[llvm] r213805 - ArgPromo+DebugInfo: Handle updating debug info over multiple applications of argument promotion.

[David Blaikie]

Author: dblaikie
Date: Wed Jul 23 17:09:29 2014
New Revision: 213805

URL: http://llvm.org/viewvc/llvm-project?rev=213805&view=rev
Log:
ArgPromo+DebugInfo: Handle updating debug info over multiple applications of argument promotion.

While the subprogram map cache used by Dead Argument Elimination works
there, I made a mistake when reusing it for Argument Promotion in
r212128 because ArgPromo may transform functions more than once whereas
DAE transforms each function only once, removing all the dead arguments
in one go.

To address this, ensure that the map is updated after each argument
promotion.

In retrospect it might be a little wasteful to create a map of all
subprograms when only handling a single CGSCC, but the alternative is
walking the debug info for each function in the CGSCC that gets updated.
It's not clear to me what the right tradeoff is there, but since the
current tradeoff seems to be working OK (and the code to keep things
updated is very cheap), let's stick with that for now.

Modified:
    llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp
    llvm/trunk/test/Transforms/ArgumentPromotion/dbg.ll

Modified: llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp?rev=213805&r1=213804&r2=213805&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/ArgumentPromotion.cpp Wed Jul 23 17:09:29 2014
@@ -615,9 +615,13 @@ CallGraphNode *ArgPromotion::DoPromotion
 
   // Patch the pointer to LLVM function in debug info descriptor.
   auto DI = FunctionDIs.find(F);
-  if (DI != FunctionDIs.end())
-    DI->second.replaceFunction(NF);
-  
+  if (DI != FunctionDIs.end()) {
+    DISubprogram SP = DI->second;
+    SP.replaceFunction(NF);
+    FunctionDIs.erase(DI);
+    FunctionDIs[NF] = SP;
+  }
+
   DEBUG(dbgs() << "ARG PROMOTION:  Promoting to:" << *NF << "\n"
         << "From: " << *F);
   

Modified: llvm/trunk/test/Transforms/ArgumentPromotion/dbg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ArgumentPromotion/dbg.ll?rev=213805&r1=213804&r2=213805&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ArgumentPromotion/dbg.ll (original)
+++ llvm/trunk/test/Transforms/ArgumentPromotion/dbg.ll Wed Jul 23 17:09:29 2014
@@ -4,14 +4,15 @@
 
 declare void @sink(i32)
 
-define internal void @test(i32* %X) {
-  %1 = load i32* %X, align 8
-  call void @sink(i32 %1)
+define internal void @test(i32** %X) {
+  %1 = load i32** %X, align 8
+  %2 = load i32* %1, align 8
+  call void @sink(i32 %2)
   ret void
 }
 
-define void @caller(i32* %Y) {
-  call void @test(i32* %Y)
+define void @caller(i32** %Y) {
+  call void @test(i32** %Y)
   ret void
 }
 
@@ -20,6 +21,6 @@ define void @caller(i32* %Y) {
 
 !0 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
 !1 = metadata !{i32 8, i32 0, metadata !2, null}
-!2 = metadata !{i32 786478, null, null, metadata !"test", metadata !"test", metadata !"", i32 3, null, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i32*)* @test, null, null, null, i32 3}
+!2 = metadata !{i32 786478, null, null, metadata !"test", metadata !"test", metadata !"", i32 3, null, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i32**)* @test, null, null, null, i32 3}
 !3 = metadata !{i32 786449, null, i32 4, metadata !"clang version 3.5.0 ", i1 false, metadata !"", i32 0, null, null, metadata !4, null, null, metadata !"", i32 2} ; [ DW_TAG_compile_unit ] [/usr/local/google/home/blaikie/dev/scratch/pr20038/reduce/<stdin>] [DW_LANG_C_plus_plus]
 !4 = metadata !{metadata !2}