[Lldb-commits] [PATCH] D61018: RegisterContextLLDB: Push CFA value on DWARF stack when evaluating register expressions

[Pavel Labath via Phabricator via lldb-commits]

labath updated this revision to Diff 196253.
labath added a comment.

This is the version that should at least compile on a mac (it turns out asm is more portable than I expected). I am still building lldb to see if the test will pass.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D61018/new/

https://reviews.llvm.org/D61018

Files:
  lit/Unwind/Inputs/call-asm.c
  lit/Unwind/Inputs/eh-frame-dwarf-unwind.s
  lit/Unwind/eh-frame-dwarf-unwind.test
  source/Plugins/Process/Utility/RegisterContextLLDB.cpp


Index: source/Plugins/Process/Utility/RegisterContextLLDB.cpp
===================================================================
--- source/Plugins/Process/Utility/RegisterContextLLDB.cpp
+++ source/Plugins/Process/Utility/RegisterContextLLDB.cpp
@@ -1507,9 +1507,11 @@
     DWARFExpression dwarfexpr(opcode_ctx, dwarfdata, nullptr, 0,
                               unwindplan_regloc.GetDWARFExpressionLength());
     dwarfexpr.SetRegisterKind(unwindplan_registerkind);
+    Value cfa_val = Scalar(m_cfa);
+    cfa_val.SetValueType(Value::eValueTypeLoadAddress);
     Value result;
     Status error;
-    if (dwarfexpr.Evaluate(&exe_ctx, this, 0, nullptr, nullptr, result,
+    if (dwarfexpr.Evaluate(&exe_ctx, this, 0, &cfa_val, nullptr, result,
                            &error)) {
       addr_t val;
       val = result.GetScalar().ULongLong();
Index: lit/Unwind/eh-frame-dwarf-unwind.test
===================================================================
--- /dev/null
+++ lit/Unwind/eh-frame-dwarf-unwind.test
@@ -0,0 +1,22 @@
+# Test handing of dwarf expressions specifying the location of registers, if
+# those expressions refer to the frame's CFA value.
+
+# REQUIRES: target-x86_64, native
+
+# RUN: %clang %p/Inputs/call-asm.c %p/Inputs/eh-frame-dwarf-unwind.s -o %t
+# RUN: %lldb %t -s %s -o exit | FileCheck %s
+
+breakpoint set -n bar
+# CHECK: Breakpoint 1: where = {{.*}}`bar
+
+process launch
+# CHECK: stop reason = breakpoint 1.1
+
+thread backtrace
+# CHECK: frame #0: {{.*}}`bar
+# CHECK: frame #1: {{.*}}`foo + 5
+# CHECK: frame #2: {{.*}}`asm_main + 22
+
+target modules show-unwind -n foo
+# CHECK: eh_frame UnwindPlan:
+# CHECK: row[0]: 0: CFA=rsp +8 => rip=DW_OP_lit8 , DW_OP_minus , DW_OP_deref , DW_OP_const1u 0x47, DW_OP_minus
Index: lit/Unwind/Inputs/eh-frame-dwarf-unwind.s
===================================================================
--- /dev/null
+++ lit/Unwind/Inputs/eh-frame-dwarf-unwind.s
@@ -0,0 +1,39 @@
+        .text
+        .globl  bar
+bar:
+        .cfi_startproc
+        leal    (%edi, %edi), %eax
+        ret
+        .cfi_endproc
+
+        .globl  foo
+foo:
+        .cfi_startproc
+        .cfi_escape 0x16, 0x10, 0x06, 0x38, 0x1c, 0x06, 0x08, 0x47, 0x1c
+        call    bar
+        addl    $1, %eax
+        popq    %rdi
+        subq    $0x47, %rdi
+        jmp     *%rdi # Return
+        .cfi_endproc
+
+        .globl  asm_main
+asm_main:
+        .cfi_startproc
+        pushq   %rbp
+        .cfi_def_cfa_offset 16
+        .cfi_offset 6, -16
+        movq    %rsp, %rbp
+        .cfi_def_cfa_register 6
+        movl    $47, %edi
+
+        # Non-standard calling convention. The real return address must be
+        # decremented by 0x47.
+        leaq    0x47+1f(%rip), %rax
+        pushq   %rax
+        jmp     foo # call
+1:
+        popq    %rbp
+        .cfi_def_cfa 7, 8
+        ret
+        .cfi_endproc
Index: lit/Unwind/Inputs/call-asm.c
===================================================================
--- /dev/null
+++ lit/Unwind/Inputs/call-asm.c
@@ -0,0 +1,3 @@
+int asm_main() asm("asm_main");
+
+int main() { return asm_main(); }


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