Iasm and obj lowering for advanced switch lowering.
Jump table emission is delayed until offsets are known. X86 local jumps can be
near or far. Sanboxing is applied to indirect jumps from jump table.
BUG=
R=stichnot@chromium.org, jvoung
Review URL: https://codereview.chromium.org/1257283004.
diff --git a/src/IceSwitchLowering.h b/src/IceSwitchLowering.h
index 5dfcec3..34c9373 100644
--- a/src/IceSwitchLowering.h
+++ b/src/IceSwitchLowering.h
@@ -14,8 +14,7 @@
#ifndef SUBZERO_SRC_ICESWITCHLOWERING_H
#define SUBZERO_SRC_ICESWITCHLOWERING_H
-#include "IceCfgNode.h"
-#include "IceInst.h"
+#include "IceDefs.h"
namespace Ice {
@@ -38,8 +37,8 @@
CaseCluster &operator=(const CaseCluster &) = default;
/// Create a cluster of a single case represented by a unitary range.
- CaseCluster(uint64_t Value, CfgNode *Label)
- : Kind(Range), Low(Value), High(Value), Label(Label) {}
+ CaseCluster(uint64_t Value, CfgNode *Target)
+ : Kind(Range), Low(Value), High(Value), Target(Target) {}
/// Create a case consisting of a jump table.
CaseCluster(uint64_t Low, uint64_t High, InstJumpTable *JT)
: Kind(JumpTable), Low(Low), High(High), JT(JT) {}
@@ -47,15 +46,18 @@
CaseClusterKind getKind() const { return Kind; }
uint64_t getLow() const { return Low; }
uint64_t getHigh() const { return High; }
- CfgNode *getLabel() const {
+ CfgNode *getTarget() const {
assert(Kind == Range);
- return Label;
+ return Target;
}
InstJumpTable *getJumpTable() const {
assert(Kind == JumpTable);
return JT;
}
+ bool isUnitRange() const { return Low == High; }
+ bool isPairRange() const { return Low == High - 1; }
+
/// Discover cases which can be clustered together and return the clusters
/// ordered by case value.
static CaseClusterArray clusterizeSwitch(Cfg *Func, const InstSwitch *Inst);
@@ -65,7 +67,7 @@
uint64_t Low;
uint64_t High;
union {
- CfgNode *Label; /// Target for a range.
+ CfgNode *Target; /// Target for a range.
InstJumpTable *JT; /// Jump table targets.
};
@@ -73,6 +75,36 @@
bool tryAppend(const CaseCluster &New);
};
+/// Store the jump table data so that it can be emitted later in the correct
+/// ELF section once the offsets from the start of the function are known.
+class JumpTableData {
+ JumpTableData() = delete;
+ JumpTableData(const JumpTableData &) = delete;
+ JumpTableData &operator=(const JumpTableData &) = delete;
+
+public:
+ JumpTableData(IceString FuncName, SizeT Id, SizeT NumTargets)
+ : FuncName(FuncName), Id(Id) {
+ TargetOffsets.reserve(NumTargets);
+ }
+ JumpTableData(JumpTableData &&) = default;
+
+ void pushTarget(intptr_t Offset) { TargetOffsets.emplace_back(Offset); }
+
+ const IceString &getFunctionName() const { return FuncName; }
+ SizeT getId() const { return Id; }
+ const std::vector<intptr_t> &getTargetOffsets() const {
+ return TargetOffsets;
+ }
+
+private:
+ const IceString FuncName;
+ const SizeT Id;
+ std::vector<intptr_t> TargetOffsets;
+};
+
+using JumpTableDataList = std::vector<JumpTableData>;
+
} // end of namespace Ice
#endif // SUBZERO_SRC_ICESWITCHLOWERING_H
