Subzero: Also dump live-end info for stack vars under -asm-verbose.

It's sometimes useful to know whether a use of a stack variable (as opposed to a physical register) is the last use of that variable. For example, in a code sequence like: movl %edx, 24(%esp) movl 24(%esp), %edx it would be nice to know whether the code sequence is merely bad (i.e., 24(%esp) will be used later), or horrible (i.e., this ends 24(%esp)'s live range). We add stack variables to the per-instruction live-range-end annotation, but not to the per-block live-in and live-out annotations, because the latter would clutter the output greatly while adding very little actionable information. BUG= https://code.google.com/p/nativeclient/issues/detail?id=4135 R=jvoung@chromium.org Review URL: https://codereview.chromium.org/1113133002

Subzero: Also dump live-end info for stack vars under -asm-verbose.
4175b2a6 · Jim Stichnoth · 76dcf1a8 · 4175b2a6
Commit 4175b2a6 authored Apr 30, 2015 by Jim Stichnoth
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Showing with 10 additions and 7 deletions

IceCfgNode.cpp src/IceCfgNode.cpp +10 -7

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--- a/src/IceCfgNode.cpp
+++ b/src/IceCfgNode.cpp
@@ -824,8 +824,8 @@ void emitLiveRangesEnded(Ostream &Str, const Cfg *Func, const Inst *Instr,
    SizeT NumVars = Src->getNumVars();
    for (SizeT J = 0; J < NumVars; ++J) {
      const Variable *Var = Src->getVar(J);
-      if (Var->hasReg()) {
+      if (Instr->isLastUse(Var) &&
-        if (Instr->isLastUse(Var) && --LiveRegCount[Var->getRegNum()] == 0) {
+          (!Var->hasReg() || --LiveRegCount[Var->getRegNum()] == 0)) {
        if (First)
          Str << " \t# END=";
        else
@@ -835,7 +835,6 @@ void emitLiveRangesEnded(Ostream &Str, const Cfg *Func, const Inst *Instr,
      }
    }
  }
-  }
 }
 void updateStats(Cfg *Func, const Inst *I) {
@@ -870,8 +869,10 @@ void CfgNode::emit(Cfg *Func) const {
      Liveness && Func->getContext()->getFlags().getDecorateAsm();
  Str << getAsmName() << ":\n";
  std::vector<SizeT> LiveRegCount(Func->getTarget()->getNumRegisters());
-  if (DecorateAsm)
+  if (DecorateAsm) {
-    emitRegisterUsage(Str, Func, this, true, LiveRegCount);
+    const bool IsLiveIn = true;
+    emitRegisterUsage(Str, Func, this, IsLiveIn, LiveRegCount);
+  }
  for (const Inst &I : Phis) {
    if (I.isDeleted())
@@ -894,8 +895,10 @@ void CfgNode::emit(Cfg *Func) const {
    Str << "\n";
    updateStats(Func, &I);
  }
-  if (DecorateAsm)
+  if (DecorateAsm) {
-    emitRegisterUsage(Str, Func, this, false, LiveRegCount);
+    const bool IsLiveIn = false;
+    emitRegisterUsage(Str, Func, this, IsLiveIn, LiveRegCount);
+  }
 }
 // Helper class for emitIAS().