[SPEC2DEF] Implement support for import symbol aliases

sdk/cmake/msvc.cmake

@@ -317,11 +317,12 @@ function(generate_import_lib _libname _dllname _spec_file __version_arg)
 
     set(_def_file ${CMAKE_CURRENT_BINARY_DIR}/${_libname}_implib.def)
     set(_asm_stubs_file ${CMAKE_CURRENT_BINARY_DIR}/${_libname}_stubs.asm)
+    set(_asm_impalias_file ${CMAKE_CURRENT_BINARY_DIR}/${_libname}_impalias.asm)
 
-    # Generate the def and asm stub files
+    # Generate the def, asm stub and alias files
     add_custom_command(
-        OUTPUT ${_asm_stubs_file} ${_def_file}
+        OUTPUT ${_asm_stubs_file} ${_def_file} ${_asm_impalias_file}
-        COMMAND native-spec2def --ms ${__version_arg} -a=${SPEC2DEF_ARCH} --implib -n=${_dllname} -d=${_def_file} -l=${_asm_stubs_file} ${CMAKE_CURRENT_SOURCE_DIR}/${_spec_file}
+        COMMAND native-spec2def --ms ${__version_arg} -a=${SPEC2DEF_ARCH} --implib -n=${_dllname} -d=${_def_file} -l=${_asm_stubs_file} -i=${_asm_impalias_file} ${CMAKE_CURRENT_SOURCE_DIR}/${_spec_file}
         DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${_spec_file} native-spec2def)
 
     # Compile the generated asm stub file
@@ -351,7 +352,7 @@ function(generate_import_lib _libname _dllname _spec_file __version_arg)
     # By giving the import lib as an object input, LIB extracts the relevant object files and make a new library.
     # This allows us to treat the implib as a regular static library
     set_source_files_properties(${_libfile_tmp} PROPERTIES EXTERNAL_OBJECT TRUE)
-    add_library(${_libname} STATIC ${_libfile_tmp})
+    add_library(${_libname} STATIC ${_libfile_tmp} ${_asm_impalias_file})
 
     set_target_properties(${_libname} PROPERTIES LINKER_LANGUAGE "C")
 endfunction()

sdk/tools/spec2def/spec2def.c

@@ -85,6 +85,7 @@ enum
     FL_NORELAY = 16,
     FL_RET64 = 32,
     FL_REGISTER = 64,
+    FL_IMPSYM = 128,
 };
 
 enum
@@ -612,6 +613,11 @@ PrintName(FILE *fileDest, EXPORT *pexp, PSTRING pstr, int fDeco)
             fprintf(fileDest, "%.*s@%d", nNameLength, pcName, pexp->nStackBytes);
         }
     }
+    else if (fDeco && (pexp->nCallingConvention == CC_CDECL) && gbMSComp)
+    {
+        /* Print with cdecl decoration */
+        fprintf(fileDest, "_%.*s", nNameLength, pcName);
+    }
     else
     {
         /* Print the undecorated function name */
@@ -685,7 +691,7 @@ OutputLine_def_GCC(FILE *fileDest, EXPORT *pexp)
         DbgPrint("Got redirect '%.*s'\n", pexp->strTarget.len, pexp->strTarget.buf);
 
         /* print the target name, don't decorate if it is external */
-        fprintf(fileDest, "=");
+        fprintf(fileDest, pexp->uFlags & FL_IMPSYM ? "==" : "=");
         PrintName(fileDest, pexp, &pexp->strTarget, !fIsExternal);
     }
     else if (((pexp->uFlags & FL_STUB) || (pexp->nCallingConvention == CC_STUB)) &&
@@ -747,6 +753,17 @@ OutputLine_def(FILE *fileDest, EXPORT *pexp)
         return 1;
     }
 
+    /* Handle import symbols */
+    if (pexp->uFlags & FL_IMPSYM)
+    {
+        /* Skip these, if we are not creating an import lib, or if this is MS */
+        if (!gbImportLib || gbMSComp)
+        {
+            DbgPrint("OutputLine_def: skipping import symbol '%.*s'...\n", pexp->strName.len, pexp->strName.buf);
+            return 1;
+        }
+    }
+
     /* For MS linker, forwarded externs are managed via #pragma comment(linker,"/export:_data=org.data,DATA") */
     if (gbMSComp && !gbImportLib && (pexp->nCallingConvention == CC_EXTERN) &&
         (pexp->strTarget.buf != NULL) && !!ScanToken(pexp->strTarget.buf, '.'))
@@ -790,6 +807,54 @@ OutputLine_def(FILE *fileDest, EXPORT *pexp)
     return 1;
 }
 
+void
+PrintNameOrImpName(FILE *fileDest, EXPORT *pexp, PSTRING pstr, int fDeco, int fImp)
+{
+    if (fImp)
+    {
+        fprintf(fileDest, "__imp_");
+    }
+
+    PrintName(fileDest, pexp, pstr, fDeco);
+}
+
+void
+OutputAlias(FILE *fileDest, EXPORT *pexp, int fImp)
+{
+    if ((giArch == ARCH_ARM) || (giArch == ARCH_ARM64))
+    {
+        fprintf(fileDest, "    IMPORT ");
+        PrintNameOrImpName(fileDest, pexp, &pexp->strName, 1, fImp);
+        fprintf(fileDest, ", WEAK ");
+        PrintNameOrImpName(fileDest, pexp, &pexp->strTarget, 1, fImp);
+        fprintf(fileDest, "\n");
+    }
+    else
+    {
+        fprintf(fileDest, "    EXTERN ");
+        PrintNameOrImpName(fileDest, pexp, &pexp->strTarget, 1, fImp);
+        fprintf(fileDest, ":PROC\n    ALIAS <");
+        PrintNameOrImpName(fileDest, pexp, &pexp->strName, 1, fImp);
+        fprintf(fileDest, "> = <");
+        PrintNameOrImpName(fileDest, pexp, &pexp->strTarget, 1, fImp);
+        fprintf(fileDest, ">\n");
+    }
+}
+
+int
+OutputLine_implib_asm(FILE *fileDest, EXPORT *pexp)
+{
+    if ((pexp->uFlags & FL_IMPSYM) == 0)
+    {
+        return 1;
+    }
+
+    OutputAlias(fileDest, pexp, 0);
+    OutputAlias(fileDest, pexp, 1);
+
+    return 1;
+}
+
 void
 Fatalv(
     const char* filename,
@@ -1090,6 +1155,10 @@ ParseFile(char* pcStart, FILE *fileDest, unsigned *cExports)
             {
                 exp.uFlags |= FL_ORDINAL | FL_NONAME;
             }
+            else if (CompareToken(pc, "-impsym"))
+            {
+                exp.uFlags |= FL_IMPSYM;
+            }
             else if (CompareToken(pc, "-ordinal"))
             {
                 exp.uFlags |= FL_ORDINAL;
@@ -1298,6 +1367,12 @@ ParseFile(char* pcStart, FILE *fileDest, unsigned *cExports)
             Fatal(pszSourceFileName, nLine, pcLine, pc, 0, "Ordinal export without ordinal");
         }
 
+        /* Check for import symbol without target */
+        if ((exp.uFlags & FL_IMPSYM) && (exp.strTarget.buf == NULL))
+        {
+            Fatal(pszSourceFileName, nLine, pcLine, pc, 1, "Import symbol without target");
+        }
+
         /*
          * Check for special handling of OLE exports, only when MSVC
          * is not used, since otherwise this is handled by MS LINK.EXE.
@@ -1395,6 +1470,7 @@ void usage(void)
            "  -l=<file>               generate an asm lib stub\n"
            "  -d=<file>               generate a def file\n"
            "  -s=<file>               generate a stub file\n"
+           "  -i=<file>               generate an import alias file\n"
            "  --ms                    MSVC compatibility\n"
            "  -n=<name>               name of the dll\n"
            "  --version=<version>     Sets the version to create exports for\n"
@@ -1408,6 +1484,7 @@ int main(int argc, char *argv[])
 {
     size_t nFileSize;
     char *pszSource, *pszDefFileName = NULL, *pszStubFileName = NULL, *pszLibStubName = NULL;
+    char *pszImpLibAliasFileName = NULL;
     const char* pszVersionOption = "--version=0x";
     char achDllName[40];
     FILE *file;
@@ -1441,6 +1518,10 @@ int main(int argc, char *argv[])
         {
             pszStubFileName = argv[i] + 3;
         }
+        else if (argv[i][1] == 'i' && argv[i][2] == '=')
+        {
+            pszImpLibAliasFileName = argv[i] + 3;
+        }
         else if (argv[i][1] == 'n' && argv[i][2] == '=')
         {
             pszDllName = argv[i] + 3;
@@ -1574,7 +1655,7 @@ int main(int argc, char *argv[])
         file = fopen(pszDefFileName, "w");
         if (!file)
         {
-            fprintf(stderr, "error: could not open output file %s\n", argv[i + 1]);
+            fprintf(stderr, "error: could not open output file %s\n", pszDefFileName);
             return -5;
         }
 
@@ -1595,7 +1676,7 @@ int main(int argc, char *argv[])
         file = fopen(pszStubFileName, "w");
         if (!file)
         {
-            fprintf(stderr, "error: could not open output file %s\n", argv[i + 1]);
+            fprintf(stderr, "error: could not open output file %s\n", pszStubFileName);
             return -5;
         }
 
@@ -1616,7 +1697,7 @@ int main(int argc, char *argv[])
         file = fopen(pszLibStubName, "w");
         if (!file)
         {
-            fprintf(stderr, "error: could not open output file %s\n", argv[i + 1]);
+            fprintf(stderr, "error: could not open output file %s\n", pszLibStubName);
             return -5;
         }
 
@@ -1632,6 +1713,28 @@ int main(int argc, char *argv[])
         fclose(file);
     }
 
+    if (pszImpLibAliasFileName)
+    {
+        /* Open output file */
+        file = fopen(pszImpLibAliasFileName, "w");
+        if (!file)
+        {
+            fprintf(stderr, "error: could not open output file %s\n", pszImpLibAliasFileName);
+            return -5;
+        }
+
+        OutputHeader_asmstub(file, pszDllName);
+
+        for (i = 0; i < cExports; i++)
+        {
+            if (pexports[i].bVersionIncluded)
+                OutputLine_implib_asm(file, &pexports[i]);
+        }
+
+        fprintf(file, "\n    END\n");
+        fclose(file);
+    }
+
     free(pexports);
 
     return 0;