From 28f514acfeec1dd105d663d9c3d269fa46dd002e Mon Sep 17 00:00:00 2001
From: clc5q <clc5q@git.zephyr-software.com>
Date: Mon, 11 Jan 2016 16:05:28 +0000
Subject: [PATCH] Detect chains of tail calls that cause return to orphaned
code.
Former-commit-id: dbfd0f99ba3a6c364d9a639af771b1b143470144
---
include/base/SMPFunction.h | 3 +++
src/base/SMPFunction.cpp | 10 +++++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/base/SMPFunction.h b/include/base/SMPFunction.h
index f4310796..de25c986 100644
--- a/include/base/SMPFunction.h
+++ b/include/base/SMPFunction.h
@@ -295,6 +295,7 @@ public:
inline void SetIsSpeculative(bool IsS) { IsSpeculative = IsS; };
inline void SetIsMutuallyRecursive(void) { MutuallyRecursive = true; };
inline void SetIsCalledFromOrphanedCode(void) { CalledFromOrphanCode = true; };
+ inline void SetIsTailCallChainFromOrphanedCode(void) { TailCallChainFromOrphanCode = true; };
inline void SetHasHashingCode(bool Hashes) { HasHashingCode = Hashes; };
void AddCallSource(STARS_ea_t addr); // Add a caller to the list of all callers of this function.
bool AddDirectCallTarget(STARS_ea_t addr); // Add a direct call target; return true if new target, false if target already added
@@ -384,6 +385,7 @@ public:
inline bool IsRegPreserved(std::size_t RegNum) const { return (PreservedRegsBitmap[RegNum] != 0); };
inline bool IsPossibleIndirectCallTarget(void) const { return PossibleIndirectCallTarget; };
inline bool IsCalledFromOrphanedCode(void) const { return CalledFromOrphanCode; };
+ inline bool IsTailCallChainFromOrphanedCode(void) const { return TailCallChainFromOrphanCode; };
// Printing methods
void Dump(void); // debug dump
@@ -465,6 +467,7 @@ private:
bool UnsharedChunks; // Does function have noncontiguous fragments that are not shared with other funcs?
bool MultipleEntryPoints; // Does function have multiple entry points from other functions?
bool CalledFromOrphanCode; // function is called from orphaned code, so program CFG is not complete at this function.
+ bool TailCallChainFromOrphanCode; // Part of chain orphancode ... func.. tailcallsfunc2 ... which can return to orphaned code
bool CallsAlloca; // Does function allocate stack space after initial allocation? NOTE:SMPInstr::IsAllocaCall() excludes immediate value alloca calls
bool PushAfterLocalVarAlloc; // Does function push onto the stack after allocating local var space?
bool LinkerStub; // Is function just a stub to be filled in by the linker, e.g. a PLT stub?
diff --git a/src/base/SMPFunction.cpp b/src/base/SMPFunction.cpp
index 1e789c18..724815aa 100644
--- a/src/base/SMPFunction.cpp
+++ b/src/base/SMPFunction.cpp
@@ -159,6 +159,7 @@ SMPFunction::SMPFunction(STARS_Function_t *Info, SMPProgram* pgm) {
this->UnsharedChunks = false;
this->MultipleEntryPoints = false;
this->CalledFromOrphanCode = false;
+ this->TailCallChainFromOrphanCode = false;
this->CallsAlloca = false;
this->PushAfterLocalVarAlloc = false;
this->LinkerStub = false;
@@ -9227,6 +9228,9 @@ bool SMPFunction::ComputeReturnTargets(bool FirstIteration) {
IncompleteCaller = true;
UnresolvedCallers.insert(CallingFunc);
}
+ if (CallingFunc->IsCalledFromOrphanedCode() || CallingFunc->IsTailCallChainFromOrphanedCode()) {
+ this->SetIsTailCallChainFromOrphanedCode();
+ }
}
else if (STARS_LIVEIN_PSEUDO_ID == FallThroughAddr) { // error case; could not find fall-through
this->ReturnTargetsComputed = true;
@@ -9262,6 +9266,9 @@ bool SMPFunction::ComputeReturnTargets(bool FirstIteration) {
IncompleteCaller = true;
UnresolvedCallers.insert(CallingFunc);
}
+ if (CallingFunc->IsCalledFromOrphanedCode() || CallingFunc->IsTailCallChainFromOrphanedCode()) {
+ this->SetIsTailCallChainFromOrphanedCode();
+ }
}
}
this->ReturnTargetsComputed = (!IncompleteCaller);
@@ -9601,6 +9608,7 @@ void SMPFunction::EmitAnnotations(FILE *AnnotFile, FILE *InfoAnnotFile) {
// Emit Indirect Branch Target destinations for return instructions in this func.
void SMPFunction::EmitReturnTargetAnnotations(void) {
if (!this->ReturnTargets.empty()) {
+ bool OrphanCodeProblem = (this->IsCalledFromOrphanedCode() || this->IsTailCallChainFromOrphanedCode());
for (size_t BlockIndex = 0; BlockIndex < this->RPOBlocks.size(); ++BlockIndex) {
SMPBasicBlock *CurrBlock = this->RPOBlocks[BlockIndex];
if (CurrBlock->HasReturn()) {
@@ -9617,7 +9625,7 @@ void SMPFunction::EmitReturnTargetAnnotations(void) {
bool TailCallFlag = (this->TailReturnTargets.find(RetTargetAddr) != this->TailReturnTargets.end());
global_STARS_program->PrintReturnInstXref(ReturnInstAddr, RetTargetAddr, RetInstSize, TailCallFlag);
}
- if (!(this->PossibleIndirectCallTarget || this->MultipleEntryPoints || this->IsCalledFromOrphanedCode())) {
+ if (!(this->PossibleIndirectCallTarget || this->MultipleEntryPoints || OrphanCodeProblem)) {
global_STARS_program->PrintCodeToCodeXrefComplete(ReturnInstAddr, RetInstSize, this->ReturnTargets.size());
}
}
--
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