release/20.x: [AsmPrinter] Always emit global equivalents if there is non-global uses (#145648) #145690
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…es (llvm#145648) A case found from rust-lang/rust#142752: https://llvm.godbolt.org/z/T7ce9saWh. We should emit `@bar_0` for the following code: ```llvm target triple = "x86_64-unknown-linux-gnu" @rel_0 = private unnamed_addr constant [1 x i32] [ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_0 to i64), i64 ptrtoint (ptr @rel_0 to i64)) to i32)] @bar_0 = internal unnamed_addr constant ptr @foo_0, align 8 @foo_0 = external global ptr, align 8 define void @foo(ptr %arg0) { store ptr @bar_0, ptr %arg0, align 8 ret void } ``` (cherry picked from commit 630d55c)
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@nikic What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-mc Author: None (llvmbot) ChangesBackport 630d55c Requested by: @dianqk Full diff: https://github.com/llvm/llvm-project/pull/145690.diff 2 Files Affected:
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index e77abf429e6b4..c8f567e5f4195 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2139,16 +2139,20 @@ void AsmPrinter::emitFunctionBody() {
}
/// Compute the number of Global Variables that uses a Constant.
-static unsigned getNumGlobalVariableUses(const Constant *C) {
- if (!C)
+static unsigned getNumGlobalVariableUses(const Constant *C,
+ bool &HasNonGlobalUsers) {
+ if (!C) {
+ HasNonGlobalUsers = true;
return 0;
+ }
if (isa<GlobalVariable>(C))
return 1;
unsigned NumUses = 0;
for (const auto *CU : C->users())
- NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
+ NumUses +=
+ getNumGlobalVariableUses(dyn_cast<Constant>(CU), HasNonGlobalUsers);
return NumUses;
}
@@ -2159,7 +2163,8 @@ static unsigned getNumGlobalVariableUses(const Constant *C) {
/// candidates are skipped and are emitted later in case at least one cstexpr
/// isn't replaced by a PC relative GOT entry access.
static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
- unsigned &NumGOTEquivUsers) {
+ unsigned &NumGOTEquivUsers,
+ bool &HasNonGlobalUsers) {
// Global GOT equivalents are unnamed private globals with a constant
// pointer initializer to another global symbol. They must point to a
// GlobalVariable or Function, i.e., as GlobalValue.
@@ -2171,7 +2176,8 @@ static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
// To be a got equivalent, at least one of its users need to be a constant
// expression used by another global variable.
for (const auto *U : GV->users())
- NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
+ NumGOTEquivUsers +=
+ getNumGlobalVariableUses(dyn_cast<Constant>(U), HasNonGlobalUsers);
return NumGOTEquivUsers > 0;
}
@@ -2189,9 +2195,13 @@ void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
for (const auto &G : M.globals()) {
unsigned NumGOTEquivUsers = 0;
- if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
+ bool HasNonGlobalUsers = false;
+ if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers, HasNonGlobalUsers))
continue;
-
+ // If non-global variables use it, we still need to emit it.
+ // Add 1 here, then emit it in `emitGlobalGOTEquivs`.
+ if (HasNonGlobalUsers)
+ NumGOTEquivUsers += 1;
const MCSymbol *GOTEquivSym = getSymbol(&G);
GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
}
diff --git a/llvm/test/MC/X86/gotpcrel-non-globals.ll b/llvm/test/MC/X86/gotpcrel-non-globals.ll
new file mode 100644
index 0000000000000..222d2d73ff728
--- /dev/null
+++ b/llvm/test/MC/X86/gotpcrel-non-globals.ll
@@ -0,0 +1,36 @@
+; RUN: llc < %s | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+; Check that we emit the `@bar_*` symbols, and that we don't emit multiple symbols.
+
+; CHECK-LABEL: .Lrel_0:
+; CHECK: .long foo_0@GOTPCREL+0
+; CHECK-LABEL: .Lrel_1_failed:
+; CHECK: .long bar_1-foo_0
+; CHECK-LABEL: .Lrel_2:
+; CHECK: .long foo_2@GOTPCREL+0
+
+; CHECK: bar_0:
+; CHECK: bar_1:
+; CHECK: bar_2_indirect:
+
+@rel_0 = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_0 to i64), i64 ptrtoint (ptr @rel_0 to i64)) to i32)]
+@rel_1_failed = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_1 to i64), i64 ptrtoint (ptr @foo_0 to i64)) to i32)]
+@rel_2 = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_2_indirect to i64), i64 ptrtoint (ptr @rel_2 to i64)) to i32)]
+@bar_0 = internal unnamed_addr constant ptr @foo_0, align 8
+@bar_1 = internal unnamed_addr constant ptr @foo_1, align 8
+@bar_2_indirect = internal unnamed_addr constant ptr @foo_2, align 8
+@foo_0 = external global ptr, align 8
+@foo_1 = external global ptr, align 8
+@foo_2 = external global ptr, align 8
+
+define void @foo(ptr %arg0, ptr %arg1) {
+ store ptr @bar_0, ptr %arg0, align 8
+ store ptr @bar_1, ptr %arg1, align 8
+ store ptr getelementptr (i8, ptr @bar_2_indirect, i32 1), ptr %arg1, align 8
+ ret void
+}
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@llvm/pr-subscribers-backend-x86 Author: None (llvmbot) ChangesBackport 630d55c Requested by: @dianqk Full diff: https://github.com/llvm/llvm-project/pull/145690.diff 2 Files Affected:
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index e77abf429e6b4..c8f567e5f4195 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2139,16 +2139,20 @@ void AsmPrinter::emitFunctionBody() {
}
/// Compute the number of Global Variables that uses a Constant.
-static unsigned getNumGlobalVariableUses(const Constant *C) {
- if (!C)
+static unsigned getNumGlobalVariableUses(const Constant *C,
+ bool &HasNonGlobalUsers) {
+ if (!C) {
+ HasNonGlobalUsers = true;
return 0;
+ }
if (isa<GlobalVariable>(C))
return 1;
unsigned NumUses = 0;
for (const auto *CU : C->users())
- NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
+ NumUses +=
+ getNumGlobalVariableUses(dyn_cast<Constant>(CU), HasNonGlobalUsers);
return NumUses;
}
@@ -2159,7 +2163,8 @@ static unsigned getNumGlobalVariableUses(const Constant *C) {
/// candidates are skipped and are emitted later in case at least one cstexpr
/// isn't replaced by a PC relative GOT entry access.
static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
- unsigned &NumGOTEquivUsers) {
+ unsigned &NumGOTEquivUsers,
+ bool &HasNonGlobalUsers) {
// Global GOT equivalents are unnamed private globals with a constant
// pointer initializer to another global symbol. They must point to a
// GlobalVariable or Function, i.e., as GlobalValue.
@@ -2171,7 +2176,8 @@ static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
// To be a got equivalent, at least one of its users need to be a constant
// expression used by another global variable.
for (const auto *U : GV->users())
- NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
+ NumGOTEquivUsers +=
+ getNumGlobalVariableUses(dyn_cast<Constant>(U), HasNonGlobalUsers);
return NumGOTEquivUsers > 0;
}
@@ -2189,9 +2195,13 @@ void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
for (const auto &G : M.globals()) {
unsigned NumGOTEquivUsers = 0;
- if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
+ bool HasNonGlobalUsers = false;
+ if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers, HasNonGlobalUsers))
continue;
-
+ // If non-global variables use it, we still need to emit it.
+ // Add 1 here, then emit it in `emitGlobalGOTEquivs`.
+ if (HasNonGlobalUsers)
+ NumGOTEquivUsers += 1;
const MCSymbol *GOTEquivSym = getSymbol(&G);
GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
}
diff --git a/llvm/test/MC/X86/gotpcrel-non-globals.ll b/llvm/test/MC/X86/gotpcrel-non-globals.ll
new file mode 100644
index 0000000000000..222d2d73ff728
--- /dev/null
+++ b/llvm/test/MC/X86/gotpcrel-non-globals.ll
@@ -0,0 +1,36 @@
+; RUN: llc < %s | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+; Check that we emit the `@bar_*` symbols, and that we don't emit multiple symbols.
+
+; CHECK-LABEL: .Lrel_0:
+; CHECK: .long foo_0@GOTPCREL+0
+; CHECK-LABEL: .Lrel_1_failed:
+; CHECK: .long bar_1-foo_0
+; CHECK-LABEL: .Lrel_2:
+; CHECK: .long foo_2@GOTPCREL+0
+
+; CHECK: bar_0:
+; CHECK: bar_1:
+; CHECK: bar_2_indirect:
+
+@rel_0 = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_0 to i64), i64 ptrtoint (ptr @rel_0 to i64)) to i32)]
+@rel_1_failed = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_1 to i64), i64 ptrtoint (ptr @foo_0 to i64)) to i32)]
+@rel_2 = private unnamed_addr constant [1 x i32] [
+ i32 trunc (i64 sub (i64 ptrtoint (ptr @bar_2_indirect to i64), i64 ptrtoint (ptr @rel_2 to i64)) to i32)]
+@bar_0 = internal unnamed_addr constant ptr @foo_0, align 8
+@bar_1 = internal unnamed_addr constant ptr @foo_1, align 8
+@bar_2_indirect = internal unnamed_addr constant ptr @foo_2, align 8
+@foo_0 = external global ptr, align 8
+@foo_1 = external global ptr, align 8
+@foo_2 = external global ptr, align 8
+
+define void @foo(ptr %arg0, ptr %arg1) {
+ store ptr @bar_0, ptr %arg0, align 8
+ store ptr @bar_1, ptr %arg1, align 8
+ store ptr getelementptr (i8, ptr @bar_2_indirect, i32 1), ptr %arg1, align 8
+ ret void
+}
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Backport 630d55c
Requested by: @dianqk