diff --git a/core/Makefile b/core/Makefile
index 907943e..9f09550 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -434,9 +434,9 @@
 pdk_fusion_log_tags_file := $(patsubst $(PRODUCT_OUT)/%,$(_pdk_fusion_intermediates)/%,$(filter $(event_log_tags_file),$(ALL_PDK_FUSION_FILES)))
 
 $(all_event_log_tags_file): PRIVATE_SRC_FILES := $(all_event_log_tags_src) $(pdk_fusion_log_tags_file)
-$(all_event_log_tags_file): $(all_event_log_tags_src) $(pdk_fusion_log_tags_file)
+$(all_event_log_tags_file): $(all_event_log_tags_src) $(pdk_fusion_log_tags_file) $(MERGETAGS) build/tools/event_log_tags.py
 	$(hide) mkdir -p $(dir $@)
-	$(hide) build/tools/merge-event-log-tags.py -o $@ $(PRIVATE_SRC_FILES)
+	$(hide) $(MERGETAGS) -o $@ $(PRIVATE_SRC_FILES)
 
 # Include tags from all packages included in this product, plus all
 # tags that are part of the system (ie, not in a vendor/ or device/
@@ -450,9 +450,9 @@
 
 $(event_log_tags_file): PRIVATE_SRC_FILES := $(event_log_tags_src) $(pdk_fusion_log_tags_file)
 $(event_log_tags_file): PRIVATE_MERGED_FILE := $(all_event_log_tags_file)
-$(event_log_tags_file): $(event_log_tags_src) $(all_event_log_tags_file) $(pdk_fusion_log_tags_file)
+$(event_log_tags_file): $(event_log_tags_src) $(all_event_log_tags_file) $(pdk_fusion_log_tags_file) $(MERGETAGS) build/tools/event_log_tags.py
 	$(hide) mkdir -p $(dir $@)
-	$(hide) build/tools/merge-event-log-tags.py -o $@ -m $(PRIVATE_MERGED_FILE) $(PRIVATE_SRC_FILES)
+	$(hide) $(MERGETAGS) -o $@ -m $(PRIVATE_MERGED_FILE) $(PRIVATE_SRC_FILES)
 
 event-log-tags: $(event_log_tags_file)
 
diff --git a/core/binary.mk b/core/binary.mk
index 8e94653..14c2b54 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -214,10 +214,15 @@
 # clang is enabled by default for host builds
 # enable it unless we've specifically disabled clang above
 ifdef LOCAL_IS_HOST_MODULE
-    ifneq ($($(my_prefix)OS),windows)
-    ifeq ($(my_clang),)
-        my_clang := true
-    endif
+    ifeq ($($(my_prefix)OS),windows)
+        ifeq ($(my_clang),true)
+            $(error $(LOCAL_MODULE_MAKEFILE): $(LOCAL_MODULE): Clang is not yet supported for windows binaries)
+        endif
+        my_clang := false
+    else
+        ifeq ($(my_clang),)
+            my_clang := true
+        endif
     endif
 # Add option to make clang the default for device build
 else ifeq ($(USE_CLANG_PLATFORM_BUILD),true)
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index 076815b..ea384b4 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -44,7 +44,7 @@
 # HOST_TOOLCHAIN_ROOT is a Darwin-specific define
 $(combo_2nd_arch_prefix)HOST_TOOLCHAIN_FOR_CLANG := $($(combo_2nd_arch_prefix)HOST_TOOLCHAIN_ROOT)
 
-$(combo_2nd_arch_prefix)HOST_AR := $(AR)
+$(combo_2nd_arch_prefix)HOST_AR := $(mac_sdk_path)/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar
 
 $(combo_2nd_arch_prefix)HOST_GLOBAL_CFLAGS += -isysroot $(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version) -DMACOSX_DEPLOYMENT_TARGET=$(mac_sdk_version)
 $(combo_2nd_arch_prefix)HOST_GLOBAL_LDFLAGS += -isysroot $(mac_sdk_root) -Wl,-syslibroot,$(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version)
diff --git a/core/combo/HOST_darwin-x86_64.mk b/core/combo/HOST_darwin-x86_64.mk
index a8541ee..eee2ee5 100644
--- a/core/combo/HOST_darwin-x86_64.mk
+++ b/core/combo/HOST_darwin-x86_64.mk
@@ -44,7 +44,7 @@
 # HOST_TOOLCHAIN_ROOT is a Darwin-specific define
 HOST_TOOLCHAIN_FOR_CLANG := $(HOST_TOOLCHAIN_ROOT)
 
-HOST_AR := $(AR)
+HOST_AR := $(mac_sdk_path)/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar
 
 HOST_GLOBAL_CFLAGS += -isysroot $(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version) -DMACOSX_DEPLOYMENT_TARGET=$(mac_sdk_version)
 HOST_GLOBAL_LDFLAGS += -isysroot $(mac_sdk_root) -Wl,-syslibroot,$(mac_sdk_root) -mmacosx-version-min=$(mac_sdk_version)
diff --git a/core/config.mk b/core/config.mk
index e686733..d2a593d 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -560,6 +560,7 @@
 
 PROGUARD := external/proguard/bin/proguard.sh
 JAVATAGS := build/tools/java-event-log-tags.py
+MERGETAGS := build/tools/merge-event-log-tags.py
 APPEND2SIMG := $(HOST_OUT_EXECUTABLES)/append2simg
 VERITY_SIGNER := $(HOST_OUT_EXECUTABLES)/verity_signer
 BUILD_VERITY_TREE := $(HOST_OUT_EXECUTABLES)/build_verity_tree
diff --git a/core/definitions.mk b/core/definitions.mk
index 5a91045..ce71f45 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1082,7 +1082,7 @@
 define transform-logtags-to-java
 @mkdir -p $(dir $@)
 @echo "logtags: $@ <= $<"
-$(hide) $(JAVATAGS) -o $@ $^
+$(hide) $(JAVATAGS) -o $@ $< $(PRIVATE_MERGED_TAG)
 endef
 
 
diff --git a/core/java.mk b/core/java.mk
index 1a3fba6..fcfb0dd 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -354,7 +354,8 @@
 logtags_java_sources := $(patsubst %.logtags,%.java,$(addprefix $(intermediates.COMMON)/src/, $(logtags_sources)))
 logtags_sources := $(addprefix $(LOCAL_PATH)/, $(logtags_sources))
 
-$(logtags_java_sources): $(intermediates.COMMON)/src/%.java: $(LOCAL_PATH)/%.logtags $(TARGET_OUT_COMMON_INTERMEDIATES)/all-event-log-tags.txt
+$(logtags_java_sources): PRIVATE_MERGED_TAG := $(TARGET_OUT_COMMON_INTERMEDIATES)/all-event-log-tags.txt
+$(logtags_java_sources): $(intermediates.COMMON)/src/%.java: $(LOCAL_PATH)/%.logtags $(TARGET_OUT_COMMON_INTERMEDIATES)/all-event-log-tags.txt $(JAVATAGS) build/tools/event_log_tags.py
 	$(transform-logtags-to-java)
 
 else
diff --git a/core/package_internal.mk b/core/package_internal.mk
index 64040e5..1ab2cf8 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -188,7 +188,10 @@
 ifeq (true,$(EMMA_INSTRUMENT_STATIC))
 ifdef LOCAL_JACK_ENABLED
 # Jack supports coverage with Jacoco
+ifneq ($(LOCAL_SRC_FILES)$(LOCAL_STATIC_JAVA_LIBRARIES)$(LOCAL_SOURCE_FILES_ALL_GENERATED),)
+# Only add jacocoagent if the package contains some java code
 LOCAL_STATIC_JAVA_LIBRARIES += jacocoagent
+endif # Contains java code
 else
 LOCAL_STATIC_JAVA_LIBRARIES += emma
 endif # LOCAL_JACK_ENABLED
@@ -198,7 +201,10 @@
 # In unbundled build merge the emma library into the apk.
 ifdef LOCAL_JACK_ENABLED
 # Jack supports coverage with Jacoco
+ifneq ($(LOCAL_SRC_FILES)$(LOCAL_STATIC_JAVA_LIBRARIES)$(LOCAL_SOURCE_FILES_ALL_GENERATED),)
+# Only add jacocoagent if the package contains some java code
 LOCAL_STATIC_JAVA_LIBRARIES += jacocoagent
+endif # Contains java code
 else
 LOCAL_STATIC_JAVA_LIBRARIES += emma
 endif # LOCAL_JACK_ENABLED
diff --git a/tools/warn.py b/tools/warn.py
index bb3b08d..9fe6925 100755
--- a/tools/warn.py
+++ b/tools/warn.py
@@ -16,7 +16,8 @@
     HIGH=2
     MEDIUM=3
     LOW=4
-    HARMLESS=5
+    TIDY=5
+    HARMLESS=6
 
 def colorforseverity(sev):
     if sev == severity.FIXMENOW:
@@ -27,6 +28,8 @@
         return 'orange'
     if sev == severity.LOW:
         return 'yellow'
+    if sev == severity.TIDY:
+        return 'peachpuff'
     if sev == severity.HARMLESS:
         return 'limegreen'
     if sev == severity.UNKNOWN:
@@ -44,6 +47,8 @@
         return 'Low severity warnings'
     if sev == severity.HARMLESS:
         return 'Harmless warnings'
+    if sev == severity.TIDY:
+        return 'Clang-Tidy warnings'
     if sev == severity.UNKNOWN:
         return 'Unknown warnings'
     return 'Unhandled warnings'
@@ -106,10 +111,15 @@
         'description':'Unused function, variable or label',
         'patterns':[r".*: warning: '.+' defined but not used",
                     r".*: warning: unused function '.+'",
+                    r".*: warning: private field '.+' is not used",
                     r".*: warning: unused variable '.+'"] },
     { 'category':'C/C++',   'severity':severity.MEDIUM,   'members':[], 'option':'-Wunused-value',
-        'description':'Statement with no effect',
-        'patterns':[r".*: warning: statement with no effect"] },
+        'description':'Statement with no effect or result unused',
+        'patterns':[r".*: warning: statement with no effect",
+                    r".*: warning: expression result unused"] },
+    { 'category':'C/C++',   'severity':severity.MEDIUM,   'members':[], 'option':'-Wunused-result',
+        'description':'Ignoreing return value of function',
+        'patterns':[r".*: warning: ignoring return value of function .+Wunused-result"] },
     { 'category':'C/C++',   'severity':severity.MEDIUM,   'members':[], 'option':'-Wmissing-field-initializers',
         'description':'Missing initializer',
         'patterns':[r".*: warning: missing initializer"] },
@@ -405,6 +415,9 @@
     { 'category':'C/C++',   'severity':severity.LOW,      'members':[], 'option':'-Wdeprecated-declarations',
         'description':'Deprecated declarations',
         'patterns':[r".*: warning: .+ is deprecated.+deprecated-declarations"] },
+    { 'category':'C/C++',   'severity':severity.LOW,      'members':[], 'option':'-Wdeprecated-register',
+        'description':'Deprecated register',
+        'patterns':[r".*: warning: 'register' storage class specifier is deprecated"] },
     { 'category':'C/C++',   'severity':severity.LOW,      'members':[], 'option':'-Wpointer-sign',
         'description':'Converts between pointers to integer types with different sign',
         'patterns':[r".*: warning: .+ converts between pointers to integer types with different sign"] },
@@ -465,9 +478,12 @@
     { 'category':'C/C++',   'severity':severity.LOW,     'members':[], 'option':'',
         'description':'Useless specifier',
         'patterns':[r".*: warning: useless storage class specifier in empty declaration"] },
+    { 'category':'C/C++',   'severity':severity.LOW,     'members':[], 'option':'-Wduplicate-decl-specifier',
+        'description':'Duplicate declaration specifier',
+        'patterns':[r".*: warning: duplicate '.+' declaration specifier"] },
     { 'category':'logtags',   'severity':severity.LOW,     'members':[], 'option':'',
         'description':'Duplicate logtag',
-        'patterns':[r".*: warning: tag "".+"" \(None\) duplicated in .+"] },
+        'patterns':[r".*: warning: tag \".+\" \(.+\) duplicated in .+"] },
     { 'category':'logtags',   'severity':severity.LOW,     'members':[], 'option':'typedef-redefinition',
         'description':'Typedef redefinition',
         'patterns':[r".*: warning: redefinition of typedef '.+' is a C11 feature"] },
@@ -521,6 +537,9 @@
     { 'category':'C/C++',   'severity':severity.LOW,     'members':[], 'option':'',
         'description':'Refers to implicitly defined namespace',
         'patterns':[r".*: warning: using directive refers to implicitly-defined namespace .+"] },
+    { 'category':'C/C++',   'severity':severity.LOW,     'members':[], 'option':'-Winvalid-pp-token',
+        'description':'Invalid pp token',
+        'patterns':[r".*: warning: missing .+Winvalid-pp-token"] },
 
     { 'category':'C/C++',   'severity':severity.MEDIUM,     'members':[], 'option':'',
         'description':'Operator new returns NULL',
@@ -610,6 +629,42 @@
         'description':'',
         'patterns':[r".*: warning: In file included from .+,"] },
 
+    # warnings from clang-tidy
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy readability',
+        'patterns':[r".*: .+\[readability-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy c++ core guidelines',
+        'patterns':[r".*: .+\[cppcoreguidelines-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy google-runtime',
+        'patterns':[r".*: .+\[google-runtime-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy google-build',
+        'patterns':[r".*: .+\[google-build-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy google-explicit',
+        'patterns':[r".*: .+\[google-explicit-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy modernize',
+        'patterns':[r".*: .+\[modernize-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy misc',
+        'patterns':[r".*: .+\[misc-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy CERT',
+        'patterns':[r".*: .+\[cert-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy llvm',
+        'patterns':[r".*: .+\[llvm-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy clang-diagnostic',
+        'patterns':[r".*: .+\[clang-diagnostic-.+\]$"] },
+    { 'category':'C/C++',   'severity':severity.TIDY,     'members':[], 'option':'',
+        'description':'clang-tidy clang-analyzer',
+        'patterns':[r".*: .+\[clang-analyzer-.+\]$",
+                    r".*: Call Path : .+$"] },
+
     # catch-all for warnings this script doesn't know about yet
     { 'category':'C/C++',   'severity':severity.UNKNOWN,  'members':[], 'option':'',
         'description':'Unclassified/unrecognized warnings',
@@ -628,6 +683,7 @@
 
 def dumphtmlprologue(title):
     output('<html>\n<head>\n<title>' + title + '</title>\n<body>\n')
+    output('<a name="PageTop">')
     output(htmlbig(title))
     output('<p>\n')
 
@@ -650,7 +706,7 @@
         output(i + '<br>')
     output('</td>')
     output('<td width="100" bgcolor="grey">' +
-           '<a align="right" href="#WarningTOC">top</a><br>' +
+           '<a align="right" href="#PageTop">top</a><br>' +
            '<a align="right" href="#anchor' + str(anchor-1) + '">previous</a><br>' +
            '<a align="right" href="#anchor' + str(anchor+1) + '">next</a>')
     output('</td></a></tr>')
@@ -696,7 +752,7 @@
 # dump table of content, list of all warning patterns
 def dumptoc():
     n = 1
-    output('<a name="WarningTOC"><blockquote>\n')
+    output('<blockquote>\n')
     for i in warnpatterns:
         i['anchor'] = 'Warning' + str(n)
         n += 1
@@ -704,6 +760,7 @@
     dumpcount(severity.HIGH)
     dumpcount(severity.MEDIUM)
     dumpcount(severity.LOW)
+    dumpcount(severity.TIDY)
     dumpcount(severity.HARMLESS)
     dumpcount(severity.UNKNOWN)
     output('</blockquote>\n<p>\n')
@@ -816,6 +873,7 @@
 dumpseverity(severity.HIGH)
 dumpseverity(severity.MEDIUM)
 dumpseverity(severity.LOW)
+dumpseverity(severity.TIDY)
 dumpseverity(severity.HARMLESS)
 dumpseverity(severity.UNKNOWN)
 dumpfixed()