Improve Packer:addLoader(). We're still somewhat limited because of gcc-bug

#29823 (see http://gcc.gnu.org/PR29823).

src/linker.cpp

@@ -344,7 +344,8 @@ void ElfLinker::setLoaderAlignOffset(int phase)
 
 int ElfLinker::addLoader(const char *sname)
 {
-    if (sname[0] == 0)
+    assert(sname != NULL);
+    if (!sname[0])
         return outputlen;
 
     char *begin = strdup(sname);

src/packer.cpp

@@ -929,31 +929,7 @@ unsigned Packer::unoptimizeReloc32(upx_byte **in, upx_byte *image,
 
 
 /*************************************************************************
-// loader util
+// loader util (interface to linker)
-**************************************************************************/
-
-upx_byte *Packer::getLoader() const
-{
-    int size = -1;
-    upx_byte *oloader = linker->getLoader(&size);
-    if (oloader == NULL || size <= 0)
-        throwBadLoader();
-    return oloader;
-}
-
-
-int Packer::getLoaderSize() const
-{
-    int size = -1;
-    upx_byte *oloader = linker->getLoader(&size);
-    if (oloader == NULL || size <= 0)
-        throwBadLoader();
-    return size;
-}
-
-
-/*************************************************************************
-// loader util
 **************************************************************************/
 
 static const char *getIdentstr(unsigned *size, int small)
@@ -1027,29 +1003,45 @@ void Packer::initLoader(const void *pdata, int plen, int small)
     linker->addSection("IDENTSTR", ident, size, 0);
 }
 
-
-#if 0
 void Packer::addLoader(const char *s)
 {
-    if (s && *s)
+    if (s)
         linker->addLoader(s);
 }
-#endif
 
-void __acc_cdecl_va Packer::addLoader(const char *s, ...)
+// provide specialization for [T = char]
+template <>
+void __acc_cdecl_va Packer::addLoader<char>(const char *s, ...)
 {
     va_list ap;
 
     va_start(ap, s);
     while (s != NULL)
     {
-        if (*s)
+        linker->addLoader(s);
-            linker->addLoader(s);
         s = va_arg(ap, const char *);
     }
     va_end(ap);
 }
 
+upx_byte *Packer::getLoader() const
+{
+    int size = -1;
+    upx_byte *oloader = linker->getLoader(&size);
+    if (oloader == NULL || size <= 0)
+        throwBadLoader();
+    return oloader;
+}
+
+int Packer::getLoaderSize() const
+{
+    int size = -1;
+    upx_byte *oloader = linker->getLoader(&size);
+    if (oloader == NULL || size <= 0)
+        throwBadLoader();
+    return size;
+}
+
 
 int Packer::getLoaderSection(const char *name, int *slen) const
 {
@@ -1062,7 +1054,6 @@ int Packer::getLoaderSection(const char *name, int *slen) const
     return ostart;
 }
 
-
 // same, but the size of the section may be == 0
 int Packer::getLoaderSectionStart(const char *name, int *slen) const
 {

src/packer.h

@@ -209,12 +209,11 @@ protected:
     virtual upx_byte *getLoader() const;
     virtual int getLoaderSize() const;
     virtual void initLoader(const void *pdata, int plen, int small=-1);
+    void addLoader(const char *);
 #if 1 && (ACC_CC_GNUC >= 0x040100)
-    //virtual void addLoader(const char *);
+    template <class T> void __acc_cdecl_va addLoader(const T *, ...) __attribute__((__sentinel__));
-    virtual void __acc_cdecl_va addLoader(const char *, ...) __attribute__((__sentinel__));
 #else
-    //virtual void addLoader(const char *);
+    template <class T> void __acc_cdecl_va addLoader(const T *, ...);
-    virtual void __acc_cdecl_va addLoader(const char *, ...);
 #endif
     virtual int getLoaderSection(const char *name, int *slen=NULL) const;
     virtual int getLoaderSectionStart(const char *name, int *slen=NULL) const;
@@ -293,6 +292,10 @@ private:
 };
 
 
+template <>
+void __acc_cdecl_va Packer::addLoader<char>(const char *s, ...);
+
+
 #endif /* already included */