Fix pr24486.

This extends the work done in r233995 so that now getFragment (in addition to
getSection) also works for variable symbols.

With that the existing logic to decide if a-b can be computed works even if
a or b are variables. Given that, the expression evaluation can avoid expanding
variables as aggressively and that in turn lets the relocation code see the
original variable.

In order for this to work with the asm streamer, there is now a dummy fragment
per section. It is used to assign a section to a symbol when no other fragment
exists.

This patch is a joint work by Maxim Ostapenko andy myself.

llvm-svn: 249303

8 files changed, 13 insertions, 13 deletions

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.cpp
index 29a903fd9f1..a540f49866a 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.cpp
@@ -85,7 +85,7 @@ void AArch64MCExpr::visitUsedExpr(MCStreamer &Streamer) const {
   Streamer.visitUsedExpr(*getSubExpr());
 }
 
-MCSection *AArch64MCExpr::findAssociatedSection() const {
+MCFragment *AArch64MCExpr::findAssociatedFragment() const {
   llvm_unreachable("FIXME: what goes here?");
 }
 
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h
index b111e7c2ded..db36a65564c 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h
@@ -149,7 +149,7 @@ public:
 
   void visitUsedExpr(MCStreamer &Streamer) const override;
 
-  MCSection *findAssociatedSection() const override;
+  MCFragment *findAssociatedFragment() const override;
 
   bool evaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout,
                                  const MCFixup *Fixup) const override;
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCExpr.h b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCExpr.h
index 9146d4def75..75dde8008fc 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCExpr.h
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCExpr.h
@@ -63,8 +63,8 @@ public:
     return false;
   }
   void visitUsedExpr(MCStreamer &Streamer) const override;
-  MCSection *findAssociatedSection() const override {
-    return getSubExpr()->findAssociatedSection();
+  MCFragment *findAssociatedFragment() const override {
+    return getSubExpr()->findAssociatedFragment();
   }
 
   // There are no TLS ARMMCExprs at the moment.
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
index bf51c3515e9..1bec375f33e 100644
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
@@ -114,7 +114,7 @@ void HexagonMCELFStreamer::HexagonMCEmitCommonSymbol(MCSymbol *Symbol,
     MCSection *Section = getAssembler().getContext().getELFSection(
         SectionName, ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);
     SwitchSection(Section);
-    AssignSection(Symbol, Section);
+    AssignFragment(Symbol, getCurrentFragment());
 
     MCELFStreamer::EmitCommonSymbol(Symbol, Size, ByteAlignment);
     SwitchSection(CrntSection);
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.h
index fd2ed17ee78..e889972c5c0 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.h
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.h
@@ -51,8 +51,8 @@ public:
                                  const MCAsmLayout *Layout,
                                  const MCFixup *Fixup) const override;
   void visitUsedExpr(MCStreamer &Streamer) const override;
-  MCSection *findAssociatedSection() const override {
-    return getSubExpr()->findAssociatedSection();
+  MCFragment *findAssociatedFragment() const override {
+    return getSubExpr()->findAssociatedFragment();
   }
 
   // There are no TLS MipsMCExprs at the moment.
diff --git a/llvm/lib/Target/NVPTX/NVPTXMCExpr.h b/llvm/lib/Target/NVPTX/NVPTXMCExpr.h
index 46b4b33e7e4..81a606d7535 100644
--- a/llvm/lib/Target/NVPTX/NVPTXMCExpr.h
+++ b/llvm/lib/Target/NVPTX/NVPTXMCExpr.h
@@ -68,7 +68,7 @@ public:
     return false;
   }
   void visitUsedExpr(MCStreamer &Streamer) const override {};
-  MCSection *findAssociatedSection() const override { return nullptr; }
+  MCFragment *findAssociatedFragment() const override { return nullptr; }
 
   // There are no TLS NVPTXMCExprs at the moment.
   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override {}
@@ -110,7 +110,7 @@ public:
     return false;
   }
   void visitUsedExpr(MCStreamer &Streamer) const override {};
-  MCSection *findAssociatedSection() const override { return nullptr; }
+  MCFragment *findAssociatedFragment() const override { return nullptr; }
 
   // There are no TLS NVPTXMCExprs at the moment.
   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override {}
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCExpr.h b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCExpr.h
index a641780516b..d42a111cc43 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCExpr.h
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCExpr.h
@@ -82,8 +82,8 @@ public:
                                  const MCAsmLayout *Layout,
                                  const MCFixup *Fixup) const override;
   void visitUsedExpr(MCStreamer &Streamer) const override;
-  MCSection *findAssociatedSection() const override {
-    return getSubExpr()->findAssociatedSection();
+  MCFragment *findAssociatedFragment() const override {
+    return getSubExpr()->findAssociatedFragment();
   }
 
   // There are no TLS PPCMCExprs at the moment.
diff --git a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.h b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.h
index d08ad86dbe0..13f08195c76 100644
--- a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.h
+++ b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.h
@@ -90,8 +90,8 @@ public:
                                  const MCAsmLayout *Layout,
                                  const MCFixup *Fixup) const override;
   void visitUsedExpr(MCStreamer &Streamer) const override;
-  MCSection *findAssociatedSection() const override {
-    return getSubExpr()->findAssociatedSection();
+  MCFragment *findAssociatedFragment() const override {
+    return getSubExpr()->findAssociatedFragment();
   }
 
   void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override;