S/390: Implement instruction set extensions

[external/binutils.git] / gas / doc / internals.texi

diff --git a/gas/doc/internals.texi b/gas/doc/internals.texi
index 3dc3148..0008367 100644 (file)
--- a/gas/doc/internals.texi
+++ b/gas/doc/internals.texi
@@ -1,5 +1,5 @@
 \input texinfo
-@c  Copyright (C) 1991-2015 Free Software Foundation, Inc.
+@c  Copyright (C) 1991-2019 Free Software Foundation, Inc.
 @setfilename internals.info
 @node Top
 @top Assembler Internals
@@ -41,11 +41,10 @@ This section describes some fundamental GAS data types.
 @cindex symbolS structure
 
 The definition for the symbol structure, @code{symbolS}, is located in
-@file{struc-symbol.h}.
+@file{symbols.c}.
 
-In general, the fields of this structure may not be referred to directly.
+The fields of this structure may not be referred to directly.
 Instead, you must use one of the accessor functions defined in @file{symbol.h}.
-These accessor functions should work for any GAS version.
 
 Symbol structures contain the following fields:
 
@@ -151,10 +150,6 @@ Set the name of the symbol.
 @cindex S_IS_EXTERNAL
 Return non-zero if the symbol is externally visible.
 
-@item S_IS_EXTERN
-@cindex S_IS_EXTERN
-A synonym for @code{S_IS_EXTERNAL}.  Don't use it.
-
 @item S_IS_WEAK
 @cindex S_IS_WEAK
 Return non-zero if the symbol is weak, or if it is a @code{weakref} alias or
@@ -402,12 +397,6 @@ deal with local symbols.  @code{struct local_symbol} is much smaller than
 @code{symbolS} (which also automatically creates a bfd @code{asymbol}
 structure), so this saves space when assembling large files.
 
-The first field of @code{symbolS} is @code{bsym}, the pointer to the BFD
-symbol.  The first field of @code{struct local_symbol} is a pointer which is
-always set to NULL.  This is how the symbol accessor functions can distinguish
-local symbols from ordinary symbols.  The symbol accessor functions
-automatically convert a local symbol into an ordinary symbol when necessary.
-
 @node Expressions
 @subsection Expressions
 @cindex internals, expressions
@@ -1100,11 +1089,6 @@ You may define this macro to parse an expression used in a data allocation
 pseudo-op such as @code{.word}.  You can use this to recognize relocation
 directives that may appear in such directives.
 
-@item BITFIELD_CONS_EXPRESSION
-@cindex BITFIELD_CONS_EXPRESSION
-If you define this macro, GAS will recognize bitfield instructions in data
-allocation pseudo-ops, as used on the i960.
-
 @item REPEAT_CONS_EXPRESSION
 @cindex REPEAT_CONS_EXPRESSION
 If you define this macro, GAS will recognize repeat counts in data allocation
@@ -1233,7 +1217,7 @@ the relax table.
 @item LINKER_RELAXING_SHRINKS_ONLY
 @cindex LINKER_RELAXING_SHRINKS_ONLY
 If you define this macro, and the global variable @samp{linkrelax} is set
-(because of a command line option, or unconditionally in @code{md_begin}), a
+(because of a command-line option, or unconditionally in @code{md_begin}), a
 @samp{.align} directive will cause extra space to be allocated.  The linker can
 then discard this space when relaxing the section.
 
@@ -1473,6 +1457,12 @@ completed, but before the relocations have been generated.
 If you define this macro, GAS will call it after the relocs have been
 generated.
 
+@item tc_cfi_reloc_for_encoding
+@cindex tc_cfi_reloc_for_encoding
+This macro is used to indicate whether a cfi encoding requires a relocation.
+It should return the required relocation type.  Defining this macro implies
+that Compact EH is supported.
+
 @item md_post_relax_hook
 If you define this macro, GAS will call it after relaxing and sizing the
 segments.
@@ -1591,7 +1581,7 @@ if it is necessary to add object file format specific code to the CPU file.
 
 @item obj_begin
 If you define this macro, GAS will call it at the start of the assembly, after
-the command line arguments have been parsed and all the machine independent
+the command-line arguments have been parsed and all the machine independent
 initializations have been completed.
 
 @item obj_app_file
@@ -1751,12 +1741,6 @@ no-op instructions, it must be able to expand or shrink the section contents
 while still preserving intra-section references and meeting alignment
 requirements.
 
-For the i960 using b.out format, no expansion is done; instead, each
-@samp{.align} directive causes extra space to be allocated, enough that when
-the linker is relaxing a section and removing unneeded space, it can discard
-some or all of this extra padding and cause the following data to be correctly
-aligned.
-
 For the H8/300, I think the linker expands calls that can't reach, and doesn't
 worry about alignment issues; the cpu probably never needs any significant
 alignment beyond the instruction size.