commit 77ce9d3b1a4675b7df00686b7157258d3a0324b7
author Michael Kuperstein <michael.m.kuperstein@intel.com> Sun Dec 06 13:06:20 2015 +0000
committer Michael Kuperstein <michael.m.kuperstein@intel.com> Sun Dec 06 13:06:20 2015 +0000
tree 5d88ee42fa6d8a61d561dd59cfb160c39bcc19f7
parent 076dfe5c12b029e9109bf898710d0296f6188f64

[X86] Always generate precise CFA adjustments.

This removes the code path that generate "synchronous" (only correct at call site) CFA.
We will probably want to re-introduce it once we are capable of emitting different
.eh_frame and .debug_frame sections.

Differential Revision: http://reviews.llvm.org/D14948

llvm-svn: 254874

llvm/lib/Target/X86/X86CallFrameOptimization.cpp

diff --git a/llvm/lib/Target/X86/X86CallFrameOptimization.cpp b/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
index 23990b0..fc6ee17 100644
--- a/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
+++ b/llvm/lib/Target/X86/X86CallFrameOptimization.cpp
@@ -500,7 +500,8 @@
 
     // For debugging, when using SP-based CFA, we need to adjust the CFA
     // offset after each push.
-    if (!TFL->hasFP(MF) && MF.getMMI().usePreciseUnwindInfo())
+    // TODO: This is needed only if we require precise CFA.
+    if (!TFL->hasFP(MF))
       TFL->BuildCFI(MBB, std::next(Push), DL, 
                     MCCFIInstruction::createAdjustCfaOffset(nullptr, 4));
 

llvm/lib/Target/X86/X86FrameLowering.cpp

diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index 682f75c..2e7ed58 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -2524,10 +2524,10 @@
     // (Pushes of argument for frame setup, callee pops for frame destroy)
     Amount -= InternalAmt;
 
-    // If this is a callee-pop calling convention, and we're emitting precise
-    // SP-based CFI, emit a CFA adjust for the amount the callee popped.
-    if (isDestroy && InternalAmt && DwarfCFI && !hasFP(MF) && 
-        MMI.usePreciseUnwindInfo())
+    // TODO: This is needed only if we require precise CFA.
+    // If this is a callee-pop calling convention, emit a CFA adjust for
+    // the amount the callee popped.
+    if (isDestroy && InternalAmt && DwarfCFI && !hasFP(MF))
       BuildCFI(MBB, I, DL, 
                MCCFIInstruction::createAdjustCfaOffset(nullptr, -InternalAmt));
 
@@ -2548,11 +2548,14 @@
       // offset to be correct at each call site, while for debugging we want
       // it to be more precise.
       int CFAOffset = Amount;
-      if (!MMI.usePreciseUnwindInfo())
-        CFAOffset += InternalAmt;
-      CFAOffset = isDestroy ? -CFAOffset : CFAOffset;
-      BuildCFI(MBB, I, DL, 
-               MCCFIInstruction::createAdjustCfaOffset(nullptr, CFAOffset));
+      // TODO: When not using precise CFA, we also need to adjust for the
+      // InternalAmt here.
+
+      if (CFAOffset) {
+        CFAOffset = isDestroy ? -CFAOffset : CFAOffset;
+        BuildCFI(MBB, I, DL, 
+                 MCCFIInstruction::createAdjustCfaOffset(nullptr, CFAOffset));
+      }
     }
 
     return;

llvm/lib/Target/X86/X86MCInstLower.cpp

diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index 8878c9f..af38680 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -1143,8 +1143,10 @@
     const X86FrameLowering* FrameLowering =
         MF->getSubtarget<X86Subtarget>().getFrameLowering();
     bool hasFP = FrameLowering->hasFP(*MF);
-
-    bool NeedsDwarfCFI = MMI->usePreciseUnwindInfo();
+    
+    // TODO: This is needed only if we require precise CFA.
+    bool NeedsDwarfCFI = 
+         (MMI->hasDebugInfo() || MF->getFunction()->needsUnwindTableEntry());
     int stackGrowth = -RI->getSlotSize();
 
     if (NeedsDwarfCFI && !hasFP) {