gas: Enhance arch-specific SFrame configuration descriptions

Explicitly mention "SFrame" in the descriptions for the architecture-
specific SFrame configuration macros, variables, and functions.

Use the term "frame pointer" (FP) instead of "base pointer". This aligns
with the terminology used in the SFrame specification. Additionally it
helps not to confuse "base-pointer register" with the term "BASE_REG"
used in the specification to denote either the SP or FP register.

Specify what the SFRAME_CFA_*_REG register numbers are used for:
- SP (stack pointer): CFA tracking
- FP (frame pointer): CFA and FP tracking
- RA (return address): RA tracking

Align the descriptions for definitions in the source files to the
declarations in the header files.

gas/
	* config/tc-aarch64.h: Enhance architecture-specific SFrame
	configuration descriptions.
	* config/tc-aarch64.c: Likewise.
	* config/tc-i386.h: Likewise.
	* config/tc-i386.c: Likewise.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>

4 files changed, 19 insertions, 14 deletions

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 6ad4fae..077cbd4 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -8870,7 +8870,7 @@ aarch64_support_sframe_p (void)
   return (aarch64_abi == AARCH64_ABI_LP64);
 }
 
-/* Specify if RA tracking is needed.  */
+/* Whether SFrame return-address tracking is needed.  */
 
 bool
 aarch64_sframe_ra_tracking_p (void)
@@ -8878,8 +8878,8 @@ aarch64_sframe_ra_tracking_p (void)
   return true;
 }
 
-/* Specify the fixed offset to recover RA from CFA.
-   (useful only when RA tracking is not needed).  */
+/* The fixed offset from CFA for SFrame to recover the return address.
+   (useful only when SFrame RA tracking is not needed).  */
 
 offsetT
 aarch64_sframe_cfa_ra_offset (void)
diff --git a/gas/config/tc-aarch64.h b/gas/config/tc-aarch64.h
index 1b8bada..63acbd4 100644
--- a/gas/config/tc-aarch64.h
+++ b/gas/config/tc-aarch64.h
@@ -267,24 +267,24 @@ extern void aarch64_after_parse_args (void);
 extern bool aarch64_support_sframe_p (void);
 #define support_sframe_p aarch64_support_sframe_p
 
-/* The stack-pointer register number for SFrame stack trace info.  */
+/* The stack-pointer DWARF register number for SFrame CFA tracking.  */
 extern unsigned int aarch64_sframe_cfa_sp_reg;
 #define SFRAME_CFA_SP_REG aarch64_sframe_cfa_sp_reg
 
-/* The base-pointer register number for CFA stack trace info.  */
+/* The frame-pointer DWARF register number for SFrame CFA and FP tracking.  */
 extern unsigned int aarch64_sframe_cfa_fp_reg;
 #define SFRAME_CFA_FP_REG aarch64_sframe_cfa_fp_reg
 
-/* The return address register number for CFA stack trace info.  */
+/* The return-address DWARF register number for SFrame RA tracking.  */
 extern unsigned int aarch64_sframe_cfa_ra_reg;
 #define SFRAME_CFA_RA_REG aarch64_sframe_cfa_ra_reg
 
-/* Specify if RA tracking is needed.  */
+/* Whether SFrame return-address tracking is needed.  */
 extern bool aarch64_sframe_ra_tracking_p (void);
 #define sframe_ra_tracking_p aarch64_sframe_ra_tracking_p
 
-/* Specify the fixed offset to recover RA from CFA.
-   (useful only when RA tracking is not needed).  */
+/* The fixed offset from CFA for SFrame to recover the return address.
+   (useful only when SFrame RA tracking is not needed).  */
 extern offsetT aarch64_sframe_cfa_ra_offset (void);
 #define sframe_cfa_ra_offset aarch64_sframe_cfa_ra_offset
 
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 8f6bd32..0ecf39d 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -11217,6 +11217,7 @@ x86_cleanup (void)
     subseg_set (seg, subseg);
 }
 
+/* Whether SFrame stack trace info is supported.  */
 bool
 x86_support_sframe_p (void)
 {
@@ -11224,6 +11225,7 @@ x86_support_sframe_p (void)
   return (x86_elf_abi == X86_64_ABI);
 }
 
+/* Whether SFrame return-address tracking is needed.  */
 bool
 x86_sframe_ra_tracking_p (void)
 {
@@ -11233,6 +11235,8 @@ x86_sframe_ra_tracking_p (void)
   return false;
 }
 
+/* The fixed offset from CFA for SFrame to recover the return address.
+   (useful only when SFrame RA tracking is not needed).  */
 offsetT
 x86_sframe_cfa_ra_offset (void)
 {
@@ -11240,6 +11244,7 @@ x86_sframe_cfa_ra_offset (void)
   return (offsetT) -8;
 }
 
+/* The abi/arch indentifier for SFrame.  */
 unsigned char
 x86_sframe_get_abi_arch (void)
 {
diff --git a/gas/config/tc-i386.h b/gas/config/tc-i386.h
index 7aae7a3..e983621 100644
--- a/gas/config/tc-i386.h
+++ b/gas/config/tc-i386.h
@@ -441,20 +441,20 @@ extern bool x86_scfi_callee_saved_p (uint32_t dw2reg_num);
 extern bool x86_support_sframe_p (void);
 #define support_sframe_p x86_support_sframe_p
 
-/* The stack-pointer register number for SFrame stack trace info.  */
+/* The stack-pointer DWARF register number for SFrame CFA tracking.  */
 extern unsigned int x86_sframe_cfa_sp_reg;
 #define SFRAME_CFA_SP_REG x86_sframe_cfa_sp_reg
 
-/* The frame-pointer register number for SFrame stack trace info.  */
+/* The frame-pointer DWARF register number for SFrame CFA and FP tracking.  */
 extern unsigned int x86_sframe_cfa_fp_reg;
 #define SFRAME_CFA_FP_REG x86_sframe_cfa_fp_reg
 
-/* Specify if RA tracking is needed.  */
+/* Whether SFrame return-address tracking is needed.  */
 extern bool x86_sframe_ra_tracking_p (void);
 #define sframe_ra_tracking_p x86_sframe_ra_tracking_p
 
-/* Specify the fixed offset to recover RA from CFA.
-   (useful only when RA tracking is not needed).  */
+/* The fixed offset from CFA for SFrame to recover the return address.
+   (useful only when SFrame RA tracking is not needed).  */
 extern offsetT x86_sframe_cfa_ra_offset (void);
 #define sframe_cfa_ra_offset x86_sframe_cfa_ra_offset