btrace: indicate speculative execution

Indicate speculatively executed instructions with a leading '?'.  We use the
space that is normally used for the PC prefix.  In the case where the
instruction at the current PC had been executed speculatively before, the PC
prefix will be partially overwritten resulting in "?> ".

As a side-effect, the /p modifier to omit the PC prefix in the "record
instruction-history" command now uses a 3-space PC prefix "   " in order to
have enough space for the speculative execution indication.

gdb/
	* btrace.c (btrace_compute_ftrace_bts): Clear insn flags.
	(pt_btrace_insn_flags): New.
	(ftrace_add_pt): Call pt_btrace_insn_flags.
	* btrace.h (btrace_insn_flag): New.
	(btrace_insn) <flags>: New.
	* record-btrace.c (btrace_insn_history): Print insn prefix.
	* NEWS: Announce it.

doc/
	* gdb.texinfo (Process Record and Replay): Document prefixing of
	speculatively executed instructions in the "record instruction-history"
	command.

testsuite/
	* gdb.btrace/instruction_history.exp: Update.
	* gdb.btrace/tsx.exp: New.
	* gdb.btrace/tsx.c: New.
	* lib/gdb.exp (skip_tsx_tests, skip_btrace_pt_tests): New.

1 files changed, 124 insertions, 0 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 5659906c0b9..ad2ad6e00ac 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -2562,6 +2562,63 @@ gdb_caching_proc skip_vsx_tests {
     return $skip_vsx_tests
 }
 
+# Run a test on the target to see if it supports TSX hardware.  Return 0 if so,
+# 1 if it does not.  Based on 'check_vmx_hw_available' from the GCC testsuite.
+
+gdb_caching_proc skip_tsx_tests {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "skip_tsx_tests"
+
+    set src [standard_temp_file tsx[pid].c]
+    set exe [standard_temp_file tsx[pid].x]
+
+    gdb_produce_source $src {
+    int main() {
+        asm volatile ("xbegin .L0");
+        asm volatile ("xend");
+        asm volatile (".L0: nop");
+        return 0;
+    }
+    }
+
+    verbose "$me:  compiling testfile $src" 2
+    set lines [gdb_compile $src $exe executable {nowarnings quiet}]
+    file delete $src
+
+    if ![string match "" $lines] then {
+        verbose "$me:  testfile compilation failed." 2
+        return 1
+    }
+
+    # No error message, compilation succeeded so now run it via gdb.
+
+    gdb_exit
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load "$exe"
+    gdb_run_cmd
+    gdb_expect {
+        -re ".*Illegal instruction.*${gdb_prompt} $" {
+            verbose -log "$me:  TSX hardware not detected."
+            set skip_tsx_tests 1
+        }
+        -re ".*$inferior_exited_re normally.*${gdb_prompt} $" {
+            verbose -log "$me:  TSX hardware detected."
+            set skip_tsx_tests 0
+        }
+        default {
+            warning "\n$me:  default case taken."
+            set skip_tsx_tests 1
+        }
+    }
+    gdb_exit
+    remote_file build delete $exe
+
+    verbose "$me:  returning $skip_tsx_tests" 2
+    return $skip_tsx_tests
+}
+
 # Run a test on the target to see if it supports btrace hardware.  Return 0 if so,
 # 1 if it does not.  Based on 'check_vmx_hw_available' from the GCC testsuite.
 
@@ -2628,6 +2685,73 @@ gdb_caching_proc skip_btrace_tests {
     return $skip_btrace_tests
 }
 
+# Run a test on the target to see if it supports btrace pt hardware.
+# Return 0 if so, 1 if it does not.  Based on 'check_vmx_hw_available'
+# from the GCC testsuite.
+
+gdb_caching_proc skip_btrace_pt_tests {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "skip_btrace_tests"
+    if { ![istarget "i?86-*-*"] && ![istarget "x86_64-*-*"] } {
+        verbose "$me:  target does not support btrace, returning 1" 2
+        return 1
+    }
+
+    # Set up, compile, and execute a test program.
+    # Include the current process ID in the file names to prevent conflicts
+    # with invocations for multiple testsuites.
+    set src [standard_temp_file btrace[pid].c]
+    set exe [standard_temp_file btrace[pid].x]
+
+    gdb_produce_source $src {
+	int main(void) { return 0; }
+    }
+
+    verbose "$me:  compiling testfile $src" 2
+    set compile_flags {debug nowarnings quiet}
+    set lines [gdb_compile $src $exe executable $compile_flags]
+
+    if ![string match "" $lines] then {
+        verbose "$me:  testfile compilation failed, returning 1" 2
+	file delete $src
+        return 1
+    }
+
+    # No error message, compilation succeeded so now run it via gdb.
+
+    gdb_exit
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load $exe
+    if ![runto_main] {
+	file delete $src
+        return 1
+    }
+    file delete $src
+    # In case of an unexpected output, we return 2 as a fail value.
+    set skip_btrace_tests 2
+    gdb_test_multiple "record btrace pt" "check btrace support" {
+        -re "You can't do that when your target is.*\r\n$gdb_prompt $" {
+            set skip_btrace_tests 1
+        }
+        -re "Target does not support branch tracing.*\r\n$gdb_prompt $" {
+            set skip_btrace_tests 1
+        }
+        -re "Could not enable branch tracing.*\r\n$gdb_prompt $" {
+            set skip_btrace_tests 1
+        }
+        -re "^record btrace pt\r\n$gdb_prompt $" {
+            set skip_btrace_tests 0
+        }
+    }
+    gdb_exit
+    remote_file build delete $exe
+
+    verbose "$me:  returning $skip_btrace_tests" 2
+    return $skip_btrace_tests
+}
+
 # Skip all the tests in the file if you are not on an hppa running
 # hpux target.