make/util.mk

   1 # Generic Makefile Utilities
   2
   3 ###
   4 # Utility functions
   5
   6 # Function: streq LHS RHS
   7 #
   8 # Return "true" if LHS == RHS, otherwise "".
   9 #
  10 # LHS == RHS <=> (LHS subst RHS is empty) and (RHS subst LHS is empty)
  11 streq = $(if $(1),$(if $(subst $(1),,$(2))$(subst $(2),,$(1)),,true),$(if $(2),,true))
  12
  13 # Function: strneq LHS RHS
  14 #
  15 # Return "true" if LHS != RHS, otherwise "".
  16 strneq = $(if $(call streq,$(1),$(2)),,true)
  17
  18 # Function: contains list item
  19 #
  20 # Return "true" if 'list' contains the value 'item'.
  21 contains = $(if $(strip $(foreach i,$(1),$(if $(call streq,$(2),$(i)),T,))),true,)
  22
  23 # Function: is_subset a b
  24 # Return "true" if 'a' is a subset of 'b'.
  25 is_subset = $(if $(strip $(set_difference $(1),$(2))),,true)
  26
  27 # Function: set_difference a b
  28 # Return a - b.
  29 set_difference = $(foreach i,$(1),$(if $(call contains,$(2),$(i)),,$(i)))
  30
  31 # Function: Set variable value
  32 #
  33 # Set the given make variable to the given value.
  34 Set = $(eval $(1) := $(2))
  35
  36 # Function: Append variable value
  37 #
  38 # Append the given value to the given make variable.
  39 Append = $(eval $(1) += $(2))
  40
  41 # Function: IsDefined variable
  42 #
  43 # Check whether the given variable is defined.
  44 IsDefined = $(call strneq,undefined,$(flavor $(1)))
  45
  46 # Function: IsUndefined variable
  47 #
  48 # Check whether the given variable is undefined.
  49 IsUndefined = $(call streq,undefined,$(flavor $(1)))
  50
  51 # Function: VarOrDefault variable default-value
  52 #
  53 # Get the value of the given make variable, or the default-value if the variable
  54 # is undefined.
  55 VarOrDefault = $(if $(call IsDefined,$(1)),$($(1)),$(2))
  56
  57 # Function: CheckValue variable
  58 #
  59 # Print the name, definition, and value of a variable, for testing make
  60 # utilities.
  61 #
  62 # Example:
  63 #   foo = $(call streq,a,a)
  64 #   $(call CheckValue,foo)
  65 # Example Output:
  66 #   CHECKVALUE: foo: $(call streq,,) - true
  67 CheckValue = $(info CHECKVALUE: $(1): $(value $(1)) - $($(1)))
  68
  69 # Function: CopyVariable src dst
  70 #
  71 # Copy the value of the variable 'src' to 'dst', taking care to not define 'dst'
  72 # if 'src' is undefined. The destination variable must be undefined.
  73 CopyVariable = \
  74   $(call AssertValue,$(call IsUndefined,$(2)),destination is already defined)\
  75   $(if $(call IsUndefined,$(1)),,\
  76        $(call Set,$(2),$($(1))))
  77
  78 # Function: Assert value message
  79 #
  80 # Check that a value is true, or give an error including the given message
  81 Assert = $(if $(1),,\
  82            $(error Assertion failed: $(2)))
  83
  84 # Function: AssertEqual variable expected-value
  85 #
  86 # Check that the value of a variable is 'expected-value'.
  87 AssertEqual = \
  88   $(if $(call streq,$($(1)),$(2)),,\
  89        $(error Assertion failed: $(1): $(value $(1)) - $($(1)) != $(2)))
  90
  91 # Function: CheckCommandLineOverrides list
  92 #
  93 # Check that all command line variables are in the given list. This routine is
  94 # useful for validating that users aren't trying to override something which
  95 # will not work.
  96 CheckCommandLineOverrides = \
  97   $(foreach arg,$(MAKEOVERRIDES),\
  98     $(call Set,varname,$(firstword $(subst =, ,$(arg)))) \
  99     $(if $(call contains,$(1),$(varname)),,\
 100       $(error "Invalid command line override: $(1) $(varname) (not supported)")))
 101
 102 ###
 103 # Clean up make behavior
 104
 105 # Cancel all suffix rules. We don't want no stinking suffix rules.
 106 .SUFFIXES:
 107
 108 ###
 109 # Debugging
 110
 111 # General debugging rule, use 'make print-XXX' to print the definition, value
 112 # and origin of XXX.
 113 make-print-%:
 114         $(error PRINT: $(value $*) = "$($*)" (from $(origin $*)))