[PECOFF] Support yet another new type of weak symbol.

COMDAT_SELECT_LARGEST is a COMDAT type that make linker to choose the largest
definition from among all of the definition of a symbol. If the size is the
same, the choice is arbitrary.

Differential Revision: http://llvm-reviews.chandlerc.com/D3011

llvm-svn: 204172

3 files changed, 74 insertions, 0 deletions

diff --git a/lld/test/pecoff/Inputs/merge-largest1.obj.yaml b/lld/test/pecoff/Inputs/merge-largest1.obj.yaml
new file mode 100644
index 00000000000..40ba41f3672
--- /dev/null
+++ b/lld/test/pecoff/Inputs/merge-largest1.obj.yaml
@@ -0,0 +1,25 @@
+---
+header:
+  Machine:         IMAGE_FILE_MACHINE_I386
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       16
+    SectionData:     00112233
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    NumberOfAuxSymbols: 1
+    AuxiliaryData:   0700000000000000C979F796000006000000
+  - Name:            "_foo"
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...
diff --git a/lld/test/pecoff/Inputs/merge-largest2.obj.yaml b/lld/test/pecoff/Inputs/merge-largest2.obj.yaml
new file mode 100644
index 00000000000..962489a20a1
--- /dev/null
+++ b/lld/test/pecoff/Inputs/merge-largest2.obj.yaml
@@ -0,0 +1,25 @@
+---
+header:
+  Machine:         IMAGE_FILE_MACHINE_I386
+  Characteristics: [  ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       16
+    SectionData:     0011223344556677
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    NumberOfAuxSymbols: 1
+    AuxiliaryData:   0700000000000000C979F796000006000000
+  - Name:            "_foo"
+    Value:           6
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...
diff --git a/lld/test/pecoff/merge-largest.test b/lld/test/pecoff/merge-largest.test
new file mode 100644
index 00000000000..73d2d940660
--- /dev/null
+++ b/lld/test/pecoff/merge-largest.test
@@ -0,0 +1,24 @@
+# RUN: yaml2obj %p/Inputs/merge-largest1.obj.yaml > %t1.obj
+# RUN: yaml2obj %p/Inputs/merge-largest2.obj.yaml > %t2.obj
+#
+# RUN: lld -flavor link /out:%t.exe /subsystem:console /opt:noref /force \
+# RUN:   -- %t1.obj %t2.obj 2>&1 > %t.log
+#
+# FileCheck complains if the input files is empty, so add a dummy line.
+# RUN: echo foo >> %t.log
+# RUN: FileCheck -check-prefix=STDERR %s < %t.log
+#
+# RUN: llvm-readobj -sections %t.exe | FileCheck -check-prefix=READOBJ %s
+
+STDERR-NOT: duplicate symbol error
+
+READOBJ:      Format: COFF-i386
+READOBJ-NEXT: Arch: i386
+READOBJ-NEXT: AddressSize: 32bit
+READOBJ-NEXT: Sections [
+READOBJ-NEXT:   Section {
+READOBJ-NEXT:     Number: 1
+READOBJ-NEXT:     Name: .text (2E 74 65 78 74 00 00 00)
+READOBJ-NEXT:     VirtualSize: 0x8
+READOBJ-NEXT:     VirtualAddress: 0x1000
+READOBJ-NEXT:     RawDataSize: 8