android: compute possible size of a symbol of unknown size

Under specific circumstances, setting 2048 as a size of symbol of unknown
size causes that symbol crosses unmapped region. This further causes an
assertion in Valgrind.

Compute possible size by computing maximal size the symbol can have within
its section.

Patch by Tamara Vlahovic.

diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c
index 3c8e62bd29428ca2e26612d27352bd1a930fa818..e612250502a8c3d4a7b227616f5c42a5b3c16854 100644 (file)
--- a/coregrind/m_debuginfo/readelf.c
+++ b/coregrind/m_debuginfo/readelf.c
@@ -282,6 +282,16 @@ Bool get_elf_symbol_info (
    Bool in_text, in_data, in_sdata, in_rodata, in_bss, in_sbss;
    Addr text_svma, data_svma, sdata_svma, rodata_svma, bss_svma, sbss_svma;
    PtrdiffT text_bias, data_bias, sdata_bias, rodata_bias, bss_bias, sbss_bias;
+#     if defined(VGPV_arm_linux_android) \
+         || defined(VGPV_x86_linux_android) \
+         || defined(VGPV_mips32_linux_android) \
+         || defined(VGPV_arm64_linux_android)
+   Addr available_size = 0;
+#define COMPUTE_AVAILABLE_SIZE(segsvma, segsize) \
+        available_size = segsvma + segsize - sym_svma
+#else
+#define COMPUTE_AVAILABLE_SIZE(segsvma, segsize)
+#endif
 
    /* Set defaults */
    *sym_name_out_ioff = sym_name_ioff;
@@ -360,6 +370,7 @@ Bool get_elf_symbol_info (
        && sym_svma < text_svma + di->text_size) {
       *is_text_out = True;
       (*sym_avmas_out).main += text_bias;
+      COMPUTE_AVAILABLE_SIZE(text_svma, di->text_size);
    } else
    if (di->data_present
        && di->data_size > 0
@@ -367,6 +378,7 @@ Bool get_elf_symbol_info (
        && sym_svma < data_svma + di->data_size) {
       *is_text_out = False;
       (*sym_avmas_out).main += data_bias;
+      COMPUTE_AVAILABLE_SIZE(data_svma, di->data_size);
    } else
    if (di->sdata_present
        && di->sdata_size > 0
@@ -374,6 +386,7 @@ Bool get_elf_symbol_info (
        && sym_svma < sdata_svma + di->sdata_size) {
       *is_text_out = False;
       (*sym_avmas_out).main += sdata_bias;
+      COMPUTE_AVAILABLE_SIZE(sdata_svma, di->sdata_size);
    } else
    if (di->rodata_present
        && di->rodata_size > 0
@@ -381,6 +394,7 @@ Bool get_elf_symbol_info (
        && sym_svma < rodata_svma + di->rodata_size) {
       *is_text_out = False;
       (*sym_avmas_out).main += rodata_bias;
+      COMPUTE_AVAILABLE_SIZE(rodata_svma, di->rodata_size);
    } else
    if (di->bss_present
        && di->bss_size > 0
@@ -388,6 +402,7 @@ Bool get_elf_symbol_info (
        && sym_svma < bss_svma + di->bss_size) {
       *is_text_out = False;
       (*sym_avmas_out).main += bss_bias;
+      COMPUTE_AVAILABLE_SIZE(bss_svma, di->bss_size);
    } else
    if (di->sbss_present
        && di->sbss_size > 0
@@ -395,6 +410,7 @@ Bool get_elf_symbol_info (
        && sym_svma < sbss_svma + di->sbss_size) {
       *is_text_out = False;
       (*sym_avmas_out).main += sbss_bias;
+      COMPUTE_AVAILABLE_SIZE(sbss_svma, di->sbss_size);
    } else {
       /* Assume it's in .text.  Is this a good idea? */
       *is_text_out = True;
@@ -463,7 +479,7 @@ Bool get_elf_symbol_info (
          || defined(VGPV_x86_linux_android) \
          || defined(VGPV_mips32_linux_android) \
          || defined(VGPV_arm64_linux_android)
-      *sym_size_out = 2048;
+      *sym_size_out = available_size ? available_size : 2048;
 #     else
       if (TRACE_SYMTAB_ENABLED) {
          HChar* sym_name = ML_(img_strdup)(escn_strtab->img,