ELF: more section creation cleanup

Summary:
This patch attempts to move as much code as possible out of the
CreateSections function to make room for future improvements there. Some
of this may be slightly over-engineered (VMAddressProvider), but I
wanted to keep the logic of this function very simple, because once I
start taking segment headers into acount (as discussed in D55356), the
function is going to grow significantly.

While in there, I also added tests for various bits of functionality.

This should be NFC, except that I changed the order of hac^H^Heuristicks
for determining section type slightly. Previously, name-based deduction
(.symtab -> symtab) would take precedence over type-based (SHT_SYMTAB ->
symtab) one. In fact we would assert if we ran into a .text section with
type SHT_SYMTAB. Though unlikely to matter in practice, this order
seemed wrong to me, so I have inverted it.

Reviewers: clayborg, krytarowski, espindola

Subscribers: emaste, arichardson, lldb-commits

Differential Revision: https://reviews.llvm.org/D55706

llvm-svn: 349268

lldb/lit/Modules/ELF/compressed-sections.yaml

@@ -19,15 +19,13 @@ Sections:
 
 # CHECK: Name: .hello_elf
 # CHECK-NEXT: Type: regular
-# CHECK-NEXT: Thread specific: no
-# CHECK-NEXT: VM size: 0
+# CHECK: VM size: 0
 # CHECK-NEXT: File size: 28
 # CHECK-NEXT: Data:
 # CHECK-NEXT: 20304050 60708090
 
 # CHECK: Name: .bogus
 # CHECK-NEXT: Type: regular
-# CHECK-NEXT: Thread specific: no
-# CHECK-NEXT: VM size: 0
+# CHECK: VM size: 0
 # CHECK-NEXT: File size: 8
 # CHECK-NEXT: Data: ()

lldb/lit/Modules/ELF/section-addresses.yaml

@@ -0,0 +1,58 @@
+# RUN: yaml2obj %s > %t
+# RUN: lldb-test object-file %t | FileCheck %s
+
+# CHECK-LABEL: Name: .one
+# CHECK: VM address: 0x0
+
+# CHECK-LABEL: Name: .nonalloc
+# CHECK: VM address: 0x0
+
+# CHECK-LABEL: Name: .two
+# CHECK: VM address: 0x8
+
+# CHECK-LABEL: Name: .three
+# CHECK: VM address: 0xc
+
+# CHECK-LABEL: Name: .four
+# CHECK: VM address: 0xc
+
+# CHECK-LABEL: Name: .five
+# CHECK: VM address: 0x1000
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+  Entry:           0x00000000000007A0
+Sections:
+  - Name:            .one
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+  - Name:            .nonalloc
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+  - Name:            .two
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         DE
+  - Name:            .three
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+  - Name:            .four
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+  - Name:            .five
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    AddressAlign:    0x0000000000001000
+    Content:         DEADBEEFBAADF00D
+...

lldb/lit/Modules/ELF/section-permissions.yaml

@@ -0,0 +1,34 @@
+# RUN: yaml2obj %s > %t
+# RUN: lldb-test object-file %t | FileCheck %s
+
+# CHECK-LABEL: Name: .r-x
+# CHECK: Permissions: r-x
+#
+# CHECK-LABEL: Name: .rw-
+# CHECK: Permissions: rw-
+
+# CHECK-LABEL: Name: .---
+# CHECK: Permissions: ---
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+  Entry:           0x00000000000007A0
+Sections:
+  - Name:            .r-x
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Content:         DEADBEEFBAADF00D
+  - Name:            .rw-
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+  - Name:            .---
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000001
+    Content:         DEADBEEFBAADF00D
+...

lldb/lit/Modules/ELF/section-types-edgecases.yaml

@@ -0,0 +1,35 @@
+# This test doesn't attempt to mandate a specific section classification. It is
+# here to document the existing behavior and to make sure we don't do something
+# completely crazy (like crashing).
+
+# RUN: yaml2obj %s > %t
+# RUN: lldb-test object-file %t | FileCheck %s
+
+# The section is called .data, but it has the SHF_EXECINSTR flag set. Have
+# the flag take precedence over the name.
+# CHECK-LABEL: Name: .data
+# CHECK-NEXT: Type: code
+
+# Section type (SHT_SYMTAB) takes precedence over name-based deduction.
+# CHECK-LABEL: Name: .text
+# CHECK-NEXT: Type: elf-symbol-table
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+  Entry:           0x00000000000007A0
+Sections:
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_EXECINSTR, SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+  - Name:            .text
+    Type:            SHT_SYMTAB
+    Flags:           [ ]
+    AddressAlign:    0x0000000000000004
+    Content:         DEADBEEFBAADF00D
+...

lldb/lit/Modules/ELF/section-types.yaml

@@ -25,11 +25,11 @@
 
 # CHECK-LABEL: Name: .tdata
 # CHECK-NEXT: Type: data
-# CHECK-NEXT: Thread specific: yes
+# CHECK: Thread specific: yes
 
 # CHECK-LABEL: Name: .tbss
 # CHECK-NEXT: Type: zero-fill
-# CHECK-NEXT: Thread specific: yes
+# CHECK: Thread specific: yes
 
 --- !ELF
 FileHeader:

lldb/lit/Modules/MachO/subsections.yaml

@@ -5,36 +5,46 @@
 #CHECK-NEXT:  Index: 0
 #CHECK-NEXT:  Name: __PAGEZERO
 #CHECK-NEXT:  Type: container
+#CHECK-NEXT:  Permissions: ---
 #CHECK-NEXT:  Thread specific: no
+#CHECK-NEXT:  VM address: 0x0
 #CHECK-NEXT:  VM size: 4294967296
 #CHECK-NEXT:  File size: 0
 #CHECK-NEXT:  There are no subsections
 #
 #CHECK:       Index: 1
 #CHECK-NEXT:  Name: __TEXT
 #CHECK-NEXT:  Type: container
+#CHECK-NEXT:  Permissions: r-x
 #CHECK-NEXT:  Thread specific: no
+#CHECK-NEXT:  VM address: 0x100000000
 #CHECK-NEXT:  VM size: 4096
 #CHECK-NEXT:  File size: 4096
 #CHECK-NEXT:  Showing 3 subsections
 #CHECK-NEXT:    Index: 0
 #CHECK-NEXT:    Name: __text
 #CHECK-NEXT:    Type: code
+#CHECK-NEXT:    Permissions: r-x
 #CHECK-NEXT:    Thread specific: no
+#CHECK-NEXT:    VM address: 0x100000f30
 #CHECK-NEXT:    VM size: 22
 #CHECK-NEXT:    File size: 22
 #
 #CHECK:         Index: 1
 #CHECK-NEXT:    Name: __unwind_info
 #CHECK-NEXT:    Type: compact-unwind
+#CHECK-NEXT:    Permissions: r-x
 #CHECK-NEXT:    Thread specific: no
+#CHECK-NEXT:    VM address: 0x100000f48
 #CHECK-NEXT:    VM size: 76
 #CHECK-NEXT:    File size: 76
 #
 #CHECK:         Index: 2
 #CHECK-NEXT:    Name: __eh_frame
 #CHECK-NEXT:    Type: eh-frame
+#CHECK-NEXT:    Permissions: r-x
 #CHECK-NEXT:    Thread specific: no
+#CHECK-NEXT:    VM address: 0x100000f98
 #CHECK-NEXT:    VM size: 104
 #CHECK-NEXT:    File size: 104