[mips] Add assembler support for the .cprestore directive.
Summary:
This assembler directive is used in O32 PIC to restore the current function's $gp after executing JAL's. The $gp is first stored on the stack at a user-specified offset.
It has the following format: ".cprestore 8" (where 8 is the offset).
This fixes llvm.org/PR20967.
Patch by Toma Tabacu.
Reviewers: seanbruno, tomatabacu
Subscribers: brooks, seanbruno, emaste, llvm-commits
Differential Revision: http://reviews.llvm.org/D6267
llvm-svn: 247897
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
index dc4673d..50a92a5 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
@@ -89,6 +89,10 @@
void MipsTargetStreamer::emitDirectiveSetDsp() { forbidModuleDirective(); }
void MipsTargetStreamer::emitDirectiveSetNoDsp() { forbidModuleDirective(); }
void MipsTargetStreamer::emitDirectiveCpLoad(unsigned RegNo) {}
+void MipsTargetStreamer::emitDirectiveCpRestore(
+ SmallVector<MCInst, 3> &StoreInsts, int Offset) {
+ forbidModuleDirective();
+}
void MipsTargetStreamer::emitDirectiveCpsetup(unsigned RegNo, int RegOrOffset,
const MCSymbol &Sym, bool IsReg) {
}
@@ -358,6 +362,12 @@
forbidModuleDirective();
}
+void MipsTargetAsmStreamer::emitDirectiveCpRestore(
+ SmallVector<MCInst, 3> &StoreInsts, int Offset) {
+ MipsTargetStreamer::emitDirectiveCpRestore(StoreInsts, Offset);
+ OS << "\t.cprestore\t" << Offset << "\n";
+}
+
void MipsTargetAsmStreamer::emitDirectiveCpsetup(unsigned RegNo,
int RegOrOffset,
const MCSymbol &Sym,
@@ -752,6 +762,24 @@
forbidModuleDirective();
}
+void MipsTargetELFStreamer::emitDirectiveCpRestore(
+ SmallVector<MCInst, 3> &StoreInsts, int Offset) {
+ MipsTargetStreamer::emitDirectiveCpRestore(StoreInsts, Offset);
+ // .cprestore offset
+ // When PIC mode is enabled and the O32 ABI is used, this directive expands
+ // to:
+ // sw $gp, offset($sp)
+ // and adds a corresponding LW after every JAL.
+
+ // Note that .cprestore is ignored if used with the N32 and N64 ABIs or if it
+ // is used in non-PIC mode.
+ if (!Pic || (getABI().IsN32() || getABI().IsN64()))
+ return;
+
+ for (const MCInst &Inst : StoreInsts)
+ getStreamer().EmitInstruction(Inst, STI);
+}
+
void MipsTargetELFStreamer::emitDirectiveCpsetup(unsigned RegNo,
int RegOrOffset,
const MCSymbol &Sym,