diff --git a/lld/COFF/MinGW.cpp b/lld/COFF/MinGW.cpp --- a/lld/COFF/MinGW.cpp +++ b/lld/COFF/MinGW.cpp @@ -238,6 +238,19 @@ for (const WrappedSymbol &w : wrapped) { map[w.sym] = w.wrap; map[w.real] = w.sym; + if (Defined *d = dyn_cast(w.wrap)) { + Symbol *imp = symtab->find(("__imp_" + w.sym->getName()).str()); + // Create a new defined local import for the wrap symbol. If + // no imp prefixed symbol existed, there's no need for it. + // (We can't easily distinguish whether any object file actually + // referenced it or not, though.) + if (imp) { + DefinedLocalImport *wrapimp = make( + saver.save("__imp_" + w.wrap->getName()), d); + symtab->localImportChunks.push_back(wrapimp->getChunk()); + map[imp] = wrapimp; + } + } } // Update pointers in input files. diff --git a/lld/test/COFF/wrap-dllimport.s b/lld/test/COFF/wrap-dllimport.s new file mode 100644 --- /dev/null +++ b/lld/test/COFF/wrap-dllimport.s @@ -0,0 +1,42 @@ +// REQUIRES: x86 + +// Check that we can wrap a dllimported symbol, so that references to +// __imp_ gets redirected to a defined local import instead. + +// RUN: split-file %s %t.dir +// RUN: llvm-mc -filetype=obj -triple=i686-win32-gnu %t.dir/main.s -o %t.main.obj +// RUN: llvm-mc -filetype=obj -triple=i686-win32-gnu %t.dir/other.s -o %t.other.obj + +// RUN: lld-link -dll -out:%t.dll %t.other.obj -noentry -safeseh:no -export:foo -implib:%t.lib +// RUN: lld-link -out:%t.exe %t.main.obj %t.lib -entry:entry -subsystem:console -debug:symtab -safeseh:no -wrap:foo -lldmap:%t.map +// RUN: llvm-objdump -s -d --print-imm-hex %t.exe | FileCheck %s + +// CHECK: Contents of section .rdata: +// CHECK-NEXT: 402000 06104000 + +// CHECK: Disassembly of section .text: +// CHECK-EMPTY: +// CHECK: 00401000 <_entry>: +// CHECK-NEXT: 401000: ff 25 00 20 40 00 jmpl *0x402000 +// CHECK-EMPTY: +// CHECK-NEXT: 00401006 <___wrap_foo>: +// CHECK-NEXT: 401006: c3 retl + +// The jmpl instruction in _entry points at an address in 0x402000, +// which is the first 4 bytes of the .rdata section (above), which is a +// pointer that points at ___wrap_foo. + +#--- main.s +.global _entry +_entry: + jmpl *__imp__foo + +.global ___wrap_foo +___wrap_foo: + ret + +#--- other.s +.global _foo + +_foo: + ret diff --git a/lld/test/COFF/wrap-import.ll b/lld/test/COFF/wrap-import.ll --- a/lld/test/COFF/wrap-import.ll +++ b/lld/test/COFF/wrap-import.ll @@ -1,7 +1,8 @@ // REQUIRES: x86 // Check that wrapping works when the wrapped symbol is imported from a -// different DLL. +// different DLL, redirecting references that used to point at the import +// thunk, towards the local wrap function instead. // RUN: split-file %s %t.dir // RUN: llc %t.dir/main.ll -o %t.main.obj --filetype=obj