[yaml2obj] Add new command line option -docnum.

Input YAML file might contain multiple object file definitions.
New option `-docnum` allows to specify an ordinal number (starting from 1)
of definition used for an object file generation.

Patch reviewed by Sean Silva.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209967 91177308-0d34-0410-b5e6-96231b3b80d8

test/Object/yaml2obj-coff-multi-doc.test

@@ -0,0 +1,91 @@
+# RUN: yaml2obj -format=coff -docnum=1 %s \
+# RUN:   | llvm-readobj -symbols - | FileCheck -check-prefix=DOC1 %s
+# RUN: yaml2obj -format=coff -docnum=2 %s \
+# RUN:   | llvm-readobj -symbols - | FileCheck -check-prefix=DOC2 %s
+# RUN: not yaml2obj -format=coff -docnum=3 %s 2>&1 \
+# RUN:   | FileCheck -check-prefix=DOC3 %s
+
+# DOC1: Name: _sym1
+# DOC2: Name: _sym2
+# DOC3: yaml2obj: Cannot find the 3rd document
+
+---
+header:
+  Machine: IMAGE_FILE_MACHINE_I386
+  Characteristics: [ IMAGE_FILE_DEBUG_STRIPPED ]
+
+sections:
+  - Name: .text
+    Alignment: 16
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE,
+                       IMAGE_SCN_MEM_READ ]
+    SectionData: "00000000"
+
+symbols:
+  - Name: .text
+    Value: 0
+    SectionNumber: 1
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_NULL
+    StorageClass: IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 3
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+
+  - Name: _main
+    Value: 0
+    SectionNumber: 1
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+
+  - Name: _sym1
+    Value: 0
+    SectionNumber: 0
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_NULL
+    StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+
+---
+header:
+  Machine: IMAGE_FILE_MACHINE_I386
+  Characteristics: [ IMAGE_FILE_DEBUG_STRIPPED ]
+
+sections:
+  - Name: .text
+    Alignment: 16
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE,
+                       IMAGE_SCN_MEM_READ ]
+    SectionData: "00000000"
+
+symbols:
+  - Name: .text
+    Value: 0
+    SectionNumber: 1
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_NULL
+    StorageClass: IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 3
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+
+  - Name: _main
+    Value: 0
+    SectionNumber: 1
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+
+  - Name: _sym2
+    Value: 0
+    SectionNumber: 0
+    SimpleType: IMAGE_SYM_TYPE_NULL
+    ComplexType: IMAGE_SYM_DTYPE_NULL
+    StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+...

test/Object/yaml2obj-elf-multi-doc.test

@@ -0,0 +1,56 @@
+# RUN: yaml2obj -format=elf -docnum=1 %s \
+# RUN:   | llvm-readobj -symbols - | FileCheck -check-prefix=DOC1 %s
+# RUN: yaml2obj -format=elf -docnum=2 %s \
+# RUN:   | llvm-readobj -symbols - | FileCheck -check-prefix=DOC2 %s
+# RUN: not yaml2obj -format=elf -docnum=3 %s 2>&1 \
+# RUN:   | FileCheck -check-prefix=DOC3 %s
+
+# DOC1: Name: T1 (1)
+# DOC2: Name: T2 (1)
+# DOC3: yaml2obj: Cannot find the 3rd document
+
+--- !ELF
+FileHeader: !FileHeader
+  Class: ELFCLASS32
+  Data: ELFDATA2LSB
+  Type: ET_REL
+  Machine: EM_MIPS
+  Flags: [EF_MIPS_CPIC]
+
+Sections:
+- Name: .text
+  Type: SHT_PROGBITS
+  Content:  "0000000000000000"
+  AddressAlign: 16
+  Flags: [SHF_EXECINSTR, SHF_ALLOC]
+
+Symbols:
+  Global:
+    - Name: T1
+      Section: .text
+      Type: STT_FUNC
+      Value: 0x0
+      Size: 8
+
+--- !ELF
+FileHeader: !FileHeader
+  Class: ELFCLASS32
+  Data: ELFDATA2LSB
+  Type: ET_REL
+  Machine: EM_MIPS
+
+Sections:
+- Name: .text
+  Type: SHT_PROGBITS
+  Content:  "00000000"
+  AddressAlign: 16
+  Flags: [SHF_EXECINSTR, SHF_ALLOC]
+
+Symbols:
+  Global:
+    - Name: T2
+      Section: .text
+      Type: STT_FUNC
+      Value: 0x0
+      Size: 4
+...