[PATCH] D62598: [AArch64][ELF][llvm-objdump] Add support for PLT decoding with BTI instructions present

[Peter Smith via Phabricator via llvm-commits]

peter.smith updated this revision to Diff 202736.
peter.smith added a comment.

Corrected matching of "BTI c" to only match "BTI c".


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62598/new/

https://reviews.llvm.org/D62598

Files:
  lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
  test/tools/llvm-objdump/AArch64/plt.test


Index: test/tools/llvm-objdump/AArch64/plt.test
===================================================================
--- test/tools/llvm-objdump/AArch64/plt.test
+++ test/tools/llvm-objdump/AArch64/plt.test
@@ -1,5 +1,60 @@
-// RUN: llvm-objdump -d %p/Inputs/cfi.elf-aarch64 | FileCheck %s
+# RUN: llvm-objdump -d %p/Inputs/cfi.elf-aarch64 | FileCheck %s
 
 # CHECK: Disassembly of section .plt:
 # CHECK: __cfi_slowpath at plt:
+# CHECK-NEXT: adrp      x16, {{.*}}
 # CHECK: bl {{.*}} <__cfi_slowpath at plt>
+
+# RUN: yaml2obj %s -o %t.aarch64
+# RUN: llvm-objdump -d -mattr=+bti %t.aarch64 | \
+# RUN:   FileCheck --check-prefix=CHECK-BTI %s
+# CHECK-BTI: bl {{.*}} <f1 at plt>
+# CHECK-BTI: bl {{.*}} <f2 at plt>
+# CHECK-BTI: Disassembly of section .plt:
+# CHECK-BTI: f1 at plt:
+# CHECK-BTI-NEXT: bti   c
+# CHECK-BTI-NEXT: adrp  x16, {{.*}}
+# CHECK-BTI: f2 at plt:
+# CHECK-BTI-NEXT: bti   c
+# CHECK-BTI-NEXT: adrp  x16, {{.*}}
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_AARCH64
+Sections:
+  - Name:    .rela.plt
+    Type:    SHT_RELA
+    Flags:   [ SHF_ALLOC ]
+    EntSize: 0x0000000000000018
+    Info:    .got.plt
+    Relocations:
+      - Offset: 0x0000000000230018
+        Symbol: f1
+        Type:   R_AARCH64_JUMP_SLOT
+      - Offset: 0x0000000000230020
+        Symbol: f2
+        Type:   R_AARCH64_JUMP_SLOT
+  - Name:    .text
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address: 0x0000000000210000
+    Content: 0C00009411000094C0035FD6
+  - Name:    .plt
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address: 0x0000000000210010
+    Content: 5F2403D5F07BBFA910010090110A40F91042009120021FD61F2003D51F2003D55F2403D510010090110E40F9106200919F2103D520021FD65F2403D510010090111240F9108200919F2103D520021FD6
+  - Name:    .got.plt
+    Type:    SHT_PROGBITS
+    Content: '000000000000000000000000000000000000000000000000100021000000000010002100000000001000210000000000'
+Symbols:
+  - Name:    f1
+    Type:    STT_FUNC
+    Binding: STB_GLOBAL
+  - Name:    f2
+    Type:    STT_FUNC
+    Binding: STB_GLOBAL
+...
Index: lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
===================================================================
--- lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
+++ lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
@@ -333,12 +333,20 @@
     for (uint64_t Byte = 0, End = PltContents.size(); Byte + 7 < End;
          Byte += 4) {
       uint32_t Insn = support::endian::read32le(PltContents.data() + Byte);
+      uint64_t Off = 0;
+      // Check for optional bti c that prefixes adrp in BTI enabled entries
+      if (Insn == 0xd503245f) {
+         Off = 4;
+         Insn = support::endian::read32le(PltContents.data() + Byte + Off);
+      }
       // Check for adrp.
       if ((Insn & 0x9f000000) != 0x90000000)
         continue;
+      Off += 4;
       uint64_t Imm = (((PltSectionVA + Byte) >> 12) << 12) +
             (((Insn >> 29) & 3) << 12) + (((Insn >> 5) & 0x3ffff) << 14);
-      uint32_t Insn2 = support::endian::read32le(PltContents.data() + Byte + 4);
+      uint32_t Insn2 =
+          support::endian::read32le(PltContents.data() + Byte + Off);
       // Check for: ldr Xt, [Xn, #pimm].
       if (Insn2 >> 22 == 0x3e5) {
         Imm += ((Insn2 >> 10) & 0xfff) << 3;


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