[Qemu-devel] [PATCH v1 4/4] trace-gen: auto-generate wrappers to call TCG trace helpers

[Lluís <xscript@gmx.net>]

Auto-generates file "trace-gen.h" with instrumentable wrappers to generate calls
to TCG trace helpers.

Such wrappers are named 'trace_gen_##name', also reachable as
'trace_gen_##name##_backend' when instrumented.

Events with the "gen" property are also able to use TCG types on the trace event
declaration, which are gracefully handled when generating trace functions.

Only trace events with the 'gen' property are affected.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 Makefile     |    8 +++-
 trace-events |    3 +
 tracetool    |  130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 139 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 5975926..2831dc3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 # Makefile for QEMU.
 
-GENERATED_HEADERS = config-host.h trace.h trace-helper.h trace-helper.c
+GENERATED_HEADERS = config-host.h trace.h trace-helper.h trace-helper.c trace-gen.h
 
 ifneq ($(wildcard config-host.mak),)
 # Put the all: rule here so that config-host.mak can contain dependencies.
@@ -130,6 +130,11 @@ trace-helper.c-timestamp: $(SRC_PATH)/trace-events config-host.mak
 
 trace-helper.o: trace-helper.c $(GENERATED_HEADERS)
 
+trace-gen.h: trace-gen.h-timestamp
+trace-gen.h-timestamp: $(SRC_PATH)/trace-events config-host.mak
+	$(call quiet-command,sh $(SRC_PATH)/tracetool $(TRACETOOL_EXTRA) --gen --$(TRACE_BACKEND) -h < $< > $@,"  GEN   trace-gen.h")
+	@cmp -s $@ trace-gen.h || cp $@ trace-gen.h
+
 simpletrace.o: simpletrace.c $(GENERATED_HEADERS)
 
 version.o: $(SRC_PATH)/version.rc config-host.mak
@@ -167,6 +172,7 @@ clean:
 	rm -f qemu-img-cmds.h
 	rm -f trace.c trace.h trace.c-timestamp trace.h-timestamp
 	rm -f trace-helper.c trace-helper.h trace-helper.h-timestamp trace-helper.c-timestamp
+	rm -f trace-gen.h-timestamp trace-gen.c-timestamp
 	$(MAKE) -C tests clean
 	for d in $(ALL_SUBDIRS) libhw32 libhw64 libuser libdis libdis-user; do \
 	if test -d $$d; then $(MAKE) -C $$d $@ || exit 1; fi; \
diff --git a/trace-events b/trace-events
index 4a89d97..a54fa03 100644
--- a/trace-events
+++ b/trace-events
@@ -43,6 +43,9 @@
 #   Provide trace events suitable for using during TCG code generation.
 #   Generates TCG function helpers reachable through 'helper_trace_gen_##name'
 #   which proxy their calls onto 'trace_##name'.
+#   As an extra aid, functions named 'trace_gen_##name' are generated into
+#   "trace-gen.h", which can be reched through 'trace_gen_##name##_backend' when
+#   the event is instrumented.
 
 # qemu-malloc.c
 disable qemu_malloc(size_t size, void *ptr) "size %zu ptr %p"
diff --git a/tracetool b/tracetool
index 588f442..e99da0c 100755
--- a/tracetool
+++ b/tracetool
@@ -602,6 +602,134 @@ void helper_trace_proxy_$name($args)
 EOF
 }
 
+### Gen - H
+traceto_h_gen()
+{
+     cat <<EOF
+#ifndef TRACE_GEN_H
+#define TRACE_GEN_H
+
+/* This file is autogenerated by tracetool, do not edit. */
+EOF
+
+    convert h $1 nil
+
+    if [ "$had_instrument" = "1" ]; then
+        echo '#include "trace-instrument.h"'
+    fi
+    echo "#endif /* TRACE_GEN_H */"
+}
+
+line_h_gen_parse_pre()
+{
+    case "$3" in
+        "uint32_t") echo "TCGv_i32 __arg_$1 = tcg_const_i32($2);" ;;
+        "uint64_t") echo "TCGv_i64 __arg_$1 = tcg_const_i64($2);" ;;
+        "void *")   echo "TCGv_ptr __arg_$1 = tcg_const_ptr((int64_t)$2);" ;;
+    esac
+}
+
+line_h_gen_parse_args()
+{
+    case "$3" in
+        "uint64_t") echo "__arg_$1" ;;
+        "uint32_t") echo "__arg_$1" ;;
+        "void *")   echo "__arg_$1" ;;
+        *)          echo "$2"       ;;
+    esac
+}
+
+line_h_gen_parse_post()
+{
+    case "$3" in
+        "uint32_t") echo "tcg_temp_free_i32(__arg_$1);" ;;
+        "uint64_t") echo "tcg_temp_free_i64(__arg_$1);" ;;
+        "void *")   echo "tcg_temp_free_i64(__arg_$1);" ;;
+    esac
+}
+ 
+line_h_gen()
+{
+    local gen
+    gen=$(get_property "$1" "gen")
+    [ "$gen" = "1" ] || return
+
+    local name args
+    name=$(get_event_name "$1")
+    args=$(get_args "$1")
+
+    local gen_pre gen_post gen_args i
+    gen_pre=""
+    gen_post=""
+    gen_args=""
+
+    local argname
+    i=1
+    for argname in $(get_argnames "$1"); do
+        argname=${argname%,}
+        eval __argname_$i=$argname
+        i=$(($i + 1))
+    done
+
+    local argtypes argtype accum _pre _arg _post
+    argtypes=$(get_argtypes "$1")
+    i=1
+    accum=""
+    for argtype in $argtypes; do
+        accum="$accum ${argtype%,}"
+        if [ "$argtype" = "${argtype%,}" ]; then
+            continue
+        fi
+        argtype="${accum# }"
+        accum=""
+
+        eval argname=\$__argname_$i
+
+        _pre=$(line_h_gen_parse_pre $i $argname "$argtype")
+        gen_pre="$gen_pre
+$_pre"
+        _arg=$(line_h_gen_parse_arg $i $argname "$argtype")
+        gen_args="$gen_args$_arg"
+        _post=$(line_h_gen_parse_post $i $argname "$argtype")
+        gen_post="$gen_post
+$_post"
+
+        i=$(($i + 1))
+    done
+    argtype="${accum# }"
+    eval argname=\$__argname_$i
+
+    _pre=$(line_h_gen_parse_pre $i $argname "$argtype")
+    gen_pre="$gen_pre
+$_pre"
+    _arg=$(line_h_gen_parse_args $i $argname "$argtype")
+    gen_args="$gen_args, $_arg"
+    _post=$(line_h_gen_parse_post $i $argname "$argtype")
+    gen_post="$gen_post
+$_post"
+
+    gen_args="${gen_args#, }"
+
+    cat <<EOF
+static inline void trace_gen_${name}_backend($args)
+{
+$gen_pre
+    gen_helper_trace_proxy_$name($gen_args);
+$gen_post
+}
+EOF
+
+    # XXX: should still provide instrumentation if event is disabled?
+    local instrument
+    instrument=$(get_property "$1" "instrument")
+    if [ "$instrument" = "1" ]; then
+        had_instrument="1"
+        return
+    fi
+
+    echo "#define trace_gen_$name trace_gen_${name}_backend"
+}
+
 ################################################################################
 ### Generic code
 
@@ -663,7 +791,7 @@ EOF
 while [ $# -gt 0 ]; do
     case $1 in
         "--instrument") enable_instrument="1" ;;
-        "--regular"|"--helper") frontend="${1#--}" ;;
+        "--regular"|"--helper"|"--gen") frontend="${1#--}" ;;
         "--nop"|"--simple"|"--ust") backend="${1#--}" ;;
         "-h"|"-c") output="${1#-}" ;;
         "--check-backend") check=1 ;; # used by ./configure to test for backend