Duncan Sands b0f1e1780c Add a new codegen pass that normalizes dwarf exception handling ... code in preparation for code generation. The main thing it does is handle the case when eh.exception calls (and, in a future patch, eh.selector calls) are far away from landing pads. Right now in practice you only find eh.exception calls close to landing pads: either in a landing pad (the common case) or in a landing pad successor, due to loop passes shifting them about. However future exception handling improvements will result in calls far from landing pads: (1) Inlining of rewinds. Consider the following case: In function @f: ... invoke @g to label %normal unwind label %unwinds ... unwinds: %ex = call i8* @llvm.eh.exception() ... In function @g: ... invoke @something to label %continue unwind label %handler ... handler: %ex = call i8* @llvm.eh.exception() ... perform cleanups ... "rethrow exception" Now inline @g into @f. Currently this is turned into: In function @f: ... invoke @something to label %continue unwind label %handler ... handler: %ex = call i8* @llvm.eh.exception() ... perform cleanups ... invoke "rethrow exception" to label %normal unwind label %unwinds unwinds: %ex = call i8* @llvm.eh.exception() ... However we would like to simplify invoke of "rethrow exception" into a branch to the %unwinds label. Then %unwinds is no longer a landing pad, and the eh.exception call there is then far away from any landing pads. (2) Using the unwind instruction for cleanups. It would be nice to have codegen handle the following case: invoke @something to label %continue unwind label %run_cleanups ... handler: ... perform cleanups ... unwind This requires turning "unwind" into a library call, which necessarily takes a pointer to the exception as an argument (this patch also does this unwind lowering). But that means you are using eh.exception again far from a landing pad. (3) Bugpoint simplifications. When bugpoint is simplifying exception handling code it often generates eh.exception calls far from a landing pad, which then causes codegen to assert. Bugpoint then latches on to this assertion and loses sight of the original problem. Note that it is currently rare for this pass to actually do anything. And in fact it normally shouldn't do anything at all given the code coming out of llvm-gcc! But it does fire a few times in the testsuite. As far as I can see this is almost always due to the LoopStrengthReduce codegen pass introducing pointless loop preheader blocks which are landing pads and only contain a branch to another block. This other block contains an eh.exception call. So probably by tweaking LoopStrengthReduce a bit this can be avoided. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72276 91177308-0d34-0410-b5e6-96231b3b80d8		2009-05-22 20:36:31 +00:00
..
ADT	Add llvm::triple constructor from arch, vendor, os strings, and recognize	2009-05-22 02:24:11 +00:00
Analysis	Fix broken logic in DominatorTreeBase::Split. Part of PR4238.	2009-05-21 21:47:54 +00:00
Assembly
Bitcode	give bitstreamreader an API to ignore names for blocks/records,	2009-04-27 20:04:08 +00:00
CodeGen	Add a new codegen pass that normalizes dwarf exception handling	2009-05-22 20:36:31 +00:00
CompilerDriver
Config	Forgot this file in my last commit.	2009-05-19 22:25:55 +00:00
Debugger
ExecutionEngine	Allow the JIT ExecutionEngine to report details about the generated machine code.	2009-05-18 21:06:40 +00:00
Support	Add an accessor method to return the insertion point.	2009-05-20 21:45:41 +00:00
System	Use DataTypes.h instead of stdint.h.	2009-05-21 00:48:13 +00:00
Target	Run code placement optimization for targets that want it (arm and x86 for now).	2009-05-13 21:42:09 +00:00
Transforms	Re-apply 70645, converting ScalarEvolution to use	2009-05-04 22:30:44 +00:00
AbstractTypeUser.h
Argument.h
Attributes.h
AutoUpgrade.h
BasicBlock.h
CallGraphSCCPass.h
CallingConv.h
CMakeLists.txt
Constant.h
Constants.h	Add a getAlignOf helper for getting the ABI alignment of a	2009-05-21 15:52:21 +00:00
DerivedTypes.h
Function.h
GlobalAlias.h
GlobalValue.h
GlobalVariable.h
InlineAsm.h
InstrTypes.h
Instruction.def
Instruction.h	Allow readonly functions to unwind exceptions. Teach	2009-05-06 06:49:50 +00:00
Instructions.h	Remove getType() overrides for ExtractValueInst and InsertValueInst.	2009-05-18 18:46:57 +00:00
IntrinsicInst.h
Intrinsics.h
Intrinsics.td	Update the names of the exception handling sjlj instrinsics to	2009-05-14 00:46:35 +00:00
IntrinsicsAlpha.td
IntrinsicsARM.td
IntrinsicsCellSPU.td
IntrinsicsPowerPC.td
IntrinsicsX86.td
IntrinsicsXCore.td
LinkAllPasses.h
LinkAllVMCore.h
Linker.h
MDNode.h	Needed #includes. Thanks Fritz van Bommel!	2009-05-10 23:27:41 +00:00
Module.h
ModuleProvider.h
OperandTraits.h
Pass.h
PassAnalysisSupport.h
PassManager.h
PassManagers.h
PassSupport.h
SymbolTableListTraits.h
Type.h
TypeSymbolTable.h
Use.h	Add a comment to refer to the section of the programmer's manual that explains what the pointer tagging in Use is for.	2009-04-30 23:28:50 +00:00
User.h
Value.h
ValueSymbolTable.h