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| author | Petar Jovanovic <petar.jovanovic@mips.com> | 2018-04-24 10:32:08 +0000 |
|---|---|---|
| committer | Petar Jovanovic <petar.jovanovic@mips.com> | 2018-04-24 10:32:08 +0000 |
| commit | e2bfcd6394e18e4cf04bc367758c4d667f43c97b (patch) | |
| tree | dd558314b418b8a9a92d90a56840612c82b4d3fc /llvm/test/CodeGen/X86/push-cfi-obj.ll | |
| parent | fce722e6f87f7b4825a7e9b4b1ff61fa69469d96 (diff) | |
| download | bcm5719-llvm-e2bfcd6394e18e4cf04bc367758c4d667f43c97b.tar.gz bcm5719-llvm-e2bfcd6394e18e4cf04bc367758c4d667f43c97b.zip | |
Correct dwarf unwind information in function epilogue
This patch aims to provide correct dwarf unwind information in function
epilogue for X86.
It consists of two parts. The first part inserts CFI instructions that set
appropriate cfa offset and cfa register in emitEpilogue() in
X86FrameLowering. This part is X86 specific.
The second part is platform independent and ensures that:
* CFI instructions do not affect code generation (they are not counted as
instructions when tail duplicating or tail merging)
* Unwind information remains correct when a function is modified by
different passes. This is done in a late pass by analyzing information
about cfa offset and cfa register in BBs and inserting additional CFI
directives where necessary.
Added CFIInstrInserter pass:
* analyzes each basic block to determine cfa offset and register are valid
at its entry and exit
* verifies that outgoing cfa offset and register of predecessor blocks match
incoming values of their successors
* inserts additional CFI directives at basic block beginning to correct the
rule for calculating CFA
Having CFI instructions in function epilogue can cause incorrect CFA
calculation rule for some basic blocks. This can happen if, due to basic
block reordering, or the existence of multiple epilogue blocks, some of the
blocks have wrong cfa offset and register values set by the epilogue block
above them.
CFIInstrInserter is currently run only on X86, but can be used by any target
that implements support for adding CFI instructions in epilogue.
Patch by Violeta Vukobrat.
Differential Revision: https://reviews.llvm.org/D42848
llvm-svn: 330706
Diffstat (limited to 'llvm/test/CodeGen/X86/push-cfi-obj.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/push-cfi-obj.ll | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/llvm/test/CodeGen/X86/push-cfi-obj.ll b/llvm/test/CodeGen/X86/push-cfi-obj.ll index 8b3c3adec2e..1371acb1db3 100644 --- a/llvm/test/CodeGen/X86/push-cfi-obj.ll +++ b/llvm/test/CodeGen/X86/push-cfi-obj.ll @@ -12,7 +12,7 @@ ; LINUX-NEXT: ] ; LINUX-NEXT: Address: 0x0 ; LINUX-NEXT: Offset: 0x5C -; LINUX-NEXT: Size: 64 +; LINUX-NEXT: Size: 72 ; LINUX-NEXT: Link: 0 ; LINUX-NEXT: Info: 0 ; LINUX-NEXT: AddressAlignment: 4 @@ -22,8 +22,9 @@ ; LINUX-NEXT: SectionData ( ; LINUX-NEXT: 0000: 1C000000 00000000 017A504C 5200017C |.........zPLR..|| ; LINUX-NEXT: 0010: 08070000 00000000 1B0C0404 88010000 |................| -; LINUX-NEXT: 0020: 1C000000 24000000 00000000 1D000000 |....$...........| +; LINUX-NEXT: 0020: 24000000 24000000 00000000 1D000000 |$...$...........| ; LINUX-NEXT: 0030: 04000000 00410E08 8502420D 05432E10 |.....A....B..C..| +; LINUX-NEXT: 0040: 540C0404 410C0508 |T...A...| ; LINUX-NEXT: ) declare i32 @__gxx_personality_v0(...) @@ -35,7 +36,7 @@ entry: to label %continue unwind label %cleanup continue: ret void -cleanup: +cleanup: landingpad { i8*, i32 } cleanup ret void |
