[DebugInfo] Support DWARF expressions in eh_frame

This patch enhances DWARFDebugFrame with the capability of parsing and
printing DWARF expressions in CFI instructions. It also makes FDEs and
CIEs accessible to lib users, so they can process them in client tools
that rely on LLVM. To make it self-contained with a test case, it
teaches llvm-readobj to be able to dump EH frames and checks they are
correct in a unit test. The llvm-readobj code is Maksim Panchenko's work
(maksfb).

Reviewers: JDevlieghere, espindola

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D43313

llvm-svn: 326932

2 files changed, 216 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-readobj/Inputs/dwarf-exprs.exe-x86-64.yaml b/llvm/test/tools/llvm-readobj/Inputs/dwarf-exprs.exe-x86-64.yaml
new file mode 100644
index 00000000000..5b8f3671bc3
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/Inputs/dwarf-exprs.exe-x86-64.yaml
@@ -0,0 +1,46 @@
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+  Entry:           0x0000000000400000
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x0000000000400000
+    AddressAlign:    16
+    Content:         50C704240020400031C05AC3
+  - Name:            .eh_frame_hdr
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x00000000004013c0
+    AddressAlign:    4
+    Content:         011B033B3C00000006000000E0F0FFFF8800000010F1FFFF58000000F6F1FFFFB000000010F2FFFFD000000090FEFFFF0001000000FFFFFF30010000
+  - Name:            .eh_frame
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000000000401400
+    AddressAlign:    8
+    Content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
+Symbols:
+  Global:
+    - Name:            myfunc
+      Type:            STT_FUNC
+      Section:         .text
+      Value:           0x0000000000400000
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x00400000
+    PAddr: 0x00400000
+    Sections:
+      - Section: .text
+  - Type: PT_GNU_EH_FRAME
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x004013C0
+    PAddr: 0x004013C0
+    Sections:
+      - Section: .eh_frame_hdr
+...
diff --git a/llvm/test/tools/llvm-readobj/unwind.test b/llvm/test/tools/llvm-readobj/unwind.test
new file mode 100644
index 00000000000..72c591048c8
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/unwind.test
@@ -0,0 +1,170 @@
+RUN: yaml2obj %p/Inputs/dwarf-exprs.exe-x86-64.yaml > %t.exe
+RUN: llvm-readobj -unwind %t.exe | FileCheck %s
+
+CHECK:      EH_FRAME Header [
+CHECK-NEXT:  Address: 0x4013c0
+CHECK-NEXT:  Offset: 0x27c
+CHECK-NEXT:  Size: 0x3c
+CHECK-NEXT:  Corresponding Section: .eh_frame_hdr
+CHECK-NEXT:  Header {
+CHECK-NEXT:    version: 1
+CHECK-NEXT:    eh_frame_ptr_enc: 0x1b
+CHECK-NEXT:    fde_count_enc: 0x3
+CHECK-NEXT:    table_enc: 0x3b
+CHECK-NEXT:    eh_frame_ptr: 0x401400
+CHECK-NEXT:    fde_count: 6
+CHECK-NEXT:    entry 0 {
+CHECK-NEXT:      initial_location: 0x4004a0
+CHECK-NEXT:      address: 0x401448
+CHECK-NEXT:    }
+CHECK-NEXT:    entry 1 {
+CHECK-NEXT:      initial_location: 0x4004d0
+CHECK-NEXT:      address: 0x401418
+CHECK-NEXT:    }
+CHECK-NEXT:    entry 2 {
+CHECK-NEXT:      initial_location: 0x4005b6
+CHECK-NEXT:      address: 0x401470
+CHECK-NEXT:    }
+CHECK-NEXT:    entry 3 {
+CHECK-NEXT:      initial_location: 0x4005d0
+CHECK-NEXT:      address: 0x401490
+CHECK-NEXT:    }
+CHECK-NEXT:    entry 4 {
+CHECK-NEXT:      initial_location: 0x401250
+CHECK-NEXT:      address: 0x4014c0
+CHECK-NEXT:    }
+CHECK-NEXT:    entry 5 {
+CHECK-NEXT:      initial_location: 0x4012c0
+CHECK-NEXT:      address: 0x4014f0
+CHECK-NEXT:    }
+CHECK-NEXT:  }
+CHECK-NEXT:]
+
+CHECK:      .eh_frame section at offset 0x2b8 address 0x401400:
+CHECK-NEXT:  [0x401400] CIE length=20
+CHECK-NEXT:    version: 1
+CHECK-NEXT:    augmentation: zR
+CHECK-NEXT:    code_alignment_factor: 1
+CHECK-NEXT:    data_alignment_factor: -8
+CHECK-NEXT:    return_address_register: 16
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_def_cfa: reg7 +8
+CHECK-NEXT:      DW_CFA_offset: reg16 -8
+CHECK-NEXT:      DW_CFA_undefined: reg16
+
+CHECK:       [0x401418] FDE length=20 cie=[0x401400]
+CHECK-NEXT:    initial_location: 0x4004d0
+CHECK-NEXT:    address_range: 0x2a (end : 0x4004fa)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x401430] CIE length=20
+CHECK-NEXT:    version: 1
+CHECK-NEXT:    augmentation: zR
+CHECK-NEXT:    code_alignment_factor: 1
+CHECK-NEXT:    data_alignment_factor: -8
+CHECK-NEXT:    return_address_register: 16
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_def_cfa: reg7 +8
+CHECK-NEXT:      DW_CFA_offset: reg16 -8
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x401448] FDE length=36 cie=[0x401430]
+CHECK-NEXT:    initial_location: 0x4004a0
+CHECK-NEXT:    address_range: 0x20 (end : 0x4004c0)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_def_cfa_offset: +16
+CHECK-NEXT:      DW_CFA_advance_loc: 6
+CHECK-NEXT:      DW_CFA_def_cfa_offset: +24
+CHECK-NEXT:      DW_CFA_advance_loc: 10
+CHECK-NEXT:      DW_CFA_def_cfa_expression: DW_OP_breg7 +8, DW_OP_breg16 +0, DW_OP_lit15, DW_OP_and, DW_OP_lit11, DW_OP_ge, DW_OP_lit3, DW_OP_shl, DW_OP_plus
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x401470] FDE length=28 cie=[0x401430]
+CHECK-NEXT:    initial_location: 0x4005b6
+CHECK-NEXT:    address_range: 0x10 (end : 0x4005c6)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_advance_loc: 1
+CHECK-NEXT:      DW_CFA_def_cfa_offset: +16
+CHECK-NEXT:      DW_CFA_offset: reg6 -16
+CHECK-NEXT:      DW_CFA_advance_loc: 3
+CHECK-NEXT:      DW_CFA_def_cfa_register: reg6
+CHECK-NEXT:      DW_CFA_advance_loc: 11
+CHECK-NEXT:      DW_CFA_def_cfa: reg7 +8
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x401490] FDE length=44 cie=[0x401430]
+CHECK-NEXT:    initial_location: 0x4005d0
+CHECK-NEXT:    address_range: 0xc7f (end : 0x40124f)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_advance_loc: 5
+CHECK-NEXT:      DW_CFA_def_cfa: reg10 +0
+CHECK-NEXT:      DW_CFA_advance_loc: 9
+CHECK-NEXT:      DW_CFA_expression: reg6 DW_OP_breg6 +0
+CHECK-NEXT:      DW_CFA_advance_loc: 5
+CHECK-NEXT:      DW_CFA_def_cfa_expression: DW_OP_breg6 -8, DW_OP_deref
+CHECK-NEXT:      DW_CFA_advance_loc2: 3174
+CHECK-NEXT:      DW_CFA_def_cfa: reg10 +0
+CHECK-NEXT:      DW_CFA_advance_loc: 5
+CHECK-NEXT:      DW_CFA_def_cfa: reg7 +8
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x4014c0] FDE length=44 cie=[0x401430]
+CHECK-NEXT:    initial_location: 0x401250
+CHECK-NEXT:    address_range: 0x66 (end : 0x4012b6)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_advance_loc: 1
+CHECK-NEXT:      DW_CFA_def_cfa_offset: +16
+CHECK-NEXT:      DW_CFA_offset: reg6 -16
+CHECK-NEXT:      DW_CFA_advance_loc: 3
+CHECK-NEXT:      DW_CFA_def_cfa_register: reg6
+CHECK-NEXT:      DW_CFA_advance_loc: 2
+CHECK-NEXT:      DW_CFA_offset: reg15 -24
+CHECK-NEXT:      DW_CFA_advance_loc: 5
+CHECK-NEXT:      DW_CFA_offset: reg14 -32
+CHECK-NEXT:      DW_CFA_advance_loc: 7
+CHECK-NEXT:      DW_CFA_offset: reg13 -40
+CHECK-NEXT:      DW_CFA_offset: reg12 -48
+CHECK-NEXT:      DW_CFA_advance_loc: 8
+CHECK-NEXT:      DW_CFA_offset: reg3 -56
+CHECK-NEXT:      DW_CFA_advance_loc1: 75
+CHECK-NEXT:      DW_CFA_def_cfa: reg7 +8
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+
+CHECK:       [0x4014f0] FDE length=20 cie=[0x401430]
+CHECK-NEXT:    initial_location: 0x4012c0
+CHECK-NEXT:    address_range: 0x1 (end : 0x4012c1)
+
+CHECK:         Program:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop:
+CHECK-NEXT:      DW_CFA_nop: