[elfabi] Add support for reading DT_SONAME from binarieslinaro-local/ci/tcwg_kernel/llvm-master-aarch64-next-allnoconfig

This change gives the llvm-elfabi tool the ability to read DT_SONAME from a binary ELF file into an ELFStub.

Added:

 - DynamicEntries struct for storing dynamic entries that are relevant to elfabi.
 - terminatedSubstr() retrieves a null-terminated substring from a StringRef.
 - appendToError() appends a string to an error, allowing more specific error messages.

Differential Revision: https://reviews.llvm.org/D55629

12 files changed, 537 insertions, 20 deletions

diff --git a/llvm/test/tools/llvm-elfabi/binary-read-add-soname.test b/llvm/test/tools/llvm-elfabi/binary-read-add-soname.test
new file mode 100644
index 00000000000..dbc5a00bb57
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-add-soname.test
@@ -0,0 +1,48 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-elfabi --elf %t --emit-tbe=- --soname=best.so | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_AARCH64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000
+    Content:         "00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0008
+    AddressAlign:    8
+    Content:         "0a0000000000000001000000000000000500000000000000000000000000000000000000000000000000000000000000"
+      # DT_STRSZ      1 (0x1)
+      # DT_STRTAB     0x0
+      # DT_NULL       0x0
+    Size:            48
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x0000
+    PAddr: 0x0000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x0008
+    PAddr: 0x0008
+    Sections:
+      - Section: .dynamic
+
+# CHECK:      --- !tapi-tbe
+# CHECK-NEXT: TbeVersion: {{[1-9]\d*\.(0|([1-9]\d*))}}
+# CHECK-NEXT: SoName: best.so{{$}}
+# CHECK-NEXT: Arch: AArch64
+# CHECK-NEXT: Symbols: {}
+# CHECK-NEXT: ...
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-arch.test b/llvm/test/tools/llvm-elfabi/binary-read-arch.test
index ecb2fb81446..f2c2d8bd56d 100644
--- a/llvm/test/tools/llvm-elfabi/binary-read-arch.test
+++ b/llvm/test/tools/llvm-elfabi/binary-read-arch.test
@@ -1,5 +1,5 @@
 # RUN: yaml2obj %s > %t
-# RUN: llvm-elfabi %t --emit-tbe=- | FileCheck %s
+# RUN: llvm-elfabi --elf %t --emit-tbe=- | FileCheck %s
 
 !ELF
 FileHeader:
@@ -7,6 +7,38 @@ FileHeader:
   Data:            ELFDATA2LSB
   Type:            ET_DYN
   Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000
+    Content:         "00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0008
+    AddressAlign:    8
+    Content:         "0a0000000000000001000000000000000500000000000000000000000000000000000000000000000000000000000000"
+      # DT_STRSZ      1 (0x1)
+      # DT_STRTAB     0x0
+      # DT_NULL       0x0
+    Size:            48
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x0000
+    PAddr: 0x0000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x0008
+    PAddr: 0x0008
+    Sections:
+      - Section: .dynamic
 
 # CHECK:      --- !tapi-tbe
 # CHECK-NEXT: TbeVersion: {{[1-9]\d*\.(0|([1-9]\d*))}}
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-bad-soname.test b/llvm/test/tools/llvm-elfabi/binary-read-bad-soname.test
new file mode 100644
index 00000000000..cc7205b15eb
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-bad-soname.test
@@ -0,0 +1,44 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000
+    Content:         "00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0008
+    AddressAlign:    8
+    Content:         "0e000000000000000d000000000000000a0000000000000001000000000000000500000000000000000000000000000000000000000000000000000000000000"
+      # DT_SONAME     13 (0x0d)
+      # DT_STRSZ      1 (0x01)
+      # DT_STRTAB     0x0
+      # DT_NULL       0x0
+    Size:            64
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x0000
+    PAddr: 0x0000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x0008
+    PAddr: 0x0008
+    Sections:
+      - Section: .dynamic
+
+# CHECK: DT_SONAME string offset (0x000000000000000d) outside of dynamic string table
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-bad-vaddr.test b/llvm/test/tools/llvm-elfabi/binary-read-bad-vaddr.test
new file mode 100644
index 00000000000..5dc96df38a2
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-bad-vaddr.test
@@ -0,0 +1,44 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1000
+    Content:         "00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1008
+    AddressAlign:    8
+    Content:         "0e0000000000000000000000000000000a0000000000000001000000000000000500000000000000600200000000000000000000000000000000000000000000"
+      # DT_SONAME     0
+      # DT_STRSZ      1
+      # DT_STRTAB     0x0260 # Bad vaddr (no PT_LOAD for 0x0000 to 0x0FFF)
+      # DT_NULL       0x0
+    Size:            64
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x1000
+    PAddr: 0x1000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x1008
+    PAddr: 0x1008
+    Sections:
+      - Section: .dynamic
+
+# CHECK: Virtual address is not in any segment when locating .dynstr section contents
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strsz.test b/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strsz.test
new file mode 100644
index 00000000000..09e514ad412
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strsz.test
@@ -0,0 +1,43 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000
+#                     \0 b a z\0
+    Content:         "0062617a00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0008
+    AddressAlign:    8
+    Content:         "0500000000000000000000000000000000000000000000000000000000000000"
+      # DT_STRTAB     0x0
+      # DT_NULL       0x0
+    Size:            32
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x0000
+    PAddr: 0x0000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x0008
+    PAddr: 0x0008
+    Sections:
+      - Section: .dynamic
+
+# CHECK: Couldn't determine dynamic string table size (no DT_STRSZ entry)
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strtab.test b/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strtab.test
new file mode 100644
index 00000000000..25fcbdc2f84
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-no-dt-strtab.test
@@ -0,0 +1,42 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000
+    Content:         "00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0008
+    AddressAlign:    8
+    Content:         "0a00000000000000010000000000000000000000000000000000000000000000"
+      # DT_STRSZ      1 (0x1)
+      # DT_NULL       0x0
+    Size:            32
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x0000
+    PAddr: 0x0000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x0008
+    PAddr: 0x0008
+    Sections:
+      - Section: .dynamic
+
+# CHECK: Couldn't locate dynamic string table (no DT_STRTAB entry)
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-no-dynamic.test b/llvm/test/tools/llvm-elfabi/binary-read-no-dynamic.test
new file mode 100644
index 00000000000..475d7bf7b84
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-no-dynamic.test
@@ -0,0 +1,11 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+
+# CHECK: No .dynamic section found
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-replace-soname.test b/llvm/test/tools/llvm-elfabi/binary-read-replace-soname.test
new file mode 100644
index 00000000000..23f0ba3308e
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-replace-soname.test
@@ -0,0 +1,48 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-elfabi --elf %t --emit-tbe=- | FileCheck %s --check-prefix=ORIGINAL
+# RUN: llvm-elfabi --elf %t --emit-tbe=- --soname=libbest.so | FileCheck %s --check-prefix=REPLACED
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1000
+#                     \0 b a z\0 s o m e l i b . s o\0 f o o\0
+    Content:         "0062617a00736f6d656c69622e736f00666f6f00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1018
+    AddressAlign:    8
+    Content:         "0e0000000000000005000000000000000a0000000000000014000000000000000500000000000000001000000000000000000000000000000000000000000000"
+      # DT_SONAME     5 (0x05)
+      # DT_STRSZ      20 (0x14)
+      # DT_STRTAB     0x1000
+      # DT_NULL       0x0
+    Size:            64
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x1000
+    PAddr: 0x1000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x1018
+    PAddr: 0x1018
+    Sections:
+      - Section: .dynamic
+
+# ORIGINAL: SoName: somelib.so{{$}}
+
+# REPLACED: SoName: libbest.so{{$}}
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-soname-no-null.test b/llvm/test/tools/llvm-elfabi/binary-read-soname-no-null.test
new file mode 100644
index 00000000000..224407d9310
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-soname-no-null.test
@@ -0,0 +1,45 @@
+# RUN: yaml2obj %s > %t
+# RUN: not llvm-elfabi --elf %t --emit-tbe=%t.tbe 2>&1 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1000
+#                     \0 b a z\0 s o m e l i b . s o z z z
+    Content:         "0062617a00736f6d656c69622e736f7a7a7a"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1018
+    AddressAlign:    8
+    Content:         "0e0000000000000005000000000000000a000000000000000f000000000000000500000000000000001000000000000000000000000000000000000000000000"
+      # DT_SONAME     5 (0x05)
+      # DT_STRSZ      15 (0x0F)
+      # DT_STRTAB     0x1000
+      # DT_NULL       0x0
+    Size:            64
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x1000
+    PAddr: 0x1000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x1018
+    PAddr: 0x1018
+    Sections:
+      - Section: .dynamic
+
+# CHECK: String overran bounds of string table (no null terminator) when reading DT_SONAME
diff --git a/llvm/test/tools/llvm-elfabi/binary-read-soname.test b/llvm/test/tools/llvm-elfabi/binary-read-soname.test
new file mode 100644
index 00000000000..b6877c64bdc
--- /dev/null
+++ b/llvm/test/tools/llvm-elfabi/binary-read-soname.test
@@ -0,0 +1,50 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-elfabi --elf %t --emit-tbe=- | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .dynstr
+    Type:            SHT_STRTAB
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1000
+#                     \0 b a z\0 s o m e l i b . s o\0 f o o\0
+    Content:         "0062617a00736f6d656c69622e736f00666f6f00"
+  - Name:            .dynamic
+    Type:            SHT_DYNAMIC
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1018
+    AddressAlign:    8
+    Content:         "0e0000000000000005000000000000000a0000000000000014000000000000000500000000000000001000000000000000000000000000000000000000000000"
+      # DT_SONAME     5 (0x05)
+      # DT_STRSZ      20 (0x14)
+      # DT_STRTAB     0x1000
+      # DT_NULL       0x0
+    Size:            64
+    Link:            .dynstr
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_R ]
+    VAddr: 0x1000
+    PAddr: 0x1000
+    Align: 8
+    Sections:
+      - Section: .dynstr
+      - Section: .dynamic
+  - Type: PT_DYNAMIC
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x1018
+    PAddr: 0x1018
+    Sections:
+      - Section: .dynamic
+
+# CHECK:      --- !tapi-tbe
+# CHECK-NEXT: TbeVersion: {{[1-9]\d*\.(0|([1-9]\d*))}}
+# CHECK-NEXT: SoName: somelib.so{{$}}
+# CHECK-NEXT: Arch: x86_64
+# CHECK-NEXT: Symbols: {}
+# CHECK-NEXT: ...
diff --git a/llvm/test/tools/llvm-elfabi/replace-soname-tbe.test b/llvm/test/tools/llvm-elfabi/replace-soname-tbe.test
deleted file mode 100644
index 71d50a83b83..00000000000
--- a/llvm/test/tools/llvm-elfabi/replace-soname-tbe.test
+++ /dev/null
@@ -1,16 +0,0 @@
-# RUN: yaml2obj %s > %t
-# RUN: llvm-elfabi %t --emit-tbe=- --soname=best.so | FileCheck %s
-
-!ELF
-FileHeader:
-  Class:           ELFCLASS64
-  Data:            ELFDATA2LSB
-  Type:            ET_DYN
-  Machine:         EM_AARCH64
-
-# CHECK:      --- !tapi-tbe
-# CHECK-NEXT: TbeVersion: {{[1-9]\d*\.(0|([1-9]\d*))}}
-# CHECK-NEXT: SoName: best.so
-# CHECK-NEXT: Arch: AArch64
-# CHECK-NEXT: Symbols: {}
-# CHECK-NEXT: ...
diff --git a/llvm/tools/llvm-elfabi/ELFObjHandler.cpp b/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
index 412c299c1f7..4c8e61db6ac 100644
--- a/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
+++ b/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
@@ -21,23 +21,149 @@ using llvm::object::ELFObjectFile;
 
 using namespace llvm;
 using namespace llvm::object;
-using namespace llvm::elfabi;
 using namespace llvm::ELF;
 
 namespace llvm {
 namespace elfabi {
 
+// Simple struct to hold relevant .dynamic entries.
+struct DynamicEntries {
+  uint64_t StrTabAddr = 0;
+  uint64_t StrSize = 0;
+  Optional<uint64_t> SONameOffset;
+};
+
+/// This function behaves similarly to StringRef::substr(), but attempts to
+/// terminate the returned StringRef at the first null terminator. If no null
+/// terminator is found, an error is returned.
+///
+/// @param Str Source string to create a substring from.
+/// @param Offset The start index of the desired substring.
+static Expected<StringRef> terminatedSubstr(StringRef Str, size_t Offset) {
+  size_t StrEnd = Str.find('\0', Offset);
+  if (StrEnd == StringLiteral::npos) {
+    return createError(
+        "String overran bounds of string table (no null terminator)");
+  }
+
+  size_t StrLen = StrEnd - Offset;
+  return Str.substr(Offset, StrLen);
+}
+
+/// This function takes an error, and appends a string of text to the end of
+/// that error. Since "appending" to an Error isn't supported behavior of an
+/// Error, this function technically creates a new error with the combined
+/// message and consumes the old error.
+///
+/// @param Err Source error.
+/// @param After Text to append at the end of Err's error message.
+Error appendToError(Error Err, StringRef After) {
+  std::string Message;
+  raw_string_ostream Stream(Message);
+  Stream << Err;
+  Stream << " " << After;
+  consumeError(std::move(Err));
+  return createError(Stream.str().c_str());
+}
+
+/// This function populates a DynamicEntries struct using an ELFT::DynRange.
+/// After populating the struct, the members are validated with
+/// some basic sanity checks.
+///
+/// @param Dyn Target DynamicEntries struct to populate.
+/// @param DynTable Source dynamic table.
+template <class ELFT>
+static Error populateDynamic(DynamicEntries &Dyn,
+                             typename ELFT::DynRange DynTable) {
+  if (DynTable.empty())
+    return createError("No .dynamic section found");
+
+  // Search .dynamic for relevant entries.
+  bool FoundDynStr = false;
+  bool FoundDynStrSz = false;
+  for (auto &Entry : DynTable) {
+    switch (Entry.d_tag) {
+    case DT_SONAME:
+      Dyn.SONameOffset = Entry.d_un.d_val;
+      break;
+    case DT_STRTAB:
+      Dyn.StrTabAddr = Entry.d_un.d_ptr;
+      FoundDynStr = true;
+      break;
+    case DT_STRSZ:
+      Dyn.StrSize = Entry.d_un.d_val;
+      FoundDynStrSz = true;
+      break;
+    }
+  }
+
+  if (!FoundDynStr) {
+    return createError(
+        "Couldn't locate dynamic string table (no DT_STRTAB entry)");
+  }
+  if (!FoundDynStrSz) {
+    return createError(
+        "Couldn't determine dynamic string table size (no DT_STRSZ entry)");
+  }
+  if (Dyn.SONameOffset.hasValue() && *Dyn.SONameOffset >= Dyn.StrSize) {
+    return createStringError(
+        object_error::parse_failed,
+        "DT_SONAME string offset (0x%016x) outside of dynamic string table",
+        *Dyn.SONameOffset);
+  }
+
+  return Error::success();
+}
+
 /// Returns a new ELFStub with all members populated from an ELFObjectFile.
 /// @param ElfObj Source ELFObjectFile.
 template <class ELFT>
-Expected<std::unique_ptr<ELFStub>>
+static Expected<std::unique_ptr<ELFStub>>
 buildStub(const ELFObjectFile<ELFT> &ElfObj) {
+  using Elf_Dyn_Range = typename ELFT::DynRange;
+  using Elf_Phdr_Range = typename ELFT::PhdrRange;
   std::unique_ptr<ELFStub> DestStub = make_unique<ELFStub>();
   const ELFFile<ELFT> *ElfFile = ElfObj.getELFFile();
+  // Fetch .dynamic table.
+  Expected<Elf_Dyn_Range> DynTable = ElfFile->dynamicEntries();
+  if (!DynTable) {
+    return DynTable.takeError();
+  }
+
+  // Fetch program headers.
+  Expected<Elf_Phdr_Range> PHdrs = ElfFile->program_headers();
+  if (!PHdrs) {
+    return PHdrs.takeError();
+  }
+
+  // Collect relevant .dynamic entries.
+  DynamicEntries DynEnt;
+  if (Error Err = populateDynamic<ELFT>(DynEnt, *DynTable))
+    return std::move(Err);
+
+  // Convert .dynstr address to an offset.
+  Expected<const uint8_t *> DynStrPtr =
+      ElfFile->toMappedAddr(DynEnt.StrTabAddr);
+  if (!DynStrPtr)
+    return appendToError(DynStrPtr.takeError(),
+                         "when locating .dynstr section contents");
 
+  StringRef DynStr(reinterpret_cast<const char *>(DynStrPtr.get()),
+                   DynEnt.StrSize);
+
+  // Populate Arch from ELF header.
   DestStub->Arch = ElfFile->getHeader()->e_machine;
 
-  // TODO: Populate SoName from .dynamic entries and linked string table.
+  // Populate SoName from .dynamic entries and dynamic string table.
+  if (DynEnt.SONameOffset.hasValue()) {
+    Expected<StringRef> NameOrErr =
+        terminatedSubstr(DynStr, *DynEnt.SONameOffset);
+    if (!NameOrErr) {
+      return appendToError(NameOrErr.takeError(), "when reading DT_SONAME");
+    }
+    DestStub->SoName = *NameOrErr;
+  }
+
   // TODO: Populate NeededLibs from .dynamic entries and linked string table.
   // TODO: Populate Symbols from .dynsym table and linked string table.