From: Cherry Zhang <cherryyz@google.com>
Date: Sun, 9 Feb 2020 22:00:27 +0000 (-0500)
Subject: cmd/link: handle absolute address relocation in C objects for internal linking PIE
X-Git-Tag: go1.15beta1~1143
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=baea3cd7c9e7ae27f7e5d44874a9afd249458df5;p=gostls13.git

cmd/link: handle absolute address relocation in C objects for internal linking PIE

For an absolute address relocation in C objects (e.g.
R_X86_64_64), we turn it into an R_ADDR relocation and handle it
the same way. For internal linking PIE, this R_ADDR relocation
cannot be resolved statically. We need to generate a dynamic
relocation for it. This CL makes it so.

This fixes internal linking PIE on the dev.boringcrypto branch.
Test will be enabled in the next CL.

Change-Id: I9bdd6517ccd79cbbe9c64844a31536bf3da37616
Reviewed-on: https://go-review.googlesource.com/c/go/+/218837
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
---

diff --git a/src/cmd/link/internal/amd64/asm.go b/src/cmd/link/internal/amd64/asm.go
index 74fa8dbb90..5de77180fc 100644
--- a/src/cmd/link/internal/amd64/asm.go
+++ b/src/cmd/link/internal/amd64/asm.go
@@ -174,6 +174,12 @@ func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool {
 			ld.Errorf(s, "unexpected R_X86_64_64 relocation for dynamic symbol %s", targ.Name)
 		}
 		r.Type = objabi.R_ADDR
+		if ctxt.BuildMode == ld.BuildModePIE && ctxt.LinkMode == ld.LinkInternal {
+			// For internal linking PIE, this R_ADDR relocation cannot
+			// be resolved statically. We need to generate a dynamic
+			// relocation. Let the code below handle it.
+			break
+		}
 		return true
 
 	// Handle relocations found in Mach-O object files.
diff --git a/src/cmd/link/internal/arm64/asm.go b/src/cmd/link/internal/arm64/asm.go
index 690116de01..ef9540b2a7 100644
--- a/src/cmd/link/internal/arm64/asm.go
+++ b/src/cmd/link/internal/arm64/asm.go
@@ -172,6 +172,12 @@ func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool {
 			ld.Errorf(s, "unexpected R_AARCH64_ABS64 relocation for dynamic symbol %s", targ.Name)
 		}
 		r.Type = objabi.R_ADDR
+		if ctxt.BuildMode == ld.BuildModePIE && ctxt.LinkMode == ld.LinkInternal {
+			// For internal linking PIE, this R_ADDR relocation cannot
+			// be resolved statically. We need to generate a dynamic
+			// relocation. Let the code below handle it.
+			break
+		}
 		return true
 
 	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_AARCH64_LDST8_ABS_LO12_NC):