[LowerTypeTests] Limit when icall jumptable entries are emitted

Summary:
Currently LowerTypeTests emits jumptable entries for all live external
and address-taken functions; however, we could limit the number of
functions that we emit entries for significantly.

For Cross-DSO CFI, we continue to emit jumptable entries for all
exported definitions.  In the non-Cross-DSO CFI case, we only need to
emit jumptable entries for live functions that are address-taken in live
functions. This ignores exported functions and functions that are only
address taken in dead functions. This change uses ThinLTO summary data
(now emitted for all modules during ThinLTO builds) to determine
address-taken and liveness info.

The logic for emitting jumptable entries is more conservative in the
regular LTO case because we don't have summary data in the case of
monolithic LTO builds; however, once summaries are emitted for all LTO
builds we can unify the Thin/monolithic LTO logic to only use summaries
to determine the liveness of address taking functions.

This change is a partial fix for PR37474. It reduces the build size for
nacl_helper by ~2-3%, the reduction is due to nacl_helper compiling in
lots of unused code and unused functions that are address taken in dead
functions no longer being being considered live due to emitted jumptable
references. The reduction for chromium is ~0.1-0.2%.

Reviewers: pcc, eugenis, javed.absar

Reviewed By: pcc

Subscribers: aheejin, dexonsmith, dschuff, mehdi_amini, eraman, steven_wu, llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D47652

llvm-svn: 337038

9 files changed, 143 insertions, 32 deletions

diff --git a/llvm/test/Transforms/LowerTypeTests/Inputs/export-icall.yaml b/llvm/test/Transforms/LowerTypeTests/Inputs/export-icall.yaml
new file mode 100644
index 00000000000..b85cfd2eb00
--- /dev/null
+++ b/llvm/test/Transforms/LowerTypeTests/Inputs/export-icall.yaml
@@ -0,0 +1,29 @@
+---
+GlobalValueMap:
+  42:
+    - Live: true
+      # guid("f"), guid("f2"), guid("f3"), guid("g"), guid("h"), guid("external"), guid("external_weak")
+      Refs: [14740650423002898831, 8471399308421654326, 4197650231481825559, 13146401226427987378, 8124147457056772133, 5224464028922159466, 5227079976482001346]
+      TypeTests: [14276520915468743435, 15427464259790519041] # guid("typeid1"), guid("typeid2")
+  14740650423002898831: # guid("f")
+    - Linkage: 0 # external
+      Live: true
+  8471399308421654326: # guid("f2")
+    - Linkage: 0 # external
+      Live: true
+  4197650231481825559: # guid("f3")
+    - Linkage: 0 # external
+      Live: true
+  13146401226427987378: # guid("g")
+    - Linkage: 0 # external
+      Live: true
+  8124147457056772133: # guid("h")
+    - Linkage: 0 # external
+      Live: true
+  5224464028922159466: # guid("external")
+    - Linkage: 0 # external
+      Live: true
+  5227079976482001346: # guid("external_weak")
+    - Linkage: 9 # extern_weak
+      Live: true
+...
diff --git a/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml b/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml
new file mode 100644
index 00000000000..5457e36573b
--- /dev/null
+++ b/llvm/test/Transforms/LowerTypeTests/Inputs/exported-funcs.yaml
@@ -0,0 +1,22 @@
+---
+GlobalValueMap:
+  42:
+    - Live: true
+      Refs: [16594175687743574550, 2415377257478301385] # guid("external_addrtaken"), guid("external_addrtaken2")
+      TypeTests: [14276520915468743435, 15427464259790519041] # guid("typeid1"), guid("typeid2")
+  5224464028922159466: # guid("external")
+    - Linkage: 0 # external
+      Live: true
+  16430208882958242304: # guid("external2")
+    - Linkage: 0 # external
+      Live: true
+  16594175687743574550: # guid("external_addrtaken")
+    - Linkage: 0 # external
+      Live: true
+  2415377257478301385: # guid("external_addrtaken2")
+    - Linkage: 0 # external
+      Live: true
+  15859245615183425489: # guid("internal")
+    - Linkage: 7 # internal
+      Live: true
+...
diff --git a/llvm/test/Transforms/LowerTypeTests/export-alias.ll b/llvm/test/Transforms/LowerTypeTests/export-alias.ll
index 6e9c074068d..2ad8835475b 100644
--- a/llvm/test/Transforms/LowerTypeTests/export-alias.ll
+++ b/llvm/test/Transforms/LowerTypeTests/export-alias.ll
@@ -1,21 +1,21 @@
-; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/use-typeid1-typeid2.yaml | FileCheck %s
+; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml | FileCheck %s
 ;
-; CHECK: @alias1 = weak alias void (), void ()* @f
-; CHECK: @alias2 = hidden alias void (), void ()* @f
-; CHECK: declare !type !1 void @alias3()
+; CHECK: @alias1 = weak alias void (), void ()* @external_addrtaken
+; CHECK: @alias2 = hidden alias void (), void ()* @external_addrtaken
 ; CHECK-NOT: @alias3 = alias
+; CHECK-NOT: @not_present
 
 target triple = "x86_64-unknown-linux"
 
 !cfi.functions = !{!0, !2, !3}
 !aliases = !{!4, !5, !6}
 
-!0 = !{!"f", i8 0, !1}
+!0 = !{!"external_addrtaken", i8 0, !1}
 !1 = !{i64 0, !"typeid1"}
 !2 = !{!"alias1", i8 1, !1}
 ; alias2 not included here, this could happen if the only reference to alias2
 ; is in a module compiled without cfi-icall
 !3 = !{!"alias3", i8 1, !1}
-!4 = !{!"alias1", !"f", i8 0, i8 1}
-!5 = !{!"alias2", !"f", i8 1, i8 0}
+!4 = !{!"alias1", !"external_addrtaken", i8 0, i8 1}
+!5 = !{!"alias2", !"external_addrtaken", i8 1, i8 0}
 !6 = !{!"alias3", !"not_present", i8 0, i8 0}
diff --git a/llvm/test/Transforms/LowerTypeTests/export-cross-dso-cfi.ll b/llvm/test/Transforms/LowerTypeTests/export-cross-dso-cfi.ll
new file mode 100644
index 00000000000..c3b01ffda21
--- /dev/null
+++ b/llvm/test/Transforms/LowerTypeTests/export-cross-dso-cfi.ll
@@ -0,0 +1,39 @@
+; Test that external functions have jumptable entries emitted even if they are
+; not address-taken when Cross-DSO CFI is used, but not otherwise.
+
+; RUN: opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml < %s | FileCheck --check-prefixes=CHECK,CROSSDSO %s
+; RUN: cat %s | grep -v "llvm.module.flags" | opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml | FileCheck --check-prefixes=CHECK,NORMAL %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+;;; Defined in the ThinLTO portion of the build (e.g. the summary)
+; CROSSDSO: declare !type !1 !type !2 hidden void @external.cfi()
+; NORMAL: declare !type !1 !type !2 void @external()
+declare !type !1 !type !2 void @external()
+
+; Don't emit jumptable entries for external declarations/non-external definitions
+; CHECK-NOT: @external2
+; CHECK-NOT: @internal
+
+;;; Defined in the regular LTO portion of the build
+; CROSSDSO: define hidden void @regularlto_external.cfi()
+; NORMAL: define void @regularlto_external()
+define void @regularlto_external() !type !1 !type !2 {
+  ret void
+}
+
+; CHECK: define internal void @regularlto_internal()
+define internal void @regularlto_internal() !type !1 !type !2 {
+  ret void
+}
+
+!cfi.functions = !{!0, !3, !4}
+!llvm.module.flags = !{!5}
+
+!0 = !{!"external", i8 0, !1, !2}
+!1 = !{i64 0, !"typeid1"}
+!2 = !{i64 0, i64 1234}
+!3 = !{!"external2", i8 1, !1, !2}
+!4 = !{!"internal", i8 0, !1, !2}
+!5 = !{i32 4, !"Cross-DSO CFI", i32 1}
diff --git a/llvm/test/Transforms/LowerTypeTests/export-icall.ll b/llvm/test/Transforms/LowerTypeTests/export-icall.ll
index 35971809deb..54c2f568b60 100644
--- a/llvm/test/Transforms/LowerTypeTests/export-icall.ll
+++ b/llvm/test/Transforms/LowerTypeTests/export-icall.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/use-typeid1-typeid2.yaml -lowertypetests-write-summary=%t < %s | FileCheck %s
+; RUN: opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/export-icall.yaml -lowertypetests-write-summary=%t < %s | FileCheck %s
 ; RUN: FileCheck --check-prefix=SUMMARY %s < %t
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
diff --git a/llvm/test/Transforms/LowerTypeTests/export-symver.ll b/llvm/test/Transforms/LowerTypeTests/export-symver.ll
index e2b58fcbb44..82ec9a9109a 100644
--- a/llvm/test/Transforms/LowerTypeTests/export-symver.ll
+++ b/llvm/test/Transforms/LowerTypeTests/export-symver.ll
@@ -1,16 +1,16 @@
-; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/use-typeid1-typeid2.yaml | FileCheck %s
+; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml | FileCheck %s
 ;
-; CHECK: module asm ".symver exported_and_symver, alias1"
-; CHECK-NOT: .symver exported
-; CHECK-NOT: .symver symver
+; CHECK: module asm ".symver external_addrtaken, alias1"
+; CHECK-NOT: .symver external_addrtaken2
+; CHECK-NOT: .symver not_exported
 
 target triple = "x86_64-unknown-linux"
 
 !cfi.functions = !{!0, !1}
 !symvers = !{!3, !4}
 
-!0 = !{!"exported_and_symver", i8 2, !2}
-!1 = !{!"exported", i8 2, !2}
+!0 = !{!"external_addrtaken", i8 0, !2}
+!1 = !{!"external_addrtaken2", i8 0, !2}
 !2 = !{i64 0, !"typeid1"}
-!3 = !{!"exported_and_symver", !"alias1"}
-!4 = !{!"symver", !"alias2"}
+!3 = !{!"external_addrtaken", !"alias1"}
+!4 = !{!"not_exported", !"alias2"}
diff --git a/llvm/test/Transforms/LowerTypeTests/function-arm-thumb.ll b/llvm/test/Transforms/LowerTypeTests/function-arm-thumb.ll
index 0e92207a27f..8a205f4e683 100644
--- a/llvm/test/Transforms/LowerTypeTests/function-arm-thumb.ll
+++ b/llvm/test/Transforms/LowerTypeTests/function-arm-thumb.ll
@@ -22,6 +22,12 @@ define void @h2() "target-features"="-thumb-mode" !type !1 {
   ret void
 }
 
+declare void @takeaddr(void()*, void()*, void()*, void()*, void()*)
+define void @addrtaken() {
+  call void @takeaddr(void()* @f1, void()* @g1, void()* @f2, void()* @g2, void()* @h2)
+  ret void
+}
+
 !0 = !{i32 0, !"typeid1"}
 !1 = !{i32 0, !"typeid2"}
 
diff --git a/llvm/test/Transforms/LowerTypeTests/function-ext.ll b/llvm/test/Transforms/LowerTypeTests/function-ext.ll
index f6191e9e09a..3b256e3d8a9 100644
--- a/llvm/test/Transforms/LowerTypeTests/function-ext.ll
+++ b/llvm/test/Transforms/LowerTypeTests/function-ext.ll
@@ -1,26 +1,41 @@
-; RUN: opt -S -lowertypetests -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck --check-prefix=X64 %s
-; RUN: opt -S -lowertypetests -mtriple=wasm32-unknown-unknown < %s | FileCheck --check-prefix=WASM32 %s
+; RUN: opt -S -lowertypetests -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck --check-prefixes=CHECK,X64 %s
+; RUN: opt -S -lowertypetests -mtriple=wasm32-unknown-unknown < %s | FileCheck --check-prefixes=CHECK,WASM32 %s
 
 ; Tests that we correctly handle external references, including the case where
 ; all functions in a bitset are external references.
 
 ; WASM32: private constant [0 x i8] zeroinitializer
 
-; WASM32: declare !type !{{[0-9]+}} void @foo()
-declare !type !0 void @foo()
+; WASM32: declare !type !{{[0-9]+}} !wasm.index !{{[0-9]+}} void @foo1()
+declare !type !0 void @foo1()
+; WASM32: declare !type !{{[0-9]+}} void @foo2()
+declare !type !1 void @foo2()
 
+; CHECK-LABEL: @bar
 define i1 @bar(i8* %ptr) {
-  ; X64: icmp eq i64 {{.*}}, ptrtoint (void ()* @[[JT:.*]] to i64)
-  ; WASM32: ret i1 false
-  %p = call i1 @llvm.type.test(i8* %ptr, metadata !"void")
+  ; CHECK: %[[ICMP:[0-9]+]] = icmp eq
+  ; CHECK: ret i1 %[[ICMP]]
+  %p = call i1 @llvm.type.test(i8* %ptr, metadata !"type1")
   ret i1 %p
 }
 
+; CHECK-LABEL: @baz
+define i1 @baz(i8* %ptr) {
+  ; CHECK: ret i1 false
+  %p = call i1 @llvm.type.test(i8* %ptr, metadata !"type2")
+  ret i1 %p
+}
+
+; CHECK-LABEL: @addrtaken
+define void()* @addrtaken() {
+  ; X64: ret void ()* @[[JT:.*]]
+  ret void()* @foo1
+}
+
 declare i1 @llvm.type.test(i8* %ptr, metadata %bitset) nounwind readnone
 
-!0 = !{i64 0, !"void"}
-; WASM-NOT: !{i64 0}
-; WASM-NOT: !{i64 1}
+!0 = !{i64 0, !"type1"}
+!1 = !{i64 0, !"type2"}
 
 ; X64: define private void @[[JT]]() #{{.*}} align {{.*}} {
-; X64:   call void asm sideeffect "jmp ${0:c}@plt\0Aint3\0Aint3\0Aint3\0A", "s"(void ()* @foo)
+; X64:   call void asm sideeffect "jmp ${0:c}@plt\0Aint3\0Aint3\0Aint3\0A", "s"(void ()* @foo1)
diff --git a/llvm/test/Transforms/LowerTypeTests/pr37625.ll b/llvm/test/Transforms/LowerTypeTests/pr37625.ll
index e4b704eadb3..04952ed2b6d 100644
--- a/llvm/test/Transforms/LowerTypeTests/pr37625.ll
+++ b/llvm/test/Transforms/LowerTypeTests/pr37625.ll
@@ -1,14 +1,14 @@
-; RUN: opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/use-typeid1-typeid2.yaml -lowertypetests-write-summary=%t < %s | FileCheck %s
+; RUN: opt -S -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/exported-funcs.yaml -lowertypetests-write-summary=%t < %s | FileCheck %s
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-declare !type !2 extern_weak void @h(i8)
+declare !type !2 extern_weak void @external_addrtaken(i8)
 
 !cfi.functions = !{!0, !1}
 
-!0 = !{!"h", i8 2, !2}
-!1 = !{!"h", i8 0, !2}
+!0 = !{!"external_addrtaken", i8 2, !2}
+!1 = !{!"external_addrtaken", i8 0, !2}
 !2 = !{i64 0, !"typeid1"}
 
-; CHECK-DAG: @h = alias void (i8), bitcast
+; CHECK-DAG: @external_addrtaken = alias void (i8), bitcast