Bug 1464170 - Support PGO in clang builds on Linux. r=dmajor

This uses the same code path as for clang-cl builds.

Makefile.in

@@ -304,26 +304,24 @@ package-generated-sources:
 
 #XXX: this is a hack, since we don't want to clobber for MSVC
 # PGO support, but we can't do this test in client.mk
-ifneq ($(OS_ARCH)_$(GNU_CC), WINNT_)
 # No point in clobbering if PGO has been explicitly disabled.
-ifndef NO_PROFILE_GUIDED_OPTIMIZE
-maybe_clobber_profiledbuild: clean
-else
+ifdef NO_PROFILE_GUIDED_OPTIMIZE
 maybe_clobber_profiledbuild:
-endif
 else
-ifdef CLANG_CL
+ifneq ($(CC_TYPE),msvc)
 maybe_clobber_profiledbuild: clean
-# 32-bit PGO is currently blocked by bug 1479800
-ifeq ($(CPU_ARCH),x86_64)
+ifneq (,$(findstring clang,$(CC_TYPE)))
+# 32-bit Windows PGO is currently blocked by bug 1479800
+ifneq ($(CC_TYPE)_$(CPU_ARCH),clang-cl_x86)
 	$(LLVM_PROFDATA) merge -o $(DEPTH)/merged.profdata $(DEPTH)/*.profraw
 endif
+endif
 else
 maybe_clobber_profiledbuild:
 	$(RM) $(DIST)/bin/*.pgc
 	find $(DIST)/$(MOZ_APP_NAME) -name '*.pgc' -exec mv {} $(DIST)/bin \;
-endif # CLANG_CL
-endif
+endif # msvc
+endif # NO_PROFILE_GUIDED_OPTIMIZE
 
 .PHONY: maybe_clobber_profiledbuild
 

build/moz.configure/toolchain.configure

@@ -1250,7 +1250,7 @@ def pgo_flags(compiler, build_env, target):
     if topobjdir.endswith('/js/src'):
         topobjdir = topobjdir[:-7]
 
-    if compiler.type in ('gcc', 'clang'):
+    if compiler.type == 'gcc':
         return namespace(
             gen_cflags=['-fprofile-generate'],
             gen_ldflags=['-fprofile-generate'],
@@ -1259,18 +1259,26 @@ def pgo_flags(compiler, build_env, target):
             use_ldflags=['-fprofile-use'],
         )
 
-    if compiler.type == 'clang-cl':
+    if compiler.type in ('clang-cl', 'clang'):
         profdata = os.path.join(topobjdir, 'merged.profdata')
-        # 32-bit PGO is currently blocked by bug 1479800
-        if target.cpu == 'x86_64':
-          return namespace(
-              gen_cflags=['-fprofile-instr-generate'],
-              gen_ldflags=['clang_rt.profile-x86_64.lib'],
-              use_cflags=['-fprofile-instr-use=%s' % profdata,
-                          '-Wno-error=profile-instr-out-of-date',
-                          '-Wno-error=profile-instr-unprofiled'],
-              use_ldflags=[],
-          )
+        if compiler.type == 'clang-cl':
+            # 32-bit PGO is currently blocked by bug 1479800
+            if target.cpu == 'x86_64':
+                gen_ldflags = ['clang_rt.profile-x86_64.lib']
+            else:
+                gen_ldflags = None
+        else:
+            gen_ldflags = ['-fprofile-instr-generate']
+
+        if gen_ldflags:
+            return namespace(
+                gen_cflags=['-fprofile-instr-generate'],
+                gen_ldflags=gen_ldflags,
+                use_cflags=['-fprofile-instr-use=%s' % profdata,
+                            '-Wno-error=profile-instr-out-of-date',
+                            '-Wno-error=profile-instr-unprofiled'],
+                use_ldflags=[],
+            )
 
     if compiler.type == 'msvc':
         num_cores = min(8, multiprocessing.cpu_count())