[lld] r193385 - [PECOFF] Handle edge case where no section alignment is specified.

[Rui Ueyama]

Author: ruiu
Date: Thu Oct 24 19:54:13 2013
New Revision: 193385

URL: http://llvm.org/viewvc/llvm-project?rev=193385&view=rev
Log:
[PECOFF] Handle edge case where no section alignment is specified.

Modified:
    lld/trunk/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
    lld/trunk/test/pecoff/Inputs/alignment.obj.yaml
    lld/trunk/test/pecoff/alignment.test

Modified: lld/trunk/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp?rev=193385&r1=193384&r2=193385&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp (original)
+++ lld/trunk/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp Thu Oct 24 19:54:13 2013
@@ -92,10 +92,20 @@ DefinedAtom::ContentPermissions getPermi
 DefinedAtom::Alignment getAlignment(const coff_section *section) {
   if (section->Characteristics & llvm::COFF::IMAGE_SCN_TYPE_NO_PAD)
     return DefinedAtom::Alignment(0);
+
   // Bit [20:24] contains section alignment information. We need to decrease
   // the value stored by 1 in order to get the real exponent (e.g, ALIGN_1BYTE
   // is 0x00100000, but the exponent should be 0)
-  int powerOf2 = ((section->Characteristics >> 20) & 0xf) - 1;
+  uint32_t charactersitcis = (section->Characteristics >> 20) & 0xf;
+
+  // If all bits are off, we treat it as if ALIGN_1BYTE was on. The PE/COFF spec
+  // does not say anything about this case, but CVTRES.EXE does not set any bit
+  // in characteristics[20:24], and its output is intended to be copied to .rsrc
+  // section with no padding, so I think doing this is the right thing.
+  if (charactersitcis == 0)
+    return DefinedAtom::Alignment(0);
+
+  uint32_t powerOf2 = charactersitcis - 1;
   return DefinedAtom::Alignment(powerOf2);
 }
 

Modified: lld/trunk/test/pecoff/Inputs/alignment.obj.yaml
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/pecoff/Inputs/alignment.obj.yaml?rev=193385&r1=193384&r2=193385&view=diff
==============================================================================
--- lld/trunk/test/pecoff/Inputs/alignment.obj.yaml (original)
+++ lld/trunk/test/pecoff/Inputs/alignment.obj.yaml Thu Oct 24 19:54:13 2013
@@ -6,22 +6,23 @@ sections:
   - Name:            .text
     Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
     Alignment:       256
-    SectionData:     5589E583EC14C745FC00000000C744240C00000000C744240807000000C744240400000000C7042400000000FF150000000083EC1031C083C4145DC3
-    Relocations:
-      - VirtualAddress:  25
-        SymbolName:      .data
-        Type:            IMAGE_REL_I386_DIR32
-      - VirtualAddress:  33
-        SymbolName:      .data
-        Type:            IMAGE_REL_I386_DIR32
+    SectionData:     CC
   - Name:            .text$1
     Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
     Alignment:       4096
     SectionData:     00
-  - Name:            .data
+  - Name:            .data$1
     Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
     Alignment:       4
-    SectionData:     576F726C64210048656C6C6F2C00
+    SectionData:     00
+  - Name:            .data$2
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       4
+    SectionData:     11
+  - Name:            .data$3
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
+    Alignment:       0
+    SectionData:     22
 symbols:
   - Name:            .text
     Value:           0
@@ -29,16 +30,30 @@ symbols:
     SimpleType:      IMAGE_SYM_TYPE_NULL
     ComplexType:     IMAGE_SYM_DTYPE_NULL
     StorageClass:    IMAGE_SYM_CLASS_STATIC
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:   3C0000000300000000000000010000000000
-  - Name:            .data
+  - Name:            .text$1
     Value:           0
     SectionNumber:   2
     SimpleType:      IMAGE_SYM_TYPE_NULL
     ComplexType:     IMAGE_SYM_DTYPE_NULL
     StorageClass:    IMAGE_SYM_CLASS_STATIC
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:   0E0000000000000000000000020000000000
+  - Name:            .data$1
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .data$2
+    Value:           0
+    SectionNumber:   4
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .data$3
+    Value:           0
+    SectionNumber:   5
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
   - Name:            _start
     Value:           0
     SectionNumber:   1

Modified: lld/trunk/test/pecoff/alignment.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/pecoff/alignment.test?rev=193385&r1=193384&r2=193385&view=diff
==============================================================================
--- lld/trunk/test/pecoff/alignment.test (original)
+++ lld/trunk/test/pecoff/alignment.test Thu Oct 24 19:54:13 2013
@@ -3,4 +3,8 @@
 # RUN: lld -flavor link /out:%t1 /subsystem:console /force /entry:start \
 # RUN:   -- %t.obj && llvm-readobj -sections %t1 | FileCheck %s
 
-CHECK: VirtualSize: 0x1001
+CHECK:      Name: .text
+CHECK-NEXT: VirtualSize: 0x1001
+
+CHECK:      Name: .data
+CHECK-NEXT: VirtualSize: 0x6