // For special functions
     { "tohash", "toHash" },

src/ddmd/toobj.d

@@ -1115,7 +1115,41 @@ void toObjFile(Dsymbol ds, bool multiobj)
                 Symbol *s = toSymbol(f);
                 obj_startaddress(s);
             }
+
             visit(cast(AttribDeclaration)pd);
+
+            if (pd.ident == Id.crt_constructor || pd.ident == Id.crt_destructor)
+            {
+                immutable isCtor = pd.ident == Id.crt_constructor;
+
+                static uint recurse(Dsymbol s, bool isCtor)
+                {
+                    if (auto ad = s.isAttribDeclaration())
+                    {
+                        uint nestedCount;
+                        auto decls = ad.include(null, null);
+                        if (decls)
+                        {
+                            for (size_t i = 0; i < decls.dim; ++i)
+                                nestedCount += recurse((*decls)[i], isCtor);
+                        }
+                        return nestedCount;
+                    }
+                    else if (auto f = s.isFuncDeclaration())
+                    {
+                        objmod.setModuleCtorDtor(s.csym, isCtor);
+                        if (f.linkage != LINKc)
+                            f.error("must be extern(C) for pragma %s", isCtor ? "crt_constructor".ptr : "crt_destructor".ptr);
+                        return 1;
+                    }
+                    else
+                        return 0;
+                    assert(0);
+                }
+
+                if (recurse(pd, isCtor) > 1)
+                    pd.error("can only apply to a single declaration");
+            }
         }
 
         override void visit(TemplateInstance ti)
@@ -1482,5 +1516,3 @@ private size_t emitVtbl(ref DtBuilder dtb, BaseClass *b, ref FuncDeclarations bv
     }
     return id_vtbl_dim * Target.ptrsize;
 }
-
-

test/fail_compilation/test17868.d

@@ -0,0 +1,24 @@
+/*
+TEST_OUTPUT:
+----
+fail_compilation/test17868.d(10): Error: pragma crt_constructor takes no argument
+fail_compilation/test17868.d(11): Error: pragma crt_constructor takes no argument
+fail_compilation/test17868.d(12): Error: pragma crt_constructor takes no argument
+fail_compilation/test17868.d(13): Error: pragma crt_constructor takes no argument
+----
+ */
+pragma(crt_constructor, ctfe())
+pragma(crt_constructor, 1.5f)
+pragma(crt_constructor, "foobar")
+pragma(crt_constructor, S())
+void foo()
+{
+}
+
+int ctfe()
+{
+    __gshared int val;
+    return val;
+}
+
+struct S {}

test/fail_compilation/test17868b.d

@@ -0,0 +1,16 @@
+/*
+TEST_OUTPUT:
+----
+fail_compilation/test17868b.d(10): Error: function test17868b.foo must be extern(C) for pragma crt_constructor
+fail_compilation/test17868b.d(14): Error: function test17868b.bar must be extern(C) for pragma crt_constructor
+fail_compilation/test17868b.d(9): Error: pragma crt_constructor can only apply to a single declaration
+----
+ */
+pragma(crt_constructor):
+void foo()
+{
+}
+
+void bar()
+{
+}

test/runnable/extra-files/test17868-postscript.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+# trim off the first line which contains the path of the file which differs between windows and non-windows
+# also trim off compiler debug message
+grep -v 'runnable\|DEBUG' $1 > ${RESULTS_DIR}/runnable/test17868.d.out.2
+
+diff --strip-trailing-cr runnable/extra-files/test17868.d.out ${RESULTS_DIR}/runnable/test17868.d.out.2
+if [ $? -ne 0 ]; then
+    exit 1;
+fi
+
+rm ${RESULTS_DIR}/runnable/test17868.d.out.2

test/runnable/extra-files/test17868.d.out

@@ -0,0 +1,5 @@
+init
+init
+main
+fini
+fini

test/runnable/test17868.d

@@ -0,0 +1,35 @@
+// REQUIRED_ARGS: -betterC
+// POST_SCRIPT: runnable/extra-files/test17868-postscript.sh
+import core.stdc.stdio;
+
+extern(C):
+
+pragma(crt_constructor)
+void init()
+{
+    puts("init");
+}
+
+pragma(crt_destructor)
+void fini2()
+{
+    puts("fini");
+}
+
+pragma(crt_constructor)
+void foo()
+{
+    puts("init");
+}
+
+pragma(crt_destructor)
+void bar()
+{
+    puts("fini");
+}
+
+int main()
+{
+    puts("main");
+    return 0;
+}