From 803a17402a2e18b028b632f7d68ca45155c09007 Mon Sep 17 00:00:00 2001
From: jdh8d <jdh8d@git.zephyr-software.com>
Date: Thu, 2 Jun 2016 20:00:55 +0000
Subject: [PATCH] working on building dominators and post dominators
Former-commit-id: 4acf40b8c0d0c8ddfa78dc5d338bd79c7b0d556a
---
.gitattributes | 1 +
libIRDB/include/cfg/BasicBlock.hpp | 8 ++++-
libIRDB/include/cfg/CFG.hpp | 1 +
libIRDB/include/cfg/domgraph.hpp | 50 ++++++++++++++++++++++++++++
libIRDB/include/libIRDB-cfg.hpp | 1 +
libIRDB/src/cfg/BasicBlock.cpp | 53 ++++++++++++++++++++++++++++--
libIRDB/src/cfg/CFG.cpp | 29 +++++++++++++---
libIRDB/src/cfg/SConscript | 3 +-
libIRDB/test/fix_calls.cpp | 9 +++++
9 files changed, 146 insertions(+), 9 deletions(-)
create mode 100644 libIRDB/include/cfg/domgraph.hpp
diff --git a/.gitattributes b/.gitattributes
index 5d6462a71..ce4a0f652 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -204,6 +204,7 @@ libIRDB/SConstruct -text
libIRDB/include/cfg/BasicBlock.hpp -text
libIRDB/include/cfg/CFG.hpp -text
libIRDB/include/cfg/callgraph.hpp -text
+libIRDB/include/cfg/domgraph.hpp -text
libIRDB/include/core/address.hpp -text
libIRDB/include/core/archdesc.hpp -text
libIRDB/include/core/baseobj.hpp -text
diff --git a/libIRDB/include/cfg/BasicBlock.hpp b/libIRDB/include/cfg/BasicBlock.hpp
index bd61587db..340c9d697 100644
--- a/libIRDB/include/cfg/BasicBlock.hpp
+++ b/libIRDB/include/cfg/BasicBlock.hpp
@@ -36,9 +36,15 @@ class BasicBlock_t
BasicBlockSet_t& GetPredecessors() { return predecessors; }
BasicBlockSet_t& GetSuccessors() { return successors; }
BasicBlockSet_t& GetIndirectTargets() { return indirect_targets; }
-
BasicBlock_t* GetFallthrough();
BasicBlock_t* GetTarget();
+
+ // for const correctness if you aren't modifying.
+ const InstructionVector_t& GetInstructions() const { return instructions; }
+ const BasicBlockSet_t& GetPredecessors() const { return predecessors; }
+ const BasicBlockSet_t& GetSuccessors() const { return successors; }
+ const BasicBlockSet_t& GetIndirectTargets() const { return indirect_targets; }
+
bool EndsInBranch();
bool EndsInIndirectBranch();
bool EndsInConditionalBranch();
diff --git a/libIRDB/include/cfg/CFG.hpp b/libIRDB/include/cfg/CFG.hpp
index afb0e63bb..532570be5 100644
--- a/libIRDB/include/cfg/CFG.hpp
+++ b/libIRDB/include/cfg/CFG.hpp
@@ -42,6 +42,7 @@ class ControlFlowGraph_t
public:
friend std::ostream& operator<<(std::ostream& os, const ControlFlowGraph_t& cfg);
BasicBlockSet_t& GetBlocks() { return blocks; }
+ const BasicBlockSet_t& GetBlocks() const { return blocks; }
};
diff --git a/libIRDB/include/cfg/domgraph.hpp b/libIRDB/include/cfg/domgraph.hpp
new file mode 100644
index 000000000..d5de10e5e
--- /dev/null
+++ b/libIRDB/include/cfg/domgraph.hpp
@@ -0,0 +1,50 @@
+
+
+
+typedef std::map<const BasicBlock_t*, BasicBlockSet_t> DominatorMap_t;
+typedef std::map<const BasicBlock_t*, BasicBlock_t*> BlockToBlockMap_t;
+
+class DominatorGraph_t
+{
+ public:
+ DominatorGraph_t(const ControlFlowGraph_t* p_cfg, bool needs_postdoms=false, bool needs_idoms=false);
+
+
+ // get the (post) dominators for a node
+ BasicBlockSet_t& GetDominators(const BasicBlock_t* node) { return dom_graph[node]; }
+ BasicBlockSet_t& GetPostDominators(const BasicBlock_t* node) { return post_dom_graph[node]; }
+
+ const BasicBlockSet_t& GetDominators(const BasicBlock_t* node) const { return dom_graph.at(node); }
+ const BasicBlockSet_t& GetPostDominators(const BasicBlock_t* node) const { return post_dom_graph.at(node); }
+
+
+ // get the immeidate (post) dominators for a node
+ const BasicBlock_t* GetImmediateDominator(const BasicBlock_t* node) const
+ { auto it=idom_graph.find(node); return (it!=idom_graph.end()) ? it->second : NULL; }
+ const BasicBlock_t* GetImmediatePostDominators(const BasicBlock_t* node) const
+ { auto it=post_idom_graph.find(node); return (it!=post_idom_graph.end()) ? it->second : NULL; }
+
+
+ private:
+
+ typedef const BasicBlockSet_t& (*pred_func_ptr_t) (const BasicBlock_t* node);
+
+ DominatorMap_t Dom_Comp(const BasicBlockSet_t& N, pred_func_ptr_t pred_func, BasicBlock_t* r);
+ BlockToBlockMap_t Idom_Comp(const BasicBlockSet_t& N, const DominatorMap_t &Domin, BasicBlock_t* r);
+
+
+ DominatorMap_t dom_graph;
+ BlockToBlockMap_t idom_graph;
+
+ DominatorMap_t post_dom_graph;
+ BlockToBlockMap_t post_idom_graph;
+
+ const ControlFlowGraph_t& cfg; // a reference to our cfg.
+
+ friend std::ostream& operator<<(std::ostream& os, const DominatorGraph_t& cfg);
+
+};
+
+std::ostream& operator<<(std::ostream& os, const DominatorGraph_t& cfg);
+
+
diff --git a/libIRDB/include/libIRDB-cfg.hpp b/libIRDB/include/libIRDB-cfg.hpp
index 6cfc423df..1a720ec61 100644
--- a/libIRDB/include/libIRDB-cfg.hpp
+++ b/libIRDB/include/libIRDB-cfg.hpp
@@ -36,6 +36,7 @@ namespace libIRDB
#include <cfg/BasicBlock.hpp>
#include <cfg/CFG.hpp>
#include <cfg/callgraph.hpp>
+#include <cfg/domgraph.hpp>
};
diff --git a/libIRDB/src/cfg/BasicBlock.cpp b/libIRDB/src/cfg/BasicBlock.cpp
index 8cf835061..f45440423 100644
--- a/libIRDB/src/cfg/BasicBlock.cpp
+++ b/libIRDB/src/cfg/BasicBlock.cpp
@@ -69,6 +69,35 @@ void BasicBlock_t::BuildBlock
successors.insert(target_block);
}
+ /* This is also the end of the block if this is a function exit instruction */
+ if(insn->IsFunctionExit())
+ {
+ is_exit_block=true;
+ }
+
+ // handle fixed-call fallthroughs.
+ for_each(insn->GetRelocations().begin(), insn->GetRelocations().end(), [this,&insn2block_map](Relocation_t* reloc)
+ {
+ /* and has a reloc that's a pcrel with a WRT object */
+ if( reloc->GetType()==string("fix_call_fallthrough"))
+ {
+ assert(reloc->GetWRT()!=NULL);
+ Instruction_t* fix_call_fallthrough_insn=dynamic_cast<Instruction_t*>(reloc->GetWRT());
+ assert(fix_call_fallthrough_insn);
+
+ // this block has a fallthrough to the return block.
+ if(is_in_container(insn2block_map,fix_call_fallthrough_insn))
+ {
+ BasicBlock_t* fix_call_fallthrough_blk=find_map_object(insn2block_map,fix_call_fallthrough_insn);
+ successors.insert(fix_call_fallthrough_blk);
+ fix_call_fallthrough_blk->GetPredecessors().insert(this);
+ }
+
+ is_exit_block=false;
+ }
+ });
+
+
/* if there's a fallthrough block, insert it into the appropriate sets */
if(ft_block)
{
@@ -81,16 +110,34 @@ void BasicBlock_t::BuildBlock
break;
/* or if there is a fallthrough block already built */
- if(target_insn || ft_block)
+ if(ft_block)
break;
- /* This is also the end of the block if this is a function exit instruction */
- if(insn->IsFunctionExit())
+ /* check for a fallthrough out of the function */
+ if(ft_insn && !is_in_container(func->GetInstructions(),ft_insn))
break;
+
/* otherwise, move to the fallthrough */
insn=ft_insn;
}
+
+ // deal with IB targets for the end of the block
+
+ insn=instructions[instructions.size()-1]; // get last instruction.
+ assert(insn);
+ if(insn->GetIBTargets())
+ {
+ for_each(insn->GetIBTargets()->begin(), insn->GetIBTargets()->end(), [this,&insn2block_map,func](Instruction_t* target)
+ {
+ if(is_in_container(insn2block_map,target) && target!=func->GetEntryPoint()) // don't link calls to the entry block.
+ {
+ BasicBlock_t* target_block=find_map_object(insn2block_map,target);
+ target_block->GetPredecessors().insert(this);
+ successors.insert(target_block);
+ }
+ });
+ }
}
diff --git a/libIRDB/src/cfg/CFG.cpp b/libIRDB/src/cfg/CFG.cpp
index 3203c947c..2e1b80c83 100644
--- a/libIRDB/src/cfg/CFG.cpp
+++ b/libIRDB/src/cfg/CFG.cpp
@@ -139,7 +139,18 @@ void ControlFlowGraph_t::Build(Function_t* func)
ostream& libIRDB::operator<<(ostream& os, const ControlFlowGraph_t& cfg)
{
int i=0;
+
+ map<BasicBlock_t*,int> blk_numbers;
+ for(
+ set<BasicBlock_t*>::const_iterator it=cfg.blocks.begin();
+ it!=cfg.blocks.end();
+ ++it
+ )
+ {
+ blk_numbers[*it]=i++;
+ }
+
for(
set<BasicBlock_t*>::const_iterator it=cfg.blocks.begin();
it!=cfg.blocks.end();
@@ -152,11 +163,21 @@ ostream& libIRDB::operator<<(ostream& os, const ControlFlowGraph_t& cfg)
os<<"**** Entry ";
else
os<<"---- NotEntry ";
- os<<"block "<<std::dec<<i<<endl;
- i++;
-
+ os<<"block "<<std::dec<<blk_numbers[block]<<endl;
+ os<<"Successors: ";
+ for_each(block->GetSuccessors().begin(), block->GetSuccessors().end(), [&](BasicBlock_t* succ)
+ {
+ os<<blk_numbers[succ]<<", ";
+
+ });
+ os<<endl;
+ os<<"Predecessors: ";
+ for_each(block->GetPredecessors().begin(), block->GetPredecessors().end(), [&](BasicBlock_t* pred)
+ {
+ os<<blk_numbers[pred]<<", ";
+ });
+ os<<endl;
os << *block;
-
}
return os;
diff --git a/libIRDB/src/cfg/SConscript b/libIRDB/src/cfg/SConscript
index ad91f9943..572af8276 100644
--- a/libIRDB/src/cfg/SConscript
+++ b/libIRDB/src/cfg/SConscript
@@ -8,7 +8,7 @@ myenv.Replace(SECURITY_TRANSFORMS_HOME=os.environ['SECURITY_TRANSFORMS_HOME'])
libname="IRDB-cfg"
files= '''
- BasicBlock.cpp callgraph.cpp CFG.cpp
+ BasicBlock.cpp callgraph.cpp CFG.cpp domgraph.cpp
'''
cpppath='''
$SECURITY_TRANSFORMS_HOME/include/
@@ -18,6 +18,7 @@ cpppath='''
'''
#myenv.Append(CCFLAGS=" -Wall -W -Wextra -Wconversion ")
+myenv.Append(CCFLAGS=" -Wall -W -Wextra -Wconversion -std=c++11")
myenv=myenv.Clone(CPPPATH=Split(cpppath))
lib=myenv.Library(libname, Split(files))
diff --git a/libIRDB/test/fix_calls.cpp b/libIRDB/test/fix_calls.cpp
index 533dc8889..b96895c2e 100644
--- a/libIRDB/test/fix_calls.cpp
+++ b/libIRDB/test/fix_calls.cpp
@@ -677,6 +677,15 @@ void fix_call(Instruction_t* insn, FileIR_t *firp, bool can_unpin)
}
}
+
+ // mark in the IR what the fallthrough of this insn is.
+ Relocation_t* fix_call_reloc=new Relocation_t();
+ fix_call_reloc->SetOffset(0);
+ fix_call_reloc->SetType("fix_call_fallthrough");
+ fix_call_reloc->SetWRT(newindirtarg);
+ callinsn->GetRelocations().insert(fix_call_reloc);
+ firp->GetRelocations().insert(fix_call_reloc);
+
}
--
GitLab