[pull] master from openssl:master

.github/workflows/coveralls.yml

@@ -116,6 +116,7 @@ jobs:
              --exclude "${PWD}/fuzz/*"
              --exclude "/usr/include/*"
              --ignore-errors mismatch
+             --branch-coverage
               -o ./lcov.info
     - name: Coveralls upload
       uses: coverallsapp/github-action@v2.3.2

Configurations/10-main.conf

@@ -679,7 +679,8 @@ my %targets = (
         CXX              => "g++",
         CFLAGS           => picker(default => "-Wall",
                                    debug   => "-O0 -g",
-                                   release => "-O3"),
+                                   release => "-O3",
+                                   pgo => "-O3 -fprofile-use -Wno-coverage-mismatch"),
         CXXFLAGS         => picker(default => "-Wall",
                                    debug   => "-O0 -g",
                                    release => "-O3"),

Configurations/unix-Makefile.tmpl

@@ -540,6 +540,9 @@ debuginfo: $(SHLIBS)
 		$(OBJCOPY) --strip-debug --add-gnu-debuglink=$$i.debug $$i; \
 	done;
 
+cov-report: $(SHLIBS)
+	@set -e; gcovr -r . --txt-metric=branch --html --html-details -o openssl-metrics.html
+
 ##@ Documentation
 build_generated_pods: $(GENERATED_PODS)
 build_docs: build_man_docs build_html_docs ## Create documentation

Configure

@@ -1017,6 +1017,10 @@ while (@argvcopy)
                 {
                 $config{build_type} = "release";
                 }
+        elsif (/^--pgo$/)
+                {
+                $config{build_type} = "pgo";
+                }
         elsif (/^386$/)
                 { $config{processor}=386; }
         elsif (/^rsaref$/)

INSTALL.md

@@ -335,6 +335,14 @@ Build OpenSSL with debugging symbols and zero optimization level.
 
 Build OpenSSL without debugging symbols.  This is the default.
 
+    --coverage
+
+Build OpenSSL with gcov profiling information included
+
+    --pgo
+
+Build OpenSSL optimized using gcov data obtained from --coverage build
+
 Directories
 -----------
 
@@ -2033,6 +2041,24 @@ around the problem by forcing the build procedure to use the following script:
 instead of the real clang. In which case it doesn't matter what clang version
 is used, as it is the version of the GNU assembler that will be checked.
 
+Notes on profile guided optimization
+------------------------------------
+
+Some compilers support the concept of profile guided optimization.  This feature
+allows a user to build openssl and use profiling data gathered while running an
+application such that it can then be rebuilt in a way that is optimized specifically
+for that application, increasing performance.  Currently this feature is built into
+the openssl build system for x86_64 only.
+
+1) Configure openssl with the --coverage option.  This will configure the compiler to
+   record profiling data for the libcrypto and libssl libraries
+2) Run the application(s) which you wish to optimize for, ensuring that they use
+   the libraries compiled in step (1) (note this may entail the use of LD_LIBRARY_PATH)
+3) Clean the openssl build with make clean.  Note that the profile data (the .gcda and .gcno
+   files are retained through the clean operation). This is intentional.
+4) Configure openssl again, but this time select the --pgo build type.  This will use the
+   profiled data to optimize code layout for the application in question.
+
 ---
 
 <!-- Links  -->