编译JDK9步骤：
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brew install hg
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brew install freetype
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hg clone http://hg.openjdk.java.net/jdk9/jdk9
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sh ./get_source.sh
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bash configure --with-debug-level=slowdebug \ --with-freetype=/usr/local/opt/freetype \ --disable-warnings-as-errors
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cd jdk9 -
make
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如果在make的过程中代码报错，主要有以下3点错误，每一行diff代表一个
diff -r b756e7a2ec33 src/share/vm/memory/virtualspace.cpp --- a/src/share/vm/memory/virtualspace.cpp Thu Aug 03 18:56:57 2017 +0000 +++ b/src/share/vm/memory/virtualspace.cpp Sat Oct 07 21:27:59 2017 +0800 @@ -581,7 +581,8 @@ assert(markOopDesc::encode_pointer_as_mark(&_base[size])->decode_pointer() == &_base[size], "area must be distinguishable from marks for mark-sweep"); - if (base() > 0) { + // if (base() > 0) { + if (base() != NULL) { MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap); } } diff -r b756e7a2ec33 src/share/vm/opto/lcm.cpp --- a/src/share/vm/opto/lcm.cpp Thu Aug 03 18:56:57 2017 +0000 +++ b/src/share/vm/opto/lcm.cpp Sat Oct 07 21:27:59 2017 +0800 @@ -39,7 +39,8 @@ // Check whether val is not-null-decoded compressed oop, // i.e. will grab into the base of the heap if it represents NULL. static bool accesses_heap_base_zone(Node *val) { - if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops. + // if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops. + if (Universe::narrow_oop_base() != NULL) { // Implies UseCompressedOops. if (val && val->is_Mach()) { if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) { // This assumes all Decodes with TypePtr::NotNull are matched to nodes that diff -r b756e7a2ec33 src/share/vm/opto/loopPredicate.cpp --- a/src/share/vm/opto/loopPredicate.cpp Thu Aug 03 18:56:57 2017 +0000 +++ b/src/share/vm/opto/loopPredicate.cpp Sat Oct 07 21:27:59 2017 +0800 @@ -270,7 +270,8 @@ Node* ctrl = iff->in(0); // Match original condition since predicate's projections could be swapped. - assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); + // assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); + // assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int()->_hi >= 0, "must be"); Node* opq = new Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1)); igvn->C->add_predicate_opaq(opq); @@ -900,7 +901,7 @@ Node* idx = cmp->in(1); assert(!invar.is_invariant(idx), "index is variant"); Node* rng = cmp->in(2); - assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be"); + // assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be"); assert(invar.is_invariant(rng), "range must be invariant"); int scale = 1; Node* offset = zero;
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打开clion，只要hotspot文件夹，右上角的configuration使用进入build出来的目录下的jdk9/build/macosx-x86_64-normal-server-slowdebug/jdk/bin/java，取消在debug之前的build，在jni.cpp第3884行打断点，忽略clion的各种红色报错，就可以顺利debug虚拟机
编译好的jdk就在项目目录中，可以在build文件夹下找到
OpenJDK(JVM、Javac)源代码学习研究(包括代码注释、文档、用于代码分析的测试用例)
jdk8: 从openjdk8-b132 里抽取hotspot、javac目录得来的。