Fix GCC array bounds warning when accessing g_usrvars

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6258 212acab6-be3b-0410-9dea-997c60f758d6

Source/ResourceEditor.cpp

@@ -514,14 +514,14 @@ DWORD CResourceEditor::Save(BYTE* pbBuf, DWORD &dwSize) {
 // This function scans exe sections and after find a match with given name
 // increments it's virtual size (auto fixes image size based on section alignment, etc)
 // Jim Park: The section name must be ASCII code.  Do not TCHAR this stuff.
-bool CResourceEditor::AddExtraVirtualSize2PESection(const char* pszSectionName, int addsize)
+bool CResourceEditor::SetPESectionVirtualSize(const char* pszSectionName, DWORD newsize)
 {
   PIMAGE_SECTION_HEADER sectionHeadersArray = IMAGE_FIRST_SECTION(m_ntHeaders);
 
   // Refresh the headers of the sections that come after the resource section, and the data directory
   for (int i = 0; i < ConvertEndianness(m_ntHeaders->FileHeader.NumberOfSections); i++) {
     if (!strcmp((LPCSTR)sectionHeadersArray[i].Name, pszSectionName)) {
-      sectionHeadersArray[i].Misc.VirtualSize = AlignVA(AdjustVA(sectionHeadersArray[i].Misc.VirtualSize, addsize));
+      sectionHeadersArray[i].Misc.VirtualSize = AlignVA(ConvertEndianness(newsize));
 
       sectionHeadersArray[i].Characteristics &= ConvertEndianness((DWORD) ~IMAGE_SCN_MEM_DISCARDABLE);
 

Source/ResourceEditor.h

@@ -121,7 +121,7 @@ public:
   void  FreeResource(BYTE* pbResource);
 
   // The section name must be in ASCII.
-  bool  AddExtraVirtualSize2PESection(const char* pszSectionName, int addsize);
+  bool  SetPESectionVirtualSize(const char* pszSectionName, DWORD newsize);
   DWORD Save(BYTE* pbBuf, DWORD &dwSize);
 
   // utitlity functions

Source/build.cpp

@@ -2321,9 +2321,8 @@ int CEXEBuild::SetVarsSection()
 
     VerifyDeclaredUserVarRefs(&m_UserVarNames);
     int MaxUserVars = m_UserVarNames.getnum();
-    // -1 because the default size is 1
     int stringSize = NSIS_MAX_STRLEN*(build_unicode?sizeof(TCHAR):sizeof(char));
-    if (!res_editor->AddExtraVirtualSize2PESection(NSIS_VARS_SECTION, (MaxUserVars - 1) * stringSize))
+    if (!res_editor->SetPESectionVirtualSize(NSIS_VARS_SECTION, MaxUserVars * stringSize))
     {
       ERROR_MSG(_T("Internal compiler error #12346: invalid exehead cannot find section \"%s\"!\n"), _T(NSIS_VARS_SECTION));
       return PS_ERROR;

Source/exehead/state.h

@@ -18,7 +18,15 @@
 
 #include "fileform.h"
 
-extern NSIS_STRING g_usrvars[1];
+#ifdef __GNUC__
+// GCC warns about array bounds when accessing g_usrvarssection[2] because it is only [1] at compile time, 
+// the other part of this hack is in util.c where g_usrvarsstart is initialized.
+extern const NSIS_STRING*const g_usrvarsstart;
+#define g_usrvars ( (NSIS_STRING*) (g_usrvarsstart) )
+#else
+extern NSIS_STRING g_usrvarssection[1];
+#define g_usrvars g_usrvarssection
+#endif
 
 #define state_command_line        g_usrvars[20]
 #define state_install_directory   g_usrvars[21]

Source/exehead/util.c

@@ -42,12 +42,15 @@ TCHAR g_log_file[1024];
 // nsis then removes the "DISCARDABLE" style from section (for safe)
 #ifdef _MSC_VER
 #  pragma bss_seg(NSIS_VARS_SECTION)
-NSIS_STRING g_usrvars[1];
+NSIS_STRING g_usrvarssection[1];
 #  pragma bss_seg()
 #  pragma comment(linker, "/section:" NSIS_VARS_SECTION ",rwd")
 #else
 #  ifdef __GNUC__
-NSIS_STRING g_usrvars[1] __attribute__((section (NSIS_VARS_SECTION)));
+// GCC does not treat g_usrvarssection as a bss section so we keep the size as small as possible.
+// NSIS_STRING g_usrvarssection[31] is required to remove this hack but that really bloats the exehead.
+char g_usrvarssection[1] __attribute__((section (NSIS_VARS_SECTION)));
+const NSIS_STRING*const g_usrvarsstart = (const NSIS_STRING*const) g_usrvarssection;
 #  else
 #    error Unknown compiler. You must implement the seperate PE section yourself.
 #  endif