When merging files without trailing newlines at the end of the file, two
config fragments end up at the same row if file1.config doens't have a
trailing newline at the end of the file.

file1.config "CONFIG_1=y"
file2.config "CONFIG_2=y"
./scripts/kconfig/merge_config.sh -m .config file1.config file2.config

This will generate a .config looking like this.
cat .config
...
CONFIG_1=yCONFIG_2=y"

Making sure so we add a newline at the end of every config file that is
passed into the script.

Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Move array_size.h, hashtable.h, list.h, list_types.h from scripts/kconfig/
to scripts/include/.

These headers will be useful for other host programs.

Remove scripts/mod/list.h.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This prevents segfault when getting filename and lineno in recursive
checks.

If the following snippet is found in Kconfig:

[Test code 1]

config FOO
        bool
        depends on BAR
        select BAR

... without BAR defined; then there is a segfault.

  Kconfig:34:error: recursive dependency detected!
  Kconfig:34:	symbol FOO depends on BAR
  make[4]: *** [scripts/kconfig/Makefile:85: allnoconfig] Segmentation fault

This is because of the following. BAR is a fake entry created by
sym_lookup() with prop being NULL. In the recursive check, there is a
NULL check for prop to fall back to stack->sym->prop if stack->prop is
NULL. However, in this case, stack->sym points to the fake BAR entry
created by sym_lookup(), so prop is still NULL. prop was then referenced
without additional NULL checks, causing segfault.

As the previous email thread suggests, the file and lineno for select is
also wrong:

[Test code 2]

config FOO
       bool

config BAR
       bool

config FOO
       bool "FOO"
       depends on BAR
       select BAR

  $ make defconfig
  *** Default configuration is based on 'x86_64_defconfig'
  Kconfig:1:error: recursive dependency detected!
  Kconfig:1: symbol FOO depends on BAR
  Kconfig:4: symbol BAR is selected by FOO
  [...]

Kconfig:4 should be Kconfig:10.

This patch deletes the wrong and segfault-prone filename/lineno
inference completely. With this patch, Test code 1 yields:

error: recursive dependency detected!
	symbol FOO depends on BAR
	symbol BAR is selected by FOO

Signed-off-by: HONG Yifan <elsk@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I do not think the macros 'e1' and 'e2' are readable.

The statement:

    e1 = expr_alloc_symbol(...);

affects the caller's variable, but this is not sufficiently clear from the code.

Remove the macros. No functional change intended.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This flag is unneeded because a choice member can be detected by
other means.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Clarify that the given structures are not modified.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Kconfig simplifies expressions, but redundant '&&' and '||' operators
involving constant symbols 'y' and 'n' are sometimes trimmed and
sometimes not.

[Test Code]

    config DEP
            def_bool y

    config A
            bool "A"
            depends on DEP && y

    config B
            bool "B"
            depends on DEP && y && y

[Result]

    $ make helpnewconfig
      [ snip ]
    -----

    There is no help available for this option.
    Symbol: A [=n]
    Type  : bool
    Defined at Kconfig:4
      Prompt: A
      Depends on: DEP [=y] && y [=y]
      Location:
        -> A (A [=n])

    -----
    -----

    There is no help available for this option.
    Symbol: B [=n]
    Type  : bool
    Defined at Kconfig:8
      Prompt: B
      Depends on: DEP [=y]
      Location:
        -> B (B [=n])

    -----

The dependency for A, 'DEP && y', remains as-is, while that for B,
'DEP && y && y', has been reduced to 'DEP'.

Currently, expr_eliminate_dups() calls expr_eliminate_yn() only when
trans_count != 0, in other words, only when expr_eliminate_dups1() has
trimmed at least one leaf. It fails to trim a single '&& y', etc.

To fix this inconsistent behavior, expr_eliminate_yn() should be called
at least once even if no leaf has been trimmed.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Improve the error messages and clean up redundant code.

[1] remove redundant next_sym->name checks

If 'next_sym' is a choice, the first 'if' block is executed. In the
subsequent 'else if' blocks, 'next_sym" is not a choice, hence
next_sym->name is not NULL.

[2] remove redundant sym->name checks

A choice is never selected or implied by anyone because it has no name
(it is syntactically impossible). If it is, sym->name is not NULL.

[3] Show the location of choice instead of "<choice>"

"part of choice <choice>" does not convey useful information. Since a
choice has no name, it is more informative to display the file name and
line number.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Kconfig detects recursive dependencies in a choice block, but the error
message is unclear.

[Test Code]

    choice
            prompt "choose"
            depends on A

    config A
            bool "A"

    config B
            bool "B"

    endchoice

[Result]

    Kconfig:1:error: recursive dependency detected!
    Kconfig:1:      choice <choice> contains symbol A
    Kconfig:5:      symbol A is part of choice <choice>
    For a resolution refer to Documentation/kbuild/kconfig-language.rst
    subsection "Kconfig recursive dependency limitations"

The phrase "contains symbol A" does not accurately describe the problem.
The issue is that the choice depends on A, which is a member of itself.

The first if-block does not print a sensible message. Remove it.

This commit improves the error message to:

    Kconfig:1:error: recursive dependency detected!
    Kconfig:1:      symbol <choice> symbol is visible depending on A
    Kconfig:5:      symbol A is part of choice <choice>
    For a resolution refer to Documentation/kbuild/kconfig-language.rst
    subsection "Kconfig recursive dependency limitations"

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

A choice member must not depend on another member within the same choice
block.

Kconfig detects this, but the error message is not sensible.

[Test Code]

    choice
            prompt "choose"

    config A
            bool "A"
            depends on B

    config B
            bool "B"

    endchoice

[Result]

    Kconfig:1:error: recursive dependency detected!
    Kconfig:1:      choice <choice> contains symbol A
    Kconfig:4:      symbol A is part of choice B
    Kconfig:8:      symbol B is part of choice <choice>
    For a resolution refer to Documentation/kbuild/kconfig-language.rst
    subsection "Kconfig recursive dependency limitations"

The phrase "part of choice B" is weird because B is not a choice block,
but a choice member.

To determine whether the current symbol is a part of a choice block,
sym_is_choice(next_sym) must be checked.

This commit improves the error message to:

    Kconfig:1:error: recursive dependency detected!
    Kconfig:1:      choice <choice> contains symbol A
    Kconfig:4:      symbol A symbol is visible depending on B
    Kconfig:8:      symbol B is part of choice <choice>
    For a resolution refer to Documentation/kbuild/kconfig-language.rst
    subsection "Kconfig recursive dependency limitations"

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>