libgo: add Debugging section to README

    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/176001

From-SVN: r271019

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 919127300350580be65d52355fd8dff6903715b5..7c884a988dae279acd752f0e2b2ab95251b81878 100644 (file)
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-859e8ed3d632d9fe43d03fb81f6abefecf5fe3a6
+f813c670deb8e0454c3f64de74bedb5dcedd10b4
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

diff --git a/libgo/README b/libgo/README
index d5af7e2fd168e6bbb9879259034134648b676387..a39d524df96d309f51d2cd08cebb5cd026edbe0d 100644 (file)
--- a/libgo/README
+++ b/libgo/README
@@ -42,3 +42,28 @@ http://code.google.com/legal/corporate-cla-v1.0.html.
 If the copyright holder for your code has already completed the
 agreement in connection with another Google open source project, it
 does not need to be completed again.
+
+Debugging
+=========
+
+This describes how to test libgo when built as part of gccgo.
+
+To test a specific package, cd to the libgo build directory
+(TARGET/libgo) and run `make PKG/check`.  For example, `make
+bytes/check`.
+
+To see the exact commands that it runs, including how the compiler is
+invoked, run `make GOTESTFLAGS=--trace bytes/check`.  This will
+display the commands if the test fails.  If the test passes, the
+commands and other output will be visible in a file named
+check-testlog in a subdirectory with the name of the package being
+checked.  In the case of bytes/check, this will create
+bytes/check-testlog.
+
+To leave the test program behind, run `make GOTESTFLAGS=--keep
+bytes/check`.  That will leave a gotestNNNN/test directory in the
+libgo build directory.  In that directory you can run
+`LD_LIBRARY_PATH=../../.libs ./a.out -test.short` to run the tests.
+You can run specific failing tests using a -test.run option.  You can
+see the tests being run with the -test.v option.  You can run the
+program under a debugger such as gdb.