plugin-gen: add module for TCG-related code

We first inject empty instrumentation from translator_loop.
After translation, we go through the plugins to see what
they want to register for, filling in the empty instrumentation.
If if turns out that some instrumentation remains unused, we
remove it.

This approach supports the following features:

- Inlining TCG code for simple operations. Note that we do not
  export TCG ops to plugins. Instead, we give them a C API to
  insert inlined ops. So far we only support adding an immediate
  to a u64, e.g. to count events.

- "Direct" callbacks. These are callbacks that do not go via
  a helper. Instead, the helper is defined at run-time, so that
  the plugin code is directly called from TCG. This makes direct
  callbacks as efficient as possible; they are therefore used
  for very frequent events, e.g. memory callbacks.

- Passing the host address to memory callbacks. Most of this
  is implemented in a later patch though.

- Instrumentation of memory accesses performed from helpers.
  See the corresponding comment, as well as a later patch.

Signed-off-by: Emilio G. Cota <cota@braap.org>
[AJB: add alloc_tcg_plugin_context, use glib, rm hwaddr]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

4 files changed, 60 insertions, 0 deletions

diff --git a/include/exec/helper-gen.h b/include/exec/helper-gen.h
index 22381a1708..236ff40524 100644
--- a/include/exec/helper-gen.h
+++ b/include/exec/helper-gen.h
@@ -70,6 +70,7 @@ static inline void glue(gen_helper_, name)(dh_retvar_decl(ret)          \
 #include "trace/generated-helpers.h"
 #include "trace/generated-helpers-wrappers.h"
 #include "tcg-runtime.h"
+#include "plugin-helpers.h"
 
 #undef DEF_HELPER_FLAGS_0
 #undef DEF_HELPER_FLAGS_1
diff --git a/include/exec/helper-proto.h b/include/exec/helper-proto.h
index 74943edb13..1c4ba9bc78 100644
--- a/include/exec/helper-proto.h
+++ b/include/exec/helper-proto.h
@@ -33,6 +33,7 @@ dh_ctype(ret) HELPER(name) (dh_ctype(t1), dh_ctype(t2), dh_ctype(t3), \
 #include "helper.h"
 #include "trace/generated-helpers.h"
 #include "tcg-runtime.h"
+#include "plugin-helpers.h"
 
 #undef DEF_HELPER_FLAGS_0
 #undef DEF_HELPER_FLAGS_1
diff --git a/include/exec/helper-tcg.h b/include/exec/helper-tcg.h
index 268e0f804b..573c2ce2e9 100644
--- a/include/exec/helper-tcg.h
+++ b/include/exec/helper-tcg.h
@@ -55,6 +55,7 @@
 #include "helper.h"
 #include "trace/generated-helpers.h"
 #include "tcg-runtime.h"
+#include "plugin-helpers.h"
 
 #undef str
 #undef DEF_HELPER_FLAGS_0
diff --git a/include/exec/plugin-gen.h b/include/exec/plugin-gen.h
new file mode 100644
index 0000000000..de519883b1
--- /dev/null
+++ b/include/exec/plugin-gen.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
+ *
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ *
+ * plugin-gen.h - TCG-dependent definitions for generating plugin code
+ *
+ * This header should be included only from plugin.c and C files that emit
+ * TCG code.
+ */
+#ifndef QEMU_PLUGIN_GEN_H
+#define QEMU_PLUGIN_GEN_H
+
+#include "qemu/plugin.h"
+#include "tcg/tcg.h"
+
+struct DisasContextBase;
+
+#ifdef CONFIG_PLUGIN
+
+bool plugin_gen_tb_start(CPUState *cpu, const TranslationBlock *tb);
+void plugin_gen_tb_end(CPUState *cpu);
+void plugin_gen_insn_start(CPUState *cpu, const struct DisasContextBase *db);
+void plugin_gen_insn_end(void);
+
+void plugin_gen_disable_mem_helpers(void);
+void plugin_gen_empty_mem_callback(TCGv addr, uint32_t info);
+
+#else /* !CONFIG_PLUGIN */
+
+static inline
+bool plugin_gen_tb_start(CPUState *cpu, const TranslationBlock *tb)
+{
+    return false;
+}
+
+static inline
+void plugin_gen_insn_start(CPUState *cpu, const struct DisasContextBase *db)
+{ }
+
+static inline void plugin_gen_insn_end(void)
+{ }
+
+static inline void plugin_gen_tb_end(CPUState *cpu)
+{ }
+
+static inline void plugin_gen_disable_mem_helpers(void)
+{ }
+
+static inline void plugin_gen_empty_mem_callback(TCGv addr, uint32_t info)
+{ }
+
+#endif /* CONFIG_PLUGIN */
+
+#endif /* QEMU_PLUGIN_GEN_H */
+