github.com/undoio/delve@v1.9.0/pkg/dwarf/reader/variables.go (about)

     1  package reader
     2  
     3  import (
     4  	"debug/dwarf"
     5  
     6  	"github.com/undoio/delve/pkg/dwarf/godwarf"
     7  )
     8  
     9  type Variable struct {
    10  	*godwarf.Tree
    11  	// Depth represents the depth of the lexical block in which this variable
    12  	// was declared, relative to a root scope (e.g. a function) passed to
    13  	// Variables(). The depth is used to figure out if a variable is shadowed at
    14  	// a particular pc by another one with the same name declared in an inner
    15  	// block.
    16  	Depth int
    17  }
    18  
    19  // VariablesFlags specifies some configuration flags for the Variables function.
    20  type VariablesFlags uint8
    21  
    22  const (
    23  	VariablesOnlyVisible VariablesFlags = 1 << iota
    24  	VariablesSkipInlinedSubroutines
    25  	VariablesTrustDeclLine
    26  	VariablesNoDeclLineCheck
    27  )
    28  
    29  // Variables returns a list of variables contained inside 'root'.
    30  //
    31  // If the VariablesOnlyVisible flag is set, only variables visible at 'pc' will be
    32  // returned. If the VariablesSkipInlinedSubroutines is set, variables from
    33  // inlined subroutines will be skipped.
    34  func Variables(root *godwarf.Tree, pc uint64, line int, flags VariablesFlags) []Variable {
    35  	return variablesInternal(nil, root, 0, pc, line, flags)
    36  }
    37  
    38  // variablesInternal appends to 'v' variables from 'root'. The function calls
    39  // itself with an incremented scope for all sub-blocks in 'root'.
    40  func variablesInternal(v []Variable, root *godwarf.Tree, depth int, pc uint64, line int, flags VariablesFlags) []Variable {
    41  	switch root.Tag {
    42  	case dwarf.TagInlinedSubroutine:
    43  		if flags&VariablesSkipInlinedSubroutines != 0 {
    44  			return v
    45  		}
    46  		fallthrough
    47  	case dwarf.TagLexDwarfBlock, dwarf.TagSubprogram:
    48  		// Recurse into blocks and functions, if the respective block contains
    49  		// pc (or if we don't care about visibility).
    50  		if (flags&VariablesOnlyVisible == 0) || root.ContainsPC(pc) {
    51  			for _, child := range root.Children {
    52  				v = variablesInternal(v, child, depth+1, pc, line, flags)
    53  			}
    54  		}
    55  		return v
    56  	default:
    57  		o := 0
    58  		if root.Tag != dwarf.TagFormalParameter && (flags&VariablesTrustDeclLine != 0) {
    59  			// visibility for variables starts the line after declaration line,
    60  			// except for formal parameters, which are visible on the same line they
    61  			// are defined.
    62  			o = 1
    63  		}
    64  		if declLine, ok := root.Val(dwarf.AttrDeclLine).(int64); (flags&VariablesNoDeclLineCheck != 0) || !ok || line >= int(declLine)+o {
    65  			return append(v, Variable{root, depth})
    66  		}
    67  		return v
    68  	}
    69  }