[lld] r305876 - Define __guard_{iat,longjmp}_{count,table} symbols.

Rui Ueyama via llvm-commits llvm-commits at lists.llvm.org
Tue Jun 20 19:26:19 PDT 2017


Author: ruiu
Date: Tue Jun 20 21:26:19 2017
New Revision: 305876

URL: http://llvm.org/viewvc/llvm-project?rev=305876&view=rev
Log:
Define __guard_{iat,longjmp}_{count,table} symbols.

VC2017 contains these new symbols as undefined symobls. They are used
for /guard:cf. Since we do not support the control flow guard, but we
want to at least ignore these symbols so that we can link against VS2017
libraries.

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=727193.

Added:
    lld/trunk/test/COFF/guardcf.test
Modified:
    lld/trunk/COFF/Driver.cpp

Modified: lld/trunk/COFF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=305876&r1=305875&r2=305876&view=diff
==============================================================================
--- lld/trunk/COFF/Driver.cpp (original)
+++ lld/trunk/COFF/Driver.cpp Tue Jun 20 21:26:19 2017
@@ -1034,9 +1034,13 @@ void LinkerDriver::link(ArrayRef<const c
 
   // We do not support /guard:cf (control flow protection) yet.
   // Define CFG symbols anyway so that we can link MSVC 2015 CRT.
-  Symtab.addAbsolute(mangle("__guard_fids_table"), 0);
   Symtab.addAbsolute(mangle("__guard_fids_count"), 0);
+  Symtab.addAbsolute(mangle("__guard_fids_table"), 0);
   Symtab.addAbsolute(mangle("__guard_flags"), 0x100);
+  Symtab.addAbsolute(mangle("__guard_iat_count"), 0);
+  Symtab.addAbsolute(mangle("__guard_iat_table"), 0);
+  Symtab.addAbsolute(mangle("__guard_longjmp_count"), 0);
+  Symtab.addAbsolute(mangle("__guard_longjmp_table"), 0);
 
   // This code may add new undefined symbols to the link, which may enqueue more
   // symbol resolution tasks, so we need to continue executing tasks until we

Added: lld/trunk/test/COFF/guardcf.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/guardcf.test?rev=305876&view=auto
==============================================================================
--- lld/trunk/test/COFF/guardcf.test (added)
+++ lld/trunk/test/COFF/guardcf.test Tue Jun 20 21:26:19 2017
@@ -0,0 +1,74 @@
+# RUN: yaml2obj < %s > %t.obj
+# RUN: lld-link /entry:main /out:%t.exe %t.obj
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: []
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     000000000000
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          6
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          0
+  - Name:            main
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_fids_count
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_fids_table
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_flags
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_iat_count
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_iat_table
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_longjmp_count
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __guard_longjmp_table
+    Value:           0
+    SectionNumber:   0
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...




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