maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[AVR] Fix reads of uninitialized variables from constructor of AVRSubtarget 

The initialization order was not correct. These bugs were discovered by
valgrind. They appear to work fine in practice but this patch should
unblock switching the AVR backend on by default as now a standard AVR
llc invocation runs without memory errors.

The AVRISelLowering constructor would run before the subtarget boolean
fields were initialized to false. Now, the initialization order is
correct.
This commit is contained in:
Dylan McKay 2020-03-13 00:51:30 +13:00
parent d5edcb9064
commit 2cf4b4de0c
2 changed files with 11 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
llvm/lib/Target/AVR/AVRSubtarget.cpp
View File

@ -29,8 +29,8 @@ namespace llvm {
AVRSubtarget::AVRSubtarget(const Triple &TT, const std::string &CPU,
const std::string &FS, const AVRTargetMachine &TM)
: AVRGenSubtargetInfo(TT, CPU, FS), ELFArch(0), InstrInfo(), FrameLowering(),
TLInfo(TM, initializeSubtargetDependencies(CPU, FS, TM)), TSInfo(),
: AVRGenSubtargetInfo(TT, CPU, FS),
ELFArch(0),
// Subtarget features
m_hasSRAM(false), m_hasJMPCALL(false), m_hasIJMPCALL(false),
@ -38,7 +38,10 @@ AVRSubtarget::AVRSubtarget(const Triple &TT, const std::string &CPU,
m_hasMOVW(false), m_hasLPM(false), m_hasLPMX(false), m_hasELPM(false),
m_hasELPMX(false), m_hasSPM(false), m_hasSPMX(false), m_hasDES(false),
m_supportsRMW(false), m_supportsMultiplication(false), m_hasBREAK(false),
m_hasTinyEncoding(false), m_FeatureSetDummy(false) {
m_hasTinyEncoding(false), m_FeatureSetDummy(false),
InstrInfo(), FrameLowering(),
TLInfo(TM, initializeSubtargetDependencies(CPU, FS, TM)), TSInfo() {
// Parse features string.
ParseSubtargetFeatures(CPU, FS);
}

10
llvm/lib/Target/AVR/AVRSubtarget.h
View File

@ -85,11 +85,6 @@ private:
/// The ELF e_flags architecture.
unsigned ELFArch;
AVRInstrInfo InstrInfo;
AVRFrameLowering FrameLowering;
AVRTargetLowering TLInfo;
AVRSelectionDAGInfo TSInfo;
// Subtarget feature settings
// See AVR.td for details.
bool m_hasSRAM;
@ -114,6 +109,11 @@ private:
// Dummy member, used by FeatureSet's. We cannot have a SubtargetFeature with
// no variable, so we instead bind pseudo features to this variable.
bool m_FeatureSetDummy;
AVRInstrInfo InstrInfo;
AVRFrameLowering FrameLowering;
AVRTargetLowering TLInfo;
AVRSelectionDAGInfo TSInfo;
};
} // end namespace llvm